Nanostructure-containing silica composite microparticles

Abstract

The present invention is in the field of nanostructures. The present invention provides nanostructures and microparticles comprising silica. Also provided are methods for making the microparticles, films comprising the microparticles, and devices comprising the microparticles. Also provided is a display backlight unit (BLU) that does not include a barrier layer.

Description

[Technical field]

[0001] The present invention is in the field of nanostructures. In the present invention, silica composite microparticles containing nanostructures are provided. Also provided are methods for making the microparticles, films containing the microparticles, and devices containing the microparticles. Also provided is a display backlight unit (BLU) that does not contain a barrier layer. [Background technology]

[0002] Quantum dot enhanced films (QDEFs) are multi-layer structures consisting of nanostructures embedded in a polymer resin sandwiched between one or more barrier layers. The barrier layers provide stability in operating conditions such as flux, temperature, and humidity. However, the barrier layers add additional cost to the product. A need exists for films comprising nanostructure compositions that have improved stability without the need for a barrier layer. Summary of the Invention

[0003] A unique approach is provided to provide a QDEF film that includes nanostructure-containing silica microparticles without the need for a barrier layer. The nanostructure-containing silica microparticles can be embedded into any optical grade polymer film by extrusion or similar process, and the film can be used as a QDEF for a display device. The cost of the device that includes the microparticles is reduced because the particles are stable and no barrier layer is required. In some embodiments, the QDEF is as shown in FIG. 1.

[0004] In the present disclosure, a composition is provided that includes a population of nanostructures that include a nanocrystalline core, where the nanostructures are embedded within silica microparticles.

[0005] In some embodiments, the nanocrystalline core is selected from the group consisting of Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, Al2CO, AgInGaS, and combinations thereof.

[0006] In some embodiments, the nanocrystalline core comprises InP. In some embodiments, the nanocrystalline core comprises CdSe. In some embodiments, the nanocrystalline core comprises at least one shell.

[0007] In some embodiments, at least one shell is ZnSe. In some embodiments, at least one shell is ZnS.

[0008] In some embodiments, the nanostructures comprise silver, indium, gallium, and sulfur (AIGS). In some embodiments, the silicate microparticles have a diameter of about 1 μm to about 20 μm. In some embodiments, the silica microparticles have an average particle size of about 2 μm to about 12 μm.

[0009] The present disclosure also provides a method of making the compositions described herein, the method including: (a) mixing the nanostructures and a metal silicate or ammonium silicate in water; (b) adding the mixture obtained in (a) to a solution containing a nonionic surfactant in a non-polar aprotic solvent and mixing to obtain a first microemulsion; (c) removing water from the first microemulsion obtained in (b); (d) combining acetic acid, a non-ionic surfactant and a non-polar aprotic solvent to obtain a second microemulsion; (e) combining the first and second microemulsions to obtain silica microparticles containing nanostructures; and (f) isolating the microparticles obtained in (e).

[0010] In some embodiments, the first and second microemulsions are passed through a filter having pores less than 10 μm prior to combining in (e).

[0011] In some embodiments, the non-polar aprotic solvent consists of 1-octadecene, 1-hexadecene, 1-eicosene, eicosane, octadecane, hexadecane, tetradecane, squalene, or squalane, or combinations thereof. In some embodiments, the non-polar aprotic solvent comprises 1-octadecene.

[0012] The present disclosure also provides a nanostructure film comprising: (a) a composition as described herein, and (b) at least one organic resin.

[0013] In some embodiments, the microparticles are embedded in at least one organic resin that forms a film. In some embodiments, the film is cured. In some embodiments, the membrane is formed by extrusion. In some embodiments, the membrane does not include a barrier layer adjacent to the membrane that has low oxygen and moisture permeability.

[0014] The present disclosure also provides a nanostructure molded article comprising: (a) First conductive layer (b) a second conductive layer, and (c) a nanostructured layer between the first conductive layer and the second conductive layer, the nanostructured layer comprising a composition described herein. In some embodiments, the nanostructure article does not include a barrier layer adjacent to the membrane that has low oxygen and moisture permeability.

[0015] The present disclosure also provides a display device comprising the composition described herein. In some embodiments, the microparticles are embedded in a matrix that forms a film within the display device. In some embodiments, the film is disposed on a light guide plate. In some embodiments, the display device does not include a barrier layer adjacent to the film that has low oxygen and moisture permeability.

[0016] The present disclosure also provides a display backlight unit (BLU) comprising: at least one primary light source that emits primary light; a light guide plate (LGP) optically coupled to the at least one primary light source, where the primary light is uniformly transmitted through the light guide plate; and an extruded film disposed on the light guide plate, where the primary light is uniformly transmitted through the light guide plate to the extruded film, wherein the extruded film is not directly physically coupled to the light guide plate and comprises one or more populations of nanostructures configured to emit secondary light, where at least a portion of the primary light is absorbed by the nanostructures and re-emitted by the nanostructures as the secondary light, and the BLU does not include a barrier layer.

[0017] In some embodiments, the nanostructure comprises a nanocrystalline core selected from the group consisting of Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, Al2CO, AgInGaS, and combinations thereof.

[0018] In some embodiments, the nanocrystalline core comprises InP. In some embodiments, the nanocrystalline core comprises CdSe. In some embodiments, the nanocrystalline core comprises at least one shell.

[0019] In some embodiments, at least one shell is ZnSe. In some embodiments, at least one shell is ZnS.

[0020] In some embodiments, the nanostructures comprise silver, indium, gallium, and sulfur (AIGS). In some embodiments, the extruded film comprises at least one organic resin. In some embodiments, the at least one organic resin is poly(methyl methacrylate) (PMMA), polyethylene terephthalate (PET), or a combination thereof. In some embodiments, one or more populations of nanostructures are encapsulated by an inorganic material. In some embodiments, the inorganic material comprises silica microparticles.

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the invention and, together with the description, serve to explain the principles of the invention and enable one skilled in the relevant art to make and use the invention. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram showing an extruded polymer film 101 containing embedded silica microparticles 102 that contain nanostructures 103. [Diagram 2] FIG. 2 is a process flow diagram for the synthesis of nanostructured calcium silicate microparticles. [Diagram 3] 3A-3C are scanning electron microscope (SEM) images of nanostructure-containing calcium silicate microparticles at different magnifications. [Figure 4] FIG. 4 is a graph showing the particle size distribution of the nanostructure-containing calcium silicate microparticles of FIGS. 3A to 3C. [Diagram 5] 5A-5D are graphs showing the ejection power at 50° C. under high flux (1, 10 and 68 times, FIG. 5A), under accelerated conditions at 80° C. under high flux (FIG. 5B), at 85° C. under dark storage (FIG. 5C), and under storage at 60° C. and 90% relative humidity. [Figure 6] FIG. 6 is a process flow diagram for the synthesis of nanostructured calcium silicate microparticles. [Figure 7] 7A-7B are SEM images of nanostructure-containing calcium silicate microparticles at different magnifications and the particle size distribution (FIG. 7C). [Figure 8] FIG. 8 is a process flow diagram for the synthesis of nanostructure-containing silica microparticles. [Figure 9] 9A-9C are SEM images of nanostructure-containing silica microparticles at different magnifications and the particle size distribution (FIG. 9D). [Figure 10] 10A-10C are SEM images of nanostructure-containing silica microparticles at different magnifications and the particle size distribution (FIG. 10D). [Figure 11] 11A-11C are SEM images of cross sections of extruded polymethyl methacrylate (PMMA) films containing nanostructured silica microparticles, showing the particle distribution and stability after the extrusion process. [Figure 12] 12A-12D are graphs showing the ejection power of a quantum dot enhanced film (QDEF) under dark storage at 85°C (FIG. 12A), under 1x and 10x flux at 50°C (FIG. 12B), under storage at 60°C / 90% relative humidity (FIG. 12C), and under 1x and 10x flux at 80°C. [Figure 13] FIG. 13 is a process flow diagram for the synthesis of nanostructured calcium silicate microparticles. [Figure 14] 14A-14C are SEM images of nanostructure-containing calcium silicate microparticles at different magnifications and the particle size distribution (FIG. 14D). [Figure 15] 15A-15D are graphs showing the ejection power of QDEF under 1, 10 and 68 times flux at 50°C (FIG. 15A), QDEF under 1 and 10 times flux at 80°C (FIG. 15B), QDEF under dark storage at 85°C (FIG. 15C), and QDEF under storage at 60°C / 90% relative humidity (FIG. 15D). [Figure 16] Figures 16A-16B are SEM images of nanostructure-containing silica microparticles obtained by reaction of ammonium silicate with acetic acid as described in Example 4. Figure 16C is a table showing the chemical composition of the silica microparticles, which are comprised of CdS / ZnSe nanostructures and silica. [Figure 17] Figures 17A-17B are SEM images of nanostructure-containing silica microparticles obtained by the emulsion process described in Example 2. Figure 17C is a table showing the presence of silicon, calcium, cadmium, zinc, sulfur and selenium in the silica microparticles, which are shown to consist of CdS / ZnSe nanostructures and calcium silicate. [Figure 18]Figures 18A-18B are SEM images of nanostructure-containing silica microparticles obtained by the emulsion process described in Example 2 using lithium silicate as the starting material, and Figure 18C is a table showing the chemical composition of the silicate microparticles, which are shown to consist of CdS / ZnSe nanostructures and calcium silicate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] All technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs, unless otherwise defined. The following definitions are supplementary to those of ordinary skill in the art and are directed to this application, and are not to be attributed to related or unrelated cases, such as commonly owned patents or applications. Although any methods and materials similar or equivalent to those described herein can be actually used for testing, the preferred materials and methods are described herein. Therefore, the terms used herein are only for describing specific embodiments, and are not intended to be limiting.

