Synthesis, Capping, and Dispersion of High Refractive Index Nanocrystals and Nanocomposites

Abstract

Preparation of capped metal oxide nanocrystals containing photocatalytically and thermally stable metal oxide shells, and their dispersions in monomers, oligomers, and polymers, and the resulting formulations and nanocomposite films. These nanocrystals are highly monodisperse, with nanocrystal sizes between 3-100 nm. The resulting formulations incorporating these nanocrystals and matrix materials are extremely stable, have high refractive indices, are highly transparent, and undergo minimal to no change in absorbance upon thermal or UV treatment, resulting in nanocomposites that are optically transparent at visible wavelengths and have very little or no scattering.

Description

[Technical field]

[0001]

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 292,197, filed December 21, 2021, the entire contents of which are incorporated herein by reference.

[0002] In various embodiments, the present application describes the preparation of photocatalytically and thermally stable, capped, metal oxide nanocrystals of ZrO2 and TiO2 containing a metal oxide shell, and their dispersion in monomers, oligomers, and / or polymers, and the resulting nanocomposite films. These nanocrystals are highly monodisperse, with nanocrystal sizes between 3-100 nm. Dispersions of these nanocrystals are formed in a variety of solvents, monomers, oligomers, and / or polymers. These dispersions typically have high loadings, high transmittance, and low viscosity. The resulting formulations incorporating these nanocrystals and matrix materials are typically extremely stable, have high refractive indices, have low absorption, experience minimal to no change in absorption upon thermal or UV treatment, and result in nanocomposites that are optically transparent at visible wavelengths and have very little or no scattering. [Background technology]

[0002]

[0003] Titanium dioxide (TiO2), or titania, is one of the most widely used multifunctional ceramic materials due to its unique physical and chemical characteristics, combined with its abundance and non-toxicity. Due to its bulk properties, including high refractive index and (UV) light absorption, TiO2 is commercially produced in millions of tons and is commonly found in pigments, paints, sunscreens, and coatings. In addition to traditional applications, titania is also being investigated for use in many applications, including optoelectronics, photovoltaics, catalysis, fuel cells, batteries, smart windows, sensors, and self-cleaning surfaces.

[0003]

[0004] Titanium dioxide, especially sub-nm sized particles, has generated great interest for optical applications due to its high refractive index. The two crystalline phases of titanium dioxide, anatase and rutile, possess refractive indices of 2.55 and 2.76, respectively. Furthermore, when combined with monomers, oligomers or polymers, these metal oxides demonstrate high transparency and high refractive index. However, TiO2 particles are excellent UV absorbers. The energy band gaps for anatase and rutile are 3.23 eV and 3.06 eV, respectively. As a result of this large energy band gap, TiO2 is photochemically active. When exposed to high energy wavelengths, electrons are excited from the valence band to the conduction band, generating electron-hole pairs. These electron-hole pairs diffuse to the surface of TiO2, creating radical species that are in turn harmful to surface organics and can lead to their decomposition. This decomposition of surface organics leads to the collapse of the polymer, resulting in defects such as chalking and yellowing. Summary of the Invention [Problem to be solved by the invention]

[0004]

[0005] As the demand for higher refractive index materials increases, so does the need for photochemically and thermally stable TiO2. Due to the limited options of available organic materials, inorganic-organic nanocomposite materials remain the only option to achieve such high refractive index demands. [Means for solving the problem]

[0005]

[0006] The present disclosure provides a method for making TiO2 nanocrystals that have lower photocatalytic activity and are thermally stable at high temperatures.

[0007] The present disclosure provides methods for making TiO2 and ZrO2 nanocrystals that include a crystalline core and a thin shell of a metal oxide, forming nanocrystals with a core-shell structure. The shell material can include, but is not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof.

[0006]

[0008] The present disclosure includes a method for capping core-shell nanocrystals having a crystalline core and an outer shell / coating of a metal oxide. The core-shell nanocrystals are separated and / or purified and capped with at least one capping agent to produce at least partially capped nanocrystals. The at least partially capped nanocrystals may be further purified and / or separated according to the method of the present disclosure. The nanocrystals and capped nanocrystals may also be dispersed in a material comprising a solvent, a monomer, a polymer, or some combination thereof in the method of the present disclosure.

[0007]

[0009] The present disclosure further includes a method of surface passivation of TiO2 and ZrO2 nanocrystals coated with metal oxide outer shell / coating and further treatment with at least one inorganic passivation agent. The core-shell nanocrystals of the present disclosure are treated with at least one inorganic passivation agent before or after capping with at least one capping agent. The resulting at least partially capped nanocrystals with inorganic treatment are further purified and / or separated according to the method of the present disclosure. In the method of the present disclosure, the nanocrystals and capped nanocrystals are dispersed in a material including a solvent, a polymer, or some combination thereof.

[0008]

[0010] The present disclosure includes a method of passivating TiO2 and ZrO2 nanocrystals without an outer shell with at least one inorganic passivation agent. The TiO2 and ZrO2 nanocrystals of the present disclosure are optionally treated with at least one inorganic passivation agent before or after capping. The at least partially capped nanocrystals with inorganic treatment are further purified and / or separated according to the method of the present disclosure. In the method of the present disclosure, the nanocrystals and capped nanocrystals are dispersed in a material including a solvent, a polymer, or some combination thereof.

[0009]

[0011] The present disclosure further includes dispersions and formulations of core-shell nanocrystals having a core metal oxide and an outer shell of at least one shell metal oxide. These dispersions may be in solvents and formulations that include monomers, oligomers and / or polymers, in addition to other additives.

[0010]

[0012] The present disclosure further includes nanocomposite materials containing a matrix and nanocrystals, which are, for example, mixed, stirred, or dispersed within the nanocomposite material. Nanocomposites according to the present disclosure are fabricated, for example, by UV curing, thermal curing, melt blending, in situ polymerization, and / or solvent mixing of the nanocrystals and the matrix material or precursors of the matrix. The nanocrystals include one or more of ZrO2 nanocrystals, TiO2 nanocrystals, and core-shell nanocrystals.

[0011]

[0013] The present disclosure includes methods for evaluating the photocatalytic activity and thermal stability of TiO2 nanocrystals embedded in a polymer matrix.

[0014] The present disclosure also provides exemplary embodiments, such as those shown in the Examples section, those recited in embodiments 1-42, and those set forth in claims 1-62 herein.

[0012]

[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention herein. [Brief description of the drawings]

[0013] [Figure 1]

[0016] FIG. 1 shows an exemplary intensity vs. particle size DLS plot of inorganically passivated, ZrO2 shell-capped titanium dioxide nanocrystals as described in Example 6, showing an average particle size of 37.15 nanometers at 5 wt % in PGMEA. [Diagram 2]

[0017] FIG. 1 shows an exemplary volume vs. particle size DLS plot of inorganically passivated, ZrO2 shell-capped titanium dioxide nanocrystals as described in Example 6, showing an average particle size of 25.46 nanometers at 5 wt % in PGMEA. [Diagram 3]

[0018] FIG. 1 shows an exemplary TEM image of titanium oxide nanocrystals having an outer ZrO 2 shell as described in Example 6, exhibiting an average particle size of less than 20 nanometers and in which Zr and Ti atoms are present in the same particle. [Figure 4a]

[0019] 1 is a graph showing an exemplary optical transmittance of a 1 micron thick spin-coated nanocomposite containing at least partially capped TiO2 nanocrystals with a ZrO2 shell and a combination of acrylic monomers as described in Example 19, using nanocrystals from Example 5, when exposed to 450 nm wavelength for 1000 hours of continuous exposure. [Figure 4b] 1 is a graph showing an exemplary optical transmittance of a 1 micron thick spin-coated nanocomposite containing at least partially capped TiO2 nanocrystals with a ZrO2 shell and a combination of acrylic monomers as described in Example 19, using nanocrystals from Example 6, when exposed to 450 nm wavelength for 1000 hours of continuous exposure. [Figure 4c]1 is a graph showing an exemplary optical transmittance of a 1 micron thick spin-coated nanocomposite including at least partially capped TiO2 nanocrystals with a ZrO2 shell and a combination of acrylic monomers as described in Example 19, using nanocrystals from Example 7, when exposed to 450 nm wavelength for 1000 hours of continuous exposure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0020] Table 1: Ranking of discoloration of inorganic free TiO2 nanocrystals when exposed to UV radiation with and without ZrO2 shell before capping, as well as the post-baking step.

[0015]

[0021] Table 2: Ranking of at least partially capped TiO2 nanocrystals without any metal oxide shell and those with different inorganic treatments upon exposure to UV irradiation and discoloration upon post-baking step.

[0016]

[0022] Table 3: Color change ranking of at least partially capped TiO2 with and without a ZrO2 shell and / or with and without inorganic treatment when heated at different temperatures.

[0017]

[0023] Table 4: Optical properties of nanocomposites made using the formulations described in Example 19.

[0024] Table 5: Prepared as described in Example 19, and exposed to wavelengths of 320-390 nm for 158 hours (average intensity 4 mW / cm 2 ) Optical properties of the nanocomposite with continuous exposure.

[0018]

[0025] Table 6: Prepared as described in Example 19 and exposed to a wavelength of 405 nm for 148 hours (average intensity 25 mW / cm 2 ) Optical properties of the nanocomposite with continuous exposure.

[0026] Table 7: Prepared as described in Example 19 and exposed to a wavelength of 450 nm for 1000 hours (average intensity 16 mW / cm 2 ) Optical properties of the nanocomposite with continuous exposure.

[0019]

[0027] Table 8a: Summary of formulation compositions and properties, including samples with titania nanocrystals and titania-zirconia nanocrystals.

[0028] Table 8c: Optical properties of the nanocomposites described in Example 21 when exposed to UVA light for 72 hours.

[0020]

[0029] Table 8d: Optical properties of the nanocomposites described in Example 21 when exposed to QUV accelerated weathering for 72 hours.

[0030] Table 9a: Summary of compositions and viscosities of formulations described in Example 22.

[0021]

[0031] Table 9b: Optical properties of nanocomposites on glass substrates described in Example 22 when exposed to 405 nm light for 150 hours.

[0032] Table 10a: Viscosity and optical properties of nanocomposites made using the formulations described in Example 23.

[0022]

[0033] Table 10b: Optical properties of the nanocomposites described in Example 23 when exposed to QUV accelerated weathering for 72 hours.

[0034] Table 10c: Optical properties of the nanocomposite described in Example 23 when exposed to 405 nm wavelength continuously for 148 hours.

[0023]

[0035] Zirconium oxide and titanium oxide nanocrystals used for various processes of the present disclosure can usually be prepared by a solvothermal method, in which titanium oxide or zirconium oxide precursors are mixed or dissolved in at least one solvent and allowed to react for a certain period of time. In some cases, pressure and / or heat are used. The resulting TiO2 or ZrO2 nanocrystals are optionally separated and purified by precipitation, centrifugation, filtration and other separation methods known in the art. In the solvothermal process, the solvent is not water. When water is used as the majority of the solvent, the synthesis method is called a hydrothermal synthesis method. In the solvothermal synthesis of TiO2 and ZrO2 nanocrystals, the addition of a small amount of water to the reaction mixture as a reactant rather than as a solvent provides better control of particle size and size distribution than reactions carried out without the addition of water. Exemplary methods useful for the synthesis, capping and dispersion of the TiO2 and ZrO2 nanocrystals herein include those described in International Applications: PCT / US2011 / 057822 (published as WO2012 / 058271), and PCT / US2019 / 062439 (published as WO2020 / 106860), the contents of each of which are incorporated by reference in their entirety.

[0024]

[0036] Precursors of titanium dioxide nanocrystals are typically alkoxides, such as titanium methoxide (Ti(OCH3)4), titanium ethoxide (Ti(OCH2CH3)4), titanium n-propoxide (Ti(OCH2CH2CH3)4), titanium isopropoxide (Ti(OCH(CH3)2)4), titanium n-butoxide (Ti(OCH2CH2CH2CH3)4); acetylacetonates, such as titanium oxyacetylacetonate (TiO(CH3COCH COCH3)2); halides, such as titanium chloride (TiCl4); and mixed halides and alkoxides, such as titanium chlorotriisopropoxytitanium (TiCl(OCH(CH3)2)3), chlorotributoxytitanium (TiCl(OCH2CH2CH2CH3)3), or titanium dichloride diethoxide (TiCl2(OCH2CH3)2) or other organometallic compounds.

[0025]

[0037] Precursors of zirconium oxide nanocrystals are typically alkoxides, such as zirconium methoxide (Zr(OCH3)4), zirconium ethoxide (Zr(OCH2CH3)4), zirconium n-propoxide (Zr(OCH2CH2CH3)4), zirconium isopropoxide (Zr(OCH(CH3)2)4), zirconium n-butoxide (Zr(OCH2CH2CH2CH3)4); acetylacetonates, such as zirconium oxyacetylacetonate (ZrO(CH3COCH C OCH3)2); halides, such as zirconium chloride (ZrCl4); and mixed halides and alkoxides, such as zirconium chlorotriisopropoxytitanium (ZrCl(OCH(CH3)2)3), chlorotributoxyzirconium (ZrCl(OCH2CH2CH2CH3)3), or zirconium dichloride diethoxide (ZrCl2(OCH2CH3)2) or other organometallic compounds.

[0026]

[0038] Examples of solvents for the synthesis of nanocrystals of the present disclosure typically include alcohols, such as benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, 2-(isopentyloxy)ethanol, 2-propoxy-propanol (PnP), 2-(hexyloxy)ethanol; ethers and cyclic ethers, such as tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, dipropylene ... and diethylene glycol monoethyl ether; glycols such as diethylene glycol, dipropylene glycol; ketones and cyclic ketones such as acetone; esters such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl butoxyacetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate; aromatics such as benzene, toluene; and water, as well as any combination or mixture thereof.

[0027]

[0039] The titanium oxide or zirconium oxide of the present disclosure is typically coated with an outer shell comprising at least one metal oxide. The method of coating the outer oxide shell generally involves converting a precursor of the oxide shell around the zirconium oxide or titanium oxide nanocrystals. Examples of oxides used as shell materials include, but are not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof. The process includes mixing or suspending the optionally isolated and purified TiO2 or ZrO2 nanocrystals in a solvent, and adding at least one precursor of the shell metal oxide to the solution. The solution is then reacted for a period of time to promote the reaction between the core metal oxide and the shell oxide precursor. Heat and / or pressure are optionally applied during the reaction. This produces core-shell nanocrystals. The core-shell nanocrystals are optionally isolated and purified.

[0028]

[0040] Examples of precursors of oxide shells on TiO2 or ZrO2 nanocrystals include, but are not limited to, metal alkoxides, e.g., metal alkoxides having the formula M(OR)4, compounds having the formula M(OR)xGy, or combinations thereof, where M can be Ce, Zr, Si, Hf, NB, Al, Ta, Ti, Ba, each R group can independently be an alkyl group (e.g., a C1-C6 alkyl group) or a substituted alkyl group, and G groups, in each occurrence, are independently halogens (e.g., Cl), x is an integer from 0 to 4, and y is an integer from 0 to 4, with the proviso that x+y is 4, metal oxyhalides, metal halides, metals, or any combination thereof. Examples of precursors of shell metal oxides include, but are not limited to, zirconium oxychloride, titanium oxychloride, hafnium oxychloride, sodium aluminate, aluminum isopropoxide, tetraethylorthosilicate, tetramethylorthosilicate, cerium chloride, cerium carbonate, or any combination thereof.

[0029]

[0041] Optionally, a base or acid is present to facilitate the conversion of the shell metal oxide precursor to an oxide shell on the TiO2 or ZrO2 nanocrystals. Examples of bases or acids in the present disclosure include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0030]

[0042] Examples of solvents used to facilitate the conversion of the shell metal oxide precursor to an oxide shell on the TiO2 or ZrO2 nanocrystals include, but are not limited to, water, PGMEA, PGME, ethanol, methanol, isopropanol, benzyl alcohol, or any combination thereof.

[0031]

[0043] Examples of solvents used for purification include, but are not limited to, water, THF, acetone, heptane, toluene, PGMEA, PGME, ethanol, methanol, isopropanol, or any combination thereof.

[0032]

[0044] Optionally, a base or acid is present to help neutralize excess acid or base present during purification. Examples of bases or acids of the present disclosure include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0033]

[0045] The production of sub-nanometer sized nanocrystals often results in agglomeration, which leads to scattering and loss of transparency of the resulting nanocomposite. The key to producing well-dispersed nanocomposites is to use nanocrystals that do not agglomerate before starting to mix with the matrix or medium. One way to achieve agglomerated nanocrystals is to control the surface chemistry of the nanocrystals by the introduction of ligand ions or molecules called capping agents. These capping agents, when added to the surface of the nanocrystal, create a new effective surface of the nanocrystal. This effective surface is the surface of a shell created by complete or partial surface coverage by the capping agent. By tuning the chemistry of this effective surface, a chemical environment distinct from the actual or initial surface of the nanocrystal can be created, which promotes dispersion while preventing or reducing agglomeration.

[0034]

[0046] In some embodiments, the surface of the core-shell titanium oxide or zirconium oxide nanocrystals of the present disclosure is capped with at least one capping agent. The capping process includes suspending the optionally separated and purified core-shell nanocrystals in a capping solvent and adding a capping agent to the solution (referred to as a reaction mixture). The reaction mixture is allowed to react for a period of time. Optionally, heat and / or pressure are applied during the reaction. Optionally, a base or acid is added to the solution to promote the reaction. Optionally, a second capping agent is added to the reaction mixture and allowed to react for a period of time. Optionally, heat and / or pressure are applied during the reaction. The resulting capped product is optionally separated and purified to produce at least partially capped core-shell nanocrystals. Optionally, the separated and purified at least partially capped core-shell nanocrystals are dried and then dispersed in a solvent.

[0035]

[0047] In one embodiment, the at least partially capped core-shell nanocrystals of the present disclosure can also be further treated with an inorganic passivation reagent. The treatment process includes suspending the isolated and purified as-synthesized core-shell nanocrystals in a capping solvent and adding a capping agent to the solution. The solution is allowed to react for a period of time, optionally applying heat and / or pressure during the reaction. A base or acid is optionally added to the solution to promote the reaction. After a set reaction time, at least one inorganic passivation agent is added to the solution. Optionally, heat and / or pressure is applied during the reaction. The resulting product is optionally separated and purified to produce at least partially capped as-synthesized core-shell nanocrystals with inorganic treatment. Optionally, the capped inorganic treated material is separated, purified, dried, and then dispersed in a solvent.

[0036]

[0048] In another embodiment, the surface of the core-shell titanium oxide or zirconium oxide nanocrystals of the present disclosure is treated with an inorganic passivation agent before capping with at least one capping agent. This treatment process typically includes suspending the optionally isolated and purified core-shell nanocrystals in a solvent and adding at least one inorganic passivation agent to the suspension. The suspension is mixed for a period of time. The nanocrystals are then isolated, purified, and resuspended in the capping solvent. At least one capping agent is added to the suspension and allowed to react for a period of time. Heat and / or pressure are optionally applied during the reaction. Optionally, a base or acid is added to the solution to promote the reaction. Optionally, a second capping agent is added to the reaction mixture and allowed to react for a period of time. Heat and / or pressure are optionally applied during the reaction. The resulting capped product is optionally isolated and purified to produce at least partially capped core-shell nanocrystals having an inorganic treatment. Optionally, the isolated and purified, inorganic treated, at least partially capped core-shell nanocrystals are dried and then dispersed in a solvent.

[0037]

[0049] Examples of suitable capping agents include, but are not limited to, silanes, alcohols, phosphates, or carboxylic acids. Examples of silanes of the present disclosure include, but are not limited to, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, methyltrimethoxysilane, ethyl ... trimethoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethylorthosilicate, or any combination thereof.

[0038]

[0050] Examples of alcohols include, but are not limited to, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol, and triethylene glycol monomethyl ether or any combination thereof.

[0039]

[0051] Examples of phosphate salts containing capping agents include, but are not limited to, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, or any combination thereof.

[0040]

[0052] Examples of carboxylic acids include, but are not limited to, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof.

[0041]

[0053] Optionally, the silane capping agent can form a second outer metal oxide layer comprising silicon dioxide that encapsulates the titanium oxide or zirconium oxide nanocrystals comprising the first metal oxide shell. Examples of first metal oxide shell materials include, but are not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof.

[0042]

[0054] Optionally, the silane capping agent can be mixed with an outer metal oxide shell material to form a shell comprising a mixture of silicon dioxide and other metal oxides that encapsulates the titanium oxide or zirconium oxide nanocrystals. Examples of other metal oxide shell materials include, but are not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, tantalum oxide, aluminum oxide, barium titanium oxide, cerium oxide, or any combination thereof.

[0043]

[0055] Examples of capping solvents include, but are not limited to, alcohols, such as benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol; ethers and cyclic ethers, such as tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. glycols, such as diethylene glycol, dipropylene glycol; ketones and cyclic ketones, such as acetone; esters, such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl butoxyacetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate; aromatics, such as benzene, toluene; and water, as well as any combination or mixture thereof.

[0044]

[0056] Examples of bases or acids of the present disclosure include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0045]

[0057] Examples of solvents used for purification include, but are not limited to, water, THF, acetone, heptane, toluene, isopropanol, propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethanol, methanol, toluene, benzyl alcohol, or any combination thereof.

[0046]

[0058] Examples of solvents used for dispersion include, but are not limited to, THF, acetone, heptane, benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether, diethylene glycol, dipropylene glycol, acetone; esters such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, butoxyethyl acetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, benzene, toluene, and water, as well as any combination or mixture thereof.

[0047]

[0059] Examples of inorganic passivation reagents include, but are not limited to, sodium polyphosphate, lithium nitrate, sodium hypochlorite, sodium hypophosphite, sodium phosphite, lithium chloride, sodium nitrate, sodium chloride, sodium aluminum phosphate, sodium hexametaphosphate, or any combination thereof.

[0048]

[0060] Optionally, an inorganic passivation agent can also be incorporated into the outer metal oxide layer of the titanium oxide or zirconium oxide nanocrystals.

[0061] In another embodiment, the titanium oxide or zirconium oxide of the present disclosure is treated with an inorganic passivation agent before coating the outer metal oxide shell. The treatment process typically includes suspending the titanium oxide or zirconium oxide, optionally separated and purified, in a solvent, and adding at least one inorganic passivation agent to the suspension. The suspension is mixed for a period of time. The inorganic passivation agent-treated nanocrystals are then separated, purified, and resuspended in a solvent for coating. The method of coating the outer oxide shell typically includes converting a precursor of the oxide shell around the zirconium oxide or titanium oxide nanocrystals. The coating process includes mixing or suspending the TiO2 or ZrO2 nanocrystals, optionally separated and purified, in a solvent, and adding at least one precursor of the shell metal oxide to the solution. The solution is then reacted for a period of time to promote the reaction between the TiO2 or ZrO2 nanocrystals and the shell oxide precursor. Heat and / or pressure are optionally applied during the reaction. This produces synthetic inorganic processed core-shell nanocrystals, which are optionally isolated and purified.

[0049]

[0062] In some embodiments, the surface of the inorganic treated core-shell titanium oxide or zirconium oxide nanocrystals of the present disclosure is capped with at least one capping agent. The capping process includes suspending the optionally separated and purified core-shell nanocrystals in a capping solvent and adding a capping agent to the solution (referred to as a reaction mixture). The reaction mixture is allowed to react for a period of time. Optionally, heat and / or pressure are applied during the reaction. Optionally, a base or acid is added to the solution to promote the reaction. Optionally, a second capping agent is added to the reaction mixture and allowed to react for a period of time. Optionally, heat and / or pressure are applied during the reaction. The resulting capped product is optionally separated and purified to produce at least partially capped core-shell nanocrystals. Optionally, the separated and purified at least partially capped core-shell nanocrystals with inorganic treatment are dried and then dispersed in a solvent.

[0050]

[0063] Examples of inorganic passivators include, but are not limited to, sodium polyphosphate, lithium nitrate, sodium hypochlorite, sodium hypophosphite, sodium phosphite, lithium chloride, sodium nitrate, sodium chloride, sodium aluminum phosphate, aluminum hypophosphite, sodium hexametaphosphate, calcium hypophosphite, or any combination thereof.

[0051]

[0064] Examples of solvents for treatment with inorganics include, but are not limited to, benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, and water, as well as any combination or mixture thereof.

[0052]

[0065] Examples of oxides used as shell materials include, but are not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof.

[0053]

[0066] Examples of shell metal oxide precursors include, but are not limited to, zirconium oxychloride, titanium oxychloride, and hafnium oxychloride, cerium chloride, cerium carbonate, or any combination thereof.

[0054]

[0067] Examples of bases or acids present to promote the conversion of the shell metal oxide precursor to an oxide shell on the TiO2 or ZrO2 nanocrystals include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid. Examples of solvents used to promote the conversion of the shell metal oxide precursor to an oxide shell on the TiO2 or ZrO2 nanocrystals include, but are not limited to, water, PGMEA, PGME, ethanol, methanol, benzyl alcohol, or any combination thereof.

[0055]

[0068] Examples of solvents used for purification include, but are not limited to, water, THF, acetone, heptane, toluene, PGMEA, PGME, ethanol, methanol, toluene, or any combination thereof.

[0056]

[0069] Optionally, a base or acid is present to help neutralize excess acid or base present during purification. Examples of bases or acids of the present disclosure include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0057]

[0070] Examples of capping solvents include, but are not limited to, alcohols, such as benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol; ethers and cyclic ethers, such as tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. glycols, such as diethylene glycol, dipropylene glycol; ketones and cyclic ketones, such as acetone; esters, such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl butoxyacetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate; aromatics, such as benzene, toluene; and water, as well as any combination or mixture thereof.

[0058]

[0071] Examples of capping agents include, but are not limited to, silanes, alcohols, phosphates, or carboxylic acids. Examples of silanes of the present disclosure include, but are not limited to, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-methyl ... -hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethylorthosilicate, or any combination thereof.

[0059]

[0072] Examples of alcohols include, but are not limited to, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol, and triethylene glycol monomethyl ether or any combination thereof.

[0060]

[0073] Examples of phosphate-containing capping agents include, but are not limited to, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, or any combination thereof.

[0061]

[0074] Examples of carboxylic acids include, but are not limited to, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof.

[0062]

[0075] Examples of bases or acids include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0063]

[0076] Examples of solvents used for purification include, but are not limited to, water, THF, acetone, heptane, toluene, propylene glycol methyl ether acetate (PGMEA / PGA), propylene glycol monomethyl ether (PGME), ethanol, methanol, toluene, benzyl alcohol, or any combination thereof.

[0064]

[0077] Examples of solvents used for dispersion include, but are not limited to, THF, acetone, heptane, benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether, diethylene glycol, dipropylene glycol, acetone; esters such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate (ETA), butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, butoxyethyl acetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, benzene, toluene, and water, as well as any combination or mixture thereof.

[0065]

[0078] Optionally, the silane capping agent can form a second outer metal oxide layer comprising silicon dioxide that encapsulates the titanium oxide or zirconium oxide nanocrystals comprising the first metal oxide shell. Examples of first metal oxide shell materials include, but are not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof.

[0066]

[0079] Optionally, the silane capping agent can be mixed with the outer metal oxide layer material to form a shell comprising a mixture of silicon dioxide and other metal oxides that encapsulates the titanium oxide or zirconium oxide nanocrystals. Examples of other metal oxide shell materials include, but are not limited to, silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, tantalum oxide, aluminum oxide, barium titanium oxide, or any combination thereof.

[0067]

[0080] Optionally, an inorganic passivation agent can be incorporated onto the outer metal oxide layer of the titanium oxide or zirconium oxide nanocrystals.

[0081] In another embodiment, the titanium oxide or zirconium oxide of the present disclosure, which does not have any outer shell, is treated with an inorganic passivation agent and subsequently capped. The treatment process typically includes suspending the titanium oxide or zirconium oxide, optionally separated and purified, in a solvent, and adding at least one inorganic passivation agent to the suspension. The suspension is mixed for a period of time. The inorganic-treated nanocrystals are then separated, purified, and resuspended in a capping solvent. At least one capping agent is added to the suspension and allowed to react for a period of time. Heat and / or pressure are optionally applied during the reaction. Optionally, a base or acid is added to the solution to promote the reaction. Optionally, a second capping agent is added to the reaction mixture and allowed to react for a period of time. Heat and / or pressure are optionally applied during the reaction. The resulting capped product is optionally separated and purified to produce at least partially capped nanocrystals having inorganic treatment. The isolated and purified, at least partially capped nanocrystals, optionally having been treated with an inorganic substance, are dried and then dispersed in a solvent.

[0068]

[0082] Examples of inorganic passivators include, but are not limited to, sodium polyphosphate, lithium nitrate, sodium hypochlorite, sodium hypophosphite, sodium phosphite, lithium chloride, sodium nitrate, sodium chloride, sodium aluminum phosphate, aluminum hypophosphite, sodium hexametaphosphate, calcium hypophosphite, or any combination thereof.

[0069]

[0083] Examples of solvents for treatment with inorganics include, but are not limited to, benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, and water, as well as any combination or mixture thereof.

[0070]

[0084] Examples of solvents used for purification include, but are not limited to, water, THF, acetone, heptane, toluene, PGMEA, PGME, ethanol, methanol, toluene, or any combination thereof.

[0071]

[0085] Optionally, a base or acid is present to help neutralize excess acid or base present during purification. Examples of bases or acids of the present disclosure include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0072]

[0086] Examples of capping solvents include, but are not limited to, alcohols, such as benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, and methanol; ethers and cyclic ethers, such as tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether; Lithium, such as diethylene glycol, dipropylene glycol; ketones and cyclic ketones, such as acetone; esters, such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate (ETA), diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl butoxyacetate, ethyl acetate, 2-(2-butoxyethoxy)acetate; aromatics, such as benzene, toluene; and water, as well as any combination or mixture thereof.

[0073]

[0087] Examples of suitable capping agents include, but are not limited to, silanes, alcohols, phosphates, or carboxylic acids. Examples of silanes of the present disclosure include, but are not limited to, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-methyl ... -hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethylorthosilicate, or any combination thereof.

[0074]

[0088] Examples of alcohols include, but are not limited to, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol, and triethylene glycol monomethyl ether or any combination thereof.

[0075]

[0089] Examples of phosphate-containing capping agents include, but are not limited to, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, or any combination thereof.

[0076]

[0090] Examples of carboxylic acids include, but are not limited to, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof.

[0077]

[0091] Examples of bases or acids include, but are not limited to, trimethylammonium hydroxide, triethylammonium hydroxide, nitric acid, ammonium hydroxide, triethylamine, polyethyleneimine, citric acid, hydrochloric acid, benzoic acid, acetic acid, or trifluoroacetic acid.

[0078]

[0092] Examples of solvents used for purification include, but are not limited to, water, THF, acetone, heptane, toluene, propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethanol, methanol, toluene, benzyl alcohol, or any combination thereof.