[0024] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "nanostructure" includes a plurality of such nanostructures.

[0025] As used herein, the term "about" indicates that a given quantity value varies by ±10% of that value. For example, "about 100 nm" encompasses a range of sizes from 90 nm to 110 nm.

[0026] A "nanostructure" is a structure having at least one region or characteristic dimension that is less than about 500 nm in dimension. In some embodiments, a nanostructure has a dimension that is less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm, e.g., 1-10 nm. Typically, the region or characteristic dimension is along the smallest axis of the structure. Examples of such structures include nanowires, nanorods, nanotubes, branched nanostructures, nanotetrapods, tripods, bipods, nanocrystals, nanodots, quantum dots, nanoparticles, and the like. Nanostructures can be, for example, substantially crystalline, substantially monocrystalline, polycrystalline, amorphous, or combinations thereof. In some embodiments, each of the three dimensions of a nanostructure has a dimension that is less than about 500 nm, less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm.

[0027] The term "heterostructure", when used with respect to nanostructures, refers to a nanostructure characterized by at least two different and / or distinguishable material types. Typically, one region of the nanostructure is composed of a first material type and a second region of the nanostructure is composed of a second material type. In some embodiments, the nanostructure is composed of a core of a first material and at least one shell of a second (or third, etc.) material, with the different material types distributed radially, for example, relative to the long axis of a nanowire, the long axis of an arm of a branched nanowire, or the center of a nanocrystal. The shell may, but does not necessarily, completely cover the adjacent material to be considered a shell or for the nanostructure to be considered a heterostructure. For example, a nanocrystal characterized by a core of one material surrounded by small islands of a second material is a heterostructure. In other embodiments, the different material types are distributed at different locations within the nanostructure, for example, along the long axis of a nanowire or along the long axis of an arm of a branched nanowire. Different regions within a heterostructure may comprise entirely different materials, or the different regions may comprise a base material (eg, silicon) with different dopants or different concentrations of the same dopant.

[0028] As used herein, the "diameter" of a nanostructure refers to the diameter of a cross section perpendicular to a first axis of the nanostructure, where the first axis has the greatest length difference with respect to the second and third axes (the second and third axes being the two axes whose lengths are most nearly equal to each other). The first axis is not necessarily the longest axis of the nanostructure. For example, for a disk-shaped nanostructure, the cross section will be a substantially circular cross section perpendicular to the short axis of the disk. If the cross section is not circular, the diameter is the average of the long and short axes of the cross section. For elongated nanostructures such as nanowires or nanostructures with high aspect ratios, the diameter is measured across a cross section perpendicular to the longest axis of the nanowire. For spherical nanostructures, the diameter is measured from one end to the other through the center of the sphere.

[0029] The term "crystalline" or "substantially crystalline", when used in reference to a nanostructure, refers to the fact that the nanostructure typically exhibits long-range order across one or more dimensions of its structure. One of skill in the art will appreciate that the term "long-range order" depends on the absolute size of a particular nanostructure, since the order of a single crystal cannot extend beyond the boundaries of the crystal. In this case, "long-range ordering" refers to substantial order across at least the majority of the dimensions of the nanostructure. In some cases, the nanostructure may have an oxide or other coating, or may include a core and at least one shell. In such cases, it will be understood that the oxide, shell, or other coating may, but need not, exhibit such order (e.g., may be amorphous, polycrystalline, or otherwise). In such cases, the phrases "crystalline", "substantially crystalline", "substantially monocrystalline", or "monocrystalline" refer to the central core of the nanostructure (excluding any coating layers or shells). As used herein, the terms "crystalline" or "substantially crystalline" are intended to encompass structures that contain various defects, stacking faults, atomic substitutions, and the like, so long as the structures exhibit substantial long-range order (e.g., order over at least about 80% of the length of at least one axis of the nanostructure or its core). Furthermore, it will be understood that the interface between the core and exterior of a nanostructure, or the interface between the core and an adjacent shell, or the interface between a shell and a second adjacent shell, may include non-crystalline regions and be amorphous. This does not prevent a nanostructure from being crystalline or substantially crystalline as defined herein.

[0030] The term "single crystal" when used in reference to a nanostructure indicates that the nanostructure is substantially crystalline and comprises substantially a single crystal. When used in reference to a nanostructure heterostructure consisting of a core and one or more shells, "single crystal" indicates that the core is substantially crystalline and comprises substantially a single crystal.

[0031] A "nanocrystal" refers to a nanostructure that is substantially monocrystalline. Thus, a nanocrystal has at least one region or characteristic dimension that is less than about 500 nm in dimension. In some embodiments, a nanocrystal has a dimension that is less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm, e.g., 1-10 nm. The term "nanocrystal" is intended to encompass substantially monocrystalline nanostructures that contain various defects, stacking faults, atomic substitutions, and the like, as well as substantially monocrystalline nanostructures that are free of such defects, stacking faults, or substitutions. In the case of nanocrystal heterostructures consisting of a core and one or more shells, the core of the nanocrystal is typically substantially monocrystalline, but the shells need not be. In some embodiments, each of the three dimensions of the nanocrystal has a dimension that is less than about 500 nm, less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm.

[0032] The term "quantum dot" (or "dot") refers to a nanocrystal that exhibits quantum or exciton confinement. Quantum dots can be substantially homogeneous in material properties or, in certain embodiments, can be heterogeneous, e.g., comprising a core and at least one shell. The optical properties of quantum dots can be affected by their particle size, chemical composition, and / or surface composition, and can be determined by suitable optical tests available in the art. The ability to tune the nanocrystal size, e.g., in the range between about 1 nm and about 15 nm, allows photoemission across the entire optical spectrum, providing highly versatile color rendering.

[0033] A "ligand" is a molecule that can interact (either strongly or weakly) with one or more facets of a nanostructure, for example, through covalent bonds, ionic bonds, van der Waals bonds, or other molecular interactions with the surface of the nanostructure.

[0034] "Photoluminescence quantum yield" (PLQY), for example, is the ratio of photons emitted to photons absorbed by a nanostructure or population of nanostructures. As known in the art, quantum yield is typically determined by comparative methods using well-characterized standards with known quantum yield values.

[0035] "Peak emission wavelength" (PWL) is the wavelength at which the radiometric emission spectrum of a light source is at a maximum.

[0036] As used herein, the term "shell" refers to material deposited on a core or on a previously deposited shell of the same or different composition resulting from a single deposition of shell material. The exact shell thickness depends on the material, precursor input and conversion and may be reported in nanometers or monolayers. As used herein, "target shell thickness" refers to the intended shell thickness used to calculate the amount of precursor required. As used herein, "actual shell thickness" refers to the amount of shell material actually deposited after synthesis and can be measured by methods known in the art. As an example, the actual shell thickness can be measured by comparing particle diameters determined from transmission electron microscope (TEM) images of nanocrystals before and after shell synthesis.

[0037] The term "full width at half maximum" (FWHM) as used herein is a measure of the size distribution of nanoparticles. The emission spectrum of nanoparticles generally has the shape of a Gaussian curve. The width of the Gaussian curve is defined as the FWHM and gives insight into the size distribution of the particles. A smaller FWHM means a narrower size distribution of the quantum dot nanocrystals. The FWHM also depends on the peak emission wavelength.

[0038] The term "half width at maximum" (HWHM) as used herein is a measure of the size distribution of nanoparticles extracted from UV-vis spectroscopy curves. The HWHM on the low-energy side of the first exciton absorption peak can be used as a suitable indicator of size distribution, with smaller HWHM values ​​corresponding to narrower size distributions.

[0039] As used herein, a microparticle is a particle having a diameter of 100 μm or less. In some embodiments, the microparticle has a diameter of about 1 to about 20 μm. In some embodiments, the microparticle has a diameter of about 1 to about 15 μm. In some embodiments, the microparticle has a diameter of about 1 to about 12 μm. In some embodiments, the microparticle has a diameter of about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, or about 20 μm. In some embodiments, the average microparticle size is about 2 to about 12 μm. In some embodiments, the average microparticle size is about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12 μm.

[0040] Microparticle composition In some embodiments, the microparticle composition comprises one or more nanostructures and silica. In some embodiments, the microparticle composition may further comprise a metal silicate, such as lithium silicate or calcium silicate. In other embodiments, the microparticle may comprise ammonium silicate.

[0041] Methods for producing microparticle compositions There is provided a method for producing a microparticle composition comprising calcium silicate as described herein, said method comprising: (a) mixing the nanostructures and a metal silicate or ammonium silicate in water; (b) adding the mixture obtained in (a) to a mixture of a non-polar aprotic solvent and a non-ionic surfactant and mixing the resulting composition to obtain a first microemulsion; (c) filtering the mixture obtained in (b); (d) removing water from the first microemulsion obtained in (c) to obtain microparticles; (e) isolating the microparticles obtained in (d); (f) mixing the isolated microparticles obtained in (e) with a calcium halide solution to obtain microparticles composed of calcium silicate; and, (g) isolating microparticles of calcium silicate.

[0042] For example, in (a), 2 mL of an aqueous dispersion of quantum dots (QDs) such as CdSe (inorganic content 9-10 wt%) + 3.4 mL of water are stirred. In some embodiments, the mixture further comprises 0.15 mL of (3-mercaptopropyl)trimethoxysilane (MPTMS). In some embodiments, the mixing of (a) is performed at room temperature to 100°C. In other embodiments, the mixing of (a) is performed at 50 to 90°C. In other embodiments, the mixing of (a) is performed at 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C. In some embodiments, the mixture is stirred at 80°C for 5 minutes. Then, a metal silicate solution (e.g., 2.8 mL of a 25 wt% solution of LiSiL) is added with good stirring.

[0043] In (b), the non-ionic surfactant / non-polar aprotic solvent mixture is added with good stirring. Examples of non-ionic surfactants include Span® 80 (e.g., 16.5 ml of 1.3 wt%) or Tween®). In some embodiments, the non-polar aprotic solvent consists of 1-octadecene, 1-hexadecene, 1-eicosene, eicosane, octadecane, hexadecane, tetradecane, squalene, or squalane, or combinations thereof. The solution becomes milky white, indicating the formation of a microemulsion.

[0044] In (c), the admixture from (b) is filtered, e.g., through a micron filter, for homogenization. In some embodiments, the filter contains pores of 1-10 μm. In some embodiments, the pores are 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 μm in diameter. Homogenization can also be achieved by a mechanical homogenizer.

[0045] In (d), water is removed from the microemulsion by heating and / or placing under reduced pressure. In some embodiments, the microemulsion is heated to 50-100° C. In some embodiments, the microemulsion is heated at 80° C. under vacuum. In some embodiments, the microemulsion is heated at a vacuum of 10 Torr for about 10-15 minutes.

[0046] In (e), the microparticles are isolated. In some embodiments, the microparticles are isolated, for example, by centrifugation. In some embodiments, the microparticles are isolated by centrifugation at 3000-4000 rpm, for example, for 5 minutes.

[0047] In (f), the isolated microparticles from (e) are mixed with a calcium halide solution to obtain microparticles composed of calcium silicate. In some embodiments, the calcium halide is calcium chloride. In some embodiments, the microparticles are dispersed in 7 ml of calcium chloride solution and stirred at 60° C. for 30 minutes.

[0048] In (g), the calcium silicate-containing microparticles are isolated / purified by washing with a non-solvent. Examples of non-solvents include acetone and ethanol. In some embodiments, the calcium silicate-containing microparticles are washed with two acetone washes and two ethanol washes. In some embodiments, the calcium silicate-containing microparticles are isolated by centrifugation and purified by washing with ethanol (e.g., twice).

[0049] In some embodiments, the resulting product is dried to a powder and dispersed in a carrier solvent. In some embodiments, this process yields about 95% calcium silicate particles per batch with a QD loading of about 20 wt%.

[0050] Also provided is a method of making the silica microparticle compositions described herein, said method including: (a) mixing the nanostructures and a metal silicate or ammonium silicate in water; (b) adding the mixture obtained in (a) to a non-polar aprotic solvent and a non-ionic surfactant and mixing the resulting composition to obtain a first microemulsion; (c) removing water from the first microemulsion obtained in (b) to isolate the microparticles; (d) mixing the microparticles obtained in (c) with acetic acid and a non-polar aprotic solvent to obtain a second microemulsion; (e) combining the first and second microemulsions to obtain silica microparticles containing nanostructures; and, (f) isolating the silica microparticles obtained in (e).

[0051] In some embodiments, the first and second microemulsions are filtered prior to combining in (c). In some embodiments, the first and second microemulsions are passed through a filter having pores of 1-10 μm prior to combining in (e). In some embodiments, the first and second microemulsions are passed through a filter having pores of 5 μm or less prior to combining in (e). In some embodiments, the first and second emulsions are passed through a filter having pores of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 μm.

[0052] In some embodiments, the non-polar aprotic solvents used in (b) and (d) are the same or different. In some embodiments, the non-polar aprotic solvent comprises 1-octadecene, 1-hexadecene, 1-eicosene, eicosane, octadecane, hexadecane, tetradecane, squalene, or squalane, or a combination thereof. In b), examples of non-ionic surfactants include Span® 80 (e.g., 1.3 wt % 16.5 ml) or Tween®.

[0053] In some embodiments, the blending of (a) is carried out at room temperature to 100° C. In other embodiments, the blending of (a) is carried out at 50 to 90° C. In other embodiments, the blending of (a) is carried out at 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., or 90° C.

[0054] In some embodiments, the metal silicate is lithium silicate, beryllium silicate, sodium silicate, or potassium silicate. In some embodiments, the ammonium silicate is NH + SiO4 = or mono-, di-, tri- or tetra-C 1-4 It is an alkyl ammonium silicate.

[0055] In (e), the microparticles are isolated. In some embodiments, the microparticles are isolated, for example, by centrifugation. In some embodiments, the microparticles are isolated by centrifugation at 3000-4000 rpm, for example, for 5 minutes.

[0056] In (d), acetic acid and a non-polar aprotic solvent are mixed. In some embodiments, the acetic acid is glacial acetic acid. In other embodiments, the ratio of acetic acid to the non-polar aprotic solvent may range from 5% to 95% wt / wt.

[0057] Also provided is a method of making a microparticle composition comprising calcium silicate as described herein, said method comprising:

[0058] 16.5 mL of 3 wt% Span80 / ODE solution was stirred at 600 rpm. 2.8 mL of 25 wt% lithium silicate solution was added with good stirring. The resulting mixture turned milky white, indicating the formation of a microemulsion. The solution was passed through a 6 μm filter and homogenized. This solution was designated "Microemulsion 1."

[0059] 2 mL of an aqueous dispersion of QDs (inorganic content 9–10 wt%) + 3.4 mL of water + 0.15 mL of MPTMS was stirred at 60°C for 5 min. 27.5 ml of 3 wt% Span80 / ODE solution was stirred at 600 rpm. The above QD solution was added dropwise. The resulting mixture turned milky white, indicating the formation of a microemulsion. The solution was passed through a 6 μm filter and homogenized. This solution was designated "Microemulsion 2."

[0060] Microemulsions 1 and 2 were mixed and kept under stirring conditions for 30 minutes. 15 ml of 3 wt% Span80 / ODE solution was stirred at 600 rpm. 3 ml of 2M calcium chloride solution was added dropwise. The resulting mixture turned milky white, indicating the formation of a microemulsion. The solution was passed through a 6 micron filter and homogenized. This solution was designated as Microemulsion 3.

[0061] Finally, microemulsion 3 was added to the mixture of microemulsions 1 and 2, and the resulting mixture was kept under stirring for 30 minutes to allow the silicate to precipitate. Finally, the particles were isolated by centrifugation and purified by washing with acetone and ethanol.The calcium silicate-containing silica particles were then dried and stored in a carrier solvent.

[0062] Nanostructure Core The core of the nanostructures used in the present invention can be made of any suitable material, preferably an inorganic material, more preferably an inorganic conductive or semiconducting material. Suitable semiconducting materials include any type of semiconductor, including II-VI semiconductors, III-V semiconductors, IV-VI semiconductors, and Group IV semiconductors. Suitable semiconductor materials include, but are not limited to, Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, Al2CO, AgInGaS, and combinations thereof.

[0063] Synthesis of II-VI nanostructures is described in U.S. Patent Nos. 6,225,198, 6,322,901, 6,207,229, 6,607,829, 6,861,155, 7,060,243, 7,125,605, 7,374,824, 7,566,476, 8,101,234, 8,158,193, and U.S. Patent Application Publication Nos. 2011 / 0262752 and 2011 / 0263062. In some embodiments, the core is a II-VI nanocrystal selected from the group consisting of ZnO, ZnSe, ZnS, ZnTe, CdO, CdSe, CdS, CdTe, HgO, HgSe, HgS, and HgTe. In some embodiments, the core is a nanocrystal selected from the group consisting of ZnSe, ZnS, CdSe, and CdS.

[0064] Although II-VI nanostructures such as CdSe and CdS quantum dots can exhibit desirable luminescence behavior, issues such as the toxicity of cadmium limit the applications in which such nanostructures can be used. Therefore, less toxic alternatives with favorable luminescence properties are highly desirable. III-V nanostructures in general, and InP-based nanostructures in particular, offer the best-known alternative to cadmium-based materials due to their compatible emission range.