[0079]

[0093] Examples of solvents used for dispersion include, but are not limited to, THF, acetone, heptane, benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether, diethylene glycol, dipropylene glycol, acetone; esters such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate (ETA), butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, butoxyethyl acetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, benzene, toluene, and water, as well as any combination or mixture thereof.

[0080]

[0094] Optionally, the silane capping agent can form an outer metal oxide layer, including silicon dioxide, that encapsulates the titanium oxide or zirconium oxide nanocrystals.

[0095] Optionally, an inorganic passivating agent can be incorporated into the outer metal oxide layer of the titanium oxide or zirconium oxide nanocrystals. TiO2 and ZrO2 nanocrystal synthesis process

[0096] Exemplary methods for the synthesis, capping and dispersion of the TiO2 and ZrO2 nanocrystals herein include those described in International Applications: PCT / US2011 / 057822 (published as WO2012 / 058271), and PCT / US2019 / 062439 (published as WO2020 / 106860), the contents of each of which are incorporated by reference in their entireties.

[0081]

[0097] In an exemplary method, titanium oxide nanocrystals are produced by a solvothermal process from a mixture of titanium(IV) butoxide, water, and benzyl alcohol in a sealed inert atmosphere in an autoclave. The ratio of titanium(IV) butoxide to water may range from 1:0.1 to 1:10, e.g., 1:0.1 to 1:0.5, 1:0.5 to 1:1, 1:1 to 1:1.5, 1:1.5 to 1:2, 1:2 to 1:2.5, 1:2.5 to 1:3, 1:3 to 1:3.5, 1:3.5 to 1:4, 1:4 to 1:4.5, 1:4.5 to 1:5, 1:5 to 1:5.5, 1:5.5 to 1:6, 1:6 to 1:6.5, 1:6.5 to 1:7, 1:7 to 1:7.5, 1:7.5 to 1:8, 1:8 to 1:8.5, 1:8.5 to 1:9, 1:9 to 1:9.5, or 1:9.5 to 1:10. The ratio of titanium(IV) butoxide to benzyl alcohol ranges from 1:0.1 to 1:100, for example, 1:0.1 to 1:5, 1:5 to 1:10, 1:10 to 1:15, 1:15 to 1:20, 1:20 to 1:25, 1:25 to 1:30, 1:30 to 1:35, 1:35 to 1:40, 1:40 to 1:45, 1:45 to 1:50, 1:50 to 1:55, 1:55 to 1:60, 1:60 to 1:65, 1:65 to 1:70, 1:70 to 1:75, 1:75 to 1:80, 1:80 to 1:85, 1:85 to 1:90, 1:90 to 1:95, or 1:95 to 1:100. The reaction mixture is heated at a temperature between 140-300°C, for example, 140-150°C, 150-160°C, 160-170°C, 170-180°C, 180-190°C, 190-200°C, 200-210°C, 210-220°C, 220-230°C, 230-240°C, 240-250°C, 250-260°C, 260-270°C, 270-280°C, 280-290°C, 290-300°C, 300-310°C, 320-330°C, 340-350°C, 350-360°C, 370-380°C, 380-390°C, 390-400°C, 400-410°C, 420-430°C, 440-450°C, 460-470°C, 480-490°C, 490-500°C, 500-510°C, 520-530°C, 540-550°C, 550-560°C, 560-570°C, 570-580°C, 580-590°C, 590-600°C, 600-610°C, 610-620°C, 620-630°C, 630-640°C, 640-650°C, 650-660°C, 660-670°C, 670 Heat to a temperature between 0°C, 280-290°C, or 290-300°C at a heating rate of 0.1-5°C / min, e.g., 0.1-0.5°C / min, 0.5-1°C / min, 1-1.5°C / min, 1.5-2°C / min, 2-2.5°C / min, 2.5-3°C / min, 3-3.5°C / min, 2.5-4°C / min, 4-4.5°C / min, or 4.5-5°C / min.Once the reaction mixture has reached the desired temperature, maintain this temperature for 1-120 minutes, e.g., 1-10 minutes, 10-20 minutes, 20-30 minutes, 30-40 minutes, 40-50 minutes, 50-60 minutes, 60-70 minutes, 70-80 minutes, 80-90 minutes, 90-100 minutes, or 100-120 minutes. After cooling the reactor to room temperature, collect the white milky solution of synthesized TiO2 nanocrystals. The pressure of the reaction will reach 50-150 psi.

[0082]

[0098] In an exemplary method, zirconium oxide nanocrystals are produced by a solvothermal process from a mixture of zirconium (IV) butoxide, water, and benzyl alcohol in a sealed inert atmosphere in an autoclave. The ratio of zirconium (IV) butoxide to water is in the range of 1:0.1 to 1:10, e.g., 1:0.1 to 1:05, 1:0.5 to 1:1, 1:1 to 1:1.5, 1:1.5 to 1:2, 1:2 to 1:2.5, 1:2.5 to 1:3, 1:3 to 1:3.5, 1:3.5 to 1:4, 1:4 to 1:4.5, 1:4.5 to 1:5, 1:5 to 1:5.5, 1:5.5 to 1:6, 1:6 to 1:6.5, 1:6.5 to 1:7, 1:7 to 1:7.5, 1:7.5 to 1:8, 1:8 to 1:8.5, 1:8.5 to 1:9, 1:9 to 1:9.5, or 1:9.5 to 1:10. The ratio of zirconium(IV) butoxide to benzyl alcohol ranges from 1:0.1 to 1:100, for example, 1:0.1 to 1:5, 1:5 to 1:10, 1:10 to 1:15, 1:15 to 1:20, 1:20 to 1:25, 1:25 to 1:30, 1:30 to 1:35, 1:35 to 1:40, 1:40 to 1:45, 1:45 to 1:50, 1:50 to 1:55, 1:55 to 1:60, 1:60 to 1:65, 1:65 to 1:70, 1:70 to 1:75, 1:75 to 1:80, 1:80 to 1:85, 1:85 to 1:90, 1:90 to 1:95, or 1:95 to 1:100. The reaction mixture is heated at a temperature between 140-350°C, e.g., 140-150°C, 150-160°C, 160-170°C, 170-180°C, 180-190°C, 190-200°C, 200-210°C, 210-220°C, 220-230°C, 230-240°C, 240-250°C, 250-260°C, 260-270°C, 270-280°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 75 Heat to a temperature between 290°C, 290°C, 300°C, or 300°C, 350°C, at a heating rate of 0.1-5°C / min, e.g., 0.1-0.5°C / min, 0.5-1°C / min, 1-1.5°C / min, 1.5-2°C / min, 2-2.5°C / min, 2.5-3°C / min, 3-3.5°C / min, 2.5-4°C / min, 4-4.5°C / min, or 4.5-5°C / min.Once the reaction mixture has reached the desired temperature, maintain this temperature for 1-120 minutes, e.g., 1-10 minutes, 10-20 minutes, 20-30 minutes, 30-40 minutes, 40-50 minutes, 50-60 minutes, 60-70 minutes, 70-80 minutes, 80-90 minutes, 90-100 minutes, or 100-120 minutes. After cooling the reactor to room temperature, collect the white milky solution of synthesized ZrO2 nanocrystals. The pressure of the reaction will reach 100-500 psi. Core-Shell Coating Process

[0099] In an exemplary method, the TiO2 or ZrO2 nanocrystals are heated at a speed of 100 to 9000 rpm, e.g., 100 to 500 rpm, 500 to 1000 rpm, 100 to 1500 rpm, 1500 to 2000 rpm, 2000 to 2500 rpm, 2500 to 3000 rpm, 3000 to 3500 rpm, 3500 to 4000 rpm, 4000 to 4500 rpm, 4500 to 5000 rpm, 5000 to 5500 rpm, 5500 to 6000 rpm, 6000 to 650 The reaction mixture is then centrifuged at 0 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, or 55-60 minutes. The supernatant is then decanted, and the purified TiO2 or ZrO2 nanocrystals form on the bottom of the centrifuge bottle as a wet cake. A solvent is added to the wet cake, and the centrifugation step is repeated 1-10 times, e.g., 1-2 times, 2-3 times, 3-4 times, 4-5 times, 5-6 times, 6-7 times, 7-8 times, 8-9 times, or 9-10 times. The wet cake is dispersed in the solvent at 5% to 50% by weight of the wet cake relative to the solvent, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% by weight of the wet cake relative to the solvent.At least one shell metal oxide precursor is present in an amount of 0.1% to 500% by weight of the precursor based on the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, %, 55%-60 wt%, 60%-70 wt%, 70%-80 wt%, 80%-90 wt%, 90%-100 wt%, 100%-110 wt%, 110%-120 wt%, 120%-130 wt%, 130%-140 wt%, 140%-150 wt%, 150%-200 wt%, 200%-300 wt%, or 300%-500 wt% of the precursor is added to the nanocrystal suspension. The mixture is then heated to 50-130°C, e.g., 50-60°C, 60-70°C, 70-80°C, 80-90°C, 90-100°C, 100-110°C, 110-120°C, or 120-130°C, for 1-400 hours, e.g., 1-10 hours, 10-20 hours, 20-30 hours, 30-40 hours, 40-50 hours, 50-60 hours, 60-70 hours, 70-80 hours, 80-90 hours, 90-100 hours, 100-120 hours, 120-150 hours, 150-200 hours, 200-250 hours, 250-300 hours, 300-350 hours, or 340-400 hours. Upon completion, the reaction mixture is then cooled to room temperature. At least one other precursor for the second and successive shell metal oxides can be added simultaneously with the first shell metal oxide precursor or after the first precursor has been heated for a period of time. The application of heat and / or pressure can be repeated after addition of the second shell material.

[0083]

[0100] Titanium oxide or zirconium oxide nanocrystals having at least one shell oxide coating are purified by precipitating the nanocrystals from the reaction mixture using a solvent or solvent mixture to form a milky suspension. The milky suspension resulting from the precipitation can be stirred at 100-9000 rpm, e.g., 100-500 rpm, 500-1000 rpm, 100-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-6500 rpm, 7000-8000 rpm, 8000-9000 rpm, 9000-10000 rpm, 1000-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-7000 rpm, 7000-8000 rpm, 8000-9000 rpm, 9000-10000 rpm, 1000-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3 Centrifuge at 500 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, for example, 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, or 55-60 minutes. The supernatant is then decanted, and a wet cake of purified core-shell titanium oxide or zirconium oxide is formed at the bottom of the centrifuge bottle. A solvent is added to the wet cake and the centrifugation step is repeated 1-10 times, e.g., 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, or 9-10 times to produce purified core-shell titanium oxide or zirconium oxide nanocrystals. Optionally, a base or acid is present to help neutralize excess acid or base present. Capping of core-shell TiO2 or ZrO2

[0101] In an exemplary method, the purified core-shell TiO2 or ZrO2 nanocrystals are capped with at least one capping agent in a solvent. The purified core-shell titanium oxide nanocrystals obtained as a wet cake are dispersed in a round-bottom flask in a solvent generally preferred for capping. The wet cake is dispersed in the capping solvent in a ratio of 5 to 80% by weight of the wet cake, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80% by weight of the wet cake relative to the solvent. At least one capping agent is added to the nanocrystal suspension in an amount of 0.1 to 100% by weight of the capping agent based on the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, 55% to 60% by weight, 60% to 70% by weight, 70% to 80% by weight, 80% to 90% by weight, 90% to 100% by weight of the capping agent based on the wet cake. The suspension is mixed for 5 minutes to 3 hours, for example, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, 45 minutes, 1 hour, 2 hours, or 3 hours, at 25 to 60° C., for example, 25° C., or 30° C., or 35° C., or 40° C., or 45° C., or 50° C., or 55° C., or 60° C. The substrate is added to the suspension in the form of 5 to 30% by weight of wet cake relative to the solvent, for example, 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, or 30% by weight of wet cake relative to the solvent. The suspension is heated at 50 to 130°C, e.g., 50 to 60°C, 60 to 70°C, 70 to 80°C, 80 to 90°C, 90 to 100°C, 100 to 110°C, 110 to 120°C, or 120 to 130°C, for 15 to 300 minutes, e.g., 15 to 30 minutes, 30 to 60 minutes, 60 to 90 minutes, 90 to 120 minutes, 120 to 150 minutes, 150 to 180 minutes, 180 to 210 minutes, 210 to 240 minutes, 240 to 270 minutes, or 270 to 300 minutes.

[0084]

[0102] In some embodiments, the second capping agent is added to the reaction mixture at 0.1 to 100% by weight of the capping agent relative to the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, 55% to 60% by weight, 60% to 70% by weight, 70% to 80% by weight, 80% to 90% by weight, or 90% to 100% by weight of the capping agent relative to the wet cake. The suspension is continued to be heated at 50-130°C, e.g., 50-60°C, 60-70°C, 70-80°C, 80-90°C, 90-100°C, 100-110°C, 110-120°C, 120-130°C, for 15-300 minutes, e.g., 15-30 minutes, 30-60 minutes, 60-90 minutes, 90-120 minutes, 120-150 minutes, 150-180 minutes, 180-210 minutes, 210-240 minutes, 240-270 minutes, or 270-300 minutes.

[0085]

[0103] In some embodiments, the inorganic passivator is added to the reaction mixture after the first or second capping agent addition step in an amount of 0.1 to 50% by weight of the inorganic passivator based on the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, or 45% to 50% by weight of the inorganic passivator based on the wet cake. The suspension is continued to be heated at 50-130°C, e.g., 50-60°C, 60-70°C, 70-80°C, 80-90°C, 90-100°C, 100-110°C, 110-120°C, or 120-130°C, for 15-300 minutes, e.g., 15-30 minutes, 30-60 minutes, 60-90 minutes, 90-120 minutes, 120-150 minutes, 150-180 minutes, 180-210 minutes, 210-240 minutes, 240-270 minutes, or 270-300 minutes.

[0086]

[0104] The reaction mixture is then cooled to room temperature to obtain at least partially capped core-shell nanocrystals. The capped core-shell nanocrystals are purified by repeated precipitation in a solvent or combination of solvents to remove excess capping agent and other by-products. The capped core-shell nanocrystals are precipitated from the reaction mixture by adding a solvent or combination of solvents, referred to as an anti-solvent, in a weight to weight ratio of solvent to reaction mixture of 0.1:1 to 3:1, e.g., a weight to weight ratio of solvent to reaction mixture of 0.1:1 to 1:1, 1:1 to 1.25:1, 1.25:1 to 1.5:1, 1.5:1 to 1.75:1, 1.75:1 to 2:1, 2:1 to 2.25:1, 2.25:1 to 2.5:1, 2.5:1 to 2.75:1, or 2.75:1 to 3:1. A poor solvent is a solvent or combination of solvents that is incompatible with the nanocrystals and causes them to precipitate from solution. This precipitation is carried out at a speed of 100-9000 rpm, e.g., 100-500 rpm, 500-1000 rpm, 100-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-6500 rpm, 7000-7500 rpm, 8000-8500 rpm, 9000-9500 rpm, 1000-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-6500 rpm, 7000-8500 rpm, 8000-9500 rpm, 9000-10500 rpm, 1000-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 350 Centrifuge at 00 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, 55-60 minutes. Decant and discard the resulting supernatant. The solid collected from the centrifugation step is then dispersed in a solvent compatible with the capped nanocrystals.The dispersed solids are then precipitated using an antisolvent in a weight to weight ratio of antisolvent to solvent of 0.1:1 to 3:1, e.g., a weight to weight ratio of antisolvent to solvent of 0.1:1 to 1:1, 1:1 to 1.25:1, 1.25:1 to 1.5:1, 1.5:1 to 1.75:1, 1.75:1 to 2:1, 2:1 to 2.25:1, 2.25:1 to 2.5:1, 2.5:1 to 2.75:1, or 2.75:1 to 3:1. The precipitate is stirred at a speed of 100 to 9000 rpm, for example, 100 to 500 rpm, 500 to 1000 rpm, 100 to 1500 rpm, 1500 to 2000 rpm, 2000 to 2500 rpm, 2500 to 3000 rpm, 3000 to 3500 rpm, 3500 to 4000 rpm, 4000 to 4500 rpm, 4500 to 5000 rpm, 5000 to 5500 rpm, 5500 to 6000 rpm, 6000 to 6500 rpm, Collect by centrifugation at 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, 55-60 minutes. Decant and discard the resulting supernatant. Repeat this process if necessary. The solids are then placed in a vacuum oven to dry overnight.

[0087]

[0105] The dried solids are redispersed in a solvent such as PGMEA, PGME or ethanol in a solvent to solid ratio of 1:1 to create a 50 wt% loaded dispersion. The resulting dispersion is filtered through a 0.45 micron, then a 0.2 micron absolute or nominal filter. Core-shell TiO2 or ZrO2 treated with inorganics followed by capping

[0106] In this disclosure, terms such as inorganic treatment, inorganic passivation treatment, alkali metal compound treatment, and inorganic salt are used interchangeably and refer to a process of treating either the core metal oxide or the core-shell metal oxide nanocrystals, before or after capping, with a compound comprising at least one of sodium polyphosphate, lithium nitrate, sodium hypochlorite, sodium hypophosphite, sodium phosphite, lithium chloride, sodium nitrate, sodium chloride, sodium aluminum phosphate, aluminum hypophosphite, sodium hexametaphosphate, calcium hypophosphite, or any hydrate thereof, or any combination thereof.

[0088]

[0107] In an exemplary method, purified core-shell TiO2 or ZrO2 nanocrystals are treated with an inorganic passivator prior to capping. The purified core-shell nanocrystals obtained as a wet cake are dispersed in a round bottom flask in a solvent of choice for inorganic treatment. The wet cake is dispersed in a solvent in the range of 5-80% by weight of the wet cake, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, or 80% by weight of the wet cake, to obtain a white slurry. At least one inorganic passivator is added to the slurry in an amount of 0.1 to 100% by weight based on the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, 55% to 60% by weight, 60% to 70% by weight, 70% to 80% by weight, 80% to 90% by weight, or 90% to 100% by weight based on the wet cake. The slurry is mixed for 0.1-12 hours, e.g., 0.1-1 hour, 1-2 hours, 2-3 hours, 3-4 hours, 4-5 hours, 5-6 hours, 6-7 hours, 7-8 hours, 8-9 hours, 9-10 hours, 10-11 hours, or 11-12 hours, at 25-60° C., e.g., 25° C., or 30° C., or 35° C., or 40° C., or 45° C., or 50° C., or 55° C., or 60° C. The processed nanocrystals are collected from the slurry by centrifugation.The slurry is rotated at 100 to 9000 rpm, for example, 100 to 500 rpm, 500 to 1000 rpm, 100 to 1500 rpm, 1500 to 2000 rpm, 2000 to 2500 rpm, 2500 to 3000 rpm, 3000 to 3500 rpm, 3500 to 4000 rpm, 4000 to 4500 rpm, 4500 to 5000 rpm, 5000 to 5500 rpm, 5500 to 6000 rpm, 6000 to 6500 rpm Centrifuge at 1000 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, or 55-60 minutes. Decant and discard the resulting supernatant. Suspend the solids collected in the centrifugation step in a solvent or combination of solvents and centrifuge again. Repeat this process twice. Suspend the resulting solids in a round-bottom flask in the solvent generally preferred for capping. The wet cake is dispersed in the capping solvent in an amount of 5 to 80% by weight of the wet cake relative to the solvent, for example, 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 60% by weight, 70% by weight, or 80% by weight of the wet cake relative to the solvent. The first capping agent is added to the nanocrystal suspension at 0.1 to 100% by weight of the capping agent relative to the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, 55% to 60% by weight, 60% to 70% by weight, 70% to 80% by weight, 80% to 90% by weight, or 90% to 100% by weight of the capping agent relative to the wet cake.The suspension is mixed for 5 minutes to 3 hours, for example, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, 45 minutes, 1 hour, 2 hours, or 3 hours, at 25 to 60° C., for example, 25° C., or 30° C., or 35° C., or 40° C., or 45° C., or 50° C., or 55° C., or 60° C. The substrate is added to the suspension in the form of 5 to 30% by weight of wet cake relative to the solvent, for example, 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, or 30% by weight of wet cake relative to the solvent. The suspension is heated for 50-300 minutes, e.g., at 50-60°C, 60-70°C, 70-80°C, 80-90°C, 90-100°C, 100-110°C, 110-120°C, or 120-130°C for 15-30 minutes, 30-60 minutes, 60-90 minutes, 90-120 minutes, 120-150 minutes, 150-180 minutes, 180-210 minutes, 210-240 minutes, 240-270 minutes, or 270-300 minutes.

[0089]

[0108] In some embodiments, the second capping agent is added to the reaction mixture at 0.1 to 100% by weight of the capping agent relative to the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, 55% to 60% by weight, 60% to 70% by weight, 70% to 80% by weight, 80% to 90% by weight, or 90% to 100% by weight of the capping agent relative to the wet cake. The suspension is continuously heated at 50 to 130°C, for example, 50 to 60°C, 60 to 70°C, 70 to 80°C, 80 to 90°C, 90 to 100°C, 100 to 110°C, 110 to 120°C, or 120 to 130°C, for 15 to 300 minutes, for example, 15 to 30 minutes, 30 to 60 minutes, 60 to 90 minutes, 90 to 120 minutes, 120 to 150 minutes, 150 to 180 minutes, 180 to 210 minutes, 210 to 240 minutes, 240 to 270 minutes, or 270 to 300 minutes.

[0090]

[0109] In some embodiments, the inorganic passivator is added to the reaction mixture after the first or second capping agent addition step in an amount of 0.1 to 50% by weight of the inorganic passivator based on the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, or 45% to 50% by weight of the inorganic passivator based on the wet cake. The suspension is continuously heated at 50 to 130°C, for example, 50 to 60°C, 60 to 70°C, 70 to 80°C, 80 to 90°C, 90 to 100°C, 100 to 110°C, 110 to 120°C, or 120 to 130°C, for 15 to 300 minutes, for example, 15 to 30 minutes, 30 to 60 minutes, 60 to 90 minutes, 90 to 120 minutes, 120 to 150 minutes, 150 to 180 minutes, 180 to 210 minutes, 210 to 240 minutes, 240 to 270 minutes, or 270 to 300 minutes.

[0091]

[0110] The reaction mixture is then cooled to room temperature to obtain at least partially capped, inorganically treated core-shell nanocrystals. The capped, inorganically treated core-shell nanocrystals are purified by repeated precipitation in a solvent or combination of solvents to remove excess capping agent and other by-products. The capped, inorganically treated core-shell nanocrystals are precipitated from the reaction mixture by adding a solvent or combination of solvents, referred to as an anti-solvent, in a weight to weight ratio of solvent to reaction mixture of 0.1:1 to 3:1, e.g., a weight to weight ratio of solvent to reaction mixture of 0.1:1 to 1:1, 1:1 to 1.25:1, 1.25:1 to 1.5:1, 1.5:1 to 1.75:1, 1.75:1 to 2:1, 2:1 to 2.25:1, 2.25:1 to 2.5:1, 2.5:1 to 2.75:1, or 2.75:1 to 3:1. A poor solvent is a solvent or combination of solvents that is incompatible with the nanocrystals and causes them to precipitate from solution. This precipitation is carried out at a constant speed of 100-9000 rpm, e.g., 100-500 rpm, 500-1000 rpm, 100-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-7000 rpm, 7000-8000 rpm, 8000-9000 rpm, 9000-10000 rpm, 10 ... Centrifuge at 6500 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, 55-60 minutes. Decant and discard the resulting supernatant. The solid collected from the centrifugation step is then dispersed in a solvent compatible with the capped nanocrystals.The dispersed solids are then precipitated using an antisolvent in a weight to weight ratio of antisolvent to solvent of 0.1:1 to 3:1, e.g., a weight to weight ratio of antisolvent to solvent of 0.1:1 to 1:1, 1:1 to 1.25:1, 1.25:1 to 1.5:1, 1.5:1 to 1.75:1, 1.75:1 to 2:1, 2:1 to 2.25:1, 2.25:1 to 2.5:1, 2.5:1 to 2.75:1, 2.75:1 to 3:1. The precipitate is stirred at a speed of 100 to 9000 rpm, for example, 100 to 500 rpm, 500 to 1000 rpm, 100 to 1500 rpm, 1500 to 2000 rpm, 2000 to 2500 rpm, 2500 to 3000 rpm, 3000 to 3500 rpm, 3500 to 4000 rpm, 4000 to 4500 rpm, 4500 to 5000 rpm, 5000 to 5500 rpm, 5500 to 6000 rpm, 6000 to 6500 rpm , 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, 55-60 minutes, and collect by centrifugation. Decant and discard the resulting supernatant. Repeat this process if necessary. The solids are then placed in a vacuum oven to dry overnight.

[0092]

[0111] The dried solids are redispersed in a solvent such as PGMEA, PGME or ethanol in a solvent to solid ratio of 1:1 to create a 50 wt% loaded dispersion. The resulting dispersion is filtered through a 0.45 micron, then a 0.2 micron absolute or nominal filter. Treatment of shell-free nanocrystals with inorganics followed by core-shell processing

[0112] In an exemplary method, purified TiO2 or ZrO2 nanocrystals (without other metal oxide shells) are treated with an inorganic passivator prior to coating with a metal oxide. The purified nanocrystals, obtained as a wet cake, are dispersed in a round-bottom flask in a solvent generally preferred for treatment with inorganics. The wet cake is dispersed in a solvent in the range of 5-80% by weight of the wet cake, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, or 80% by weight of the wet cake, to obtain a white slurry. At least one inorganic passivator is added to the slurry in an amount of 0.1-00% by weight of the inorganic passivator based on the wet cake, 0.1%-5% by weight, 5%-10% by weight, 10%-15% by weight, 15%-20% by weight, 20%-25% by weight, 25%-30% by weight, 30%-35% by weight, 35%-40% by weight, 40%-45% by weight, 45%-50% by weight, 50%-55% by weight, 55%-60% by weight, 60%-70% by weight, 70%-80% by weight, 80%-90% by weight, or 90%-100% by weight of the inorganic passivator based on the wet cake. The slurry is mixed for 0.1-12 hours, e.g., 0.1-1 hour, 1-2 hours, 2-3 hours, 3-4 hours, 4-5 hours, 5-6 hours, 6-7 hours, 7-8 hours, 8-9 hours, 9-10 hours, 10-11 hours, or 11-12 hours, at 25-60° C., e.g., 25° C., or 30° C., or 35° C., or 40° C., or 45° C., or 50° C., or 55° C., or 60° C. The processed nanocrystals are collected from the slurry by centrifugation.The slurry is rotated at 100 to 9000 rpm, for example, 100 to 500 rpm, 500 to 1000 rpm, 100 to 1500 rpm, 1500 to 2000 rpm, 2000 to 2500 rpm, 2500 to 3000 rpm, 3000 to 3500 rpm, 3500 to 4000 rpm, 4000 to 4500 rpm, 4500 to 5000 rpm, 5000 to 5500 rpm, 5500 to 6000 rpm, 6000 to 6500 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, 55-60 minutes. Decant and discard the resulting supernatant. Suspend the solids collected from the centrifugation step in a solvent or combination of solvents and centrifuge again. Repeat this process a second time. Suspend the resulting solids or wet cake in a solvent generally preferred for the oxide shell formation process.

[0093]

[0113] The wet cake is dispersed in the solvent at 5-50% by weight of the wet cake, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% by weight of the wet cake, based on the solvent, for the coating process. At least one shell metal oxide precursor is dispersed in the solvent at 0.1-500% by weight of the precursor, for example, 0.1%-5%, 5%-10%, 10%-15%, 15%-20%, 20%-25%, 25%-30%, 30%-35%, 35%-40%, 40%-45%, 45%-50%, 50%-55% by weight of the wet cake. , 55%-60% by weight, 60%-70% by weight, 70%-80% by weight, 80%-90% by weight, 90%-100% by weight, 100%-110% by weight, 110%-120% by weight, 120%-130% by weight, 130%-140% by weight, 140%-150% by weight, 150%-200% by weight, 200%-300% by weight, or 300%-500% by weight of the precursor to the nanocrystal suspension. The mixture is then heated to 50-130°C, e.g., 50-60°C, 60-70°C, 70-80°C, 80-90°C, 90-100°C, 100-110°C, 110-120°C, 120-130°C, for 1-400 hours, e.g., 1-10 hours, 10-20 hours, 20-30 hours, 30-40 hours, 40-50 hours, 50-60 hours, 60-70 hours, 70-80 hours, 80-90 hours, 90-100 hours, 100-120 hours, 120-150 hours, 150-200 hours, 200-250 hours, 250-300 hours, 300-350 hours, or 340-400 hours. Upon completion, the reaction mixture is then cooled to room temperature.

[0094]

[0114] The inorganic treated nanocrystals having at least one oxide shell are purified by precipitating the nanocrystals from the reaction mixture using a solvent or solvent mixture to form a milky suspension. The milky suspension obtained from the precipitation is heated at a speed of 100-9000 rpm, e.g., 100-500 rpm, 500-1000 rpm, 100-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-6500 rpm, 7000-8000 rpm, 8000-9000 rpm, 9000-10000 rpm, 1000-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 rpm, 3000-3500 rpm, 3500-4000 rpm, 4000-4500 rpm, 4500-5000 rpm, 5000-5500 rpm, 5500-6000 rpm, 6000-7000 rpm, 7000-8000 rpm, 8000-9000 rpm, 9000-10000 rpm, 10000-1500 rpm, 1500-2000 rpm, 2000-2500 rpm, 2500-3000 Centrifuge at 500 rpm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, or 55-60 minutes. The supernatant is then decanted, and a wet cake is formed at the bottom of the centrifuge bottle, purified as inorganic-treated nanocrystals with an oxide shell. Solvent is added to the wet cake and the centrifugation step is repeated 1-10 times, e.g., 1-2 times, 2-3 times, 3-4 times, 4-5 times, 5-6 times, 6-7 times, 7-8 times, 8-9 times, or 9-10 times, to produce purified, inorganic-treated core-shell nanocrystals.

[0095]

[0115] Optionally, a base or acid is present to help neutralize any excess acid or base present.