[0065] Regarding the synthesis of InP-based nanostructures, for example, Xie, R., et al., 「Colloidal InP nanocrystals as efficient emitters covering blue to near-infrared」 J. Am. Chem. Soc. 129: 15432-15433 (2007), Micic, O.I., et al., 「Core-shell quantum dots of lattice-matched ZnCdSe2shells on InP cores: Experiment and theory」 J. Phys. Chem. B 104: 12149-12156 (2000), Liu, Z., et al., 「Coreduction colloidal synthesis of III-V nanocrystals: The case of InP」 Angew. Chem. Int. Ed. Engl. 47:3540-3542 (2008), Li, L. et al., 「Economic synthesis of high quality InP nanocrystals using calcium phosphide as the phosphorus precursor」 Chem. Mater. 20:2621-2623 (2008), D. Battaglia and X. Peng, 「Formation of high quality InP and InAs nanocrystals in a noncoordinating solvent」 Nano Letters 2: 1027-1030 (2002), Kim, S., et al., 「Highly luminescent InP / GaP / ZnS nanocrystals and their application to white light-emitting diodes」 J. Am. Chem. Soc. 134:3804-3809 (2012), Nann, T., et al., 「Water splitting by visible light: A nanophotocathode for hydrogen production」 Angew. Chem. Int. Ed. 49:1574-1577 (2010)、Borchert, H., et al., 「Investigation of ZnS passivated InP nanocrystals by XPS」 Nano Letters 2: 151-154 (2002)、L. Li and P. Reiss, 「One-pot synthesis of highly luminescent InP / ZnS nanocrystals without precursor injection」 J. Am. Chem. Soc. 130: 11588- 11589 (2008)、Hussain, S., et al. 「One-pot fabrication of high-quality InP / ZnS (core / shell) quantum dots and their application to cellular imaging」 Chemphyschem. 10: 1466-1470 (2009)、Xu, S., et al., 「Rapid synthesis of high-quality InP nanocrystals」 J. Am. Chem. Soc. 128:1054-1055 (2006)、Micic, O.I., et al., 「Size-dependent spectroscopy of InP quantum dots」 J. Phys. Chem. B 101:4904-4912 (1997)、Haubold, S., et al., 「Strongly luminescent InP / ZnS core-shell nanoparticles」 Chemphyschem. 5:331-334 (2001)、CrosGagneux, A., et al., 「Surface chemistry of InP quantum dots: A comprehensive study」 J. Am. Chem. Soc.132: 18147-18157 (2010), Micic, OI, et al., “Synthesis and characterization of InP, GaP, and GalnP2quantum dots” J. Phys. Chem. 99:7754-7759 (1995), Guzelian, AA, et al., “Synthesis of size-selected, "surface-passivated InP nanocrystals" J. Phys. Chem. 100:7212-7219 (1996), Lucey, DW, et al., "Monodispersed InP quantum dots prepared by colloidal chemistry in a non-coordinating solvent" Chem. Mater. 17:3754-3762 (2005), Lim, J., et al. al., “InP@ZnSeS, core@composition gradient shell quantum dots with enhanced stability" Chem. Mater. 23:4459-4463 (2011), and Zan, F., et al., "Experimental studies on blinking behavior of single InP / ZnS quantum dots: Effects of synthetic conditions and UV irradiation" J. Phys. Chem. C 116:394-3950 (2012). However, these efforts have had limited success in producing InP nanostructures with high quantum yields.

[0066] In some embodiments, the InP core is doped. In some embodiments, the dopant of the nanocrystalline core includes a metal, including one or more transition metals. In some embodiments, the dopant is a transition metal selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, and combinations thereof. In some embodiments, the dopant includes a non-metal. In some embodiments, the dopant is ZnS, ZnSe, ZnTe, CdSe, CdS, CdTe, HgS, HgSe, HgTe, CuInS2, CuInSe2, AlN, AlP, AlAs, GaN, GaP, or GaAs.

[0067] In some embodiments, the cores are purified prior to deposition of the shell, hi some embodiments, the cores are filtered to remove precipitates from the core solution.

[0068] In some embodiments, the diameter of the InP core is determined using quantum confinement. Quantum confinement in zero-dimensional nanocrystals, such as quantum dots, arises from the spatial confinement of electrons within the crystallite boundaries. Quantum confinement can be observed when the diameter of the material is as large as the de Broglie wavelength of the wave function. The electronic and optical properties of nanoparticles deviate significantly from those of bulk materials. When the confinement size is large compared to the particle's wavelength, the particle behaves as if it were free. In this state, the band gap remains at its original energy due to the continuum of energy states. However, as the confinement size decreases to a certain limit (typically the nanoscale), the energy spectrum becomes discontinuous. As a result, the band gap becomes size dependent.

[0069] In some embodiments, the nanostructures are cadmium-free. As used herein, the term "cadmium-free" contemplates that the nanostructures contain less than 100 ppm cadmium by weight. The Restriction of Hazardous Substances (RoHS) compliant definition states that cadmium should not exceed 0.01% by weight (100 ppm) in raw homogenous precursor materials. The cadmium level in the cadmium-free nanostructures of the present invention is limited by the trace metal concentration in the precursor material. The trace metal (including cadmium) concentration in the precursor material of the cadmium-free nanostructures can be measured at parts per billion (ppb) levels by inductively coupled plasma mass spectrometry (ICP-MS) analysis. In some embodiments, the "cadmium-free" nanostructures contain less than about 50 ppm, less than about 20 ppm, less than about 10 ppm, or less than about 1 ppm cadmium.

[0070] shell In some embodiments, the nanostructure core comprises one or more shells. Examples of materials for preparing the shell include, but are not limited to, Si, Ge, Sn, Se, Te, B, C (including diamond), P, Co, Au, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, Al2CO, and combinations thereof.

[0071] In some embodiments, the shell is a mixture of at least two of a zinc source, a selenium source, a sulfur source, a tellurium source, and a cadmium source. In some embodiments, the shell is a mixture of two of a zinc source, a selenium source, a sulfur source, a tellurium source, and a cadmium source. In some embodiments, the shell is a mixture of three of a zinc source, a selenium source, a sulfur source, a tellurium source, and a cadmium source. In some embodiments, the shell is a mixture of zinc and sulfur, zinc and selenium, zinc and sulfur and selenium, zinc and tellurium, zinc and tellurium and sulfur, zinc and tellurium and selenium, zinc and cadmium and sulfur, zinc and cadmium and selenium, cadmium and sulfur, cadmium and selenium, cadmium and zinc, cadmium and zinc and sulfur, cadmium and zinc and selenium, or cadmium and zinc and sulfur and selenium. In some embodiments, the shell is a mixture of zinc and selenium. In some embodiments, the shell is a mixture of zinc and sulfur.

[0072] Exemplary core / shell luminescent nanostructures include, but are not limited to, CdSe / ZnSe and InP / ZnSe (referred to as core / shell).

[0073] In some embodiments, the shell comprises ZnSe. The thickness of the shell can be controlled by varying the amount of precursors provided. For a given shell thickness, at least one of the precursors is suitably provided in an amount such that a shell of the given thickness is obtained when the growth reaction is substantially complete. In some embodiments, the molar ratio of the zinc source to the selenium source is from about 0.01:1 to about 1:1.5, from about 0.01:1 to about 1:1.25, from about 0.01:1 to about 1:1, from about 0.01:1 to about 1:1, from about 0.01:1 to about 1:0.75, from about 0.01:1 to about 1:0.5, from about 0.01:1 to about 1:0.25, from about 0.01:1 to about 1:0.05, from about 0.05:1 to about 1:1.5, from about 0.05:1 to about 1:1.25, from about 0.05:1 to about 1:1, from about 0.05:1 to about 1:0.75, from about 0.05:1 to about 1:0.5, from about 0.05:1 to about 1:0. about 1:0.25, about 0.25:1 to about 1:1.5, about 0.25:1 to about 1:1.25, about 0.25:1 to about 1:1, about 0.25:1 to about 1:0.75, about 0.25:1 to about 1:0.5, about 0.5:1 to about 1:1.5, about 0.5:1 to about 1:1.25, about 0.5:1 to about 1:1, about 0.5:1 to about 1:0.75, about 0.75:1 to about 1:1.5, about 0.75:1 to about 1:1.25, about 0.75:1 to about 1:1:1, about 1:1 to about 1:1.5, about 1:1 to about 1:1.25, or about 1:1.25 to about 1:1.5.

[0074] The thickness of the ZnSe shell layer can be controlled by varying the amounts of zinc and selenium sources provided and / or by using longer reaction times and / or higher temperatures, with at least one source being provided in an amount such that a layer of a predetermined thickness is obtained when the growth reaction is substantially complete.