[0116] In some embodiments, the nanocrystals obtained from this process are at least partially capped with a capping agent according to the process described in "Capping of Synthesized Core-Shell TiO2 or ZrO2." Capping of inorganic processed nanocrystals (no core-shell)

[0117] In an exemplary method, purified TiO2 or ZrO2 nanocrystals (without metal oxide shell) are treated with an inorganic passivator prior to coating with metal oxide. The purified nanocrystals, obtained as a wet cake, are dispersed in a round-bottom flask in a solvent generally preferred for treatment with inorganics. The wet cake is dispersed in a solvent in the range of 5-80% by weight of the wet cake, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, or 80% by weight of the wet cake, to obtain a white slurry. At least one inorganic passivator is added to the slurry in an amount of 0.1 to 100% by weight based on the wet cake, for example, 0.1% to 5% by weight, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, 20% to 25% by weight, 25% to 30% by weight, 30% to 35% by weight, 35% to 40% by weight, 40% to 45% by weight, 45% to 50% by weight, 50% to 55% by weight, 55% to 60% by weight, 60% to 70% by weight, 70% to 80% by weight, 80% to 90% by weight, or 90% to 100% by weight based on the wet cake. The slurry is mixed for 0.1-12 hours, e.g., 0.1-1 hour, 1-2 hours, 2-3 hours, 3-4 hours, 4-5 hours, 5-6 hours, 6-7 hours, 7-8 hours, 8-9 hours, 9-10 hours, 10-11 hours, or 11-12 hours, at 25-35° C., e.g., 25° C. or 30° C. or 35° C. The processed nanocrystals are collected from the slurry by centrifugation.The slurry is rotated at a speed of 100 to 9000 rpm, for example, 100 to 500 rpm, 500 to 1000 rpm, 100 to 1500 rpm, 1500 to 2000 rpm, 2000 to 2500 rpm, 2500 to 3000 rpm, 3000 to 3500 rpm, 3500 to 4000 rpm, 4000 to 4500 rpm, 4500 to 5000 rpm, 5000 to 5500 rpm, 5500 to 6000 rpm, 6000 to 6500 rpm pm, 6500-7000 rpm, 7000-7500 rpm, 7500-8000 rpm, 8000-8500 rpm, or 8500-9000 rpm for 0-60 minutes, e.g., 0-5 minutes, 5-10 minutes, 10-15 minutes, 15-20 minutes, 30-25 minutes, 25-30 minutes, 30-35 minutes, 35-40 minutes, 40-45 minutes, 45-50 minutes, 50-55 minutes, or 55-60 minutes. Decant and discard the resulting supernatant. Suspend the solids collected in the centrifugation step in a solvent or combination of solvents and centrifuge again. Repeat this process twice. Suspend the resulting solids or wet cake in a round-bottom flask in the solvent generally preferred for capping. The nanocrystals obtained from this process are at least partially capped with a capping agent according to the process described in "Capping of Core-Shell TiO2 or ZrO2." Core-shell type TiO2 and ZrO2 nanocrystals

[0118] The crystallinity of the nanocrystals described in this disclosure is analyzed by powder X-ray diffraction. The XRD patterns of titanium oxide and zirconium oxide nanocrystals containing metal oxide shells are consistent with the original anatase and tetragonal phases, respectively, indicating that the shelling and capping processes did not change the original phases.

[0096]

[0119] The at least partially capped titanium dioxide nanocrystals comprising a layer of a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure have an average particle size of less than 30 nm as measured by TEM. Preferably, the particle size is between 1-4 nm, or 4-6 nm, or 6-8 nm, or 8-10 nm, or 10-12 nm, or 12-14 nm, or 14-16 nm, or 16-18 nm, or 18-20 nm, or 20-25 nm, or 25-30 nm as measured by TEM.

[0097]

[0120] The at least partially capped zirconium oxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivating agent of the present disclosure have an average particle size of less than 30 nm as measured by TEM. Preferably, the particle size is between 1-4 nm, or 4-6 nm, or 6-8 nm, or 8-10 nm, or 10-12 nm, or 12-14 nm, or 14-16 nm, or 16-18 nm, or 18-20 nm, or 20-25 nm, or 25-30 nm as measured by TEM.

[0098]

[0121] At least partially capped titanium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure, the metal oxide shell having a thickness of less than 5 nm as measured by TEM. Preferably, the shell thickness is less than 0.05-0.1 nm, 0.1-0.2 nm, 0.2-0.3 nm, 0.3-0.4 nm, 0.4-0.5 nm, 0.5-0.6 nm, 0.6-0.7 nm, 0.7-0.8 nm, 0.8-0.9 nm, 0.9-1.0 nm, 1.0-1.2 nm, 1.2-1.4 nm, 1.4-1.6 nm, 1.6-1.8 nm, 1.8-2.0 nm, 1.9-3.0 nm, 2.0-3.2 nm, 2.1-3.4 nm, 2.2-3.6 nm, 2.3-3.8 nm, 2.4-3.8 nm, 2.5-3.9 nm, 2.6-3.9 nm, 2.7-3.1 nm, 2.8-3.2 nm, 2.9-4.1 nm, 2.8-4.2 nm, 2.9-5.1 nm, 2.1-5.2 nm, 2.2-5.3 nm, 2.3-5.4 nm, 2.4-5.5 nm, 2.5-6.1 nm, 2.6-6.1 nm, 2.7-7.1 nm, 2.8-8.1 nm, 2.9-9.1 nm, 2.8-9.2 nm, 2.9-10.2 nm, 2.9-11.1 nm, 2.9-12.1 nm, 2.9-13.1 nm, 2.9-14.1 nm, 2.9-15.1 nm, 2.9-1 .0nm, 2.0-2.2nm, 2.2-2.4nm, 2.4-2.6nm, 2.6-2.8nm, 2.8-3.0nm, 3.0-3.2nm, 3.0-3.2nm, 3.2-3.4nm, 3.4-3.6nm, 3.6-3.8nm, 3.8-4.0nm, 4.0-4.2nm, 4.2-4.4nm, 4.4-4.6nm, 4.6-4.8nm, 4.8-5.0nm.

[0099]

[0122] At least partially capped zirconium oxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivator of the present disclosure, the metal oxide shell having a thickness of less than 5 nm as measured by TEM. Preferably, the shell thickness is less than 0.05-0.1 nm, 0.1-0.2 nm, 0.2-0.3 nm, 0.3-0.4 nm, 0.4-0.5 nm, 0.5-0.6 nm, 0.6-0.7 nm, 0.7-0.8 nm, 0.8-0.9 nm, 0.9-1.0 nm, 1.0-1.2 nm, 1.2-1.4 nm, 1.4-1.6 nm, 1.6-1.8 nm, 1.8-2.1 nm, 1.9-2.2 nm, 2.0-2.3 nm, 2.1-2.4 nm, 2.2-2.5 nm, 2.3-2.6 nm, 2.4-2.7 nm, 2.5-2.8 nm, 2.6-2.9 nm, 2.7-3.1 nm, 2.8-3.2 nm, 2.9-4.2 nm, 2.8-4.3 nm, 2.9-5.4 nm, 2.9-6.5 nm, 2.9-6.6 nm, 2.9-7.7 nm, 2.9-8.8 nm, 3.0-4.1 nm, 3.0-4.2 nm, 3.0-4.1 nm, 3.0-4.2 nm, 3.0-4.3 nm, 3.0-4.4 nm, 3.0-4.5 ... 2.0nm, 2.0-2.2nm, 2.2-2.4nm, 2.4-2.6nm, 2.6-2.8nm, 2.8-3.0nm, 3.0-3.2nm, 3.0-3.2nm, 3.2-3.4nm, 3.4-3.6nm, 3.6-3.8nm, 3.8-4.0nm, 4.0-4.2nm, 4.2-4.4nm, 4.4-4.6nm, 4.6-4.8nm, 4.8-5.0nm.

[0100]

[0123] In some embodiments, at least partially capped titanium oxide or zirconium oxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure can be characterized in that the core metal oxide has a narrow particle size distribution, characterized in that: 1) a D90:D10 ratio of less than 5, preferably less than 3, or less than 2, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.8, from about 1.2 to about 3, or from about 1.5 to about 3; 2) a D90:D50 ratio of less than 3, preferably less than 2, or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.5; and / or 3) a D50:D10 ratio of less than 3, preferably less than 2, or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, or from about 1.2 to about 1.5.

[0101]

[0124] In some embodiments, the at least partially capped titanium oxide or zirconium oxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure may be characterized in that the core-shell metal oxide has a narrow particle size distribution, characterized in that: 1) a D90:D10 ratio of less than 5, preferably less than 3, or less than 2, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.8, from about 1.2 to about 3, or from about 1.5 to about 3; 2) a D90:D50 ratio of less than 3, preferably less than 2, or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.5; and / or 3) a D50:D10 ratio of less than 3, preferably less than 2, or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, or from about 1.2 to about 1.5.

[0102]

[0125] In some embodiments, the at least partially capped core-shell nanocrystals and / or nanocrystals treated with an inorganic passivation agent of the present disclosure can be characterized as having an atomic ratio of shell metal oxide to core metal oxide of less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8, less than 0.9, less than 1, less than 2, or less than 3 as measured by SEM EDX.

[0103]

[0126] In some embodiments, at least partially capped titanium dioxide nanocrystals comprising a ZrO2 shell and / or treated with an inorganic passivation agent of the present disclosure can be characterized by an atomic ratio of Zr / Ti of less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8, less than 0.9, less than 1, less than 2, less than 3, as measured by SEM EDX, for a core TiO2 nanocrystal having a shell of ZrO2 material.

[0104]

[0127] In some embodiments, the at least partially capped titanium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure can be characterized in that the metal oxide shell comprises ZrO2 and fully or partially encapsulates the TiO2 core.

[0105]

[0128] In some embodiments, the at least partially capped zirconium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivating agent of the present disclosure can be characterized in that the metal oxide shell comprises ZrO2 and fully or partially encapsulates the ZrO2 core.

[0106]

[0129] In some embodiments, the at least partially capped titanium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure can be characterized in that the shell metal oxide comprises ZrO2 and encapsulates one or more of the core TiO2 nanocrystals to form a single particle.

[0107]

[0130] In some embodiments, the at least partially capped zirconium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivating agent of the present disclosure can be characterized in that the shell metal oxide comprises ZrO2 and encapsulates one or more of the core ZrO2 nanocrystals to form a single particle.

[0108]

[0131] In some embodiments, the at least partially capped titanium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivation agent of the present disclosure can be characterized in that the metal oxide shell comprises a ZrO2 material, which can be crystalline or amorphous.

[0109]

[0132] In some embodiments, the at least partially capped zirconium dioxide nanocrystals comprising a metal oxide shell and / or treated with an inorganic passivating agent of the present disclosure can be characterized in that the metal oxide shell comprises a ZrO2 material and can be crystalline or amorphous.

[0110]

[0133] In some embodiments, the nanocrystals disclosed by the present invention having a core-shell structure comprising a core and an outer shell, in which the core is a TiO2 nanocrystal and is at least partially encapsulated with an outer shell comprising a metal oxide and / or treated with an inorganic passivation agent, further demonstrate UV stability. When exposed to UV radiation at 320 nm or more, or 340 nm or more, or 365 nm or more, or 390 nm or more, or 405 nm or more, or 450 nm or more, or 500 nm or more for 1-2 minutes, 2-5 minutes, 5-10 minutes, or 10-30 minutes, or 30-60 minutes, or 1-2 hours, 2-8 hours, 8-48 hours, 48-72 hours, 72-100 hours, 100-200 hours, 200-300 hours, 300-400 hours, 400-500 hours, 500-600 hours, 600-700 hours, 700-800 hours, 800-900 hours, 900-1000 hours, or more than 1000 hours, the TiO2 nanocrystals including a metal oxide shell undergo less change in optical properties and refractive index compared to nanocrystals without an oxide shell. These nanocrystals were measured using a haze meter to measure the b of films containing core-shell nanocrystals before and after UV exposure. * When measuring, less than 5%, 10%, 15%, 20%, 30%, 40%, or 50% b *These nanocrystals exhibit a change in refractive index at 520 nm of less than 0.001, or less than 0.002, or less than 0.004, or less than 0.006, or less than 0.008, or less than 0.01 for films less than 1 micron thick, or 1-2 microns thick, or 2-4 microns thick, or 4-6 microns thick, or 6-8 microns thick, or 8-10 microns thick, or 10-20 microns thick, or 20-30 microns thick, as measured by a prism coupler or ellipsometer before and after UV exposure. or less than 0.012, or less than 0.015, or less than 0.018, or less than 0.02, or less than 0.022, or less than 0.025, or less than 0.028, or less than 0.03, or less than 0.035, or less than 0.04, or less than 0.045, or less than 0.05, or less than 0.055, or less than 0.06, or less than 0.065, or less than 0.07, or less than 0.075, or less than 0.08, or less than 0.085, or less than 0.09, or less than 0.095, or less than 0.1.These nanocrystals result in less than 0.1, or less than 0.2, or less than 0.3, or less than 0.4, or less than 0.5, or less than 0.6, or less than 0.7, or less than 0.8, or less than 0.9, or less than 1.0, or less than 1.5, or less than 2.0, or less than 2.5, or less than 3.0, or less than 3.5, or less than 4.0, or less than 4.5, or less than 5, or less than 10 percent change in film thickness as measured by a haze meter for films incorporating the nanocrystals that are less than 1 micron thick, or between 1 and 2 microns thick, or between 2 and 4 microns thick, or between 4 and 6 microns thick, or between 6 and 8 microns thick, or between 8 and 10 microns thick, or between 10 and 20 microns thick, or between 20 and 30 microns thick, before and after UV exposure. or less than 15, or less than 20, or less than 25, or less than 50, and a % change in haze of less than 0.001, or less than 0.002, or less than 0.004, or less than 0.006, or less than 0.008, or less than 0.01, or less than 0.012, or less than 0.015, or less than 0.018, or less than 0.02, or less than 0.022, or less than 0.025, or less than 0.028, or less than 0.03, or less than 0.035, or less than 0.04, or less than 0.045, or less than 0.05, or less than 0.055, or less than 0.06, or less than 0.065, or less than 0.07, or less than 0.075, or less than 0.08, or less than 0.085, or less than 0.09, or less than 0.095, or less than 0.1.

[0111]

[0134] In some embodiments, the core-shell nanocrystals disclosed herein, including TiO2 nanocrystals that include a metal oxide shell and / or are treated with an inorganic passivation agent, further demonstrate thermal stability. When exposed to temperatures below 120°C, or between 120°C and 175°C, or between 175°C and 200°C, or between 200°C and 250°C, or between 250°C and 300°C, or above 300°C, for 5 minutes or more, or between 10 minutes or more, or between 30 minutes or more, or between 60 minutes or more, or between 120 minutes or more, under air, nitrogen, or vacuum, the core-shell nanocrystals undergo less discoloration compared to nanocrystals without an oxide shell or inorganic treatment. On a 0-6 scale of discoloration (with "0" indicating no discoloration and "6" indicating maximum discoloration, e.g., brown), the nanocrystals exhibit discoloration of 0-1, 1-2, and 2-3 compared to nanocrystals without a shell / inorganic treatment, which exhibit a discoloration of "6." TiO2 nanocrystal dispersion

[0135] The present disclosure provides compositions containing a dispersion in a solvent or at least one monomer of any of capped titanium oxide or zirconium oxide nanocrystals, capped core-shell TiO2 and ZrO2 nanocrystals comprising a metal oxide shell, capped titanium oxide or zirconium oxide nanocrystals, and core-shell nanocrystals treated with an inorganic passivation agent, wherein the capped nanocrystals are present in the solvent in an amount of less than 10% by weight of the total dispersion, or between 10% and 20% by weight, or between 20% and 30% by weight, or between 30% and 40% by weight, or between 40% and 50% by weight, or between 50% and 60% by weight, or between 60% and 70% by weight, or between 70% and 80% by weight, or between 80% and 90% by weight, or between 90% and 95% by weight. As solvents, alcohols such as benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, 2-(isopentyloxy)ethanol, 2-propoxy-propanol (PnP), 2-(hexyloxy)ethanol; ethers and cyclic ethers such as tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol butyl ether. ketones and cyclic ketones, such as acetone; esters, such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate (ETA), butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl butoxyacetate, ethyl acetate, 2-(2-butoxyethoxy)acetate; aromatics, such as benzene, toluene; and water, as well as any combination or mixture thereof.

[0112]

[0136] One common technique to characterize the size and size distribution of nanocrystals in a dispersion is dynamic light scattering (DLS). DLS usually measures nanocrystals dispersed in a liquid transparent to the wavelength of measurement. In this technique, a liquid sample with the correct concentration is held in a plastic, glass, or quartz glass cuvette, a laser beam is scattered in the liquid sample, and the time dependence of the scattered laser light (which is a result of the Brownian motion of the nanocrystals) can be measured to calculate the size and size distribution of the nanocrystals. The results are usually expressed as a size distribution of nanocrystals with equivalent diameters on the x-axis, and the y-axis can represent the scattering intensity, the volume of the scattering nanocrystals, or the number of scattering nanocrystals. The measured size often includes the size of the nanocrystals and the size of the capping agent and / or solvent groups and / or precursor groups along with a thin layer of solvent (solvent shell), and therefore the actual nanocrystal size is often smaller than that measured by DLS. In this disclosure, all references to nanocrystal size and size distribution, except where indicated "as measured by DLS", refer to the nanocrystal size as measured by TEM, and not to the size of the nanocrystal plus capping agent, and / or solvent group, and / or precursor group, or the size of the nanocrystal plus capping agent, and / or solvent group, and / or precursor group, plus solvent shell. D9999 is defined as 99.99% of the particles in the measured dispersion have a particle size less than the reported value (in nanometers) as measured by volume. A variety of DLS spectrometers are available, with each vendor often developing its own proprietary methodology and algorithms, and results may not be interchangeable, and the model specifically used to obtain the data in this disclosure is the Malvern Zetasizer Nano S DLS.

[0113]

[0137] Typical DLS measurements of particle size and size distribution by intensity or volume of nanocrystal dispersions are collected at 5 wt % nanocrystals in solvent.

[0138] When measured by intensity, the average particle size of any of the capped titanium oxide or zirconium oxide nanocrystals and core-shell and / or inorganic treated TiO2 and ZrO2 nanocrystals described in this disclosure when dispersed in a solvent at 5 wt. % is less than 100 nm when measured by dynamic light scattering. Preferably, the particle size, as measured by DLS, is between 1-4 nm, or 4-6 nm, or 6-8 nm, or 8-10 nm, or 10-12 nm, or 12-14 nm, or 14-16 nm, or 16-18 nm, or 18-20 nm, or 20-25 nm, or 25-30 nm, or 30-35 nm, or 35-40 nm, or 40-45 nm, or 45-50 nm, or 50-55 nm, or 55-60 nm, or 60-65 nm, or 65-70 nm, or 75-80 nm, or 80-85 nm, or 85-90 nm, or 90-95 nm, or 95-100 nm.

[0114]

[0139] When measured by volume, the average particle size of any of the capped titanium oxide or zirconium oxide nanocrystals and core-shell and / or inorganic treated TiO2 and ZrO2 nanocrystals described in this disclosure when dispersed at 5 wt. % in a solvent is less than 100 nm, as measured by dynamic light scattering. Preferably, the particle size, as measured by DLS, is between 1-4 nm, or 4-6 nm, or 6-8 nm, or 8-10 nm, or 10-12 nm, or 12-14 nm, or 14-16 nm, or 16-18 nm, or 18-20 nm, or 20-25 nm, or 25-30 nm, or 30-35 nm, or 35-40 nm, or 40-45 nm, or 45-50 nm, or 50-55 nm, or 55-60 nm, or 60-65 nm, or 65-70 nm, or 75-80 nm, or 80-85 nm, or 85-90 nm, or 90-95 nm, or 95-100 nm.

[0115]

[0140] Any of the capped titanium oxide, zirconium oxide nanocrystals, core-shell nanocrystals, inorganically treated nanocrystals, and core-shell and inorganically treated nanocrystals described in this disclosure, measured by volume, when dispersed at 5% by weight in a solvent, has a D9999 of less than 500 nm as measured by dynamic light scattering. Preferably, D9999 is less than 20nm, less than 30nm, less than 40nm, less than 50nm, less than 60nm, less than 70nm, less than 80nm, less than 90nm, less than 100nm, less than 110nm, less than 120nm, less than 130nm, less than 140nm, less than 150nm, less than 160nm, less than 170nm, less than 180nm, less than 190nm, less than 200nm, less than 220nm, less than 150nm, less than 240nm, less than 260nm, less than 280nm, less than 300nm, less than 400nm or less than 500nm as measured by DLS.

[0116]

[0141] In one embodiment, the at least partially capped core-shell nanocrystals comprising a core TiO2 or ZrO2 nanocrystal and a metal oxide shell comprising ZrO2 and / or treated with an inorganic passivation agent of the present disclosure have a narrow particle size distribution characterized by a D9999 of less than 20, less than 30, less than 40, less than 50, less than 60, less than 70, less than 80, less than 90, less than 100, less than 110, less than 120, less than 130, less than 140, less than 150, less than 160, less than 170, less than 180, less than 190, less than 200.

[0117]

[0142] One common technique to characterize the solids %, inorganic % and organic % in nanocrystal dispersions or nanocrystal formulations is thermogravimetric analysis (TGA). A nanocrystal formulation of the present disclosure is any dispersion containing any capped nanocrystals, monomers, oligomers, polymers and other additives described in this disclosure. Optionally, the formulation contains a solvent or a combination of solvents. In this technique, the nanocrystal dispersion or nanocrystal polymer nanocomposite is held in a crucible and heated from room temperature to about 800°C while the weight is monitored. The organic solvent, polymer and capping agent decompose at high temperatures, usually at different temperatures, leaving only the inorganic nanocrystals behind. The relative weight percentages of the various raw components in the original sample can be obtained. The TGA results usually produce a plot of temperature on the x-axis and relative weight percentages on the y-axis. A variety of TGA instruments are available, all of which are based on similar principles and, when operated properly, the results are interchangeable. The model specifically used to obtain the data in this disclosure is a TA Instrument TGA Q500.

[0118]

[0143] The dispersions disclosed by the present invention are analyzed using a TA instrument Q500 Thermogravimetric Analyzer (TGA) to determine the organic content, inorganic content, and solids content of the capped nanocrystal dispersion. The percent mass at 200°C (M200C) relative to the initial mass is considered to be the capped nanocrystals present in the dispersion, and the percent mass at 700°C (M700C) relative to the initial mass is considered to be the inorganic portion of the capped nanocrystals, i.e., inorganic solids. The organic content of the capped nanocrystals is defined as the difference between the percent mass at 200°C and the percent mass at 700°C divided by the percent mass at 200°C, i.e., % organic = (M200C - M700C) / M200C.

[0119]

[0144] A TA instrument Q500 thermogravimetric analyzer (TGA) is used to analyze the formulations disclosed by the present invention. The TGA is run with nanocrystal dispersions in solvents with boiling points below 200°C to determine the organic content of the capped nanocrystals. The percent mass at 200°C relative to the initial mass is considered to be the capped nanocrystals, and the percent mass at 700°C relative to the initial mass is considered to be the inorganic portion of the capped nanocrystals, i.e., the inorganic solids. The percent organic (%Org) of the capped nanocrystals is defined as the difference between the percent mass at 200°C (M200C) and the percent mass at 700°C (M700C) divided by the percent mass at 200°C:

[0145] %Org=(M200C-M700C) / M200C×100%

[0146] For nanocomposites or formulations, the percent solids (%S) is calculated from the inorganic content of the nanocomposite and the organic content of the capped nanocrystals, measured in solvent:

[0147] %S=M700C / (100%-%Org)×100%

[0148] The solids content of the dispersions disclosed by the present invention comprising capped titanium oxide, zirconium oxide nanocrystals, core-shell TiO2 and ZrO2 nanocrystals with metal oxide shells, and nanocrystals having inorganic treatments is typically 0-93%, e.g., 0-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93%, as measured by TGA.

[0120]

[0149] The inorganic solids content of the dispersions disclosed by the present invention, including capped titanium oxide, zirconium oxide nanocrystals, core-shell TiO2 and ZrO2 nanocrystals with metal oxide shells, and nanocrystals having inorganic treatments, is typically 0-93%, e.g., 0-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93%, as measured by TGA.

[0121]

[0150] The organic content of the dispersions disclosed by the present invention, including capped titanium oxide, zirconium oxide nanocrystals, core-shell TiO2 and ZrO2 nanocrystals with metal oxide shells, and nanocrystals having inorganic treatments, is typically 0-25% of the capped nanocrystals, e.g., 0-5%, or 5-10%, or 10-15%, or 15-20%, or 20-25%, or less than 5%, or less than 8%, or less than 10%, or less than 12%, or less than 14%, or less than 16%, or less than 18%, or less than 20%, or less than 25% as measured by TGA.

[0122]

[0151] The organic content of capped titanium oxide, zirconium oxide nanocrystals, core-shell TiO2 and ZrO2 nanocrystals with a metal oxide shell, and nanocrystals having inorganic treatments is typically 0-25% of the capped nanocrystals, e.g., 0-5%, or 5-10%, or 10-15%, or 15-20%, or 20-25%, or less than 5%, or less than 8%, or less than 10%, or less than 12%, or less than 14%, or less than 16%, or less than 18%, or less than 20%, or less than 25% as measured by TGA.

[0123]

[0152] The titanium or zirconium oxide nanocrystals, as well as core-shell TiO2 and ZrO2 nanocrystals disclosed by the present invention, whether dispersed in a solvent, monomer, polymer or as a formulation, are storage stable for at least 1 week, or 2 weeks, or 3 weeks, or 4 weeks, or 3 months, or at least 5 months, or at least 6 months, or at least 7 months, or at least 8 months, or at least 9 months, or at least 10 months, or at least 11 months, or at least 1 year, or at least 2 years, or at least 3 years, when the dispersion is stored at a temperature in the range of 18-25°C without intentional shaking or mixing of the dispersion. Formulation ingredients and properties

[0153] The present disclosure provides solvent-containing and / or solvent-free, nanoimprintable, inkjetable, and spin-coatable, highly transparent, high RI formulations comprising at least partially capped titanium dioxide or zirconium oxide nanocrystals, including a layer of a metal oxide shell, and / or treated with an inorganic passivator, dispersed in a monomer, oligomer, polymer, or mixture thereof. The formulations optionally include solvents, curing agents, adhesion promoters, wetting agents, planarizing agents, dispersants, viscosity modifiers, organic dopants, and antioxidants. These formulations allow the production of nanocomposites and thin film coatings with high refractive index and high optical transparency.

[0124]

[0154] The acrylic monomers, oligomers, and / or polymers of the formulations disclosed by the present invention include benzyl (meth)acrylate (BA and BMA), trimethylolpropane tri(meth)acrylate (TMPTA and TMPTMA), trimethylolpropane ethoxylate tri(meth)acrylate (EOTMPTA and EOTMPTMA), 1,6-hexanediol di(meth)acrylate (HDDA and HDDMA), di(ethylene glycol) di(meth)acrylate (DEGDA and DEGDMA), ethylene glycol diacrylate, glycerol 1,3-diglycerolate diacrylate, tri(propylene glycol) diacrylate, 1,6-hexanediol ethoxylate diacrylate, ethylene glycol phenyl ... Ether (meth)acrylates (PEA and PEMA), 2-hydroxy-3-phenoxypropyl acrylate (HPPA), 2-hydroxy-3-phenoxypropyl methacrylate (HPPMA), 2-phenoxybenzyl acrylate (PBA), biphenyl methacrylate (BPMA), isobornyl acrylate (IBA), 2-phenylphenol methacrylate (PPMA), isobutyl acrylate (IBA), 2-phenylethyl acrylate (2-PEA), 2-(phenylthio)ethyl acrylate (PTEA), tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA or M370), bisphenol A glycerolate dimethacrylate, esters with acrylic acid (OPPEOA), OPPEOA in 9,9-bis[4-(2-acryloyloxyethyloxy)phenyl]fluorene or bisfluorene diacrylate (HR6042), bisphenol A ethoxylate diacrylate, bisphenol A propoxylate diacrylate, bisphenol F ethoxylate (2EO / phenol) diacrylate, bisphenol A glycerolate diacrylate, bisphenol A ethoxylate dimethacrylate, ethoxylated (4) bisphenol A diacrylate (SR-601), biphenol A ethoxylate diacrylate (SR-349), tris(2-acryloyloxy)ethyl}isocyanurate, tricyclodecane dimethanol diacrylate, cresol novolac epoxy acrylate (CN112C60), tri(ethylene glycol) diacrylate, ethylene glycol diacrylate, poly(ethylene glycol) diacrylate, glycerol 1,3-diglycerolate diacrylate, and combinations thereof.

[0125]

[0155] In some preferred embodiments, the monomers, oligomers and / or polymers may be selected from 2-phenylethyl acrylate (2-PEA), biphenyl methacrylate (BPMA), 2-phenoxybenzyl acrylate (PBA), trimethylolpropane tri(meth)acrylate (TMPTA and TMPTMA), tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), 9,9-bis[4-(2-acryloyloxyethyloxy)phenyl]fluorene in OPPEOA or bisfluorene diacrylate (HR6042), and combinations thereof.

[0126]

[0156] The vinyl monomers, oligomers, and / or polymers of the formulations disclosed herein can include N-vinylpyrrolidone (NVP), phenylnorborene (norborene), styrene (STY), 4-methylstyrene, 4-vinylanisole, divinylbenzene, or combinations thereof.

[0127]

[0157] The capped nanocrystals are present in the monomer in an amount of less than 10% by weight, or 10%-20% by weight, or 20%-30% by weight, or 30%-40% by weight, or 40%-50% by weight, or 50%-60% by weight, or 60%-70% by weight, or 70%-80% by weight, or 80%-90% by weight, or 90%-95% by weight of the total weight of the monomer, oligomer, and polymer.

[0128]

[0158] The formulations disclosed herein optionally include organic dopants that increase the refractive index of the film or coating, when present, including phenanthrene (PhA), 9-cyanophenanthrene, triphenylmethane, benzoquinoline, 9-vinylcarbazole, and combinations thereof.

[0129]

[0159] The curing agent of the formulation disclosed by the present invention usually includes a photoinitiator. Any photoinitiator can be used as long as it is capable of generating active species, such as radicals with light (UV) energy, provided that it does not limit the optical and physical performance of the nanocomposite. Examples of photoinitiator curing agents include amines, such as Ebecryl® P115, or benzophenone and its derivatives, such as Ebecryl® P39, benzophenone, SpeedCure BEM (Lambson USA Ltd, Rutherford, CT, USA), or organophosphines, such as diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO), Irgacure® 819, or Irgacure® 184 (BASF USA, Florham Park, NJ, USA). The formulation includes a single photoinitiator or any combination of these. Although the formulations described herein focus on the application of UV radiation for curing, thermal curing is entirely possible with the use of an appropriate thermal initiator, such as 2,2-azobis(2-methylpropionitrile) (AIBN).

[0130]

[0160] The combination of more than one curing agent may be advantageous in certain circumstances as known to those skilled in the art.

[0161] The amount of curing agent in the formulation disclosed by the present invention is usually less than 0.5% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 0.5% and 1% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 1% and 2% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 2% and 3% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 3% and 4% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 4% and 5% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 5% and 6% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 6% and 7% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 7% and 8% by weight based on the total weight of the monomers, oligomers, and / or polymers, or between 8% and 15% by weight based on the total weight of the monomers, oligomers, and / or polymers.

[0131]

[0162] When present, the adhesion promoter is selected from organometallic compounds, such as organofunctional silanes, or from functionalized monomers and oligomers. Some suitable organofunctional silane adhesion promoters contain amino or methacryloxy groups. Exemplary silane adhesion promoters include, but are not limited to, 3-aminopropyltriethoxysilane, 3-[(methacryloyloxy)propyl]trimethoxysilane, ureidopropyltrimethoxysilane, and trimethoxy[3-(methylamino)propyl]silane, AP3000 (Dow Chemical). Functionalized monomers and oligomers adhesion promoters include, but are not limited to, CN820, CN146 (Sartomer Americas, Exton, PA, USA), SR9051, SR9053 (Sartomer Americas, Exton, PA, USA), and Ebecryl171 (Allnex USA Inc., Wallingford, CT, USA).