[0075] The thickness of the ZnSe thin shell can be determined using techniques known to those of skill in the art. In some embodiments, the thickness of the inner thin shell is determined by comparing the average diameter of the nanostructure before and after the addition of the inner thin shell. In some embodiments, the average diameter of the nanostructure before and after the addition of the inner thin shell is determined by TEM. In embodiments, the ZnSe shell has a thickness of about 0.01 nm to about 0.35 nm, about 0.01 nm to about 0.3 nm, about 0.01 nm to about 0.25 nm, about 0.01 nm to about 0.2 nm, about 0.01 nm to about 0.1 nm, about 0.01 nm to about 0.05 nm, about 0.05 nm to about 0.35 nm, about 0.05 nm to about 0.3 nm, about 0.05 nm to about 0.25 nm, about 0.05 nm to about 0.2 nm, The thickness is about 0.05 nm to about 0.1 nm, about 0.1 nm to about 0.35 nm, about 0.1 nm to about 0.3 nm, about 0.1 nm to about 0.25 nm, about 0.1 nm to about 0.2 nm, about 0.2 nm to about 0.35 nm, about 0.2 nm to about 0.3 nm, about 0.2 nm to about 0.25 nm, about 0.25 nm to about 0.35 nm, about 0.25 nm to about 0.3 nm, or about 0.3 nm to about 0.35 nm.

[0076] In some embodiments, the zinc source is a dialkyl zinc compound. In some embodiments, the zinc source is a zinc carboxylate. In some embodiments, the zinc source is diethyl zinc, dimethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof. In some embodiments, the zinc source is zinc oleate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof. In some embodiments, the zinc source is zinc oleate.

[0077] In some embodiments, the selenium source is an alkyl-substituted selenourea. In some embodiments, the selenium source is a phosphine selenide. In some embodiments, the selenium source is selected from trioctylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, tricyclohexylphosphine selenide, cyclohexylphosphine selenide, 1-octaneselenol, 1-dodecaneselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl)selenide, selenourea, and mixtures thereof. In some embodiments, the selenium source is tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, or tri(tert-butyl)phosphine selenide. In some embodiments, the selenium source is trioctylphosphine selenide.

[0078] In some embodiments, the ZnSe shell is synthesized in the presence of at least one nanostructure ligand. The ligand can, for example, increase the miscibility of the nanostructure in a solvent or polymer (allowing the nanostructure to be dispersed throughout the composition so that the nanostructure does not aggregate), increase the quantum yield of the nanostructure, and / or preserve the luminescence of the nanostructure (e.g., when the nanostructure is incorporated into a matrix). In some embodiments, the ligand(s) for the InP core synthesis and the ligand(s) for the shell synthesis are the same. In some embodiments, the ligand(s) for the core synthesis and the ligand(s) for the shell synthesis are different. After synthesis, the ligands on the nanostructure surface can be exchanged for different ligands with other desirable properties. Exemplary ligands are disclosed in U.S. Patent Nos. 7,572,395, 8,143,703, 8,425,803, 8,563,133, 8,916,064, 9,005,480, 9,139,770, and 9,169,435, and U.S. Patent Application Publication No. 2008 / 0118755.

[0079] Ligands suitable for the synthesis of the shell are known to those skilled in the art. In some embodiments, the ligand is a fatty acid selected from the group consisting of lauric acid, caproic acid, myristic acid, palmitic acid, stearic acid, and oleic acid. In some embodiments, the ligand is an organophosphine or organophosphine oxide selected from trioctylphosphine oxide (TOPO), trioctylphosphine (TOP), diphenylphosphine (DPP), triphenylphosphine oxide, and tributylphosphine oxide. In some embodiments, the ligand is an amine selected from the group consisting of dodecylamine, oleylamine, hexadecylamine, dioctylamine, and octadecylamine. In some embodiments, the ligand is oleic acid.

[0080] In some embodiments, the nanostructure composition comprises an InP / ZnSe / ZnS core-shell nanostructure, where at least one of the ZnSe and ZnS shells has a thickness between 0.7 nm and 3.5 nm, the nanostructure exhibits a photoluminescence quantum yield between 60 and 99%, the nanostructure exhibits a full width at half maximum between 35 nm and 45 nm, and the nanostructure exhibits an OD450 / peak between about 1.0 and about 3.0. Such nanostructures and methods for their manufacture are disclosed in U.S. Patent Application Publication Nos. 2017 / 0306227 and 2018 / 0199007.

[0081] In some embodiments, the nanostructure comprises a core comprised of indium phosphide and at least two shells, at least one of the shells comprised of zinc, the nanostructure exhibits a photoluminescence quantum yield of about 94% to about 100%, and the nanostructure has a full width at half maximum of less than 45 nm. In some embodiments, the nanostructure is an InP / ZnSe / ZnS nanostructure. Such nanostructures and methods for their manufacture are disclosed in U.S. Patent Application Publication No. 2020 / 0325396.

[0082] In some embodiments, the nanostructure composition comprises a core-shell nanostructure surface treated with zinc acetate and zinc fluoride. In some embodiments, the present disclosure provides a nanostructure composition comprising an InP / ZnSe core-shell nanostructure. In some embodiments, the ZnSe shell has a thickness of about 0.01 nm to about 5 nm. In some embodiments, the nanostructure is a quantum dot. Such nanostructures and methods for making the same are disclosed in U.S. Patent Application Publication No. 2021 / 0013377.

[0083] In some embodiments, the nanostructure composition comprises ZnSe having one or more shell layers. 1-x Te x In some embodiments, the nanostructure comprises a core surrounded by at least one shell, the core being ZnSe 1-x Te xIt consists of, where 0 < x < 1, and at least one shell is selected from the group consisting of ZnS, ZnSe, ZnTe, and their alloys, and the full width at half maximum (FWHM) of the nanostructure is from about 20 nm to about 30 nm. Such nanostructures and their manufacturing methods are disclosed in U.S. Patent Application Publication No. 2021 / 0047563.

[0084] In some embodiments, the nanostructure includes a nanocrystal core and at least one shell, and at least one shell contains at least one metal fluoride represented by the following formula (I). MF4 (I) In the formula, M = Zr, Hf, or Ti. In some embodiments, the nanostructure is (a) a core containing ZnSe, at least one shell containing ZnS, and at least one shell containing HfF4, or (b) a core containing ZnSe 1-x Te x (where 0 ≤ x ≤ 1), at least one shell containing ZnSe, and at least one shell containing ZnS, and at least one shell containing HfF4. Such nanostructures and their manufacturing methods are disclosed in U.S. Patent Application Publication No. 2021 / 0277307.

[0085] In some embodiments, the nanostructure includes a core surrounded by at least one shell, the core contains ZnSe 1-x Te x where 0 < x < 1, at least one shell contains ZnS or ZnSe, and the full width at half maximum (FWHM) of the nanostructure is from about 10 nm to about 30 nm. In some embodiments, the nanostructure is a ZnSe 1-x Te x / ZnSe / ZnS core / shell nanostructure. Such nanostructures and their manufacturing methods are disclosed in U.S. Patent Application Publication No. 2019 / 0390109.

[0086] In some embodiments, the nanostructure comprises a nanocrystalline core and at least one shell disposed on the core, the at least one shell comprising ZnS and a fluoride. In some embodiments, the nanostructure comprises a core comprising ZnSe and at least one shell comprising ZnS and ZnF2, a core comprising ZnSe and at least one shell comprising ZnSe and at least one shell comprising ZnS and ZnF2, a ZnSe core, where 0≦x≦1, 1-x Te x and at least one shell comprising ZnS and ZnF2, or ZnSe, where 0≦x≦1. 1-x Te x and at least one shell comprising ZnSe and at least one shell comprising ZnS and ZnF2. Such nanostructures and methods for making the same are disclosed in U.S. Patent Application Publication No. 2021 / 0009900.

[0087] In some embodiments, the nanostructures include at least one fluoride-containing ligand attached to the surface of the nanostructure (wherein the fluoride-containing ligand is selected from the group consisting of fluorozincate, tetrafluoroborate, and hexafluorophosphate) or a fluoride anion attached to the surface of the nanostructure (wherein the nanostructure composition exhibits a photoluminescence quantum yield of between about 70% and about 90%). Such nanostructures and methods for making them are disclosed in U.S. Patent Application Publication No. 2020 / 0299575.

[0088] In some embodiments, the nanostructure comprises Ag, In, Ga, and S (AIGS). In some embodiments, the nanostructure has a peak emission wavelength (PWL) in the range of 480-545 nm, at least about 80% of the emission is band edge emission, and the nanostructure exhibits a quantum yield (QY) of 80-99.9%. Such nanostructures and methods for their manufacture are disclosed in U.S. Patent No. 10,927,294.

[0089] Membranes, devices and applications The population of microparticles is optionally embedded in a matrix (e.g., organic polymer, silicon-containing polymer, inorganic, glassy, ​​and / or other matrix) that forms a film. This film can be used to manufacture nanostructure phosphors and / or incorporated into devices such as LEDs, backlights, downlights, other display or lighting units, or optical filters. Exemplary phosphors and lighting units can produce a specific color light, for example, by incorporating a population of nanostructures with an emission maximum at or near a desired wavelength, or can produce a wide color gamut by incorporating two or more different populations of nanostructures with different emission maxima. A variety of suitable matrices are known in the art. See, for example, U.S. Pat. No. 7,068,898 and U.S. Patent Application Publication Nos. 2010 / 0276638, 2007 / 0034833, and 2012 / 0113672. Exemplary nanostructure phosphor films, LEDs, backlight units, and the like are described, for example, in U.S. Patent Application Publication Nos. 2010 / 0276638, 2012 / 0113672, 2008 / 0237540, 2010 / 0110728, and 2010 / 0155749, and U.S. Patent Nos. 7,374,807, 7,645,397, 6,501,091, and 6,803,719.

[0090] In some embodiments, the nanostructure film is used to form a display device. As used herein, a display device refers to any system that has an illuminated display. Such devices include, but are not limited to, devices that include liquid crystal displays (LCDs), televisions, computers, mobile phones, smartphones, personal digital assistants (PDAs), game consoles, e-readers, digital cameras, etc.

[0091] In some embodiments, the present disclosure provides a nanostructure molded article comprising: (a) a first conductive layer; (b) a second conductive layer; and, (c) a nanostructure layer between the first conductive layer and the second conductive layer; wherein the nanostructure layer comprises a population of silica microparticles comprising nanostructures embedded in a matrix.

[0092] In some embodiments, the present disclosure provides a nanostructure film comprising: (a) at least one population of silica microparticles comprising a population of silica microparticles comprising nanostructures; and (b) at least one organic resin.

[0093] As used herein, the term "embedded" is used to indicate that the microparticles are encapsulated or encased within the matrix material. In some embodiments, the microparticles are uniformly distributed throughout the matrix material. In some embodiments, the microparticles are distributed according to an application-specific uniformity distribution function.

[0094] The matrix material may be any suitable host matrix material capable of housing the microparticles. A suitable matrix material may be chemically and optically compatible with the microparticles and the surrounding packaging materials or layers used in applying the nanostructure film to the device. A suitable matrix material may include non-yellowing optical materials that are transparent to both the primary and secondary light, thereby allowing both the primary and secondary light to transmit through the matrix material. The matrix material may include polymers, organic and inorganic oxides. A suitable polymer for use in the matrix material may be any polymer known to those skilled in the art and usable for such purposes. The polymer may be substantially translucent or substantially transparent. Matrix materials may include, but are not limited to, epoxies, acrylates, norbornenes, polyethylene, poly(vinyl butyral):poly(vinyl acetate), polyureas, polyurethanes; silicones and silicone derivatives, including but not limited to aminosilicones (AMS), polyphenylmethylsiloxanes, polyphenylalkylsiloxanes, polydiphenylsiloxanes, polydialkylsiloxanes, silsesquioxanes, fluorinated silicones, vinyl and hydride substituted silicones, and the like; acrylic-based polymers and copolymers formed from monomers such as methyl methacrylate, butyl methacrylate, lauryl methacrylate, and the like; styrenic polymers such as polystyrene, aminopolystyrene (APS), poly(acrylonitrile ethylene styrene) (AES), and the like; polymers crosslinked with difunctional monomers such as divinylbenzene; crosslinkers suitable for crosslinking ligand materials, such as, but not limited to, epoxides that combine with ligand amines (e.g., APS or polyethyleneimine ligand amines) to form epoxies.

[0095] In some embodiments, the matrix material further includes scattering microbeads, such as TiO 2 , ZnS, or glass microbeads, which can improve the light conversion efficiency of the nanostructured film. In some embodiments, the matrix material may include a light blocking component.

[0096] In some embodiments, the matrix material has low oxygen and moisture permeability, exhibits high light and chemical stability, exhibits good refractive index, and can adhere to the exterior surface of the nanostructures to provide a hermetic seal to protect the nanostructures, hi another embodiment, the matrix material may be curable with UV or thermal curing methods to facilitate roll-to-roll processing.

[0097] In some embodiments, the nanostructured film further comprises one or more barrier layers directly adjacent to the nanostructured film that have low permeability to oxygen and water to protect the nanostructures from degradation. In other embodiments, the nanostructured film has at least one surface that is exposed to ambient conditions. In some embodiments, the nanostructured film does not include a barrier layer. This is possible because the silica-containing microparticles have low permeability to oxygen and water. The use of silica-containing microparticles eliminates the use of a barrier layer, thus reducing the cost and complexity of devices that include the nanostructured film.

[0098] In some embodiments, the nanostructure film can be formed by mixing the microparticles in a polymer (e.g., photoresist) and casting the microparticle-polymer mixture onto a substrate, mixing the microparticles with a monomer and polymerizing them together, mixing the microparticles in a sol-gel to form an oxide, or any other method known to one of skill in the art.

[0099] In some embodiments, forming the nanostructured film may include a film extrusion process. The film extrusion process may include forming a homogenous mixture of the matrix material and the microparticles and introducing the homogenous mixture into a hopper mounted on top that feeds the extruder. In some embodiments, the homogenous mixture may be in the form of pellets. The film extrusion process may further include extruding the nanostructured film through a slot die and passing the extruded nanostructured film through a chill roll. In some embodiments, the extruded nanostructured film may have a thickness of less than about 75 μm, e.g., in the range of about 70 μm to about 40 μm, about 65 μm to about 40 μm, about 60 μm to about 40 μm, or about 50 μm to about 40 μm. In some embodiments, the nanostructured film has a thickness of less than about 10 μm. In some embodiments, forming the nanostructured film may optionally include a secondary step following the film extrusion process. Secondary processes may include processes such as coextrusion, thermoforming, vacuum forming, plasma treatment, molding, and / or embossing to impart texture to the top surface of the nanostructure film layer. A textured top nanostructure film may help, for example, to improve the defined light diffusion and / or defined angular light emission properties of the nanostructure film.

[0100] In some embodiments, the nanostructure composition is used to form a nanostructure molded article. In some embodiments, the nanostructure molded article is a liquid crystal display (LCD) or a light emitting diode (LED). In some embodiments, the nanostructure composition is used to form a light emitting layer of a lighting device. The lighting device can be used in a wide variety of applications, such as flexible electronics, touch screens, monitors, televisions, mobile phones, and any other high definition display. In some embodiments, the lighting device is a light emitting diode or a liquid crystal display. In some embodiments, the lighting device is a quantum dot light emitting diode (QLED). Examples of QLEDs are disclosed in U.S. Patent Application Serial No. 15 / 824,701, which is incorporated by reference in its entirety. In some embodiments, the core shell nanostructure is InP / ZnSe. In some embodiments, the molded article does not include a separate barrier layer to protect the nanostructure from oxygen and / or moisture.

[0101] In some embodiments, the present disclosure provides a light emitting diode comprising: (a) a first conductive layer; (b) a second conductive layer; and, (c) a light emitting layer between the first conductive layer and the second conductive layer; wherein the light emitting layer comprises: (i) silica microparticles comprising at least one population of nanostructures; and (ii) one or more UV curable monomers.

[0102] In some embodiments, the core-shell nanostructure is CdSe / ZnSe or InP / ZnSe. In some embodiments, the light emitting layer is a nanostructured film. In some embodiments, the light emitting diode comprises a first conductive layer, a second conductive layer, and a light emitting layer, the light emitting layer being disposed between the first conductive layer and the second conductive layer, hi some embodiments, the light emitting layer is a thin film comprising silica microparticles including one or more populations of nanostructures.

[0103] In some embodiments, the light emitting diode comprises additional layers between the first conductive layer and the second conductive layer, such as a hole injection layer, a hole transport layer, and an electron transport layer. In some embodiments, the hole injection layer, the hole transport layer, and the electron transport layer are thin films. In some embodiments, the layers are stacked on a substrate.

[0104] When a voltage is applied to the first conductive layer and the second conductive layer, holes injected into the first conductive layer migrate to the light-emitting layer through the hole injection layer and / or the hole transport layer, and electrons injected from the second conductive layer migrate to the light-emitting layer through the electron transport layer. The holes and electrons recombine in the light-emitting layer to generate excitons. In some embodiments, the hole transport layer is made of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)] (TFB).

[0105] In some embodiments, the nanostructure film is incorporated into a glass LCD display device. The LCD display device may include a nanostructure film formed directly on a light guide plate (LGP) without the need for an intermediate substrate or barrier layer. In some embodiments, the nanostructure film may be a thin film. In some embodiments, the nanostructure film may be 500 μm or less, 100 μm or less, or 50 μm or less in thickness. In some embodiments, the nanostructure film is a thin film with a thickness of about 15 μm or less. In some embodiments, the core-shell nanostructure is CdSe / ZnSe or InP / ZnSe.

[0106] The light guide plate may include an optical cavity with one or more sides, including at least the top surface, made of glass. Glass provides excellent resistance to impurities, including moisture and air. Additionally, glass can be formed as a thin substrate while maintaining structural rigidity. Thus, the light guide plate may be formed at least in part from a glass surface to provide a substrate with sufficient barrier and structural properties.

[0107] In some embodiments, a nanostructure film can be formed on a light guide plate. In some embodiments, the nanostructure film includes a population of silica microparticles including a population of one or more nanostructures embedded in a matrix material such as a resin. The nanostructure film can be formed on the light guide plate by any method known in the art, such as wet coating, painting, spin coating, screen printing, etc. In some embodiments, the nanostructure film is formed by extrusion. After deposition, the resin of the nanostructure film can be cured. In some embodiments, the one or more nanostructure films can be partially cured, further processed, and finally cured. The nanostructure film can be deposited as a layer or as separate layers, and the separate layers can include various properties. The width and height of the nanostructure film can be any desired dimension depending on the size of the display panel of the display device. For example, the nanostructure film can have a relatively small surface area in small display device embodiments such as watches and phones. Alternatively, the nanostructure film can have a large surface area in large display device embodiments such as televisions and computer monitors.