[0132]

[0163] The adhesion promoter of the formulation disclosed by this invention can be present in an amount of less than 0.5% by weight based on the weight of the monomer, oligomer, and / or polymer, or 0.5-1% by weight based on the weight of the monomer, oligomer, and / or polymer, or 1-5% by weight based on the weight of the monomer, oligomer, and / or polymer, or 5-10% by weight based on the weight of the monomer, oligomer, and / or polymer, or 10-15% by weight based on the weight of the monomer, oligomer, and / or polymer, or 15-30% by weight based on the weight of the monomer, oligomer, and / or polymer.

[0133]

[0164] In some embodiments, surfactants (which can act as wetting agents), leveling agents, defoamers and dispersants are present to reduce the surface tension of the formulation, thus improving the flow properties of the formulation and producing a more uniform dry coating surface. The surfactants are non-ionic, anionic, or a combination thereof. Representative examples of suitable wetting agents include, but are not limited to, siloxane surfactants such as BYK-331, BYK-333, BYK-377, BYK-378, (BYK Chemie, GMBH) and fluorosurfactants such as Novec 4430, Novec 4432, and Novec 4434 (3M, St.Paul, MN, USA), and Capstone FS-3100 (The Chemours Company, Wilmington, DE, USA).

[0134]

[0165] Examples of leveling agents, if present, are polyacrylate compounds such as BYK-352, BYK-353, BYK-356, and BYK-361N; aralkyl-modified polymethylalkylsiloxanes such as BYK-322, BYK-323, and BYK-350 (BYK Chemie, GMBH) and modified polyether, acrylic functional siloxanes such as BYK-UV 3530. Examples of dispersing agents include, without limitation, polyalkylene glycols and their esters, polyoxyalkylenes, alkylene oxide addition products of polyhydric alcohol esters, alkylene oxide addition products of alcohols, sulfonic acid esters, sulfonates, carboxylates, carboxylates, alkylene oxide addition products of alkylamides, alkylamines, and the like, used alone or as a mixture of two or more.

[0043] Examples of commercially available dispersants include, without limitation, DISPERBYK-101, DISPERBYK-130, DISPERBYK-140, DISPERBYK-160, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-165, DISPERBYK-166, DISPERBYK-170, DISPERBYK-171, DISPERBYK-182, DISPERBYK-2000, DISPERBYK-2001 (BYK Chemie, GMBH), Solsperse 32000, Solsperse 36000, Solsperse 28000, Solsperse 20000, Solsperse 41000, and Solsperse 45000 (Lubrizol, Wickliffe, OH, USA).

[0135]

[0166] In some embodiments, the amount of surfactant in the formulation disclosed by the present invention for the purpose of improving wetting is less than 0.05% by weight of the total formulation, or between 0.05 and 0.1% by weight of the total formulation, or between 0.1 and 0.5% by weight of the total formulation, or between 0.5 and 1% by weight of the total formulation, or between 1 and 2% by weight of the total formulation, or between 2 and 5% by weight of the total formulation. The amount of surfactant in the formulation disclosed by the present invention for the purpose of aiding dispersion varies depending on the material to be dispersed. The amount of dispersing agent is less than 3% by weight of the material to be dispersed, or between 3 and 5% by weight of the material to be dispersed, or between 5 and 10% by weight of the material to be dispersed, or between 10 and 20% by weight of the material to be dispersed, or between 20 and 40% by weight of the material to be dispersed, or between 40 and 60% by weight of the material to be dispersed, or between 60 and 80% by weight of the material to be dispersed, or between 80 and 100% by weight of the material to be dispersed, or between 100 and 150% by weight of the material to be dispersed.

[0136]

[0167] The antioxidant of the formulation disclosed by the present invention, if present, can comprise at least one primary antioxidant, which is usually selected from sterically hindered phenols such as Irganox 1010, Irganox 1076, SongNox® 1076, SongNox® 2450 or phenolic phosphites such as SongNox® 1680, or phosphines such as Irgaphos 168 (BASF USA, Florham Park, NJ, USA) or aromatic secondary or hindered amines such as SongLight® 6220 (Songwon Americas, Friendwood, TX, USA).

[0137]

[0168] The formulations of the present disclosure optionally contain a UV absorber, such as TINUVIN 405 (T405), a solid triazine-based UV absorber for coatings, and Tinuvin 400. The amount of UV absorber in the formulations disclosed by the present invention is typically less than 0.5% by weight of the total formulation, or between 0.5% and 1% by weight of the total formulation, or between 1% and 2% by weight of the total formulation, or between 2% and 3% by weight of the total formulation, or between 3% and 4% by weight of the total formulation, or between 4% and 5% by weight of the total formulation, or between 5% and 6% by weight of the total formulation, or between 6% and 7% by weight of the total formulation, or between 7% and 8% by weight of the total formulation, or between 8% and 10% by weight of the total formulation.

[0138]

[0169] The formulation of the present disclosure optionally contains at least one secondary antioxidant. This secondary antioxidant is preferably selected from compounds containing at least one unit formed from a sulfur atom bonded to two carbon atoms. Representative examples of secondary antioxidants are di(t-butyl)hydroxyphenylaminobisoctylthiotriazine and Irganox PS800 (BASF USA, Florham Park, NJ, USA).

[0139]

[0170] The amount of antioxidant in the formulations disclosed by this invention is typically less than 0.5% by weight of the total formulation, or between 0.5% and 1% by weight of the total formulation, or between 1% and 2% by weight of the total formulation, or between 2% and 3% by weight of the total formulation, or between 3% and 4% by weight of the total formulation, or between 4% and 5% by weight of the total formulation, or between 5% and 6% by weight of the total formulation, or between 6% and 7% by weight of the total formulation, or between 7% and 8% by weight of the total formulation, or between 8% and 10% by weight of the total formulation.

[0140]

[0171] The formulations disclosed by this invention may further include plasticizers, tougheners, thickeners, thinners, dispersants, or softeners, or other functional additives.

[0172] Optionally, the formulation disclosed by the present invention further comprises a solvent, the choice of which is entirely dependent on the at least partially capped titanium dioxide or zirconium oxide comprising a metal oxide shell and / or treated with an inorganic passivator, and the monomers, oligomers and polymers of the formulation selected. Examples of solvents in the low to high boiling range include alcohols, glycols, methyl acetate, ethyl acetate, esters, ketones, glycol ethers, glycol esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol butyl ether, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, butoxyethanol, butoxypropanol, ethyl ethoxyacetate, ethyl butoxyacetate, 2-(isopentyloxy)ethanol, 2-(hexyloxy)ethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol, triethylene glycol monomethyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether, ethyl acetate, THF, acetone, or any combination thereof.

[0141]

[0173] The amount of solvent in the formulation disclosed by this invention is less than 0.5% by weight of the total formulation, or between 0.5% and 1% by weight of the total formulation, or between 1% and 2% by weight of the total formulation, or between 2% and 3% by weight of the total formulation, or between 3% and 4% by weight of the total formulation, or between 4% and 5% by weight of the total formulation, or between 5% and 6% by weight of the total formulation, or between 6% and 7% by weight of the total formulation, or between 7% and 8% by weight of the total formulation, or between 8% and 10% by weight of the total formulation, or between 10% and 20% by weight of the total formulation, or between 20% and 30% by weight of the total formulation, or between 30% and 40% by weight of the total formulation, or between 40% and 50% by weight of the total formulation, or between 50% and 60% by weight of the total formulation, or between 60% and 70% by weight of the total formulation, or between 70% and 80% by weight of the total formulation, or between 80% and 90% by weight of the total formulation, or between 90% and 95% by weight of the total formulation. Formulation properties

[0174] The solids content of the formulations disclosed herein is typically 0-93%, such as 0-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93%, as measured by TGA.

[0142]

[0175] The inorganic content of the formulations disclosed herein is typically 0-93%, such as 0-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93%, as measured by TGA.

[0143]

[0176] The capped nanocrystals of the formulation disclosed herein comprise less than 10% by weight of the total formulation, or 10%-20% by weight of the total formulation, or 20%-30% by weight of the total formulation, or 30%-40% by weight of the total formulation, or 40%-50% by weight of the total formulation, or 50%-60% by weight of the total formulation, or 60%-70% by weight of the total formulation, or 70%-80% by weight of the total formulation, or 80%-90% by weight of the total formulation, or 90%-93% by weight of the total formulation.

[0144]

[0177] The capped nanocrystals of the nanocomposite disclosed by the present invention comprise less than 10 wt% of the total nanocomposite, or 10%-20 wt% of the total nanocomposite, or 20%-30 wt% of the total nanocomposite, or 30%-40 wt% of the total nanocomposite, or 40%-50 wt% of the total nanocomposite, or 50%-60 wt% of the total nanocomposite, or 60%-70 wt% of the total nanocomposite, or 70%-80 wt% of the total nanocomposite, or 80%-90 wt% of the total nanocomposite, or 90%-93 wt% of the total nanocomposite.

[0145]

[0178] One common technique for characterizing the optical transmittance and absorptance of nanocrystal formulations and / or nanocomposites is UV-Vis spectrophotometer (UV-Vis). UV-Vis technique measures the transmitted light versus the incident light of a sample in the 200 nm to 900 nm wavelength range.

[0146]

[0179] The transmittance of a sample at a given wavelength is defined as:

[0147]

number

[0148] (where I is the intensity of the transmitted light and I0 is the intensity of the incident light, both at the same wavelength.) The absorptivity of a sample at a given wavelength is defined as:

[0149]

number

[0150]

[0180] The absorbance, or optical density (OD), of a sample at a given wavelength is defined as:

[0151]

number

[0152]

[0181] A reference sample is often used to eliminate effects from other materials in the sample. For thin film samples, there are often multiple reflections involved and modeling and algorithms can be applied to extract the actual transmittance, absorptance and absorbance.

[0153]

[0182] To measure nanocrystal formulations, the sample is typically held in a plastic, glass, or fused silica cuvette with a 10 mm optical path. The sample is measured against a reference that contains the same solvent, monomer, and polymer used in the dispersion held in the same or same type of cuvette to eliminate effects from the cuvette and the solvent, monomer, and polymer. To measure nanocrystal polymer nanocomposites, the nanocomposite can be spin-cast onto a glass or fused silica wafer to form a uniform thin film, and the sample can be measured against a reference that contains the same wafer and / or the same polymer spin-cast to the same thickness onto the wafer to eliminate effects from the wafer and polymer. Modeling and algorithms can be applied to extract the exact transmittance, absorptance, and absorbance of the nanocomposite.

[0154]

[0183] There are a variety of UV-Vis spectrometers available, all based on the same principles and when operated properly, the results are interchangeable. The model specifically used to acquire the data in this disclosure is the Perkin Elmer Lambda 850.

[0155]

[0184] Formulations of the present disclosure including at least partially capped titanium dioxide nanocrystals, including any of the metal oxide shells and / or nanocrystals having inorganic treatments as described herein, have a light transmittance at 450 nm in the range of 99%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%, or 10%-5%, or 5%-3%, or 3%-2%, or 2%-1%, when measured in a cuvette with a 1 cm path length.

[0156]

[0185] The optical transmittance at 500 nm of a dispersion or formulation of the present disclosure comprising any of the at least partially capped titanium dioxide nanocrystals comprising a metal oxide shell and / or nanocrystals having an inorganic treatment as described herein, when measured in a cuvette with a 1 cm path length, is in the range of 99%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%, or 10%-5%, or 5%-3%, or 3%-2%, or 2%-1%.

[0157]

[0186] Dispersions or formulations of the present disclosure containing at least partially capped zirconium oxide nanocrystals comprising a metal oxide shell and / or nanocrystals having an inorganic treatment as described herein have a light transmittance at 450 nm of 99%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-70%, when measured in a cuvette with a path length of 1 cm. 5%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%, 10%-5%, or 5%-3%, or 3%-2%, or 2%-1%.

[0158]

[0187] Dispersions or formulations of the present disclosure containing at least partially capped zirconium oxide nanocrystals comprising a metal oxide shell and / or nanocrystals having an inorganic treatment as described herein have a light transmittance at 500 nm of 99%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-70%, when measured in a cuvette with a path length of 1 cm. 5%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%, 10%-5%, or 5%-3%, or 3%-2%, or 2%-1%.

[0159]

[0188] The formulations of the present disclosure have adjustable viscosity and / or viscosity that can be controlled by one or more components of the formulation. Parameters that can control the viscosity of the formulation include, but are not limited to, the average length and molecular weight of the monomer, oligomer, and / or polymer; and the presence and concentration of the solvent, the presence (i.e., viscosity modifying component) and concentration of the thickener, the particle size of the components present in the formulation, temperature, and combinations thereof.

[0160]

[0189] The formulations described herein may also have a viscosity of from about 1 cP to about 1000 cP, e.g., from about 1 cP to 2 cP, from about 2 cP to 5 cP, from about 5 cP to 10 cP, from about 10 cP to 15 cP, from about 15 cP to 20 cP, from about 20 cP to 25 cP, from about 25 cP to 30 cP, from about 30 cP to 40 cP, from about 40 cP to 50 cP, from about 50 cP to 60 cP, from about 60 cP to 75 cP, from about 75 cP to 100 cP, from about 100 cP to 200 cP, from about 200 cP to 500 cP, or from about 500 cP to 1,000 cP, or It can have an adjustable viscosity ranging from about 1,000 cP to 2,000 cP, or from about 2,000 cP to 3,000 cP, or from about 3,000 cP to 4,000 cP, or from about 4,000 cP to 5,000 cP, or from about 5,000 cP to 6,000 cP, or from about 6,000 cP to 7,000 cP, or from about 7,000 cP to 8,000 cP, or from about 8,000 cP to 9,000 cP, or from about 9,000 cP to 10,000 cP, or greater than 10,000 cP.

[0161]

[0190] The formulations disclosed by the present invention are stable for more than 1 week, or more than 2 weeks, or more than 3 weeks, or more than 6 weeks, or more than 8 weeks, or more than 3 months, or more than 6 months, or more than 12 months, or more than 36 months, without significant increase in viscosity. There is no visible precipitation of the capped nanocrystals, and the viscosity of the formulation changes by less than 1%, or less than 2%, or less than 3%, or less than 4%, or less than 5%, or less than 10%, or less than 20%, or less than 30%, or less than 40%. Furthermore, the light transmittance of the formulation changes by less than 0.5%, or less than 1%, or less than 2%, or less than 3%, or less than 4%, or less than 5%, or less than 10%, or less than 20%, or less than 30%, or less than 40% at 450 nm.

[0162]

[0191] Formulations for inkjet printing applications have strong resistance to wetting of the inkjet nozzle faceplate and suitable wettability to the desired substrate. Once the liquid reaches equilibrium, the liquid will wet a particular solid surface and a contact angle will form. Very low contact angle values ​​are usually around 10 ° The surface roughness is less than 45 mm, and the liquid has high wettability on the surface. High wettability allows a uniform coating to be achieved. ° Larger contact angles suggest partially wetting or non-wetting cases. A possible consequence of such cases is the possible use of irregular surfaces and lenticular printing, which often implies that the liquid has a high surface tension on a surface with low surface energy.

[0163]

[0192] For inkjet printing applications, the jetting of the formulations disclosed by the present invention is stable for more than 1 hour, more than 8 hours, more than 1 day, or more than 1 week without a significant increase in viscosity. The formulations do not dry or harden to solidify, which can lead to clogging of print head nozzles. Methods for making solvent-free or solvent-containing formulations 1. A method for making a solvent-free formulation comprising a step of direct dispersion (dispersing nanocrystals directly in a medium) whereby at least partially capped nanocrystals of the present disclosure are separated from the solvent and dried under vacuum until the solvent content is less than 5% to form dry nanocrystals; and mixing the dry nanocrystals of at least partially capped oxide nanocrystals in at least one monomer, oligomer, polymer or mixture thereof by soaking, stirring, speed mixing, microfluidization or other mixing methods.

[0164] Method 1 may further include filtering the formulation to eliminate aggregates or other contaminants. 2. Another method of making a solvent-free formulation comprising mixing a dry powder of at least partially capped oxide nanocrystals of the present disclosure in at least one solvent by soaking, stirring, speed mixing, microfluidization or other mixing methods to obtain a nanocrystal solvent dispersion, mixing said dispersion with at least one monomer, oligomer, and / or polymer or mixture or a plurality of monomers, oligomers and / or polymers to obtain a solvent-containing formulation, and removing said solvent by evaporation or other solvent removal methods, e.g., rotary evaporation.

[0165] Method 2 may further include filtering the solvent-containing or solvent-free formulation to eliminate agglomerates or other contaminants. The amount of solvent remaining in the final solvent-free formulation can be referred to as residual solvent. Residual solvent is typically less than 10% of the total formulation in the solvent-free formulation, preferably less than 5%.

[0166] Solvents for Method 2 include ethyl acetate (ETA), methyl ethyl ketone, or other low boiling point solvents. 3. A method of making a solvent-containing formulation comprising mixing a dry powder of at least partially capped oxide nanocrystals of the present disclosure in at least one solvent by soaking, stirring, speed mixing, microfluidization or other mixing methods to obtain a nanocrystal solvent dispersion, and mixing said dispersion with at least one monomer, oligomer, and / or polymer or mixture or a plurality of monomers, oligomers and / or polymers to obtain a solvent-containing formulation. Nanocomposite

[0193] Nanocomposites are films, coatings, layers, lenses on a support or free-standing structure. The present disclosure provides a nanocomposite comprising a mixture of at least partially capped titanium dioxide or zirconium oxide nanocrystals, including a metal oxide shell, and / or nanocrystals treated with an inorganic passivator, and a polymerizable matrix, wherein the capped nanocrystals are present in the nanocomposite in an amount of 20% to 95% by weight of the nanocomposite.

[0167]

[0194] The inorganic solids content of the nanocomposite coating or film disclosed by this invention is analyzed using a TA instrument Q500 Thermogravimetric Analyzer (TGA). The procedure is the same as that described previously. The percentage of the initial mass at 700°C is considered as the inorganic portion of the formulation, i.e., the solids content.

[0168]

[0195] The inorganic solids content of the nanocomposite coating disclosed by the present invention is 0.1-10% as measured by TGA, or 10-20% as measured by TGA, or 20-30% as measured by TGA, or 30-40% as measured by TGA, or 40-50% as measured by TGA, or 50-60% as measured by TGA, or 60-70% as measured by TGA, or 70-80% as measured by TGA, or 80-90% as measured by TGA, or 90-93% as measured by TGA.

[0169]

[0196] The nanocomposite films have a medium to high degree of cure, good adhesion to the intended substrate, and good film uniformity. The capped nanocrystals of the present disclosure remain dispersible or agglomerate-free in the polymer or monomer matrix. These physical characteristics of the materials disclosed by the present invention not only reduce light scattering, but also produce improved processability.

[0170]

[0197] The transmittance of the film according to the present disclosure may be normal transmittance measured with a Perkin-Elmer UV-Vis Lambda 850 spectrophotometer, the film is coated on an optically transparent substrate, such as quartz glass or glass substrate, and a blank substrate of the same type and thickness is used as a reference. Ripples in the spectrum are the result of interference of incident and reflected light, which is usually an indicator of high film quality, i.e., high smoothness, high uniformity, and high transparency.

[0171]

[0198] The nanocomposites disclosed in this invention were analyzed using a Perkin-Elmer UV-Vis Lambda Possess a high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96%, or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10% at 400 nm for films less than 20 microns thick when measured with an 850 Spectrophotometer. The transmittance of the films according to the present disclosure is normal transmittance measured by a Perkin-Elmer UV-Vis Lambda 850 spectrophotometer, and the nanocomposites are coated on optically transparent substrates, such as quartz glass or glass substrates, and a blank substrate of the same type and thickness is used as a reference.

[0172]

[0199] The nanocomposites disclosed in this invention were analyzed using a Perkin-Elmer UV-Vis Lambda Possess a high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96%, or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10% at 450 nm for films less than 20 microns thick when measured with an 850 Spectrophotometer.

[0173]

[0200] The nanocomposites disclosed in this invention were analyzed using a Perkin-Elmer UV-Vis Lambda Possess a high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96%, or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10% at 650 nm for films less than 20 microns thick when measured with an 850 Spectrophotometer.

[0174]

[0201] The nanocomposites disclosed in this invention were analyzed using a Perkin-Elmer UV-Vis Lambda Possess a high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96%, or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10% at 400 nm for films less than 1 micron thick when measured on an 850 Spectrophotometer.

[0175]

[0202] The nanocomposites disclosed in this invention were analyzed using a Perkin-Elmer UV-Vis Lambda Possess a high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96%, or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10% at 450 nm for films less than 1 micron thick when measured on an 850 Spectrophotometer.

[0176]

[0203] The nanocomposites disclosed in this invention were analyzed using a Perkin-Elmer UV-Vis Lambda Possess a high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96%, or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10% at 650 nm for films less than 1 micron thick when measured on an 850 Spectrophotometer.

[0177]

[0204] The nanocomposites disclosed by the present invention have high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96% at 450 nm for films less than 20 microns thick when the nanocrystal loading is 0.1-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93% as measured by a Perkin-Elmer UV-Vis Lambda 850 spectrophotometer. or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%.

[0178]

[0205] The nanocomposites disclosed by the present invention have high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96% at 450 nm for films less than 1 micron thick when the nanocrystal loading is 0.1-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93% as measured by a Perkin-Elmer UV-Vis Lambda 850 spectrophotometer. or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%.

[0179]

[0206] The nanocomposites disclosed by the present invention have high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96% at 520 nm for films less than 20 microns thick when the nanocrystal loading is 0.1-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93% as measured by a Perkin-Elmer UV-Vis Lambda 850 spectrophotometer. or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%.

[0180]

[0207] The nanocomposites disclosed by the present invention have high light transmittance of 99.9%-99%, or 99%-98%, or 98%-97%, or 97%-96% at 520 nm for films less than 1 micron thick when the nanocrystal loading is 0.1-10%, or 10-20%, or 20-30%, or 30-40%, or 40-50%, or 50-60%, or 60-70%, or 70-80%, or 80-90%, or 90-93% as measured by a Perkin-Elmer UV-Vis Lambda 850 spectrophotometer. or 96%-95%, or 95%-90%, or 90%-85%, or 85%-80%, or 80%-75%, or 75%-70%, or 70%-65%, or 65%-60%, or 60%-55%, or 55%-50%, or 50%-45%, or 45%-40%, or 40%-35%, or 35%-30%, or 30%-25%, or 25%-20%, or 20%-15%, or 15%-10%.

[0181]

[0208] One common technique for characterizing the color of nanocomposites is to use a colorimetric spectrophotometer to quantify the intensity of red, green, and blue wavelengths transmitted through the nanocomposite, where the intensity of light at each wavelength is multiplied by the light source to obtain X, Y, Z color values, called CIE color coordinates. The color coordinates reported in this disclosure were measured using a Hunterlab's Vista Haze Meter, which converts the CIE X, Y, Z color coordinates through a set of equations into a three-dimensional rectangular color space, giving L*, a*, b * The color space values ​​are obtained. In the color space, "L*" is on the "y-axis" and represents the lightness of the sample, "a*" is on the "x-axis" and represents the red-green shift, and "b * " represents the blue-yellow color shift, which is on the "z-axis." Typically, when degradation occurs in a nanocomposite, the color changes from clear or white to yellow, and this change is called "b * Furthermore, in all aspects of color space, film separations are measured as changes in delta L*, a* and b * This can be monitored by calculating Delta E* from Delta E*=[(L * 最終 -L * 初期 ) 2 +(a * 最終 -a * 初期 ) 2 +(b * 最終 -b * 初期 ) 2 ] 1 / 2

[0209] In addition to color, Hunterlab's Vista Haze Meter is used to quantify the haze or transparency of the optically clear nanocomposites.

[0182]

[0210] The nanocomposites disclosed in this invention typically have very low b values, which show minimal coloration of the films. * and this b *is in the range of 0.01-0.05, or 0.05-0.1, or 0.1-0.5, or 0.5-1.0, or 1.0-1.5, or 1.5-2.0 for films less than 1 micron thick, as measured with a Hunterlab Vista Haze Meter. * The value can be affected by the type of substrate, the haze of the substrate, the RI mismatch between the substrate and the film, and the film thickness. For example, when coated on a PET substrate, nanocomposites made from the same formulation have a higher b than when coated on a glass substrate. * and haze. Unless otherwise stated, the reported b * Values ​​are for films on glass substrates.

[0183]

[0211] The nanocomposites disclosed by the present invention typically possess a very low haze %, indicating high transparency of the film, with the haze % being in the range of 0.0-0.02, or 0.02-0.04, or 0.04-0.06, or 0.06-0.08, or 0.08-0.1, or 0.1-0.14, or 0.14-0.18, or 0.18-0.20, or 0.20-0.25, or 0.25-0.30, or 0.30-0.35, or 0.35-0.40, or 0.40-0.45, or 0.45-0.50 for films less than 1 micron thick, as measured with a Hunterlab Vista Haze Meter.

[0184]

[0212] The nanocomposites disclosed in this invention typically exhibit very low b * and this b * is in the range of 0.01 to 0.05, or 0.05 to 0.1, or 0.1 to 0.5, or 0.5 to 1.0, or 1.0 to 1.5, or 1.5 to 2.0, 2.0 to 2.5, or 2.5 to 3.0 for films less than 20 microns thick as measured with a Hunterlab Vista Haze Meter.

[0185]

[0213] The nanocomposites disclosed in this invention typically exhibit very low b values, showing minimal coloration of the films coated on PET substrates. * and this b * is in the range of 0.01 to 0.05, or 0.05 to 0.1, or 0.1 to 0.5, or 0.5 to 1.0, or 1.0 to 1.5, or 1.5 to 2.0, 2.0 to 2.5, or 2.5 to 3.0, or 3.0 to 3.5, or 3.5 to 4.0, or 4.0 to 4.5, or 4.5 to 5.0 for films less than 20 microns thick as measured with a Hunterlab Vista Haze Meter.

[0186]

[0214] The nanocomposites disclosed by the present invention typically possess a very low haze %, indicating high film clarity, in the range of 0.0-0.02, or 0.02-0.04, or 0.04-0.06, or 0.06-0.08, or 0.08-0.1, or 0.1-0.14, or 0.14-0.18, or 0.18-0.20, or 0.20-0.25, or 0.25-0.30, or 0.30-0.35, or 0.35-0.40, or 0.40-0.45, or 0.45-0.50 for films less than 20 microns thick, as measured with a Hunterlab Vista Haze Meter.

[0187]

[0215] One common technique for measuring and characterizing the refractive index is to use a Metricon Model 2010 / M Prism Combiner. Using a Metricon Model 2010 / M Prism Combiner with 448 nm and 635 nm laser beams, the predicted refractive index of the same material at a third wavelength can be calculated. The calculation of the refractive index at 550 nm is based on the Cauchy equation of binomial type:

[0188]

number

[0189]

[0216] Parameters A and B depend on the RI measurements at specific wavelengths, which were chosen to be 448 and 635 nm. Expressing parameters A and B as RI(448 nm) and RI(635 nm) allows the calculation of RI(550 nm) with the following equation:

[0190]

number

[0191]

[0217] RI values ​​for other wavelengths can be calculated using the same equation.

[0218] Another way to measure the refractive index is by ellipsometry. With an ellipsometer, the refractive index can be measured as a function of wavelength. Some refractive index measurements are made using a JA Woollam M2000 ellipsometer.

[0192]

[0219] The nanocomposites disclosed by the present invention typically have a refractive index at 448 nm of 1.54-1.56, 1.56-1.58, 1.58-1.60, 1.60-1.62, or 1.62-1.64, 1.64-1.66, or 1.66-1.68, or 1.68-1.70, or 1.70-1.72, or 1.72-1.74, or 1.74-1.76, or 1.76-1.78, or 1. .78 to 1.80, or 1.80 to 1.82, or 1.82 to 1.84, or 1.84 to 1.86, or 1.86 to 1.88, or 1.88 to 1.90, or 1.90 to 1.92, or 1.92 to 1.94, or 1.94 to 1.96, or 1.96 to 1.98, or 1.98 to 2.00, or 2.00 to 2.02, or 2.02 to 2.04, or 2.04 to 2.06, or is 2.06-2.08, or 2.08-2.10, or 2.10-2.12, or 2.12-2.14, or 2.14-2.16, or 2.16-2.18, or 2.18-2.20, or 2.20-2.22, or 2.22-2.24, or 2.24-2.26, or 2.26-2.28, or 2.28-2.30, or 2.30-2.32, or 2.32-2. 34, or 2.34 to 2.36, or 2.36 to 2.38, or 2.38 to 2.40, or 2.40 to 2.42, or 2.42 to 2.44, or 2.44 to 2.46, or 2.46 to 2.48, or 2.48 to 2.50, or 2.50 to 2.52, or 2.52 to 2.54, or 2.54 to 2.56, or 2.56 to 2.58, or 2.58 to 2.60.

[0193]

[0220] The nanocomposites disclosed by the present invention typically have a refractive index at 520 nm of 1.54-1.56, 1.56-1.58, 1.58-1.60, 1.60-1.62, or 1.62-1.64, 1.64-1.66, or 1.66-1.68, or 1.68-1.70, or 1.70-1.72, or 1.72-1.74, or 1.74-1.76, or 1.76-1.78, or 1. .78 to 1.80, or 1.80 to 1.82, or 1.82 to 1.84, or 1.84 to 1.86, or 1.86 to 1.88, or 1.88 to 1.90, or 1.90 to 1.92, or 1.92 to 1.94, or 1.94 to 1.96, or 1.96 to 1.98, or 1.98 to 2.00, or 2.00 to 2.02, or 2.02 to 2.04, or 2.04 to 2.06, or is 2.06-2.08, or 2.08-2.10, or 2.10-2.12, or 2.12-2.14, or 2.14-2.16, or 2.16-2.18, or 2.18-2.20, or 2.20-2.22, or 2.22-2.24, or 2.24-2.26, or 2.26-2.28, or 2.28-2.30, or 2.30-2.32, or 2.32-2. 34, or 2.34 to 2.36, or 2.36 to 2.38, or 2.38 to 2.40, or 2.40 to 2.42, or 2.42 to 2.44, or 2.44 to 2.46, or 2.46 to 2.48, or 2.48 to 2.50, or 2.50 to 2.52, or 2.52 to 2.54, or 2.54 to 2.56, or 2.56 to 2.58, or 2.58 to 2.60.

[0194]

[0221] The nanocomposites disclosed by the present invention typically have a refractive index at 589 nm of 1.54-1.56, 1.56-1.58, 1.58-1.60, 1.60-1.62, or 1.62-1.64, 1.64-1.66, or 1.66-1.68, or 1.68-1.70, or 1.70-1.72, or 1.72-1.74, or 1.74-1.76, or 1.76-1.78, or 1. .78 to 1.80, or 1.80 to 1.82, or 1.82 to 1.84, or 1.84 to 1.86, or 1.86 to 1.88, or 1.88 to 1.90, or 1.90 to 1.92, or 1.92 to 1.94, or 1.94 to 1.96, or 1.96 to 1.98, or 1.98 to 2.00, or 2.00 to 2.02, or 2.02 to 2.04, or 2.04 to 2.06, or is 2.06-2.08, or 2.08-2.10, or 2.10-2.12, or 2.12-2.14, or 2.14-2.16, or 2.16-2.18, or 2.18-2.20, or 2.20-2.22, or 2.22-2.24, or 2.24-2.26, or 2.26-2.28, or 2.28-2.30, or 2.30-2.32, or 2.32-2. 34, or 2.34 to 2.36, or 2.36 to 2.38, or 2.38 to 2.40, or 2.40 to 2.42, or 2.42 to 2.44, or 2.44 to 2.46, or 2.46 to 2.48, or 2.48 to 2.50, or 2.50 to 2.52, or 2.52 to 2.54, or 2.54 to 2.56, or 2.56 to 2.58, or 2.58 to 2.60.

[0195]

[0222] The nanocomposites disclosed by the present invention typically have a refractive index at 635 nm of 1.54-1.56, 1.56-1.58, 1.58-1.60, 1.60-1.62, or 1.62-1.64, 1.64-1.66, or 1.66-1.68, or 1.68-1.70, or 1.70-1.72, or 1.72-1.74, or 1.74-1.76, or 1.76-1.78, or 1. .78 to 1.80, or 1.80 to 1.82, or 1.82 to 1.84, or 1.84 to 1.86, or 1.86 to 1.88, or 1.88 to 1.90, or 1.90 to 1.92, or 1.92 to 1.94, or 1.94 to 1.96, or 1.96 to 1.98, or 1.98 to 2.00, or 2.00 to 2.02, or 2.02 to 2.04, or 2.04 to 2.06, or is 2.06-2.08, or 2.08-2.10, or 2.10-2.12, or 2.12-2.14, or 2.14-2.16, or 2.16-2.18, or 2.18-2.20, or 2.20-2.22, or 2.22-2.24, or 2.24-2.26, or 2.26-2.28, or 2.28-2.30, or 2.30-2.32, or 2.32-2. 34, or 2.34 to 2.36, or 2.36 to 2.38, or 2.38 to 2.40, or 2.40 to 2.42, or 2.42 to 2.44, or 2.44 to 2.46, or 2.46 to 2.48, or 2.48 to 2.50, or 2.50 to 2.52, or 2.52 to 2.54, or 2.54 to 2.56, or 2.56 to 2.58, or 2.58 to 2.60.

[0196]

[0223] The nanocomposites disclosed by the present invention typically possess hardness values ​​of 100-150 MPa, alternatively 150-200 MPa, alternatively 200-250 MPa, alternatively 250-300 MPa, alternatively 300-350 MPa, alternatively 350-400 MPa, as measured using nanoindentation.

[0197]

[0224] The nanocomposites disclosed by the present invention typically possess elastic modulus values ​​of 3.0-3.5 GPa, or 3.5-4.0 GPa, or 4.0-4.5 GPa, 4.5-5.0 GPa, or 5.0-5.5 GPa, or 5.5-6.0 GPa, or 6.0-6.5 GPa, or 6.5-7.0 GPa, or 7.0-7.5 GPa, or 7.5-8.0 GPa, or 8.0-8.5 GPa, or 8.5-9.0 GPa, or 9.0-9.5 GPa, or 9.5-10.0 GPa, or 10.0-15.0 GPa, as measured using nanoindentation.

[0198]

[0225] The nanocomposites disclosed by the present invention further demonstrate thermal stability at temperatures below 120° C., or between 120 and 175° C., or between 175 and 200° C., or between 200 and 250° C., or between 250 and 300° C., or between 300 and 400° C. Thermal stability is measured by subjecting the nanocomposite to the specified temperature for 10 seconds to 5 minutes, or between 5 and 10 minutes, or between 10 and 30 minutes, or between 30 and 60 minutes, or between 60 and 120 minutes, or greater than 120 minutes, under air, nitrogen, or vacuum without visually observable coloration, cracking, or delamination, for films less than 1 micron thick, or less than 2 microns thick, or less than 3 microns thick, or less than 4 microns thick, or less than 5 microns thick, or 10 μm thick, or between 5 and 10 μm thick, or between 1 and 2 μm thick, or less than 1 μm thick, or greater than 10 μm thick. * The change in b, as measured by a Hunterlab Vista haze meter, * or less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 50% of the original thickness.

[0199]

[0226] The nanocomposites disclosed by the present invention further demonstrate thermal stability at temperatures below 120°C, or between 120-175°C, or between 175-200°C, or between 200-250°C, or between 250-300°C, or between 300-400°C. Thermal stability is measured by subjecting the nanocomposite to the specified temperature for 10 seconds to 5 minutes, or 5 to 10 minutes, or 10 to 30 minutes, or 30 to 60 minutes, or 60 to 120 minutes, or more than 120 minutes, under air, nitrogen, or vacuum without visually observable discoloration, cracking, or delamination, and for films 1 micron thick, or less than 2 microns thick, or less than 3 microns thick, or less than 4 microns thick, or less than 5 microns thick, or less than 10 μm thick, or 5 to 10 μm thick, or 1 to 2 μm thick, or less than 1 μm thick, or greater than 10 μm thick, the change in haze % is less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 50% of the initial haze as measured with a Hunterlab Vista Haze Meter.

[0200]

[0227] The nanocomposites disclosed by the present invention further demonstrate thermal stability at temperatures below 120° C., or between 120 and 175° C., or between 175 and 200° C., or between 200 and 250° C., or between 250 and 300° C., or between 300 and 400° C. Thermal stability is measured by subjecting the nanocomposite to the specified temperature for 10 seconds to 5 minutes, or between 5 and 10 minutes, or between 10 and 30 minutes, or between 30 and 60 minutes, or between 60 and 120 minutes, or greater than 120 minutes, under air, nitrogen, or vacuum without visually observable discoloration, cracking, or delamination, and is measured using a Perkin-Elmer UV-Vis Lambda When measured with an 850 spectrophotometer, for films that are 1 micron thick, or less than 2 microns thick, or less than 3 microns thick, or less than 4 microns thick, or less than 5 microns thick, or less than 10 μm thick, or between 5 and 10 μm thick, or between 1 and 2 μm thick, or less than 1 μm thick, or greater than 10 μm thick, there is less than a 10% reduction in transmission, or less than a 20% reduction in transmission, or less than a 30% reduction in transmission, or less than a 40% reduction in transmission, or less than a 50% reduction in transmission at 400 nm.

[0201]

[0228] In various embodiments, the present disclosure refers to various properties of the nanocrystals, dispersions, formulations, and / or nanocomposites herein. Unless otherwise specified or the context to the contrary, these properties are measured according to industry standards known to those of skill in the art in light of the present disclosure. Furthermore, unless otherwise specified or the context to the contrary, it is understood that if two or more testing methods for a given nanocrystal, dispersion, formulation, or nanocomposite provide different results for a recited property, such given nanocrystal, dispersion, formulation, or nanocomposite is considered to be within the scope defined herein (e.g., claims, recited embodiments, etc.) so long as: (1) the result(s) are greater than or equal to the property of the nanocrystal, dispersion, formulation, or nanocomposite under one testing method according to the relevant method(s) shown in the Examples section of the present specification; such a test method can be verified, for example, by using the exemplary composition(s) in the Examples section herein, which compositions should yield the same results as those reported herein, within experimental error generally accepted by those of skill in the art; or (2) if no relevant method(s) are shown in the Examples section, the result(s) are within the range or definition described for the nanocrystal, dispersion, formulation, or nanocomposite property, by any test method acceptable to those of skill in the art in light of this disclosure. QUV Accelerated Weather Test:

[0229] In some embodiments, the core-shell nanocrystals disclosed by the present invention, with and without inorganic treatment, dispersions, formulations and nanocomposites made from these nanocrystals demonstrate low photocatalytic activity upon exposure to UV radiation. The Q Lab QUV accelerated weathering tester uses a commercially available unit with controlled irradiance. The QUV weathering test has two components: UV and moisture steps. For step 1, UV is 0.89 mW / cm 2The first step is 340 nm UV set at 60°C for 4 hours. Step 2 is condensation with no UV exposure at 50°C for 4 hours. This cycle is repeated 9 times for a total of 72 hours. Films used for QUV testing are deposited on glass substrates or PET substrates supported by glass substrates. Samples are inserted film side down into a sample holder and placed in the QUV accelerated weathering tester. A Metricon Model 2010 / M prism coupler was used to measure the refractive index and film thickness of the sampler, and a HunterLab haze meter was used to measure color and haze parameters. Measurements were taken before and after exposure to calculate the change in optical performance due to weathering testing.

[0202]

[0230] UVA:

[0231] For the UVA setup, two 250 watt UV-A Flood lamps (320-390 nm range) were placed with a 15 cm height difference from the round rotating sample stage, keeping the bulbs and fixtures as close to each other as possible. The 2.5 inch (6.35 cm) glass substrates with thin films were then radially organized, starting at a point below the bulbs and circumnavigating the center of the rotating plate to ensure that all films were equally exposed to the UV-A bulbs while the stage was rotating. Bulb intensity was checked before each 72 hour run.

[0203]

[0232] The film is placed face down on the tray side, allowing the UV-A wavelengths to travel through the glass substrate before reaching the film. To begin the test, the film is arranged in the orientation specified above on the rotating plate, the lamp is switched on, and the test is run for 72 to 158 hours. The bulb can get hot, so it is possible to switch the bulb off every 12 to 24 hours if necessary, but the total exposure time should be 72 hours. The average intensity is 4 mW / cm2. 2 Hold in place.

[0204]

[0233] After testing was completed, the refractive index and film thickness of the samplers were measured using a Metricon Model 2010 / M prism coupler, and color and haze parameters were measured using a HunterLab haze meter. Measurements were taken before and after exposure to calculate the change in optical performance due to weathering testing.

[0205]

[0234] In some embodiments, the nanocomposite disclosed by the present invention is further tested for photostability to 405 nm and 450 nm wavelengths. The setup is similar to that described for the UVA test setup and consists of a lamp of the desired wavelength and a flat aluminum tray placed on a turntable. The lamp is suspended 6-12 inches (15 cm-30 cm) above the flat surface facing the coated substrate. The film or nanocomposite coated on a substrate, e.g., glass, silicon wafer or plastic substrate, e.g., PET, is placed flat on the aluminum tray with the film surface facing up. The aluminum tray is then rotated at a slow speed while the film is exposed to the light for the desired period of time. The nanocomposite is exposed to light at 405 nm with an average intensity (25 mW / cm2). 2 ) and at 450 nm, the average intensity (16 mW / cm 2 ) for 148 hours (total UV dose 13000J / cm 2 ) and 1000 hours (total UV dose 57600J / cm 2 ) for 10 min. The optical properties of the nanocomposite film properties, e.g., b before and after the entire exposure, * , haze %, RI and film thickness are measured and recorded.

[0206]

[0235] In some embodiments, the nanocomposites disclosed herein demonstrate low photocatalytic activity and therefore high photostability upon UV exposure at wavelengths of 320-390 nm, or 390-420 nm, or 420-450 nm, or above 450 nm. Photocatalytic stability is when the nanocomposite is exposed to 0.5-1.0 mJ / cm at the specified exposure wavelengths without visually observable coloration, cracking, or delamination. 2 .s, or 1.0-2.0mJ / cm 2 .s, or 2.0-3.0mJ / cm 2 .s, or 3.0-4.0mJ / cm 2 .s, or 4.0-5.0mJ / cm 2 .s, or 5.0-8.0mJ / cm 2 .s, or 8.0-10.0mJ / cm 2 .s, or 10.0-12.0mJ / cm 2 .s, or 12.0-14.0mJ / cm 2 .s, or 14.0-16.0mJ / cm 2 .s, or 16.0-18.0mJ / cm 2 .s, or 18.0-20.0mJ / cm 2 .s, or 20.0-25.0mJ / cm 2 .s, or 25.0-30.0mJ / cm 2 .s, or 30.0-35.0mJ / cm 2 .s, or 35.0-40.0mJ / cm 2 .s, or 40.0-45.0mJ / cm 2 .s, or 45.0-50.0mJ / cm 2b) for a period of 30 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, 5 minutes or more, or 10 minutes or more, or 30 minutes or more, or 60 minutes or more, or 2 hours or more, or 6 hours or more, or 12 hours or more, or 24 hours or more, or 48 hours or more, or 72 hours or more, or 100 hours or more, or 120 hours or more, or 158 hours or more, or 192 hours or more, or 240 hours or more, or 288 hours or more, or 336 hours or more, or 384 hours or more, or 432 hours or more, or 500 hours or more, or 600 hours or more, or 700 hours or more, or 800 hours or more, or 900 hours or more, or 1000 hours or more, for films less than 1 micron thick, or 1-5 μm thick, or 5-10 μm thick, or 10-20 μm thick; * The change in the initial b * of the total amount of the product, or less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50%.

[0207]

[0236] In some embodiments, the nanocomposites disclosed herein demonstrate low photocatalytic activity and therefore high photostability upon UV exposure at wavelengths of 320-390 nm, or 390-420 nm, or 420-450 nm, or above 450 nm. Photocatalytic stability is when the nanocomposite is exposed to 0.5-1.0 mJ / cm at the specified exposure wavelengths without visually observable coloration, cracking, or delamination. 2 .s, or 1.0-2.0mJ / cm 2 .s, or 2.0-3.0mJ / cm 2 .s, or 3.0-4.0mJ / cm 2 .s, or 4.0-5.0mJ / cm 2 .s, or 5.0-8.0mJ / cm 2 .s, or 8.0-10.0mJ / cm 2 .s, or 10.0-12.0mJ / cm 2.s, or 12.0-14.0mJ / cm 2 .s, or 14.0-16.0mJ / cm 2 .s, or 16.0-18.0mJ / cm 2 .s, or 18.0-20.0mJ / cm 2 .s, or 20.0-25.0mJ / cm 2 .s, or 25.0-30.0mJ / cm 2 .s, or 30.0-35.0mJ / cm 2 .s, or 35.0-40.0mJ / cm 2 .s, or 40.0-45.0mJ / cm 2 .s, or 45.0-50.0mJ / cm 2The % change in haze is measured by exposure to an intensity in the range of .s for 30 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, 5 minutes or more, or 10 minutes or more, or 30 minutes or more, or 60 minutes or more, or 2 hours or more, or 6 hours or more, or 12 hours or more, or 24 hours or more, or 48 hours or more, or 72 hours or more, or 96 hours or more, or 120 hours or more, or 158 hours or more, or 192 hours or more, or 240 hours or more, or 288 hours or more, or 336 hours or more, or 384 hours or more, or 432 hours or more, or 500 hours or more, or 600 hours or more, or 700 hours or more, or 800 hours or more, or 900 hours or more, or 1000 hours or more, for films less than 1 micron thick, using Hunterlab Vista. The haze is less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50% of the initial haze as measured by a haze meter. These films also exhibit less than 10% reduction in transmission, or less than 20% reduction in transmission, or less than 30% reduction in transmission, or less than 40% reduction in transmission, or less than 50% reduction in transmission at 400 nm, or 450 nm, or 520 nm, or 550 nm for films less than 1 micron thick, or 1-5 μm thick, or 5-10 μm thick, or 10-20 μm thick, as measured by a Perkin-Elmer UV-Vis Lambda 850 Spectrophotometer.

[0208]

[0237] In some embodiments, the nanocomposites disclosed herein demonstrate low photocatalytic activity and therefore high photostability upon UV exposure at wavelengths of 320-390 nm, or 390-420 nm, or 420-450 nm, or above 450 nm. Photocatalytic stability is the ability of the nanocomposites to withstand UV radiation of 0.5-1.0 mJ / cm at the specified exposure wavelengths without significant refractive index change. 2 .s, or 1.0-2.0mJ / cm 2 .s, or 2.0-3.0mJ / cm 2 .s, or 3.0-4.0mJ / cm 2.s, or 4.0-5.0mJ / cm 2 .s, or 5.0-8.0mJ / cm 2 .s, or 8.0-10.0mJ / cm 2 .s, or 10.0-12.0mJ / cm 2 .s, or 12.0-14.0mJ / cm 2 .s, or 14.0-16.0mJ / cm 2 .s, or 16.0-18.0mJ / cm 2 .s, or 18.0-20.0mJ / cm 2 .s, or 20.0-25.0mJ / cm 2 .s, or 25.0-30.0mJ / cm 2 .s, or 30.0-35.0mJ / cm 2 .s, or 35.0-40.0mJ / cm 2 .s, or 40.0-45.0mJ / cm 2 .s, or 45.0-50.0mJ / cm 2s range of intensity for 30 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, 5 minutes or more, or 10 minutes or more, or 30 minutes or more, or 60 minutes or more, or 2 hours or more, or 6 hours or more, or 12 hours or more, or 24 hours or more, or 48 hours or more, or 72 hours or more, or 96 hours or more, or 120 hours or more, or 158 hours or more, or 192 hours or more, or 240 hours or more, or 288 hours or more, or 336 hours or more, or 384 hours or more, or 432 hours or more, or 500 hours or more, or 600 hours or more, or 700 hours or more, or 800 hours or more, or 900 hours or more, or 1000 hours or more, and is less than 1 micron thick, or between 1 and 5 μm thick, or between 5 and 10 μm thick, or For films having a thickness between 10 and 20 μm, the change in refractive index is less than 0.001, or less than 0.002, or less than 0.004, or less than 0.006, or less than 0.008, or less than 0.01, or less than 0.012, or less than 0.015, or less than 0.018, or less than 0.02, or less than 0.022, or less than 0. less than 0.025, or less than 0.028, or less than 0.03, or less than 0.035, or less than 0.04, or less than 0.045, or less than 0.05, or less than 0.055, or less than 0.06, or less than 0.065, or less than 0.07, or less than 0.075, or less than 0.08, or less than 0.085, or less than 0.09, or less than 0.095, or less than 0.1.

[0209]

[0238] In some embodiments, the nanocomposites disclosed herein demonstrate low photocatalytic activity and therefore high photostability upon UV exposure at wavelengths between 390-420 nm, or between 420-450 nm, or above 450 nm. Photocatalytic stability allows the nanocomposites to withstand UV exposure of 0.5-1.0 mJ / cm at the specified exposure wavelengths without visually observable coloration, cracking, or delamination. 2 .s, or 1.0-2.0mJ / cm 2 .s, or 2.0-3.0mJ / cm2 .s, or 3.0-4.0mJ / cm 2 .s, or 4.0-5.0mJ / cm 2 .s, or 5.0-8.0mJ / cm 2 .s, or 8.0-10.0mJ / cm 2 .s, or 10.0-12.0mJ / cm 2 .s, or 12.0-14.0mJ / cm 2 .s, or 14.0-16.0mJ / cm 2 .s, or 16.0-18.0mJ / cm 2 .s, or 18.0-20.0mJ / cm 2 .s, or 20.0-25.0mJ / cm 2 .s, or 25.0-30.0mJ / cm 2 .s, or 30.0-35.0mJ / cm 2 .s, or 35.0-40.0mJ / cm 2 .s, or 40.0-45.0mJ / cm 2 .s, or 45.0-50.0mJ / cm 2The % change in haze is measured by exposure to an intensity in the range of .s for 30 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, 5 minutes or more, or 10 minutes or more, or 30 minutes or more, or 60 minutes or more, or 2 hours or more, or 6 hours or more, or 12 hours or more, or 24 hours or more, or 48 hours or more, or 72 hours or more, or 96 hours or more, or 120 hours or more, or 158 hours or more, or 192 hours or more, or 240 hours or more, or 288 hours or more, or 336 hours or more, or 384 hours or more, or 432 hours or more, or 500 hours or more, or 600 hours or more, or 700 hours or more, or 800 hours or more, or 900 hours or more, or 1000 hours or more, for films less than 1 micron thick, as measured by Hunterlab Vista. The haze is less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50% of the initial haze as measured by a haze meter. These films also exhibit less than 10% reduction in transmission, or less than 20% reduction in transmission, or less than 30% reduction in transmission, or less than 40% reduction in transmission, or less than 50% reduction in transmission at 400 nm, or 450 nm, or 520 nm, or 550 nm for films less than 1 micron thick, or 1-5 μm thick, or 5-10 μm thick, or 10-20 μm thick as measured by a Perkin-Elmer UV-Vis Lambda 850 Spectrophotometer.

[0210]

[0239] In some embodiments, the nanocomposites disclosed herein demonstrate low photocatalytic activity and therefore high photostability upon UV exposure at wavelengths between 390 and 420 nm, or between 420 and 450 nm, or above 450 nm. Photocatalytic stability is the ability of the nanocomposites to withstand UV radiation of 0.5-1.0 mJ / cm at the specified exposure wavelengths without significant refractive index change. 2 .s, or 1.0-2.0mJ / cm 2 .s, or 2.0-3.0mJ / cm 2 .s, or 3.0-4.0mJ / cm 2.s, or 4.0-5.0mJ / cm 2 .s, or 5.0-8.0mJ / cm 2 .s, or 8.0-10.0mJ / cm 2 .s, or 10.0-12.0mJ / cm 2 .s, or 12.0-14.0mJ / cm 2 .s, or 14.0-16.0mJ / cm 2 .s, or 16.0-18.0mJ / cm 2 .s, or 18.0-20.0mJ / cm 2 .s, or 20.0-25.0mJ / cm 2 .s, or 25.0-30.0mJ / cm 2 .s, or 30.0-35.0mJ / cm 2 .s, or 35.0-40.0mJ / cm 2 .s, or 40.0-45.0mJ / cm 2 .s, or 45.0-50.0mJ / cm 2s range of intensity for 30 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, 5 minutes or more, or 10 minutes or more, or 30 minutes or more, or 60 minutes or more, or 2 hours or more, or 6 hours or more, or 12 hours or more, or 24 hours or more, or 48 hours or more, or 72 hours or more, or 96 hours or more, or 120 hours or more, or 158 hours or more, or 192 hours or more, or 240 hours or more, or 288 hours or more, or 336 hours or more, or 384 hours or more, or 432 hours or more, or 500 hours or more, or 600 hours or more, or 700 hours or more, or 800 hours or more, or 900 hours or more, or 1000 hours or more, and is less than 1 micron thick, or between 1 and 5 μm thick, or between 5 and 10 μm thick, or For films having a thickness between 10 and 20 μm, the change in refractive index is less than 0.001, or less than 0.002, or less than 0.004, or less than 0.006, or less than 0.008, or less than 0.01, or less than 0.012, or less than 0.015, or less than 0.018, or less than 0.02, or less than 0.022, or less than 0. less than 0.025, or less than 0.028, or less than 0.03, or less than 0.035, or less than 0.04, or less than 0.045, or less than 0.05, or less than 0.055, or less than 0.06, or less than 0.065, or less than 0.07, or less than 0.075, or less than 0.08, or less than 0.085, or less than 0.09, or less than 0.095, or less than 0.1. Methods for making nanocomposites

[0240] The present disclosure provides methods for making nanocomposites using the formulations disclosed herein. Nanocomposite films containing the cured or partially cured formulations of the present disclosure are described herein. The nanocomposites are cured or partially cured by UV or thermal curing techniques known to those skilled in the art.

[0211]

[0241] The present disclosure provides nanocomposite films as described herein, wherein the film is produced by spin coating, slot die coating, screen printing, inkjet printing, dip coating, draw bar coating, roll-to-roll printing, spray coating, imprinting, nanoimprinting, molding, or any combination thereof. device