[0108] In some embodiments, the present disclosure provides a display backlight unit (BLU), comprising: (a) at least one primary light source that emits primary light; (b) a light guide plate (LGP) optically coupled to the at least one primary light source, the primary light being uniformly transmitted through the light guide plate; and (c) an extruded film disposed on the light guide plate, the primary light being uniformly transmitted through the light guide plate to the extruded film; and Equipped with the extruded film is not directly physically coupled to the light guide plate and includes one or more populations of nanostructures configured to emit secondary light; at least a portion of the primary light is absorbed by the nanostructure and re-emitted by the nanostructure as the secondary light; The BLU does not include a barrier layer. Display backlight unit.

[0109] In some embodiments, one or more of the populations of nanostructures are encapsulated by an inorganic material, hi some embodiments, the inorganic material comprises silica microparticles.

[0110] In some embodiments, an optically transparent substrate is formed on the nanostructure film by any method known in the art, such as vacuum deposition, vapor deposition, etc. The optically transparent substrate can be appropriately configured to provide environmental sealing to the underlying layers and / or structures of the nanostructure film. In some embodiments, a light blocking element can be included in the optically transparent substrate. In some embodiments, the light blocking element can be included in a second polarizing filter that can be disposed between the substrate and the nanostructure film. In some embodiments, the light blocking element can be, for example, a dichroic filter that can reflect primary light (e.g., blue light, ultraviolet light, or a combination of ultraviolet and blue light) while transmitting secondary light. The light blocking element can include a specific ultraviolet filter component to remove unconverted ultraviolet light from the red and green subpixels and / or ultraviolet light from the blue subpixels.

[0111] In some embodiments, the nanostructure film is incorporated into the display device by an "on-chip" arrangement. As used herein, "on-chip" refers to the placement of the nanostructures in the LED cup. In some embodiments, the nanostructures are dissolved in a resin or fluid and filled into the LED cup. In some embodiments, the LED cup does not further comprise a barrier layer to protect the nanostructures from oxygen and / or moisture.

[0112] In some embodiments, the nanostructures are integrated into the display device in a "near-chip" configuration, which as used herein refers to coating the top surface of an LED cluster with nanostructures such that the emitted light passes through the nanostructure film.

[0113] In some embodiments, the present invention provides a display device including: (a) a display panel that emits a first light; (b) a backlight unit configured to provide the first light to the display panel; and (c) a color filter including at least one pixel region that includes a color conversion layer.

[0114] In some embodiments, the color filter comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 pixel regions. In some embodiments, when blue light is incident on the color filter, red light, white light, green light, and / or blue light can be emitted through the pixel regions, respectively. In some embodiments, the color filter is described in U.S. Patent Application Publication No. 2017 / 153366.

[0115] In some embodiments, each pixel region includes a color conversion layer. In some embodiments, the color conversion layer includes nanostructures described herein configured to convert incident light to a first color of light. In some embodiments, the color conversion layer consists of nanostructures described herein configured to convert incident light to blue light.

[0116] In some embodiments, the display device comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 color conversion layers. In some embodiments, the display device comprises one color conversion layer comprised of the nanostructures described herein. In some embodiments, the display device comprises two color conversion layers comprised of the nanostructures described herein. In some embodiments, the display device comprises three color conversion layers comprised of the nanostructures described herein. In some embodiments, the display device comprises four color conversion layers comprised of the nanostructures described herein. In some embodiments, the display device comprises at least one red color conversion layer, at least one green color conversion layer, and at least one blue color conversion layer.

[0117] In some embodiments, the color conversion layer has a thickness of about 3 μm to about 10 μm, about 3 μm to about 8 μm, about 3 μm to about 6 μm, about 6 μm to about 10 μm, about 6 μm to about 8 μm, or about 8 μm to about 10 μm. In some embodiments, the color conversion layer has a thickness of about 3 μm to about 10 μm.

[0118] The nanostructure color conversion layer can be deposited by any suitable method known in the art, including, but not limited to, painting, spray coating, solvent spraying, wet coating, adhesive coating, spin coating, tape coating, roll coating, flow coating, inkjet printing, photoresist patterning, drop casting, blade coating, mist deposition, or combinations thereof. In some embodiments, the nanostructure color conversion layer is deposited by photoresist patterning. In some embodiments, the nanostructure color conversion layer is deposited by inkjet printing.

[0119] Inkjet printing The formation of thin films using dispersions of nanostructures in organic solvents is often achieved by coating techniques such as spin-coating. However, these coating techniques are generally not suitable for the formation of thin films over large areas and do not provide a means to pattern the deposited layers, limiting their application. Inkjet printing allows for precise patterning of thin films on a large scale at low cost. Inkjet printing also allows for precise patterning of nanostructure layers, allowing the printing of display pixels and precluding photopatterning. Thus, inkjet printing is very attractive for industrial applications, especially display applications.

[0120] Commonly used solvents for inkjet printing are dipropylene glycol monomethyl ether acetate (DPMA), polyglycidyl methacrylate (PGMA), diethylene glycol monoethyl ether acetate (EDGAC), and propylene glycol methyl ether acetate (PGMEA). Volatile solvents are also often used in inkjet printing because they dry quickly. Volatile solvents include ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and tetrahydrofuran. Conventional nanostructures generally cannot dissolve in these solvents. However, the improved hydrophilicity of nanostructures containing poly(alkylene oxide) ligands allows for improved solubility in these solvents.

[0121] In some embodiments, the microparticles described herein used for inkjet printing are dispersed in a solvent selected from DPMA, PGMA, EDGAC, PGMEA, ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, tetrahydrofuran, chloroform, chlorobenzene, cyclohexane, hexane, heptane, octane, hexadecane, undecane, decane, dodecane, xylene, toluene, benzene, octadecane, tetradecane, butyl ether, or combinations thereof. In some embodiments, the nanostructures comprising the poly(alkylene oxide) ligands described herein used for inkjet printing are dispersed in a solvent selected from DPMA, PGMA, EDGAC, PGMEA, ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, tetrahydrofuran, or combinations thereof.

[0122] For application by inkjet printing or a microdispenser, the inkjet composition containing the microparticles must be dispersed in a suitable solvent, which must be capable of dispersing the microparticle composition and must not adversely affect the printhead selected.

[0123] In some embodiments, the inkjet composition further comprises one or more additional components, such as surface active compounds, lubricants, wetting agents, dispersants, hydrophobizing agents, adhesion agents, flow improvers, defoamers, degassing agents, diluents, adjuvants, colorants, dyes, pigments, sensitizers, stabilizers, and inhibitors.

[0124] In some embodiments, the microparticle compositions described herein comprise from about 0.01% to about 20% by weight of the inkjet composition. In some embodiments, the nanostructures comprising poly(alkylene oxide) ligands are present in an amount of from about 0.01% to about 20%, from about 0.01% to about 15%, from about 0.01% to about 10%, from about 0.01% to about 5%, from about 0.01% to about 2%, from about 0.01% to about 1%, from about 0.01% to about 0.1%, from about 0.01% to about 0.05%, from about 0.05% to about 20%, from about 0.05% to about 15%, from about 0.05% to about 10%, from about 0.05% to about 5%, from about 0.05% to about 2%, from about 0.05% to about 1%, from about 0.05% to about 0.1%, from about 0.1% to about 20%, or from about 0.1% to about 20%. % to about 15%, about 0.1% to about 10%, about 0.1% to about 5%, about 0.1% to about 2%, about 0.1% to about 1%, about 0.5% to about 20%, about 0.5% to about 15%, about 0.5% to about 10%, about 0.5% to about 5%, about 0.5% to about 2%, about 0.5% to about 1%, about 1% to about 20%, about 1% to about Includes 15%, about 1% to about 10%, about 1% to about 5%, about 1% to about 2%, about 2% to about 20%, about 2% to about 15%, about 2% to about 10%, about 2% to about 5%, about 5% to about 20%, about 5% to about 15%, about 5% to about 10%, about 10% to about 20%, about 10% to about 15%, or about 15% to 20%.

[0125] In some embodiments, an inkjet composition comprising the microparticles or microparticle compositions described herein is used to form an electronic device. In some embodiments, an inkjet composition comprising the microparticles or microparticle compositions described herein is used to form an electronic device selected from the group consisting of nanostructure films, display devices, lighting devices, backlight units, color filters, surface emitting devices, electrodes, magnetic storage devices, and batteries. In some embodiments, an inkjet composition comprising the microparticle compositions described herein is used to form a light emitting device. EXAMPLES

[0126] The following examples are illustrative, but not limiting, of the products and methods described herein. Suitable modifications and adaptations of the variety of conditions, processes, and other parameters normally found in the art, and which are obvious to those skilled in the art in light of this disclosure, are within the spirit and scope of the invention.