[0242] The present disclosure provides an LED, an organic LED, a micro LED, a touch screen, a display, a sensor, an augmented reality lens, a virtual reality lens, an optical lens, or a solar cell device comprising an active component, the active component comprising or containing the nanocomposite of the present disclosure. Preferred embodiments include embodiments 1-42 listed below: 1. A nanocrystal having a core-shell structure comprising a core and an outer shell, the core being at least partially encapsulated by the outer shell, the core comprising a core metal oxide and the outer shell comprising a shell metal oxide, the core metal oxide having an average particle size greater than 3 nm and less than 50 nm as measured by TEM, the outer shell having a thickness between 0.1 nm and 5 nm as measured by TEM, and the core metal oxide and shell metal oxide are the same or different. 2. The nanocrystal of embodiment 1, wherein the atomic ratio of the shell metal oxide to the core metal oxide is less than 3, e.g., less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8 nm, less than 0.9, less than 1, less than 2, less than 3, as measured by SEM EDX. Preferably, the atomic ratio of the shell metal oxide to the core metal oxide is less than 0.5. 3. Nanocrystals according to any of embodiments 1 and 2, wherein the core metal oxide and core-shell metal oxide nanocrystals have a narrow particle size distribution, characterized in that the particle size distribution is: 1) a D90:D10 ratio of less than 5, preferably less than 3 or less than 2, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.8, from about 1.2 to about 3, or from about 1.5 to about 3; 2) a D90:D50 ratio of less than 3, preferably less than 2 or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.5; and / or 3) a D50:D10 ratio of less than 3, preferably less than 2 or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.5. 4. The nanocrystal according to any of the preceding embodiments, comprising a core and / or a core-shell treated with an inorganic passivation agent, the inorganic passivation agent comprising at least one of sodium polyphosphate, lithium nitrate, sodium hypochlorite, sodium hypophosphite, sodium phosphite, lithium chloride, sodium nitrate, sodium chloride, sodium aluminum phosphate, sodium hexametaphosphate, or any combination thereof. Preferably, the inorganic passivation agent comprises NaH2PO2. 5. Methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3 -(Methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxypropyl)propyltrimethoxysilane, (silylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidyl doxoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethyl orthosilicate, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol and triethylene glycol monomethyl ether, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid,5. The nanocrystal of any one of the preceding embodiments, comprising an at least partially capped nanocrystal capped with at least one capping agent selected from 11-acryloyloxyundecylphosphonic acid, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof. Preferably, the capping agent is one or more of methyltrimethoxysilane, phenyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, or any combination thereof. 6. The nanocrystal of embodiment 5, wherein the organic content of the at least partially capped nanocrystal is less than 25% of the at least partially capped nanocrystal, e.g., less than 5%, or between 5% and 8%, or between 8% and 10%, or between 10% and 12%, or between 12% and 14%, or between 14% and 16%, or between 16% and 18%, or between 18% and 20%. 7. The nanocrystal of any one of embodiments 1-6, wherein the core metal oxide comprises titanium dioxide, zirconium dioxide, and / or barium titanate, and the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof. 8. The nanocrystal of any one of embodiments 1-6, wherein the core metal oxide comprises TiO2 and the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, cerium oxide, barium titanium oxide, or any combination thereof. 9. The nanocrystal of any one of embodiments 1-6, wherein the core metal oxide comprises TiO2 and the shell metal oxide comprises silicon dioxide, zirconium dioxide, cerium oxide, or any combination thereof. 10. Measurement of the haze of a 1 μm thick film containing core-shell structures using a haze meter before and after UV exposure * When measuring, the difference is less than 50%, for example, less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50%. * as measured by the change in β-aminobutyric acid (β-aminobutyric acid) concentration, as well as at 320-390 nm and above for 66 h at a light intensity of 4 mW / cm 2 10. The nanocrystals of any of the preceding embodiments, which exhibit low photocatalytic activity as measured by a change in refractive index of less than 0.08, e.g., less than 0.01, less than 0.02, less than 0.03, less than 0.04, less than 0.05, less than 0.06, less than 0.07, when a film comprising the core-shell nanocrystals is measured using a prism coupler or ellipsometer before and after UV exposure at 500 K. 11. Measurement of the haze of a 1 μm thick film containing core-shell structures using a haze meter before and after UV exposure * When measuring, the difference is less than 50%, for example, less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50%. *as measured by the change in 2 Before and after UV exposure at 405 nm or above for 148 hours, light intensity 25 mW / cm 2 10. The nanocrystals of any of the preceding embodiments, which exhibit low photocatalytic activity as measured by a change in refractive index of less than 0.08, e.g., less than 0.01, less than 0.02, less than 0.03, less than 0.04, less than 0.05, less than 0.06, less than 0.07, when a film comprising the core-shell nanocrystals is measured using a prism coupler or ellipsometer before and after UV exposure at 500 K. 12. The nanocrystal of any of embodiments 10-11, wherein the core metal oxide is titanium oxide and the shell metal oxide comprises zirconium oxide, the average particle size of the nanocrystals is less than 30 nm as measured by TEM, and the atomic ratio of shell Zr to core Ti is less than 3, e.g., less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8 nm, less than 0.9, less than 1, less than 2, less than 3, as measured by SEM EDX. 13. The capped nanocrystal of any one of embodiments 5 to 12, wherein the particle size distribution of the nanocrystals is characterized by a D9999 of less than 500 nm, as measured by dynamic light scattering (DLS) on a volume of nanocrystals dispersed at 5% by weight in a solvent. 14. A method for preparing core-shell TiO2 nanocrystals comprising a core comprising a TiO2 nanocrystal and a shell comprising a shell metal oxide, comprising converting a precursor of the shell metal oxide in a solvent to a shell metal oxide that at least partially encapsulates the core comprising the TiO2 nanocrystal, the converting comprising: 1) mixing the precursor of the shell metal oxide in a reaction mixture with the solvent and the core comprising the TiO2 nanocrystal; and 2) heating the reaction mixture at a reaction temperature, e.g., about 90°C, for a period of time to obtain a shell metal oxide that at least partially encapsulates the core comprising the TiO2 nanocrystal. 15. The method of embodiment 14, wherein the converting step comprises: 1) mixing a precursor of the shell metal oxide, either directly or in water, into a reaction mixture of a solvent and the cores comprising TiO2 nanocrystals; and 2) heating the reaction mixture at a reaction temperature of about 50°C to about 90°C for about 10 minutes to about 7 days, preferably about 1 hour to about 24 hours, to form a shell metal oxide that at least partially encapsulates the cores comprising TiO2 nanocrystals. 16. The shell metal oxide comprises zirconium oxide, and the precursor of the zirconium dioxide is a zirconium alkoxide, e.g., a zirconium alkoxide having the formula Zr(OR)4, x G y or a combination thereof, wherein each R group can be independently an alkyl group (e.g., a C1-C6 alkyl group) or a substituted alkyl group, and each occurrence of G group is independently a halogen (e.g., Cl), x is an integer from 0 to 4, and y is an integer from 0 to 4, with the proviso that x+y is 4; or a zirconium oxyhalide or zirconium halide, with zirconium oxyhalide being preferred. The atomic ratio of Zr / Ti of the core TiO2 nanocrystals and shell ZrO2 is less than 3, e.g., less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8 nm, less than 0.9, less than 1, less than 2, less than 3, as measured by SEM EDX. Preferably, the atomic ratio of Zr / Ti of the core TiO2 nanocrystals and shell ZrO2 is less than 1. 17. The solvent is benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, 2-(isopentyloxy)ethanol, 2-propoxy-propanol (PnP), 2-(hexyloxy)ethanol, tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, di 17. The method of any one of embodiments 14 to 16, comprising one or more solvents selected from ethylene glycol monoethyl ether, diethylene glycol, dipropylene glycol, acetone, propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl butoxyacetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, benzene, toluene, and water. Preferably, the solvent comprises water. 18. The method according to any one of the embodiments 14 to 17, wherein the core-shell TiO2 nanocrystals have an average particle size of about 3 nm to about 50 nm as measured by TEM, or an average particle size of 4 nm to 30 nm as measured by TEM. Preferably, the core-shell nanocrystals having a shell comprising a shell metal oxide have a shell thickness of 0.1 nm to 5 nm as measured by TEM. Preferably, the shell of at least one metal oxide material on the TiO2 nanocrystals fully or partially encapsulates the TiO2 nanocrystals. Furthermore, the shell comprising a shell metal oxide can be in crystalline and / or amorphous form. The core-shell TiO2 nanocrystals prepared according to the methods of embodiments 14-18 have a narrow particle size distribution, characterized in that: 1) the D90:D10 ratio is less than 5, preferably less than 3 or less than 2, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.8, from about 1.2 to about 3, or from about 1.5 to about 3; 2) the D90:D50 ratio is less than 3, preferably less than 2 or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.5; and / or 3) the D50:D10 ratio is less than 3, preferably less than 2 or less than 1.5, e.g., from about 1.1 to about 2, from about 1.5 to about 2, from about 1.2 to about 1.5. 19. A method for capping a core-shell TiO2 nanocrystal having a core comprising a TiO2 nanocrystal with a shell comprising ZrO2, comprising reacting the nanocrystal of any one of embodiments 1-5 with a first capping agent in a first capping solvent to produce a first at least partially capped core-shell TiO2 nanocrystal. Capping agents include methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyl ...2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, Methoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethylorthosilicate, heptanol, hexanol, octanol,benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol, and triethylene glycol monomethyl ether, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof. Preferably, the capping agent is one or more of methyltrimethoxysilane, phenyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, or any combination thereof. 20. A nanocrystal dispersion comprising at least partially capped core-shell nanocrystals comprising a core metal oxide having an outer shell comprising a shell metal oxide, at least one capping agent, and a dispersion medium, wherein the core metal oxide is characterized by having an average particle size greater than 3 nm and less than 50 nm as measured by TEM or DLS, and the shell is characterized by having a thickness between 0.1 nm and 5 nm as measured by TEM or DLS, and the at least partially capped core-shell nanocrystals are present in an amount greater than 10%, or greater than 20%, or greater than 30%, or greater than 40%, or greater than 50%, or greater than 60%, or greater than 70%, or greater than 80% by weight of the dispersion. The at least partially capped core-shell nanocrystals may be selected from the group consisting of methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane,4-Phenylbutyltrimethoxysilane, 2-Phenylethyltrimethoxysilane, 4-Biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-Mercaptopropyltrimethoxysilane, 8-Glycidoxyoctyltrimethoxysilane, (3-Glycidoxypropyl)trimethoxysilane, tetraethylorthosilicate, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol and triethylene glycol monomethyl ether, (2-{2- and is capped with at least one capping agent selected from mono-2-(methacryloyloxy)ethyl succinate, mono-2-(methacryloyloxy)ethyl ester ... Preferably, the capping agent is one or more of methyltrimethoxysilane, phenyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, or any combination thereof. 21. The nanocrystal dispersion of embodiment 20, wherein the core-shell nanocrystals are treated with an inorganic passivation agent comprising sodium polyphosphate, lithium nitrate, sodium hypochlorite, sodium hypophosphite, sodium phosphite, lithium chloride, sodium nitrate, sodium chloride, sodium aluminum phosphate, sodium hexametaphosphate, or any combination thereof. Preferably, the inorganic passivation agent comprises NaH2PO2. 22. The nanocrystal dispersion of any of embodiments 20-21, wherein the organic content of the at least partially capped nanocrystals is typically 0-25%, e.g., 0-5%, or 5-10%, or 10-15%, or 15-20%, or 20-25%, or less than 5%, or less than 8%, or less than 10%, or less than 12%, or less than 14%, or less than 16%, or less than 18%, or less than 20%, or less than 25% of the capped nanocrystals, as measured by TGA. 23. The nanocrystal dispersion of any of embodiments 20-22, wherein the core metal oxide comprises titanium dioxide, zirconium dioxide, and / or barium titanate, and the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof. Preferred core-shell nanocrystals comprise a TiO2 core and a ZrO2 shell metal oxide. 24. The nanocrystal dispersion of any of embodiments 20-23, wherein the at least partially capped core-shell nanocrystals are present in an amount of 50% or more by weight of the dispersion, the % organic is less than 20% of the at least partially capped core-shell nanocrystals, the core metal oxide is titanium oxide, the shell metal oxide comprises zirconium oxide, and the average particle size of the at least partially capped core-shell nanocrystals is less than 30 nm as measured by TEM or DLS. The atomic ratio of shell Zr to core Ti is less than 3, e.g., less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8 nm, less than 0.9, less than 1, less than 2, less than 3, as measured by SEM EDX. Preferably, the atomic ratio of shell Zr to core Ti is less than 1. 25. The nanocrystal dispersion of any of embodiments 20-24, wherein the particle size distribution of the at least partially capped core-shell nanocrystals is characterized by a D9999 of less than 500 nm as measured by dynamic light scattering (DLS) on a volume of at least partially capped core-shell nanocrystals dispersed in a solvent at 5 wt.%. Preferably, D9999 is less than 300 nm. 26. The nanocrystal dispersion of any of embodiments 20-25, wherein the dispersion medium comprises a solvent, a monomer, an oligomer of a polymer, or a combination thereof. Examples of solvents used for dispersion include, but are not limited to, THF, acetone, heptane, benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, ethanol, butoxyethanol, butoxypropanol, methanol, tetrahydrofuran, dimethyl ether, diethyl ether, dibutyl ether, propylene glycol monomethyl ether (PGME), diethylene glycol butyl ether, dipropylene glycol methyl ether (DPGME), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether, diethylene glycol, dipropylene glycol, acetone; esters such as propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), methyl acetate, ethyl acetate (ETA), butyl acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, butoxyethyl acetate, ethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, benzene, toluene, and water, as well as any combination or mixture thereof. Preferred solvents include THF, isopropanol, ethanol, dipropylene glycol methyl ether (DPGME), propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), ethyl acetate, toluene, and any combination or mixture thereof. Monomers include benzyl (meth)acrylate (BA and BMA), trimethylolpropane tri(meth)acrylate (TMPTA and TMPTMA), trimethylolpropane ethoxylate tri(meth)acrylate (EOTMPTA and EOTMPTMA), 1,6-hexanediol di(meth)acrylate (HDDA and HDDMA), di(ethylene glycol) di(meth)acrylate (DEGDA and DEGDMA), ethylene glycol diacrylate, glycerol 1,3-Diglycerolate diacrylate, tri(propylene glycol) diacrylate, 1,6-hexanediol ethoxylate diacrylate, ethylene glycol phenyl ether (meth)acrylate (PEA and PEMA), 2-hydroxy-3-phenoxypropyl acrylate (HPPA), 2-hydroxy-3-phenoxypropyl methacrylate (HPPMA), 2-phenoxybenzyl acrylate (PBA), biphenyl methacrylate (BPMA), isobornyl acrylate (IBA), 2-phenylphenol methacrylate (PPMA), isobutyl acrylate (IBA), 2-phenylethyl acrylate (2-PEA), 2-(phenylthio)ethyl acrylate (PTEA), tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA or M370), bisphenol A glycerolate dimethacrylate, esters with acrylic acid (OPPEOA ), 9,9-bis[4-(2-acryloyloxyethyloxy)phenyl]fluorene or bisfluorene diacrylate in OPPEOA (HR6042), bisphenol A ethoxylate diacrylate, bisphenol A propoxylate diacrylate, bisphenol F ethoxylate (2EO / phenol) diacrylate, bisphenol A glycerolate diacrylate, bisphenol A ethoxylate dimethacrylate, ethoxylated (4) bisphenol A diacrylate (SR-601), biphenol A ethoxylate diacrylate (SR-349), tris(2-acryloyloxy)ethyl}isocyanurate, tricyclodecane dimethanol diacrylate, cresol novolac epoxy acrylate (CN112C60), tri(ethylene glycol) diacrylate, ethylene glycol diacrylate, poly(ethylene glycol) diacrylate, glycerol 1,3-diglycerolate diacrylate, and combinations thereof, such as N-vinylpyrrolidone (NVP), phenylnorbornene, styrene (STY), 4-methylstyrene, 4-vinylanisole, divinylbenzene. In some preferred embodiments, the monomer, oligomer and / or polymer can be selected from 2-phenylethyl acrylate (2-PEA), biphenyl methacrylate (BPMA), 2-phenoxybenzyl acrylate (PBA), trimethylolpropane tri(meth)acrylate (TMPTA and TMPTMA), tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), 9,9-bis[4-(2-acryloyloxyethyloxy)phenyl]fluorene in OPPEOA or bisfluorene diacrylate (HR6042), and combinations thereof. The dispersions described herein can also be prepared by the method of Brookfield When measured with a RVDVII+ cone and plate viscometer, the viscosity may range from about 1 cp to about 1000 cp, e.g., from about 1 cP to 2 cP, from about 2 cP to 5 cP, from about 5 cP to 10 cP, from about 10 cP to 15 cP, from about 15 cP to 20 cP, from about 20 cP to 25 cP, from about 25 cP to 30 cP, from about 30 cP to 40 cP, from about 40 cP to 50 cP, from about 50 cP to 60 cP, from about 60 cP to 75 cP, from about 75 cP to 100 cP, from about 100 cP to 200 cP, from about 200 cP to 500 cP, or from about 500 cP to 1,000 cP, can have an adjustable viscosity ranging from about 1,000 cP to 2,000 cP, or from about 2,000 cP to 3,000 cP, or from about 3,000 cP to 4,000 cP, or from about 4,000 cP to 5,000 cP, or from about 5,000 cP to 6,000 cP, or from about 6,000 cP to 7,000 cP, or from about 7,000 cP to 8,000 cP, or from about 8,000 cP to 9,000 cP, or from about 9,000 cP to 10,000 cP, or more than 10,000 cP. 27. A nanocomposite formulation comprising: 1) at least partially capped core-shell TiO2 nanocrystals having an outer shell comprising a metal oxide; 2) a monomer, oligomer, and / or polymer; 3) optionally a solvent; and 4) a curing agent, wherein the at least partially capped core-shell TiO2 nanocrystals are present in an amount greater than 20 wt. % relative to the monomer, oligomer, and / or polymer, the core of the at least partially capped core-shell TiO2 nanocrystals comprises crystalline titanium dioxide and has been treated with at least one inorganic passivation agent, and the average particle size of the at least partially capped core-shell TiO2 nanocrystals is in the range of 3-50 nm as measured by DLS as a 5% nanocrystal dispersion in PGMEA, and the shell thickness is between 0.1 nm and 3 nm as measured by TEM. At least partially capped core-shell TiO2 nanocrystals have been synthesized using a variety of methods, including methyltrimethoxysilane, phenyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-(meth ... and is capped with at least one capping agent selected from (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, or any combination thereof. 28. The nanocomposite formulation of embodiment 27, wherein the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, cerium oxide, or any combination thereof. Preferably, the shell metal oxide comprises silicon dioxide, cerium oxide, and / or zirconium oxide. 29. The nanocomposite formulation according to any of embodiments 27-28, wherein the at least partially capped core-shell nanocrystals are present in an amount of 35% or more by weight relative to the monomer, oligomer and / or polymer, and the viscosity of the formulation is in the range of 1-10,000 cP. Preferably, the viscosity of the formulation is in the range of 1-3,000 cP. 30. At least partially capped core-shell TiO2 nanocrystals were exposed to 4 mW / cm2 at 320 nm to 390 nm for 66 hours. 2 or above 450 nm for 1000 hours, 16 mW / cm 2 or above 405 nm for 148 hours, intensity 25 mW / cm 2 or 340 nm for 72 hours, intensity 0.89 mW / cm 2 of 1-10 μm thick films made from formulations containing core-shell nanocrystals using a haze meter before and after UV exposure at * When measuring, the difference is less than 50%, for example, less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50%. * 30. The nanocomposite formulation of any of embodiments 27-29, having low photocatalytic activity as measured by a change in the at least partially capped core-shell TiO2 nanocrystals at 320 nm to 390 nm for 66 hours at 4 mW / cm 2 or above 450 nm for 1000 hours, 16 mW / cm 2 or above 405 nm for 148 hours, intensity 25 mW / cm 2 or 340 nm for 72 hours, intensity 0.89 mW / cm 230. The nanocomposite formulation of any of embodiments 27-29, having low photocatalytic activity as measured by a change in E* of less than 50%, e.g., less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, less than 30%, less than 40%, less than 50%, when E* is measured using a haze meter for a 1-10 μm thick film made from the formulation comprising core-shell nanocrystals before and after UV exposure at 200° C. 31. At least partially capped core-shell TiO2 nanocrystals were exposed to 4 mW / cm2 at 320 nm to 390 nm for 66 hours. 2 or above 450 nm for 1000 hours, 16 mW / cm 2 or above 405 nm for 148 hours, intensity 25 mW / cm 2 or 340 nm for 72 hours, intensity 0.89 mW / cm 2 31. The nanocomposite formulation of any of embodiments 27-30, having low photocatalytic activity as measured by a change in refractive index of less than 0.08, e.g., less than 0.01, less than 0.02, less than 0.03, less than 0.04, less than 0.05, less than 0.06, less than 0.07, less than 0.08, less than 0.09, less than 0.1, when measuring the refractive index of a film comprising the core-shell nanocrystals using a prism coupler or ellipsometer before and after UV exposure at 300 nm. 32. A nanocomposite comprising a cured film comprising at least partially capped core-shell TiO2 nanocrystals having an outer shell comprising a shell metal oxide, and at least one monomer, oligomer and / or polymer, wherein the at least partially capped core-shell TiO2 nanocrystals are present in an amount greater than 35% by weight of the nanocomposite, the film having a thickness of 1 micron has a transmittance of greater than 80% at wavelengths of 400 nm and greater, and the film has a refractive index of about 1.55 to about 2.20 as measured using a prism coupler or an ellipsometer. 33. The nanocomposite film of embodiment 32, wherein the at least partially capped core-shell TiO2 nanocrystals have an average particle size greater than 3 nm and less than 50 nm as measured by TEM, and a shell thickness between 0.1 nm and 3 nm as measured by TEM, and the atomic ratio of shell metal oxide / Ti is less than 0.1, less than 0.2, less than 0.3, less than 0.4, less than 0.5, less than 0.6, less than 0.7, less than 0.8, less than 0.9, less than 1 as measured by SEM EDX. At least partially capped core-shell TiO2 nanocrystals have been synthesized using a variety of methods, including methyltrimethoxysilane, phenyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-(meth ... The shell metal oxide is capped with at least one capping agent selected from: (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, or any combination thereof. The shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, cerium oxide, barium titanium oxide, or any combination thereof. 34. Benzyl (meth)acrylate (BA and BMA), trimethylolpropane tri(meth)acrylate (TMPTA and TMPTMA), trimethylolpropane ethoxylate tri(meth)acrylate (EOTMPTA and EOTMPTMA), 1,6-Hexanediol di(meth)acrylate (HDDA and HDDMA), di(ethylene glycol) di(meth)acrylate (DEGDA and DEGDMA), ethylene glycol diacrylate, glycerol 1,3-diglycerolate diacrylate, tri(propylene glycol) diacrylate, 1,6-Hexanediol ethoxylate diacrylate, ethylene glycol phenyl ether (meth)acrylate (PEA and and PEMA), 2-hydroxy-3-phenoxypropyl acrylate (HPPA), 2-hydroxy-3-phenoxypropyl methacrylate (HPPMA), 2-phenoxybenzyl acrylate (PBA), biphenyl methacrylate (BPMA), isobornyl acrylate (IBA), 2-phenylphenol methacrylate (PPMA), isobutyl acrylate (IBA), 2-phenylethyl acrylate (2-PEA), 2-(phenylthio)ethyl acrylate (PTEA), tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA or M370), bisphenol A glycerolate dimethacrylate, ester with acrylic acid (OPPEOA), OPPEOA in 9,9-Bis[4-(2-acryloyloxyethyloxy)phenyl]fluorene or bisfluorene diacrylate (HR6042), bisphenol A ethoxylate diacrylate, bisphenol A propoxylate diacrylate, bisphenol F ethoxylate (2EO / phenol) diacrylate, bisphenol A glycerolate diacrylate, bisphenol A ethoxylate dimethacrylate, ethoxylated (4) bisphenol A diacrylate (SR-601), bisphenol A ethoxylate diacrylate (SR-349), tris(2-acryloyloxy)ethyl 34. The nanocomposite of any of embodiments 32-33, comprising monomers selected from the group consisting of 1,3-dimethylphenyl}isocyanurate, tricyclodecane dimethanol diacrylate, cresol novolac epoxy acrylate (CN112C60), tri(ethylene glycol) diacrylate, ethylene glycol diacrylate, poly(ethylene glycol) diacrylate, glycerol 1,3-diglycerolate diacrylate, and N-vinylpyrrolidone (NVP), phenylnorbornene, styrene (STY), 4-methylstyrene, 4-vinylanisole, divinylbenzene, and combinations thereof. In some preferred embodiments, the monomers, oligomers and / or polymers may be selected from 2-phenylethyl acrylate (2-PEA), biphenyl methacrylate (BPMA), 2-phenoxybenzyl acrylate (PBA), trimethylolpropane tri(meth)acrylate (TMPTA and TMPTMA), tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), 9,9-bis[4-(2-acryloyloxyethyloxy)phenyl]fluorene in OPPEOA or bisfluorene diacrylate (HR6042), and combinations thereof. 35. An exemplary formulation includes at least one of acrylic monomers selected from HR6042 and BPMA, at least partially capped titanium oxide nanocrystals (e.g., any of those described herein, e.g., those preferred or exemplified herein), or at least partially capped core-shell nanocrystals (e.g., any of those described herein, e.g., those preferred or exemplified herein) comprising TiO2 as the core and ZrO2 as the shell metal oxide, with the weight ratio of nanocrystals to the total weight of monomers being 0.5:1 to 3:1. The formulation may further include a photoinitiator, TPO, and at least one solvent (e.g., any of those described herein, e.g., those preferred or exemplified herein). The formulation may be applied to a surface by spin coating and is nanoimprintable. A nanocomposite film formed by applying the formulation to a surface preferably has a transmittance of more than 80%, or more than 90%, or more than 93% at a film thickness of 40 nm to 30 μm. The nanocomposite has an RI at 520 nm in the range of 1.6 to 2.2, for example, 1.6 to 1.7, or 1.7 to 1.8, or 1.8 to 1.9, or 1.9 to 2.0. Preferably, the RI is in the range of 1.8 to 2.0. The nanocomposite also has a low haze of less than 1% and a b * has. 36. Another exemplary formulation comprises an acrylic monomer comprising PBA and / or THEICTA and at least partially capped titanium oxide nanocrystals (e.g., any of those described herein, e.g., any of those preferred or exemplified herein), or at least partially capped core-shell nanocrystals comprising TiO2 as the core and ZrO2 as the shell metal oxide (e.g., any of those described herein, e.g., any of those preferred or exemplified herein), wherein the at least partially capped nanocrystals are present in the range of 20-60% by weight of the total formulation, and the monomer is present in the range of 3-25% by weight of the total formulation, such that the ratio of nanocrystals to monomers is in the range of 3:7-8:2. The formulation may further comprise a photoinitiator (e.g., any of those described herein, e.g., any of those preferred or exemplified herein) present in the range of 0.5-2.5% by weight of the total formulation, and a solvent (e.g., any of those described herein, e.g., any of those preferred or exemplified herein) present in the range of 20-40% by weight of the total formulation. The formulation can be applied to a surface by spin coating and is nanoimprintable. Nanocomposite films formed by applying the formulation to a surface have a transmittance of greater than 80%, or greater than 90%, or greater than 93% at film thicknesses of 40 nm to 30 μm. The nanocomposites have an RI at 520 nm in the range of 1.6 to 2.2, e.g., 1.6 to 1.7, or 1.7 to 1.8, or 1.8 to 1.9, or 1.9 to 2.0. Preferably, the RI is in the range of 1.7 to 1.9. The nanocomposites also have a low haze of less than 1% and a b value of less than 1. * has. 37. Another exemplary formulation comprises at least partially capped nanocrystals, core-shell nanocrystals or core-shell nanocrystals with inorganic treatment, such as any of those described herein, such as those preferred or exemplified herein, and at least one monomer, the core-shell nanocrystals comprising a TiO2 core and a ZrO2 shell. The nanocrystals are present in a range of 35-80% by weight, preferably 65-75% by weight, based on the total formulation. The monomers preferably include at least one of 2-PEA, PTEA, PEA, PBA and / or IBA, present in a range of 3-18 weight percent, based on the total formulation, and TEICHTA, present in a range of 1-10 weight percent, based on the total formulation. The formulation optionally contains additives, such as Tinivin 405, Irganox 1010, and / or photoinitiators (e.g., any of those described herein, such as those preferred or exemplified herein), present in the range of 0.5-2.5 weight percent of the total formulation. The formulation typically contains less than 6.5% solvent. Formulations with 65-75% nanocrystal loading exhibit low viscosities of 500-5000 cP, preferably 1,000-3,000 cP. Nanocomposite films formed by applying the formulation to a surface have transmittances of greater than 80%, or greater than 90%, or greater than 93% at film thicknesses of 40 nm to 30 μm. The nanocomposite has an RI at 520 nm in the range of 1.6 to 2.2, e.g., 1.6 to 1.7, or 1.7 to 1.8, or 1.8 to 1.9, or 1.9 to 2.0. Preferably, the RI is in the range of 1.75 to 1.9. The nanocomposite also has a low haze of less than 5% and a b value of less than 2 at a thickness of about 10 μm. * has. 38. Another exemplary formulation comprises at least partially capped nanocrystals, core-shell nanocrystals or core-shell nanocrystals with inorganic treatment, such as any of those described herein, such as those preferred or exemplified herein, and at least one monomer, the core-shell nanocrystals comprising a TiO2 core and a ZrO2 shell. The nanocrystals are present in a range of 20-60 weight percent of the total formulation, a monomer blend comprising at least one BA, BPMA, and / or DVE is present in a range of 40-80 weight percent of the total formulation, and the formulation optionally contains a diluent such as STY or ethyl acetate present in a range of 0.5-5 weight percent of the total formulation, at least one photoinitiator and photosensitizer selected from Irgacure 819, ITX, and Esacure 1001M present in a range of 0.5-2.5 weight percent of the total formulation. The solvent content of the formulation is less than 6.5 weight percent of the total formulation. The formulation can be prepared as described in method 2 of the present disclosure. The formulation with 20-50% nanocrystal loading exhibits low viscosity, 10-100 cP, preferably 10-40 cP. The formulation is inkjet printable. Nanocomposite films formed by applying the formulation to a surface have transmittance of greater than 80%, or greater than 90%, or greater than 93% at film thicknesses of 40 nm to 30 μm. The nanocomposites have RI at 589 nm in the range of 1.6-1.9, e.g., 1.6-1.7, or 1.7-1.8, or 1.8-1.9. Preferably, the RI is in the range of 1.6-1.8. The nanocomposites also have low haze of less than 2% and b of less than 3 at a thickness of about 10 μm. * has. Films with thicknesses less than 39.5 μm are thermally stable when subjected to temperatures above 200° C. for 5 minutes, * The change in haze is less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, and the change in haze is less than the initial b *39. The nanocomposite of any of embodiments 32-38, wherein the molecular weight of the nanocomposite is less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%. 40. At least partially capped core-shell TiO2 nanocrystals were photoinduced by irradiation with 4 mW / cm2 at 320 nm–390 nm for 66 h. 2 or above 450 nm for 1000 hours, 16 mW / cm 2 or above 05 nm for 148 hours, intensity 25 mW / cm 2 or 340 nm for 72 hours, intensity 0.89 mW / cm 2 A haze meter was used to measure the thickness of a 1 μm film containing core-shell structures before and after UV exposure at 100 nm. * When measuring, the difference is less than 50%, for example, less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50%. * 40. The nanocomposite film of any of embodiments 32-39, having low photocatalytic activity as measured by a change in photoluminescence intensity at 320 nm to 390 nm for 66 hours, wherein the at least partially capped core-shell TiO2 nanocrystals have a photoluminescence intensity of 4 mW / cm2. 2 or above 450 nm for 1000 hours, 16 mW / cm 2 or above 405 nm for 148 hours, intensity 25 mW / cm 2 or 340 nm for 72 hours, intensity 0.89 mW / cm 239. The nanocomposite film of any of embodiments 32-39, having low photocatalytic activity as measured by a change in E* of less than 50%, e.g., less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50%, when measuring E* of a 1-10 μm thick film made from the formulation comprising the core-shell nanocrystals using a haze meter before and after UV exposure at 100° C. Additionally, the change in haze % is less than 1%, or less than 5%, or less than 10%, or less than 15%, or less than 20%, or less than 25%, or less than 30%, or less than 40%, or less than 50% of the initial haze. 41. At least partially capped core-shell TiO2 nanocrystals were photoinduced by irradiation with 4 mW / cm2 at 320 nm–390 nm for 66 h. 2 or above 450 nm for 1000 hours, 16 mW / cm 2 or above 405 nm for 148 hours, intensity 25 mW / cm 2 or 340 nm for 72 hours, intensity 0.89 mW / cm 241. The nanocomposite film of any of embodiments 32-40, having low photocatalytic activity as measured by a change in refractive index of less than 0.08, e.g., less than 0.01, less than 0.02, less than 0.03, less than 0.04, less than 0.05, less than 0.06, less than 0.07, when the refractive index of the film comprising the core-shell nanocrystals is measured using a prism coupler or an ellipsometer before and after UV exposure at 400 K. Additionally, the films exhibit a percent change in film thickness of less than 0.1 percent, or less than 0.2 percent, or less than 0.3 percent, or less than 0.4 percent, or less than 0.5 percent, or less than 0.6 percent, or less than 0.7 percent, or less than 0.8 percent, or less than 0.9 percent, or less than 1.0 percent, or less than 1.5 percent, or less than 2.0 percent, or less than 2.5 percent, or less than 3.0, or less than 3.5 percent, or less than 4.0 percent, or less than 4.5 percent, or less than 5 percent, or less than 10 percent, or less than 15 percent, or less than 20 percent, or less than 25 percent, or less than 50 percent. 42. A device comprising any of the nanocomposite films described in any of embodiments 32 to 41. EXAMPLES

[0212] Example 1 Synthesis of titanium dioxide (TiO2) nanocrystals

[0243] Titanium oxide nanocrystals with sizes ranging from 1 to 30 nm are prepared from precursors such as titanium(IV) methoxide, titanium(IV) ethoxide, titanium(IV) propoxide, titanium(IV) isopropoxide, titanium(IV) butoxide, or titanium(IV) oxyacetylacetonate. Titanium n-butoxide, chlorotriisopropoxytitanium(IV), titanium n-propoxide, titanium(IV) chloride, titanium chloride tri-n-butoxide, or titanium dichloride diethoxide are advantageously used as precursors depending on the desired end product.

[0213]

[0244] In an exemplary method, a titanium alkoxide precursor, such as but not limited to titanium n-butoxide, titanium n-propoxide, titanium isopropoxide isopropanol, or titanium ethoxide, is mixed with water, which acts as a reagent, and a solvent or solvent mixture including benzyl alcohol, phenol, oleyl alcohol, butanol, propanol, isopropanol, tetrahydrofuran, ethanol, methanol, acetonitrile, toluene, PGMEA, propylene glycol propyl ether (PGPE), PGME, 2-methyl-1-propanol, or triethylene glycol monomethyl ether, and sealed in an autoclave. The reaction mixture is heated to a temperature between 140°C and 300°C, preferably between 180°C and 250°C. Once the reaction mixture reaches the set temperature, the temperature is maintained for a period ranging from 1 hour, 20 minutes to 24 hours, preferably 30 minutes to 2 hours, depending in part on the temperature of the solvent or solvent mixture and / or reaction. Titanium oxide nanocrystals are obtained as a milky suspension. The TiO2 is separated from the suspension by centrifugation. The milky suspension is transferred to a centrifuge bottle and centrifuged at 4500 rpm for 10 minutes. The centrifugation step causes the TiO2 to collect at the bottom of the bottle and a clear supernatant liquid to collect on top. The clear supernatant liquid is decanted and discarded onto the white solid at the bottom of the bottle. This solid is referred to as the "wet cake" since most of the solvent has been expelled from it but it is still in wet form.

[0214]

[0245] In a preferred method, 879 g of 100% (w / w) titanium(IV) n-butoxide was mixed with 3550 g of benzyl alcohol and 116.3 g of water in an inerted 2 gallon (7.58 liter) Parr reactor. The setup was sealed under inert conditions, e.g., nitrogen atmosphere, to prevent oxygen contamination. The Parr reactor was then heated to 200° C. with stirring at 600 rpm and maintained at this temperature for 1 hour. After the reaction, the reactor was cooled to room temperature and a white milky solution of as-synthesized titanium oxide nanocrystals was collected. The milky suspension was transferred to a centrifuge bottle. It was centrifuged at 4500 rpm for 10 minutes and the wet cake was collected.

[0215] Example 2 Synthesis of Zirconium Oxide (ZrO2) Nanocrystals

[0246] An exemplary synthesis method using zirconium n-butoxide as precursor is as follows: 21.58 g of an 80% (w / w) solution of zirconium(IV) n-butoxide in 1-butanol (containing 17.26 g or 45 mmol of zirconium(IV) n-butoxide) was mixed with 300 ml of benzyl alcohol and then transferred to an autoclave. Optionally, water was added as a reactant in an amount of 0.1-2 mole percent of the zirconium precursor. The setup was sealed under an inert atmosphere to prevent oxygen and moisture contamination. The autoclave was then heated to 325 °C and held at this temperature for 1 h, then cooled to room temperature. A white milky solution of as-synthesized zirconium oxide nanocrystals was collected.

[0216]

[0247] Zirconium n-butoxide is received as a solution in 1-butanol (80% w / w). The 1-butanol can be removed from the precursor before synthesis, under vacuum and / or under heat (30-50°C), during synthesis by releasing the autoclave pressure when the temperature reaches about 100°C, or after the reaction is complete. The nanocrystals are spherical in shape and about 5 nm in diameter.

[0217] Example 3 Formation of high-temperature ZrO2 shell on TiO2 and subsequent surface modification

[0248] The TiO2 wet cake from Example 1 (450 g) was mixed with benzyl alcohol (1240 g). The resulting white milky suspension was centrifuged at 4500 rpm for 10 minutes. The supernatant liquid was decanted and the nanocrystals settled as a wet cake at the bottom of the centrifuge bottle. The wet cake was then dispersed again in benzyl alcohol (3400 g) and the slurry was transferred to a 2 gallon (7.58 liter) reactor. The reactor was then closed and sealed. 340 g of zirconium butoxide (80% in n-butanol) was then charged to the reactor, followed by 200 g of benzyl alcohol. The reactor was inerted with nitrogen gas and stirred for 20 minutes. The reactor was then heated to 205°C and held at that temperature for 4 hours. After cooling to room temperature, the material was discharged.

[0218]

[0249] The resulting treated TiO2 is separated from the reaction mixture via centrifugation at 4500 rpm for 10 minutes. The solids are then dispersed in PGMEA, shaken vigorously, and then collected via centrifugation at 4500 rpm for 10 minutes. At this point the PGMEA is decanted off. The material (46 g) is then transferred to a flask and dispersed in PGMEA (85 g). Methoxy(triethyleneoxy)propyltrimethoxysilane is then added (6.9 g). The reaction mixture is heated at 70° C. for 40 minutes. 3-(methacryloyloxy)propyltrimethoxysilane is then added (13.8) and heated at 70° C. for an additional 30 minutes. Water (2.3) is then added to the reaction mixture and the reaction mixture is heated at 70° C. for an additional 30 minutes to form the capped nanocrystals.

[0219]

[0250] The capped nanocrystals are separated from the reaction mixture by precipitating the nanocrystals with heptane (700 ml). The solids are collected by centrifugation. The liquid is decanted off. The solids are then dispersed in 100 ml of xylene for 2 minutes, followed by the addition of an additional 200 ml of THF and then 700 ml of heptane. The solids are collected by centrifugation. The liquid is decanted off. The solids are then dispersed in 300 ml of THF and precipitated using heptane (700 ml). The solids are collected by centrifugation and the liquid is decanted off. The solids are then dried overnight in a vacuum oven. The dried material is then dispersed in PGMEA at a loading of 50 wt% and then filtered.

[0220] Example 4 Formation of ZrO2 shell on TiO2 to generate TiO2-ZrO2 nanocrystals

[0251] The TiO2 collected as wet cake from Example 1 is dispersed in acetone and homogenized using zirconia beads. The homogenized TiO2 is separated from the reaction mixture via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as wet cake at the bottom of the centrifuge bottle. This process is repeated. The resulting wet cake (wet solid) is then dispersed in water using zirconia beads until a homogenous mixture is obtained. The TiO2 is again collected via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as wet cake at the bottom of the centrifuge bottle. This process is repeated again. The purified TiO2 wet cake is then transferred to a three-neck flask and water is added to the wet cake (10:1 by weight of water to TiO2 wet cake). The mixture is stirred until it is homogenous. ZrOCl2.8H2O is then added to the reaction mixture (30% by weight of TiO2 wet cake). The reaction mixture is then heated at 90° C. for 24 hours. After cooling to room temperature, the reaction mixture resulting after the ZrO2 shell formation process is a clear dispersion in water.

[0221] Example 5 Capping of TiO2-ZrO2 core-shell nanocrystals

[0252] The resulting TiO2-ZrO2 core-shell nanocrystals from Example 4 are purified by precipitation with THF in a weight-to-weight ratio of 1:4 relative to the THF of the reaction mixture. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The wet cake is redispersed in water in a weight-to-weight ratio of wet cake to water of 1:1 and precipitated with THF in a weight-to-weight ratio of nanocrystal dispersion to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant is decanted. The collected wet cake is redispersed in water, reprecipitated in THF, centrifuged and the purified wet cake is collected. The wet cake is dispersed in ethanol in a weight-to-weight ratio of wet cake to water of 1:1 and precipitated with acetone in a weight-to-weight ratio of nanocrystal dispersion to acetone of 1:4. The nanocrystal dispersion is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the wet cake is collected at the bottom of the bottle. This dispersion, settling and centrifugation process is repeated two more times.

[0222]

[0253] After the final centrifugation and decanting steps, the resulting wet cake is transferred to a 1.0 L round bottom flask and PGMEA is used to produce a final suspension of 25 wt% wet cake in PGMEA. The mixture is stirred at room temperature for 15 minutes to obtain a homogenous suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask as 17 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask as 15 wt% base relative to the wet cake. The mixture is heated to 120°C for 100 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0223]

[0254] The reaction mixture is then cooled to room temperature and washed to eliminate excess capping agent and impurities. The reaction mixture is precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in THF, in a weight to weight ratio of 2:1 THF to the wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in THF, in a weight to weight ratio of 2:1 THF to the wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0224]

[0255] The dried solids were redispersed in PGMEA at a 1:1 weight ratio of solids to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0225]

[0256] DLS of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in PGMEA demonstrates an average particle size by intensity of 34.30 nm and an average particle size by volume of 25.67 nm, with a narrow size distribution exhibiting a D9999 of 84.3.

[0226] Example 6 Capping of TiO2-ZrO2 core-shell nanocrystals followed by treatment with inorganic passivators

[0257] The resulting TiO2-ZrO2 core-shell nanocrystals from Example 4 are purified by precipitation with THF in a weight-to-weight ratio of 1:4 relative to the THF of the reaction mixture. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The wet cake is redispersed in water in a weight-to-weight ratio of wet cake to water of 1:1 and precipitated with THF in a weight-to-weight ratio of nanocrystal dispersion to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant is decanted. The collected wet cake is redispersed in water, reprecipitated in THF, centrifuged and the purified wet cake is collected. The wet cake is dispersed in ethanol in a weight-to-weight ratio of wet cake to water of 1:1 and precipitated with acetone in a weight-to-weight ratio of nanocrystal dispersion to acetone of 1:4. The nanocrystal dispersion is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the wet cake is collected at the bottom of the bottle. This dispersion, settling and centrifugation process is repeated two more times.

[0227]

[0258] After the final centrifugation and decanting step, the resulting wet cake is transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25 wt% wet cake in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a homogenous suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30 wt% base relative to the wet cake. The mixture is heated to 70°C for 30 minutes. After a 30 minute hold time, 3 wt% sodium hypophosphite monohydrate powder relative to the weight of the wet cake is weighed and slowly added to the reaction mixture. The mixture is continued to be heated at 70°C for an additional 30 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0228]

[0259] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of reaction mixture to THF and precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 of heptane to reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of ethanol to wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 of heptane to reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of ethanol to wet cake. The dispersed solids are again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted and discarded. The solids are then placed in a vacuum oven to dry overnight.

[0229]

[0260] The dried solid was redispersed in PGMEA in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0230]

[0261] A DLS plot of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in PGMEA is shown in Figure 1. The figure shows the DLS plot as a measure of intensity versus particle size, indicating an average particle size of 37.15 nanometers with a narrow size distribution.

[0231]

[0262] A DLS plot of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in PGMEA is shown in Figure 2. The figure shows the DLS plot as a measurement of volume vs. particle size, indicating an average particle size of 25.46 nanometers with a narrow size distribution. The D9999 of this dispersion is 91.1.

[0232]

[0263] A high-resolution TEM image with elemental mapping of Ti and Zr is shown in Figure 3. The figure shows two images of the same particle. Example 7 Inorganic surface passivation of TiO2-ZrO2 core-shell nanocrystals prior to capping

[0264] The resulting TiO2-ZrO2 core-shell nanocrystals from Example 4 are purified by precipitation with THF at a weight to weight ratio of reaction mixture to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The wet cake is redispersed in water at a weight to weight ratio of wet cake to water of 1:1 and precipitated with THF at a weight to weight ratio of nanocrystal dispersion to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant is decanted. The collected wet cake is redispersed in water, reprecipitated in THF, and centrifuged to collect the purified white wet cake. The wet cake is redispersed in ethanol at a weight to weight ratio of wet cake to water of 1:1 and precipitated with acetone at a weight to weight ratio of nanocrystal dispersion to acetone of 1:4. The nanocrystal dispersion is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the wet cake is collected at the bottom of the bottle. The dispersion, precipitation and centrifugation process is repeated two more times.

[0233]

[0265] After the final centrifugation and decanting step, the resulting wet cake is redispersed in ethanol at 50% by weight and stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3% by weight relative to the weight of the wet cake. The mixture is stirred at room temperature for 12 hours. After the desired period, the solid portion is separated from the liquid by centrifuging at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted off, leaving a white wet solid cake at the bottom of the centrifuge bottle. The wet cake is then rinsed with ethanol at a ratio of 2.75:1 weight to weight of solvent relative to the wet cake, followed by vigorous stirring. The suspension is then centrifuged again at 4500 rpm for 10 minutes, and the resulting supernatant liquid is decanted off to remove the top side. This rinsing step is repeated twice. At the end of the rinsing step, a white wet solid cake is obtained.

[0234]

[0266] The wet cake is then transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25% by weight of the wet cake in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a uniform suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30% by weight of the silane relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30% by weight of the base relative to the wet cake. The mixture is heated to 70°C for 45 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0235]

[0267] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of the reaction mixture to THF and precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 of heptane to the reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0236]

[0268] The dried solid was redispersed in PGMEA in a 1:1 ratio of solid to solvent by weight to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0237]

[0269] DLS of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in PGMEA demonstrates a narrow size distribution with an intensity-to-particle mean particle size and a volume-to-particle mean particle size of 41.37 nm and 26.47 nm, respectively. The D9999 of this dispersion is 102.

[0238] Example 8 Capping of TiO2-ZrO2 core-shell nanocrystals by inorganic surface passivation followed by further treatment with inorganic agents

[0270] The resulting TiO2-ZrO2 core-shell nanocrystals from Example 4 are purified by precipitation with THF in a weight-to-weight ratio of THF to the reaction mixture of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The wet cake is redispersed in water in a weight-to-weight ratio of wet cake to water of 1:1 and precipitated with THF in a weight-to-weight ratio of nanocrystal dispersion to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant is decanted. The collected wet cake is redispersed in water, reprecipitated in THF, and centrifuged to collect the purified white wet cake. The wet cake is redispersed in ethanol in a weight-to-weight ratio of wet cake to water of 1:1 and precipitated with acetone in a weight-to-weight ratio of nanocrystal dispersion to acetone of 1:4. The nanocrystal dispersion is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the wet cake is collected at the bottom of the bottle. The dispersion, precipitation and centrifugation process is repeated two more times.

[0239]

[0271] After the final centrifugation and decanting step, the resulting wet cake is redispersed at 50% by weight in ethanol and stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3% by weight relative to the weight of the wet cake. The mixture is stirred at room temperature for 12 hours. After the desired period, the solid portion is separated from the liquid by centrifuging at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted, leaving a white wet solid cake at the bottom of the centrifuge bottle. The wet cake is then rinsed with ethanol in a weight-to-weight ratio of solvent to wet cake of 2.75:1, followed by vigorous stirring. The suspension is then centrifuged again at 4500 rpm for 10 minutes, the resulting supernatant liquid is decanted, and the top side is removed. This rinsing step is repeated twice. At the end of the rinsing step, a white wet solid cake is obtained.

[0240]

[0272] The wet cake is then transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25 wt% wet cake in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a uniform suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30 wt% base relative to the wet cake. The mixture is heated to 70°C for 45 minutes. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at the end of the 30 minute hold time at 3 wt% relative to the weight of the wet cake. The reaction mixture is held at 70°C for an additional 30 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0241]

[0273] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 reaction mixture to THF and precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 heptane to reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 ethanol to wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 heptane to reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 ethanol to wet cake. The dispersed solids are again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solids are then placed in a vacuum oven to dry overnight.

[0242]

[0274] The dried solid was redispersed in PGMEA in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0243] Example 9 Inorganic treatment of TiO2 prior to ZrO2 shell coating, followed by capping

[0275] 50% by weight of TiO2 nanocrystals from Example 1 are redispersed in ethanol and stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3% by weight relative to the weight of the wet cake. The mixture is stirred at room temperature for 12 hours. After the desired period, the solid portion is separated from the liquid by centrifuging at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted, leaving a white wet solid cake at the bottom of the centrifuge bottle. The wet cake is then rinsed with ethanol in a weight-to-weight ratio of solvent to wet cake of 2.75:1, followed by vigorous stirring. The suspension is then centrifuged again at 4500 rpm for 10 minutes, the resulting supernatant liquid is decanted, and the top side is removed. This rinsing step is repeated twice. At the end of the rinsing step, a white wet solid cake is obtained.

[0244]

[0276] The wet cake is then dispersed in water at 10:1 water to TiO2 wet cake by weight. The mixture is stirred until it becomes homogeneous. ZrOCl2.8H2O is added to the reaction mixture (30% by weight relative to TiO2 wet cake). The reaction mixture is then heated to 90°C for 24 hours. After cooling to room temperature, the reaction mixture produced after the ZrO2 shell formation process is a clear dispersion in water.

[0245]

[0277] The resulting TiO2-ZrO2 nanocrystals from the examples are purified by precipitation with THF at a weight to weight ratio of reaction mixture to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The wet cake is redispersed in water at a weight to weight ratio of wet cake to water of 1:1 and precipitated with THF at a weight to weight ratio of nanocrystal dispersion to THF of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant is decanted. The collected wet cake is redispersed in water, reprecipitated in THF, centrifuged and the purified wet cake is collected. The wet cake is dispersed in ethanol at a weight to weight ratio of wet cake to water of 1:1 and precipitated with acetone at a weight to weight ratio of nanocrystal dispersion to acetone of 1:4. The nanocrystal dispersion is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the wet cake is collected at the bottom of the bottle. This dispersion, settling and centrifugation process is repeated two more times.

[0246]

[0278] After the final centrifugation and decanting steps, the resulting wet cake is transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25% wet cake by weight in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a uniform suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30% silane by weight relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30% base by weight relative to the wet cake. The mixture is heated to 70°C for 30 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0247]

[0279] The reaction mixture is then cooled to room temperature and washed to eliminate excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of the reaction mixture to THF and precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the reaction mixture to THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solids are again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solids are then placed in a vacuum oven to dry overnight.

[0248]

[0280] The dried solid was redispersed in PGMEA in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0249] Example 10 Inorganic treatment of TiO2 nanocrystals without metal oxide shell followed by capping

[0281] The synthesized TiO2 nanocrystals from Example 1 are redispersed in ethanol at 50% by weight and stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3% by weight relative to the weight of the wet cake. The mixture is stirred at room temperature for 12 hours. After the desired period, the solid portion is separated from the liquid by centrifuging at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted, leaving a white wet solid cake at the bottom of the centrifuge bottle. The wet cake is then rinsed with ethanol in a weight-to-weight ratio of solvent to wet cake of 2.75:1, followed by vigorous stirring. The suspension is then centrifuged again at 4500 rpm for 10 minutes, and the resulting supernatant liquid is decanted to remove the top side. This rinsing step is repeated twice. At the end of the rinsing step, a white wet solid cake is obtained.

[0250]

[0282] The wet cake is transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 30% by weight of the wet cake in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a uniform suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30% by weight of silane relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30% by weight of base relative to the wet cake. The mixture is heated to 70°C for 45 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0251]

[0283] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 reaction mixture to THF and precipitated in an anti-solvent, e.g., heptane in a weight to weight ratio of 4:1 heptane to reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 ethanol to wet cake. The dispersed solid is again precipitated in an anti-solvent, e.g., heptane in a weight to weight ratio of 4:1 heptane to reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 ethanol to wet cake. The dispersed solids are again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solids are then placed in a vacuum oven to dry overnight.

[0252]

[0284] The dried solids were redispersed in PGME at a 1:1 weight ratio of solids to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0253] Example 11 Capping of TiO2 nanocrystals with ZrO2 shells along with inorganic surface passivation

[0285] The TiO2 from Example 1, collected as a wet cake, is dispersed in acetone and homogenized with zirconia beads. The homogenized TiO2 is separated from the reaction mixture via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The purified TiO2 wet cake is then transferred to a three-neck flask and water is added to the wet cake (TiO2 wet cake to water 1:4 by weight). The mixture is stirred until the mixture is homogenous. ZrOCl2.8H2O is then added to the reaction mixture (30 wt% relative to TiO2 wet cake). The reaction mixture is then heated at 90°C for 8 hours. After cooling to room temperature, the reaction mixture produced after the ZrO2 shell formation process is a clear dispersion in water.

[0254] Example 11A

[0286] The resulting TiO2-ZrO2 core-shell nanocrystals are purified by precipitating the NCs from the mother liquor using acetone in a 1:4 weight-to-weight ratio relative to that of the reaction mixture. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min. The supernatant is decanted and the nanocrystals settle to the bottom of the centrifuge bottle as a wet cake. The wet cake is redispersed in ethanol in a 1:1 weight-to-weight ratio of wet cake to ethanol and precipitated with acetone in a 1:4 weight-to-weight ratio of the nanocrystal dispersion to acetone. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min, the supernatant is decanted and the wet cake is collected.

[0255]

[0287] The resulting wet cake is then transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25 wt% wet cake in ethanol. It is stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. After the desired period, methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 30 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30 wt% base relative to the wet cake. The mixture is heated to 70°C for 45 minutes. At the end of the 45 minute hold time, sodium hypophosphite monohydrate powder is carefully added to the reaction mixture at 3 wt% relative to the weight of the wet cake and continued to hold at 7°C for another 30 minutes. At the completion of the reaction, the mixture will have a pale milky appearance. The mixture is stirred at room temperature for 1 hour.

[0256]

[0288] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of reaction mixture to THF and precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of heptane to reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of ethanol to wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of heptane to reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of ethanol to wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of heptane to reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0257]

[0289] The dried solid was redispersed in ETA (ethyl acetate) at a 1:1 weight ratio of solid to solvent to create a 50% weight loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0258]

[0290] Capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 50 wt% in ETA have an organic % of 11.32. Example 11B

[0291] The resulting TiO2-ZrO2 core-shell nanocrystals are purified by precipitating the NCs from the mother liquor using acetone in a 1:4 weight-to-weight ratio relative to that of the reaction mixture. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min. The supernatant is decanted and the nanocrystals settle to the bottom of the centrifuge bottle as a wet cake. The wet cake is redispersed in ethanol in a 1:1 weight-to-weight ratio of wet cake to ethanol and precipitated with acetone in a 1:4 weight-to-weight ratio of nanocrystal dispersion to acetone. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min, the supernatant is decanted and the wet cake is collected.

[0259]

[0292] After the final centrifugation and decanting steps, the resulting wet cake is then transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25 wt% wet cake in ethanol. This is stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3 wt% based on the weight of the wet cake. The mixture is stirred at room temperature for 1 hour. After the desired period, methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane based on the weight of the wet cake. This mixture is then stirred at room temperature for 30 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 15 wt% base based on the weight of the wet cake. The mixture is heated to 70 °C for 45 minutes. At the end of the 45 minute hold time, 3-(methacryloyloxy)propyltrimethoxysilane is carefully added to the nanocrystal suspension at 10 wt% based on the weight of the wet cake. The reaction mixture is held at 70 °C for an additional 30 minutes. Once the reaction is complete, the mixture will have a slightly milky appearance.

[0260]

[0293] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of the reaction mixture to THF and precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0261]

[0294] The dried solids were redispersed in PGMEA or ETA (ethyl acetate) in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0262]

[0295] Capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 50 wt % in ETA have organic % 9.93 and 9.55, respectively.

[0296] DLS of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in ETA demonstrates an intensity-to-particle mean particle size of 33.850 nm and a volume-to-particle mean particle size of 24.42 nm with a narrow size distribution. The D9999 of this dispersion is 85.5.

[0263] Example 11C

[0297] The resulting TiO2-ZrO2 core-shell nanocrystals are purified by precipitating the NCs from the mother liquor using acetone in a 1:4 weight-to-weight ratio relative to that of the reaction mixture. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min. The supernatant is decanted and the nanocrystals settle to the bottom of the centrifuge bottle as a wet cake. The wet cake is redispersed in ethanol in a 1:1 weight-to-weight ratio of wet cake to ethanol and precipitated with acetone in a 1:4 weight-to-weight ratio of nanocrystal dispersion to acetone. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min, the supernatant is decanted and the wet cake is collected.

[0264]

[0298] The resulting wet cake is redispersed in PGMEA at a weight to weight ratio of wet cake to PGMEA of 1:4. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant liquid is decanted. The resulting wet cake is then transferred to a 1.0 L round bottom flask and PGMEA is used to produce a final suspension of 25 wt% wet cake in PGMEA. This is stirred at room temperature for 15 minutes to obtain a uniform distribution of solids in the solvent. After the desired period, methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 17 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 30 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 15 wt% base relative to the wet cake. The mixture is heated to 100°C for 45 minutes. At the end of the 45 minute hold time, 3-(methacryloyloxy)propyltrimethoxysilane is carefully added to the nanocrystal suspension at 30% by weight based on the weight of the wet cake. The reaction mixture is continued to be held at 100° C. for an additional 30 minutes. After this, sodium hypophosphite monohydrate powder is carefully added to the reaction mixture at 1% by weight based on the weight of the wet cake and continued to be held at 70° C. for another 30 minutes. Once the reaction is complete, the mixture will have a pale milky appearance.

[0265]

[0299] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 reaction mixture to THF and precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 heptane to reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 ethanol to wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 heptane to reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 ethanol to wet cake. The dispersed solids are again precipitated in an anti-solvent, for example, heptane, in a weight to weight ratio of 4:1 heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solids are then placed in a vacuum oven to dry overnight.

[0266]

[0300] The dried solids were redispersed in PGMEA or ETA (ethyl acetate) in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0267]

[0301] Capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 50 wt% in ETA have an organic % of 13.99.

[0302] DLS of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in ETA demonstrates an average particle size of 29.81 nm by intensity vs. particle size and 15.11 nm by volume vs. particle size, with a narrow size distribution. The D9999 of this dispersion is 88.5.

[0268] Example 11D

[0303] The resulting TiO2-ZrO2 core-shell nanocrystals are purified by precipitating the NCs from the mother liquor using acetone in a 1:4 weight-to-weight ratio relative to that of the reaction mixture. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min. The supernatant is decanted and the nanocrystals settle to the bottom of the centrifuge bottle as a wet cake. The wet cake is redispersed in water in a 1:1 weight-to-weight ratio of wet cake-to-water and precipitated using acetone in a 1:4 weight-to-weight ratio of the nanocrystal dispersion to that of acetone. The resulting white milky suspension is centrifuged at 4500 rpm for 10 min, the supernatant is decanted and the wet cake is collected.

[0269]

[0304] After the final centrifugation and decanting step, the resulting wet cake is then transferred to a 1.0 L round bottom flask with water to produce a final suspension of 15 wt% wet cake in water. It is stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3 wt% based on the weight of the wet cake. The mixture is stirred at room temperature for 1 hour. After the desired period, methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane based on the weight of the wet cake. This mixture is then stirred at room temperature for 30 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 15 wt% base based on the weight of the wet cake. The mixture is heated to 95 °C for 45 minutes. At the end of the 45 minute hold time, 3-(methacryloyloxy)propyltrimethoxysilane is carefully added to the nanocrystal suspension at 10 wt% based on the weight of the wet cake. The reaction mixture is continued to be held at 95° C. for an additional 30 minutes. Once the reaction is complete, the mixture will have a pale milky appearance.

[0270]

[0305] The reaction mixture is then cooled to room temperature to produce a slurry of a white precipitate suspended in the reaction solvent. The solid white precipitate is collected by centrifugation at 3000 rpm for 10 minutes. The resulting solid is then dispersed in THF in a weight to weight ratio of 2:1 for the THF wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 for the heptane reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted and discarded. The resulting solid is again dispersed in THF in a weight to weight ratio of 2:1 for the THF wet cake. The dispersed solid is again precipitated in an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 for the heptane reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0271]

[0306] The dried solids were redispersed in PGMEA or ETA (ethyl acetate) in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0272]

[0307] Capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 50 wt% in ETA have an organic content of 11.42%.

[0308] DLS of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in ETA demonstrates an average particle size of 43.23 nm by intensity vs. particle and 29.21 nm by volume vs. particle size, with a narrow size distribution.

[0273] Example 12

[0309] The TiO2 from Example 1, collected as a wet cake, is dispersed in acetone and homogenized with zirconia beads. The homogenized TiO2 is separated from the reaction mixture via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The purified TiO2 wet cake is then transferred to a three-neck flask and water is added to the wet cake (TiO2 wet cake to water 1:4 by weight). The mixture is stirred until it is homogenous. ZrOCl2.8H2O is then added to the reaction mixture (17% by weight relative to TiO2 wet cake), followed by CeCl3.7H2O (cerium(III) chloride heptahydrate) or Ce2CO3)3.xH2O (cerium(III) carbonate hydrate) at 3% by weight relative to TiO2 wet cake. The reaction mixture is then heated at 90°C for 24 hours. After cooling to room temperature, the reaction mixture produced after the ZrO2 shell formation process is a transparent dispersion in water.

[0274]

[0310] The resulting dispersion has a pH of 1 and is neutralized to pH 4 using aqueous ammonium hydroxide (5N). While stirring, the ammonium hydroxide solution is slowly added to the reaction mixture. The pH change of the mixture is monitored with a pH meter. Once the pH reaches 4, the NCs are collected from the reaction mixture using centrifugation. The NCs from the mother liquor are centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. The wet cake is redispersed in ethanol at a 1:1 weight to weight ratio of the wet cake to ethanol and precipitated with acetone at a 1:4 weight to weight ratio of the nanocrystal dispersion to acetone. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes and the supernatant is decanted.

[0275]

[0311] After the final centrifugation and decanting step, the resulting wet cake is redispersed in ethanol at 50% by weight and stirred at room temperature for 15 minutes to obtain a uniform distribution of the solids in the solvent. Sodium hypophosphite monohydrate powder is carefully added to the nanocrystal suspension at 3% by weight based on the weight of the wet cake. The mixture is stirred at room temperature for 12 hours. After the desired period, the solid portion is separated from the liquid by centrifuging at 4500 rpm for 10 minutes. The resulting supernatant liquid is decanted, leaving a white wet solid cake at the bottom of the centrifuge bottle. The wet cake is then rinsed with ethanol in a 2.75:1 weight to weight ratio of solvent to wet cake, followed by vigorous stirring. The suspension is then centrifuged again at 4500 rpm for 10 minutes, the resulting supernatant liquid is decanted, and the top is removed. The resulting wet cake is capped according to the procedure described in Examples 12A and 12B.

[0276] Example 12A

[0312] The wet cake from Example 12 is then transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25 wt% wet cake in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a uniform suspension. Methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 15 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 30 wt% base relative to the wet cake. The mixture is heated to 70° C. for 45 minutes. Upon completion of the reaction, the mixture will have a translucent appearance.

[0277]

[0313] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of reaction mixture to THF and precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of heptane to reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of ethanol to wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of heptane to reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of ethanol to wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of heptane to reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0278]

[0314] The dried solid was redispersed in PGMEA in a 1:1 weight ratio of solid to solvent to create a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter.

[0279]

[0315] Capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 50 wt% in PGMEA have an organic % of 8.97.

[0316] DLS plots of capped titanium dioxide nanocrystals with a ZrO2 shell dispersed at 5 wt% in PGMEA demonstrate an average particle size of 53.85 nm and an average particle size of 36.15 nm by intensity versus particle size with a narrow size distribution. The D9999 of this dispersion is 141.0.

[0280] Example 12B

[0317] The wet cake from Example 12 is then transferred to a 1.0 L round bottom flask and ethanol is used to produce a final suspension of 25 wt% wet cake in ethanol. The mixture is stirred at room temperature for 15 minutes to obtain a uniform suspension. After the desired period, methoxy(triethyleneoxy)propyltrimethoxysilane is then added to the reaction flask at 30 wt% silane relative to the wet cake. This mixture is then stirred at room temperature for 30 minutes. Aqueous ammonium hydroxide (28-30%) is carefully added to the reaction mixture in the flask at 15 wt% base relative to the wet cake. The mixture is heated to 70°C for 45 minutes. At the end of the 30 minute hold time, 3-(methacryloyloxy)propyltrimethoxysilane is carefully added to the nanocrystal suspension at 5 wt% relative to the weight of the wet cake. The reaction mixture is continued to be held at 70°C for an additional 30 minutes. Upon completion of the reaction, the mixture will have a pale milky appearance.

[0318] The reaction mixture is then cooled to room temperature and washed to remove excess capping agent and impurities. The reaction mixture is diluted in THF in a ratio of 1:2 of the reaction mixture to THF and precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture-THF. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is then dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The suspension is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The resulting solid is again dispersed in ethanol in a weight to weight ratio of 2:1 of the ethanol to the wet cake. The dispersed solid is again precipitated into an anti-solvent, for example, heptane in a weight to weight ratio of 4:1 of the heptane to the reaction mixture. The precipitate is centrifuged at 4500 rpm for 10 minutes. The resulting supernatant is decanted and discarded. The solid is then placed in a vacuum oven to dry overnight.

[0281]

[0319] The dried solids were redispersed in PGMEA at a 1:1 weight ratio of solid to solvent to produce a 50 wt% loaded dispersion. The resulting dispersion was filtered through a 0.45 micron, then a 0.2 micron absolute filter. The capped titanium dioxide nanocrystals with ZrO2 shells dispersed at 50 wt% in PGMEA have an organic % of 10.03.

[0282] Example 13 Formation of SiO2 shell on capped TiO2

[0320] The previously capped TiO2 powder (51 g) was dispersed in ethanol (1400 g) using an acoustic mixer. After standing overnight, the capped TiO2 was resuspended and transferred to a 2 gallon (7.58 liter) reactor. The reactor was then closed and sealed. Agitation in the reactor was set at 150-200 RPM. A pressure check was performed on the reactor, holding 10 PSIG for 10 minutes, then venting to 2 PSIG. Aqueous ammonia (224 g) was added to 1900 g water and then transferred to the reactor. The lines were then flushed with 470 g water. 69 g tetraethyl orthosilicate was added to the reactor, followed by 100 g ethanol. The reactor was inerted by pressurizing with N2 and then venting to 2 PSIG (this was repeated 10 times). The stirring speed was then increased to 600 rpm and the temperature was increased to 200° C. After holding at 200° C. for 3 hours, the reactor was cooled to room temperature. The reactor was then vented and the material was discharged into a container. A white slurry was obtained.

[0283] Example 14 Formation of SiO2 shell on TiO2

[0321] The TiO2 wet cake from Example 1 is rinsed with ethanol by mixing with ethanol in a 1:1 ratio to wet cake. The resulting white milky suspension is centrifuged at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. This purification step is repeated. The rinsed TiO2 wet cake (97 g) is then dispersed in ethanol (1400 g) using an acoustic mixer. This is allowed to sit overnight, after which the TiO2 is resuspended and transferred to a 2 gallon (7.58 liter) reactor. The reactor is then closed and sealed. Agitation in the reactor is set to 150-200 RPM. A pressure check is performed on the reactor and held at 10 PSIG for 10 minutes, then vented to 2 PSIG. Ammonia water (224 g) is added to 1900 g water and then transferred to the reactor. The lines are then flushed with 470 g water. 69 g of tetraethyl orthosilicate is added to the reactor, followed by 100 g of ethanol. The reactor is inerted by pressurizing with N2 and then venting to 2 PSIG (this is repeated 10 times). The agitation speed is then increased to 600 rpm and the temperature is increased to 200°C. After holding at 200°C for 3 hours, the reactor is cooled to room temperature. The reactor is then vented and the material is discharged into a container. A white slurry is obtained.

[0284] Example 15 Formation of HfO2 shell on TiO2

[0322] The TiO2 from Example 1 collected as a wet cake is dispersed in acetone and homogenized using zirconia beads. The homogenized TiO2 is separated from the reaction mixture via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. This process is repeated. The resulting wet cake (wet solid) is then dispersed in water using zirconia beads until a homogenous mixture is obtained. The TiO2 is again collected via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. This process is repeated again. The purified TiO2 wet cake is then transferred to a three-neck flask and water is added to the wet cake (10:1 with respect to the TiO2 wet cake weight). HfOCl2.8H2O is then added to the reaction mixture (38% by weight with respect to the TiO2 wet cake). The mixture is stirred until it is homogenous. The reaction mixture is then heated to 90° C. for 24 hours. After cooling to room temperature, the reaction mixture produced after the ZrO2 shell formation process is a clear dispersion in water.

[0285]

[0323] The nanocrystals are capped as described in Example 7. Example 16 Formation of Al2O3 shell on TiO2

[0324] The TiO2 from Example 1 collected as a wet cake is dispersed in acetone and homogenized using zirconia beads. The homogenized TiO2 is separated from the reaction mixture via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. This process is repeated. The resulting wet cake (wet solid) is then dispersed in water using zirconia beads until a homogenous mixture is obtained. The TiO2 is again collected via centrifugation at 4500 rpm for 10 minutes. The supernatant is decanted and the nanocrystals settle as a wet cake at the bottom of the centrifuge bottle. This process is repeated. The purified TiO2 wet cake is then transferred to a three-neck flask and water is added to the wet cake (10:1 relative to the TiO2 wet cake weight). The pH of the reaction mixture was adjusted to pH 10 using 2M NaOH solution. The mixture was then heated to 60°C and a solution of 2M NaAlO2 in water was added to the reaction mixture (the total amount of NaAlO2 added was 35% by weight of the TiO2 nanocrystals). The pH of the reaction mixture was then adjusted to pH 8 using 2M HCl solution. The temperature of the reaction mixture was increased to 90°C for 12 hours. After cooling to room temperature, the product was centrifuged and washed twice with water and then twice with ethanol.

[0286] Example 17 Tests to determine the UV stability of uncapped nanocrystals

[0325] The stability of titanium oxide and titanium oxide with metal oxide shell of the present disclosure to various film processing conditions is tested using an in-house developed color test. Polystyrene-PGMEA dispersion is prepared by dissolving 50 wt% polystyrene in PGMEA in PGMEA. Dry nanocrystal powder is vigorously mixed with the polystyrene-PGMEA dispersion at a 1:2 weight to weight ratio of nanocrystals to polystyrene / PGMEA dispersion for 10 minutes to produce a white opaque viscous paste. The viscous paste or drop cast is dispensed onto a glass surface using a pipette for processing. The drop cast is baked on a hot plate in air at 110°C for 5 minutes followed by 120 seconds of irradiation using a Hg broadband lamp (5 J / cm2). 2 ) or 365nm UV-LED lamp for 60 seconds (7.5J / cm 2 ) UV exposure. The drop casts are then baked on a hot plate in air at 135°C for 5 minutes, followed by an additional baking process in an oven at 200°C for 5 minutes. The degree of color change of the drop casts during each processing step is recorded for any discoloration. Any discoloration is evaluated as the stability for that process. UV stability. Results for various film processing conditions for TiO2 nanocrystals without and with a ZrO2 shell are shown in Tables 1 and 2.

[0287]

[0326]

[0288] [Table 1]

[0289]

[0327] Table 1: Drop casting results of pastes containing TiO2 nanocrystals without any shell, and TiO2 nanocrystals with ZrO2 shell and polystyrene as presented in this disclosure, mixed with polystyrene after each processing step. The nanocrystals are not capped and do not have any inorganic treatment. Exposure to different conditions causes the pastes to discolor. The discoloration is ranked from 0 to 6; "0" means no change and "6" means the most yellowing after the process. TiO2 without any ZrO2 shell shows the most yellowing, especially after UV irradiation. Meanwhile, TiO2 with ZrO2 shell shows less discoloration during the process.

[0290]

[0328] Paste coupons prepared by mixing at least partially capped TiO2 nanocrystals treated with an inorganic passivator during capping with polystyrene on a glass substrate and at various stages of film processing conditions are shown in Table 2. The TiO2 nanocrystals without any inorganic treatment turn yellow upon heating, while the TiO2 nanocrystals with inorganic treatment show less discoloration. Furthermore, the thermal stability of at least partially capped titanium dioxide nanocrystal powders with a ZrO2 shell subjected to high temperatures of 100°C to 200°C for a period of time is shown in Table 3.

[0291]

[0329]

[0292] [Table 2]

[0293] Example 18 Thermal stability of capped TiO2-ZrO2 core-shell nanocrystals

[0330] The thermal stability of the at least partially capped titanium oxide and core-shell nanocrystals of the present disclosure is tested by subjecting the dry powder of the capped nanocrystals, before dispersion in any solvent, to different temperatures in air for different periods of time. Approximately 1 g of the dry capped nanocrystal powder is taken in an aluminum dish and placed in an oven. The powder is baked at the desired temperature for a set period of time. The degree of color change of the powder is recorded and evaluated as thermal stability. The results of one such experiment are shown in Table 3.

[0294]

[0331] Compared to TiO2 without any oxide shell (oxide coating), TiO2 nanocrystals without ZrO2 shell and only inorganic treatment (Example 10) do not show any discoloration up to 150°C, and show a small amount of discoloration at 200°C / 10min heating (Table 3). TiO2 nanocrystals with ZrO2 shell (Example 5) but no inorganic treatment show less discoloration at lower temperatures, but start to discolor at higher temperatures. However, TiO2 nanocrystals with ZrO2 shell and inorganic treatment show better thermal stability. This indicates that inorganic treatment is necessary to produce more thermally stable nanocrystals.

[0295]

[0332]

[0296] [Table 3]

[0297] Example 19 Processing of Formulations and Nanocomposites Using TiO2 Nanocrystals Containing Metal Oxide Shells

[0333] An exemplary formulation includes PGMEA as a solvent, an acrylic monomer combination of HR6042 and BPMA (HR6042 is 1:1 by weight to BPMA), at least partially capped titanium dioxide nanocrystals of the present disclosure (1.6:1 weight ratio of nanocrystals to total monomer weight), and a photoinitiator, TPO (4 wt % based on total monomer weight).

[0298]

[0334] Monomer, HR6042 and BPMA are mixed in a 1:1 weight ratio. Capped titanium dioxide nanocrystals with ZrO2 shell at 50% by weight in propylene glycol monomethyl ether acetate (PGMEA) are mixed with the monomer in a ratio of 1.6:1 nanocrystal to total monomer weight. The mixture is blended by stirring using a magnetic stirrer or vortexing on a stir plate at a temperature of 25-30°C for 1-2 hours to allow for a homogenous mixture. Photoinitiator, TPO, is added to the formulation at 4% by weight with respect to the monomer and mixed again at room temperature on a stir plate using a magnetic stirrer at a temperature of 20-30°C for another 5-30 minutes. The resulting formulation is filtered through a membrane filter to produce a clear, transparent liquid. The viscosity of the formulation is between 5-6 cP, as measured with a Brookfield RVDV-II+PCP cone and plate viscometer.

[0299]

[0335] A nanocomposite coating or film with this formulation is coated onto a 2.5 x 2.5 inch (0.7 mm thick) soda lime glass wafer. The glass wafer is cleaned prior to application of the film, following an internal cleaning procedure, to eliminate contaminants and powders. A 1-2 micron thick film is spin coated onto the glass wafer at 2000-4000 rpm for 1 minute. Because this is a solvent-containing formulation, the coated film is processed through an initial bake process on a hotplate at 110 °C for 2 minutes to eliminate some of the solvent prior to UV exposure. The coating is then exposed to a Phoseon FireJet LED lamp (365 nm) at 125 mW / cm under nitrogen. 2 (11.25J / cm 2 ) to expose the film to a 365 nm LED for 90 seconds. The film is then subjected to a post-baking process on a hotplate at 135° C. for 2 minutes to eliminate residual solvent. The film thickness is measured using a Metricon 2010 / M prism coupler.

[0300]

[0336] Table 4 shows film properties for several exemplary 1 micron thick nanocomposites containing at least partially capped titanium oxide or core-shell nanocrystals of the present disclosure, as prepared in Example 19 below. Refractive index and film thickness were measured using a Metricon 2010 / M model prism coupler, b * and Haze % is measured with a HunterLab Vista Haze Meter. Lower Haze % means higher clarity of the film.

[0301]

[0337]

[0302] [Table 4]

[0303]

[0338] Nanocomposites produced with the formulations demonstrate high light transmittance. FIG. 4 shows the light transmittance of as-prepared (solid line) films with (a) nanocrystals from Example 5, (b) nanocrystals from Example 6, and (c) nanocrystals from Example 7, as measured on a Perkin Elmer Lambda 850 spectrophotometer with blank soda-lime glass as a reference or background. The film thickness is about 1 micron. The films show greater than 90% light transmittance at wavelengths between 375 and 800 nm. The spectral ripples are a result of the interference of incident and reflected light, which is usually an indication of high film quality, i.e., high smoothness, high uniformity, and high transparency.

[0304] Example 20 UV stability test of the nanocomposite prepared in Example 19

[0339] Nanocomposites made from the nanocrystals presented in this disclosure, prepared as described in Example 19, are evaluated for photocatalytic stability by exposing the nanocomposites to various UV wavelength bands for set periods of time. The wavelengths of exposure used were 320-390 nm (4 mW / cm 2 intensity) for 66 hours (950.4 J / cm 2dose) or 72 hours (1036.8 J / cm 2 dose), 450 nm (16 mW / cm 2 intensity) for 1000 hours (57600J / cm 2 dose) and 405 nm (25 mW / cm 2 of strength), 148 hours (13600J / cm 2 The typical film properties of nanocomposites, e.g., b * The haze, RI and film thickness are measured at different intervals during the test. At the end of the test, the b * The changes in refractive index, haze %, RI and film thickness are evaluated to determine the photostability of the nanocrystals to UV irradiation. Nanocomposites that exhibit the least change in film properties are considered to be the most photostable. Refractive index and film thickness were measured using a Metricon model 2010 / M prism coupler and b * and Haze % is measured using a HunterLab Vista Haze Meter.

[0305] Example 20A Photostability test at 320-390 nm

[0340] Nanocomposites made from TiO2 nanocrystals with a ZrO2 shell, such as those described in Examples 5, 6, 7, and 8, along with nanocrystals without a ZrO2 shell (unshelled TiO2) and inorganic treated nanocrystals of Example 10, are tested for their photostability against 320-390 nm UV irradiation. Table 5 shows the film properties of these nanocomposites before any exposure and the change in film properties after exposure (b * , haze%, RI and film thickness). Compared to the TiO2 nanocrystals without a shell and Example 10, Examples 5, 6, 7 and 8 have the smallest b * The change in haze and the change in haze % are shown. The nanocomposites of Examples 5, 6, 7 and 8 have lower b *The change indicates that TiO2 with a ZrO2 shell does not yellow as much as nanocrystals without a shell. The lower haze % change also indicates less degradation of the nanocomposite upon exposure to light. Typical indicators of TiO2 photocatalytic activity are the appearance of chalkiness and increased turbidity in the coating.

[0306]

[0341]

[0307] [Table 5]

[0308] Example 20B Photostability test at 405 nm.

[0342] Nanocomposites made with the nanocrystals described in Examples 7, 11B, 11C, 12A, 12B, along with nanocrystals without a ZrO2 shell (unshelled TiO2), are tested for their photostability against UV irradiation at 405 nm for 148 hours. Table 6 shows the film properties of these nanocomposites before any exposure and the change in film properties after exposure (b * Among the samples listed, the TiO2 nanocrystals without the ZrO2 shell had the highest initial b * and the highest b * Shows change.

[0309]

[0343]

[0310] [Table 6]

[0311] Example 20C Photostability test at 450nm

[0344] Nanocomposites made with the nanocrystals described in Examples 5, 6 and 7, along with nanocrystals without a ZrO2 shell (unshelled TiO2), are tested for their photostability against 1000 hours of UV irradiation at 450 nm. Table 7 shows the film properties of these nanocomposites before any exposure and the change in film properties after exposure (b * Among the samples listed, TiO2 nanocrystals without ZrO2 shell have the highest initial b * and the highest b * Shows change.

[0312]

[0345]

[0313] [Table 7]

[0314] Example 21 Solvent-free formulations (solvent-free)

[0346] Another exemplary formulation includes at least partially capped nanocrystals as presented in this disclosure and at least one monomer. The nanocrystals are present in a range of 65-75% by weight of the total formulation. The monomers include at least one of 2-PEA, PTEA, PEA, PBA, and / or IBA, present in a range of 3-18% by weight of the total formulation, and THEICTA (M370), present in a range of 1-10% by weight of the total formulation. The formulation optionally contains additives, such as T405 (Tinivin 405), I1010 (Irganox 1010), present in a range of 0.5-2.5% by weight of the total formulation, photoinitiator TPO, present in a range of 0.5-2.5% by weight of the total formulation, and residual solvent, present in a range of 4.0-6.5% by weight of the total formulation. The formulation is prepared as described in method 2 of this disclosure. The at least partially capped nanocrystals dispersed in a low boiling point solvent, ETA, are mixed with monomers, additives, and photoinitiators. After mixing, the formulation is rotary evaporated to remove the solvent and create a homogeneous solvent-free mixture. Several variations of the formulation are prepared using the different nanocrystals presented in this disclosure. Table 8a includes the compositions and viscosities for such formulations.

[0315]

[0347] The formulation was spin-coated onto a glass substrate and exposed to 3 J / cm 2 using a 365 nm UV lamp under N 2 . 2 The film was also coated onto a PET substrate with a glass backing, using the PET as the stamp coat, and then cured with a dose of 1 J / cm using a broadband UV lamp in air. 2 The films are cured at a dose of 1000 nm. The initial optical properties of the cured films and the change in properties after exposure to different wavelengths of light and condensation conditions are shown in Tables 8b, 8c, and 8d.

[0316] Example 21A

[0348] An exemplary formulation includes 73.0 wt.% of at least partially capped TiO2 nanocrystals without a ZrO2 shell, 14.6 wt.% 2-PEA and 7.5 wt.% THEICTA, 1.0% TPO, and 4.5% residual solvent after rotary evaporation. The viscosity of the formulation is 1030 cP at 25°C as measured with a Brookfield RVDV-II+PCP cone and plate viscometer. A 10 micron thick film produced with the formulation demonstrates a RI of 1.86 at 589 nm on glass or PET substrates. Films on glass substrates were spin-coated with the formulation and then irradiated with 365 nm UV lamp under N2 at 3 J / cm. 2 The film is made on PET with a glass backing, using PET as the stamp coat, then UV curing in air with a broadband UV lamp at a dose of 1 J / cm. 2 It hardens with a dose.

[0317] Example 21B

[0349] An exemplary formulation includes 70.0 wt% at least partially capped TiO2 nanocrystals without a ZrO2 shell, 15.9 wt% 2-PEA and 8.6 wt% THEICTA, 1.0% TPO, and 4.5% residual solvent after rotary evaporation. The viscosity of the formulation is 660 cP at 25°C as measured with a Brookfield RVDV-II+PCP cone and plate viscometer. A 10 micron thick film produced with the formulation demonstrates a RI of 1.85 at 589 nm on glass or PET substrates. Films on glass substrates were spin-coated with the formulation and then irradiated with 365 nm UV lamp under N2 at 3 J / cm. 2 The film is made on PET with a glass backing, using PET as the stamp coat, then UV curing at a dose of 1 J / cm2 using a broadband UV lamp in air. 2 It hardens with a dose.

[0318] Example 21C

[0350] An exemplary formulation includes 71.0 wt% of the at least partially capped TiO2 nanocrystals of Example 11A with a ZrO2 shell, 14.6 wt% 2-PEA and 7.9 wt% THEICTA, 2.0% TPO, and 4.5% residual solvent after rotary evaporation. The viscosity of the formulation is 700 cP at 25°C as measured with a Brookfield RVDV-II+PCP cone and plate viscometer. A 10 micron thick film produced with the formulation demonstrates a RI of 1.84 at 589 nm on glass or PET substrates. Films on glass substrates were spin-coated with the formulation and then irradiated with 365 nm UV lamp under N2 at 3 J / cm. 2 The film is made on PET with a glass backing, using PET as the stamp coat, then UV curing with a dose of 1 J / cm using a broadband UV lamp in air. 2 It hardens with a dose.

[0319] Example 21D

[0351] An exemplary formulation includes 71.0 wt% of the at least partially capped TiO2 nanocrystals of Example 11A with a ZrO2 shell, 17.2 wt% PEA and 5.3 wt% THEICTA, 2.0% TPO, and 4.5% residual solvent after rotary evaporation. The viscosity of the formulation is 950 cP at 25°C as measured with a Brookfield RVDV-II+PCP cone and plate viscometer. A 10 micron thick film produced with the formulation demonstrates a RI of 1.81 at 589 nm on a glass or PET substrate. The formulation is spin-coated and then irradiated with 3 J / cm2 UV light using a 365 nm UV lamp under N2. 2 Films are made on glass substrates by UV curing at a dose of 1 J / cm2. Films on PET have a glass backing and use PET as the stamp coat, then in air with a broadband UV lamp. 2 It hardens with a dose.

[0320] Example 21E

[0352] An exemplary formulation includes, after rotary evaporation, 71.6 wt.% of the at least partially capped TiO2 nanocrystals of Example 11B with a ZrO2 shell, 13.7 wt.% 2-PEA and 7.4 wt.% THEICTA, 1.0% TPO, and 6.4% residual solvent. The viscosity of the formulation is 1700 cP at 25°C as measured with a Brookfield RVDV-II+PCP cone and plate viscometer. A 10 micron thick film produced with the formulation demonstrates a RI of 1.82 at 589 nm on a glass or PET substrate. Th...

Claims

1. a nanocrystal having a core-shell structure comprising a core and an outer shell, the core being at least partially encapsulated by the outer shell, the core comprising a core metal oxide, and the outer shell comprising a shell metal oxide; the core metal oxide is characterized by having an average particle size greater than 3 nm and less than 50 nm as measured by TEM; the outer shell having a thickness of between 0.1 nm and 5 nm as measured by TEM; the core metal oxide and the shell metal oxide are the same or different; Nanocrystals.

2. 10. The nanocrystal of claim 1, wherein the atomic ratio of shell metal oxide to core metal oxide is less than 3 as measured by SEM EDX.

3. The core metal oxide has a narrow particle size distribution, and the narrow particle size distribution 1) a D90:D10 ratio of less than 5; 2) the D90:D50 ratio is less than 3; and / or 3) the D50:D10 ratio is less than 3, or The nanocrystals are characterized by a narrow particle size distribution, the narrow particle size distribution being 1) a D90:D10 ratio of less than 5; 2) the D90:D50 ratio is less than 3; and / or 3) Nanocrystals according to claim 1 or 2, characterized in that the D50:D10 ratio is less than 3.

4. The inorganic passivator may comprise a core and / or a core-shell treated with an inorganic passivator, wherein the inorganic passivator is NaH ２ P.O. ２ , Na ２ HPO ３ , NaCl, NaNO ３ and / or LiNO ３ 3. The nanocrystal of claim 1 or 2, comprising:

5. An at least partially capped nanocrystal comprising the nanocrystal of claim 1 or 2, comprising methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane. Silanes, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, Sisilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilylpropyl)pyrrole], 2-(trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, [methoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethyl orthosilicate, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol and triethylene glycol monomethyl ether, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid,capped with at least one capping agent selected from (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof; An at least partially capped nanocrystal, wherein the organic content of the at least partially capped nanocrystal is less than 25%.

6. (i) The core metal oxide comprises titanium dioxide, zirconium dioxide, and / or barium titanate, or (ii) the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, or any combination thereof; or (iii) The core metal oxide is TiO ２ and the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, or any combination thereof.

7. (i) 320 nm to 390 nm for 66 hours, light intensity 4 mW / cm ２ The haze of a 1 μm thick film containing the core-shell structure was measured using a haze meter before and after UV exposure at 1000 K. ＊ When measuring, less than 50% b ＊ exhibit low photocatalytic activity, as measured by a change in (ii) 1000 hours at 450 nm or higher, light intensity 16 mW / cm ２ or above 405 nm for 148 hours, light intensity 25 mW / cm ２ The haze of a 1 μm thick film containing the core-shell structure was measured using a haze meter before and after UV exposure at ＊ When measuring, less than 50% b ＊ exhibit low photocatalytic activity, as measured by a change in (iii) 148 hours at 405 nm or higher, light intensity 25 mW / cm ２ or exhibits low photocatalytic activity as measured by a change in refractive index of less than 0.08 when measuring the refractive index of a film containing core-shell nanocrystals using a prism coupler or ellipsometer before and after UV exposure at (iv) 1000 hours above 450 nm, 16 mW / cm ２ 3. The nanocrystals of claim 1 or 2, which exhibit low photocatalytic activity as measured by a change in refractive index of less than 0.08 when measuring the refractive index of a film comprising the core-shell nanocrystals using a prism coupler or an ellipsometer before and after UV exposure at 1000 K.

8. 10. The nanocrystal of claim 1, wherein the core metal oxide is titanium oxide and the shell metal oxide comprises zirconium oxide, and the average particle size of the nanocrystal is less than 30 nm as measured by TEM.

9. 9. The nanocrystal of claim 8, wherein the atomic ratio of shell Zr to core Ti is less than 3 as measured by SEM EDX.

10. 10. The nanocrystals of any one of claims 1, 2, 8 and 9, characterized in that the particle size distribution of the nanocrystals is D9999 less than 500 nm when measured by dynamic light scattering (DLS) on a volume of 5 wt% dispersed nanocrystals in a solvent.

11. 1. A nanocrystal dispersion comprising at least partially capped core-shell nanocrystals, at least one capping agent, and a dispersion medium, the core-shell nanocrystals comprise a core metal oxide and an outer shell comprising a shell metal oxide; the core metal oxide is characterized by having an average particle size of greater than 3 nm and less than 50 nm as measured by TEM or DLS, and the shell is characterized by having a thickness of between 0.1 nm and 5 nm as measured by TEM or DLS; the at least partially capped core-shell nanocrystals are present in an amount greater than 10% by weight of the dispersion; Nanocrystalline dispersions.

12. The at least partially capped core-shell nanocrystals may be prepared from methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, methyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxy ... trimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-( 4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilylpropyl)thiopropyltrimethoxysilane] (silyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethyl orthosilicate, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol and triethylene glycol monomethyl ether, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid,and / or is capped with at least one capping agent selected from (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid, 11-acryloyloxyundecylphosphonic acid, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof; The core-shell nanocrystals are prepared by ２ P.O. ２ , Na ２ HPO ３ , NaCl, NaNO ３ and / or LiNO ３ 12. The nanocrystal dispersion of claim 11, which has been treated with an inorganic passivation agent comprising: (i) the organic content of the at least partially capped nanocrystals is less than 25%; or (ii) the core metal oxide comprises titanium dioxide, zirconium dioxide, and / or barium titanate; (iii) the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, or any combination thereof; (iv) the at least partially capped core-shell nanocrystals are present in an amount of 50% or more by weight of the dispersion, and the % organics is less than 20% of the at least partially capped core-shell nanocrystals; and / or (v) The nanocrystal dispersion of claim 11 or 12, wherein the particle size distribution of the at least partially capped core-shell nanocrystals is characterized by a D9999 of less than 500 nm as measured by dynamic light scattering (DLS) on a volume of at least partially capped core-shell nanocrystals dispersed in a solvent at 5 wt.%. (i) the core metal oxide comprises titanium dioxide and the shell metal oxide comprises zirconium oxide, and the at least partially capped core-shell nanocrystals have an average particle size of less than 30 nm as measured by TEM or DLS; (ii) the atomic ratio of shell ZrO 2 to core TiO 2 is less than 3 as measured by SEM EDX; (iii) the at least partially capped core-shell nanocrystals are present in an amount of 50% or more by weight of the dispersion and the % organic is less than 20% of the at least partially capped core-shell nanocrystals; or (iv) the organic content of the at least partially capped nanocrystals is less than 25%; and / or (v) The nanocrystal dispersion of claim 11 or 12, wherein the particle size distribution of the at least partially capped core-shell nanocrystals is D9999 less than 500 nm as measured by dynamic light scattering (DLS) on a volume of at least partially capped core-shell nanocrystals dispersed in a solvent at 5 wt.%.

15. 1) At least partially capped core-shell TiO having an outer shell comprising a shell metal oxide ２ nanocrystals; 2) Monomers, oligomers, and / or polymers; 3) optionally a solvent; and 4) Hardener A nanocomposite formulation comprising an at least partially capped core-shell TiO ２ the nanocrystals are present in an amount greater than 20% by weight relative to the monomer, oligomer and / or polymer; At least partially capped core-shell TiO ２ the nanocrystalline core comprises crystalline titanium dioxide and is treated with at least one inorganic passivator; At least partially capped core-shell TiO ２ A nanocomposite formulation in which the average particle size of the nanocrystals ranges from 3 to 50 nm as measured by DLS as a 5% nanocrystal dispersion in PGMEA.

16. At least partially capped core-shell TiO ２ the nanocrystals have an average particle size of greater than 3 nm and less than 50 nm, as measured by TEM, and a shell thickness between 0.1 nm and 3 nm; or At least partially capped core-shell TiO ２ The nanocrystals may be selected from the group consisting of methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, dodecyltrimethoxysilane, m,p-ethylphenethyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, methoxy(triethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, silane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3-(4-pyridylethyl)thiopropyltrimethoxysilane, N-(3-trimethylpropyl)trimethoxysilane, 3-(4-methylpropyl)triethoxy ... (trimethoxysilylpropyl)pyrrole, 2-(3-trimethoxysilylpropylthio)thiophene, (3-trimethoxysilylpropyl)diethylenetriamine, phenyltrimethoxysilane, ((chloromethyl)phenylethyl)trimethoxysilane, 2-(diphenylphosphino)ethyltriethoxysilane, 4-phenylbutyltrimethoxysilane, 2-phenylethyltrimethoxysilane, 4-biphenylyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]allylamine, 3-mercaptopropyltrimethoxysilane, 8-glycol glycidoxyoctyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, tetraethyl orthosilicate, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleyl alcohol, dodecyl alcohol, octadecanol, and triethylene glycol monomethyl ether, (2-{2-[2-methoxy-ethoxy]-ethoxy}-ethyl)phosphonic acid, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)phosphonic acid,16. The nanocomposite formulation of claim 15, capped with at least one capping agent selected from 11-acryloyloxyundecylphosphonic acid, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, oleic acid, benzoic acid, stearic acid, trifluoroacetic acid, biphenyl-4-carboxylic acid, 2-(2-methoxyethoxy)acetic acid, methacrylic acid, mono-2-(methacryloyloxy)ethyl succinate, or any combination thereof.

17. 17. The nanocomposite formulation of claim 15 or 16, wherein the shell metal oxide comprises silicon dioxide, zirconium dioxide, hafnium dioxide, niobium oxide, aluminum oxide, tantalum oxide, barium titanium oxide, or any combination thereof.

18. 17. The nanocomposite formulation of claim 15 or 16, wherein the at least partially capped core-shell nanocrystals are present in an amount of 50% or more relative to the monomer, oligomer and / or polymer.

19. 17. The nanocomposite formulation of claim 15 or 16, wherein the viscosity of the formulation is in the range of 1 to 1000 cP. (i) At least partially capped core-shell TiO ２ The nanocrystals were measured using a haze meter to measure the b of a 1 μm thick film containing the core-shell structure before and after 100 hours of UV exposure at 320 nm to 390 nm. ＊ When measuring, less than 50% b ＊ have low photocatalytic activity, as measured by a change in (ii) At least partially capped core-shell TiO ２ The nanocrystals were measured using a haze meter to measure the b of a 1 μm thick film containing the core-shell structure before and after 1000 hours of UV exposure at 450 nm or higher. ＊ When measuring, less than 50% b ＊ have low photocatalytic activity, as measured by a change in (iii) At least partially capped core-shell TiO ２ the nanocrystals have low photocatalytic activity as measured by a change in refractive index of less than 0.08 when measuring the refractive index of a film containing the core-shell nanocrystals using a prism coupler or ellipsometer before and after 100 hours of UV exposure at 320-390 nm or greater; or (iv) At least partially capped core-shell TiO ２ 17. The nanocomposite formulation of claim 15 or 16, wherein the nanocrystals have low photocatalytic activity as measured by a change in refractive index of less than 0.08 when measuring the refractive index of a film containing the core-shell nanocrystals using a prism coupler or ellipsometer before and after 1000 hours of UV exposure at 450 nm or greater.

21. At least partially capped core-shell TiO having an outer shell comprising a shell metal oxide ２ A cured film comprising nanocrystals and a nanocomposite comprising at least one monomer, oligomer and / or polymer, the nanocomposite comprising at least a partially capped core-shell TiO ２ A nanocomposite wherein the nanocrystals are present in an amount greater than 50% by weight of the nanocomposite, and wherein the transmittance of a 1 micron thick film is greater than 80% at wavelengths of 400 nm and greater, and the film has a refractive index of about 1.60 to about 2.20 as measured using a prism coupler or an ellipsometer.

22. Films less than 5 μm thick are thermally stable when subjected to temperatures above 200° C. for 5 minutes; ＊ 22. The nanocomposite of claim 21, wherein the change in % haze is less than 25% as measured by a haze meter. (i) The nanocomposite is characterized in that the b of a 1 μm thick film comprising the core-shell structure is measured using a haze meter before and after 100 hours of UV exposure at 320 nm to 390 nm. ＊ When measuring, less than 50% b ＊ have low photocatalytic activity, as measured by a change in (ii) The nanocomposite is measured using a haze meter to measure the b of a 1 μm thick film comprising said core-shell structure before and after 1000 hours of UV exposure at 450 nm or above. ＊ When measuring, less than 50% b ＊ have low photocatalytic activity, as measured by a change in (iii) the nanocomposite has low photocatalytic activity, as measured by a change in refractive index of less than 0.08 when measuring the refractive index of a film containing the core-shell nanocrystals using a prism coupler or ellipsometer before and after 100 hours of UV exposure at 320-390 nm or greater; or (iv) The nanocomposite film of claim 21, wherein the nanocomposite has low photocatalytic activity as measured by a change in refractive index of less than 0.08 when measuring the refractive index of a film containing the core-shell nanocrystals using a prism coupler or an ellipsometer before and after 1000 hours of UV exposure at 450 nm or greater.

24. 23. A device comprising a film of the nanocomposite of claim 21 or 22.

25. A cured film of the nanocomposite formulation of claim 15.

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