[0127] Example 1 Nanostructure Ligand Exchange Process

[0128] The creation of silica microparticles involves the transfer of nanostructures from a non-polar solvent into water by ligand exchange. A typical process includes the following steps: Mercaptopropionic acid (MPA) was mixed with potassium hydroxide or tetramethylammonium hydroxide to prepare the potassium salt or tetramethylammonium salt of MPA. Ultrapure water, MPA salt, and butanol were mixed in a flask with the QDs solution in toluene / heptane. Heat the flask to 60°C for 3 hours. The solution was allowed to separate into aqueous and organic phases. The aqueous phase was separated and purified. The water-soluble nanostructures were then used for the synthesis of QD-silica particles.Several processes have been developed for the synthesis of QD-silica particles.

[0129] Example 2 Process 1: Calcium silicate encapsulated QD particles:

[0130] A typical process is summarized in Figure 2. The details of the process are as follows. ·2 mL of aqueous dispersion of QDs (inorganic content 9–10 wt%) + 3.4 mL of water + 0.15 mL of (3-mecaptopropyl)trimethoxysilane (MPTMS) was stirred at 80 °C for 5 min. · 2.8mL of 25wt% lithium silicate (LiSiL) solution was added with good stirring. 16.5 mL of a 1.3 wt% Span80 / octadecene (ODE) solution was added with good stirring. The solution turned milky white, indicating the formation of a microemulsion. · The emulsion was homogenized by passing it through a 6 micron filter 3-4 times. Water was removed from the microemulsion by heating at 80°C in vacuum, which takes about 10-15 minutes at a vacuum of 10 Torr. The microparticles were separated by centrifugation (3000-4000 rpm, 5 min). The particles were purified by washing twice with acetone and twice with ethanol. ·QD-silicate particles were dispersed in 7 ml of 1 M calcium chloride solution and stirred at 60 °C for 30 min. The product was isolated by centrifugation and purified by washing with ethanol (twice). The resulting product was dried, powdered and dispersed in a carrier solvent. · This process yields approximately 95% calcium silicate particles per batch with a QD loading of approximately 20 wt%.

[0131] This process results in a fine powder of nanostructured calcium silicate microparticles. In one embodiment, the nanostructured silicate particles consisted of red and green quantum dots when exposed to white and blue light. As expected, green and red fluorescent emissions were observed upon illumination with blue light, indicating the presence of quantum dots in the silicate microparticles.

[0132] Further characterization of the microparticles was performed by scanning electron microscopy (SEM). Figures 3A-3C are SEM images of a drop-coated film of nanostructured calcium silicate particles on a substrate. The particles were found to be well-defined and uniform with a rough surface topology. The particle size was measured from the images. The average particle size was 2.9 ± 0.9 μm (Figure 4).

[0133] Quantum dot enhanced film (QDEF) specimens were fabricated using poly(methyl methacrylate) (PMMA) and quantum dot-containing calcium silicate microparticles to investigate the stability / reliability of the particles under the conditions of use. In a typical process, 1.5 gm of QD-silicate particles were mixed with a minimum amount of IBOA to form a paste. Approximately 15 gm of PMMA pellets were added to the paste and mixed well to create a uniform mixture, which was then fabricated into sheets using an extruder. The stability of the QD-silicate microparticles was evaluated by monitoring the luminous power from the sheets as a function of time under the following conditions:

[0134] 1) Under conditions of 50°C and high flux (1, 10, 68 times). 2) Under accelerated conditions of 80°C and high flux (1 and 10 times). 3) Store in the dark at 85°C. 4)Storage at 60°C and relative humidity of 90%.

[0135] Figures 5A-5D show the emitted power from the sheet over 1000 hours. The sheet retained about 90% of its luminous power under 1x and 10x flux at 50 °C (Figure 5A) and 80 °C (Figure 5B), indicating satisfactory stability and reliability of the film. However, under very harsh conditions (50 °C, 68x flux, Figure 5A), the stability of the film was found to be insufficient. Also, no significant change in the luminous power of the sheet was observed upon dark storage at 85 °C (Figure 5C) and storage at 60 °C / 90% relative humidity (Figure 5D). This indicates that QDEF has good stability under most conditions.

[0136] Example 3 Process 2: Calcium silicate encapsulated QD microparticles:

[0137] In another approach, QD-silicate microparticles were synthesized by directional cross-linking of silicate ions with Ca-H-ions in microemulsion, the process flow of which is shown in Figure 6.

[0138] The details of the process are as follows: 16.5 mL of 3 wt% Span80 / ODE solution was stirred at 600 rpm. 2.8 mL of 25 wt% lithium silicate solution was added with good stirring. The resulting mixture turned milky white, indicating the formation of a microemulsion. This solution was passed through a 6 μm filter and homogenized. This solution was named "Microemulsion 1." ·2 mL of aqueous dispersion of QDs (inorganic content 9–10 wt%) + 3.4 mL of water + 0.15 mL of MPTMS was stirred at 60 °C for 5 min. 27.5 ml of 3 wt% Span80 / ODE solution was stirred at 600 rpm. The above QD solution was added dropwise. The resulting mixture turned milky white, indicating the formation of a microemulsion. This solution was passed through a 6 μm filter and homogenized. This solution was named "Microemulsion 2." Microemulsions 1 and 2 were mixed and kept under stirring for 30 minutes. 15 ml of 3 wt% Span80 / ODE solution was stirred at 600 rpm. 3 ml of 2 M calcium chloride solution was added dropwise. The resulting mixture turned milky white, indicating the formation of a microemulsion. This solution was passed through a 6 micron filter and homogenized. This solution was designated as Microemulsion 3. Finally, microemulsion 3 was added to the mixture of microemulsions 1 and 2 and the resulting mixture was kept under stirring for 30 minutes to allow the silicate to precipitate. Finally, the particles were isolated by centrifugation and purified by acetone and ethanol washing. The powder was dried and stored in the carrier solvent. Further characterization of the microparticles was performed by scanning electron microscopy (Figures 7A and 7B). The QD-calcium silicate particles were spherical with smooth surfaces. The particle sizes were found to range from submicron to 8 microns (Figure 7C).

[0139] Example 4 Process 3: Silica encapsulated QD microparticles:

[0140] A typical process is summarized in Figure 13. The process details are as follows: To 2 ml of the QD solution, 3 ml of water was added and the resulting solution was heated to 60°C. · 0.15ml of MPTMS was added to the above solution and kept at 60℃ for 5 minutes under stirring condition (500 rpm). This solution was mixed with 3 ml of LiSil solution under stirring for 10 minutes. · In the next step, 24 ml of Span80 / ODE (3 wt%) was added to the QD / LiSil solution to make a microemulsion, and the microemulsion was homogenized by passing it through a 5 μm syringe filter. The homogenized microemulsion was heated in air at 100°C for 60 minutes under stirring conditions (range 500-750 rpm) to remove water. Acetic acid microemulsion was prepared by mixing 3 ml of glacial acetic acid with 15 ml of ODE / Span80 (3 wt%) and homogenizing through a 5 μm filter. This microemulsion was added to the above microemulsion. The resulting microemulsion was kept at 100°C for an additional 45 minutes to complete the condensation reaction. Finally, the microparticles were isolated by centrifugation and purified by acetone and ethanol washing. · Silica powder was dried and stored in a carrier solvent.

[0141] The QD-silica particles were characterized using SEM (Figures 9A-9D). The QD-silica particles were found to have a very rough surface texture (Figures 9A-9C) with sizes ranging from 0.5 to 12 microns (Figure 9D).

[0142] Based on the input materials, this process is expected to result in a loading of quantum dots in the QD-silica particles of approximately 20 wt%. The surface area and pore size of the silica particles were analyzed by BET isotherms (Table 1). The surface area was approximately 39.36 m 2 / gm, pore diameter 30nm, pore volume 0.34cm3 / g (Table 1).

[0143] [Table 1]

[0144] The loading of quantum dots can be decreased by increasing the amount of LiSil solution. (Figures 10A-10D). In the next step, the loading of QDs in the silica particles was decreased by increasing the amount of lithium silicate. In this process, the loading of QDs in the silica particles is expected to be about 10 wt%.

[0145] The QD-silica particles were found to be well-defined with visible pores on the surface (Figure 11). The size of the particles was found to be in the range of 6–22 μm in this case.

[0146] To investigate the stability or reliability of the particles under operating conditions, specimens of quantum dot enhanced film (QDEF) were fabricated using PMMA and QD-silica particles. In a typical process, 1.5 gm of QD-silica particles were mixed with a minimum amount of IBOA to form a paste. Approximately 15 gm of PMMA pellets were added to the paste and mixed well to create a uniform mixture, and an extruder was used to fabricate a sheet. The sheet was analyzed by SEM to visualize the morphology change due to extrusion along with the distribution of the particles in the PMMA matrix. Figures 11A-11C are SEM images of the cross section of the extruded sheet, showing the uniform distribution of the particles in the film. The QD-silica particles were confirmed to be intact after extrusion, indicating its robustness and stability.

[0147] The stability of the QD-silica particles was evaluated by monitoring the emission power from the sheet as a function of time under the following conditions. Under high flux (1x, 10x, 68x) conditions at 50℃. Under high flux (1 and 10 times) accelerated conditions at 80°C. Store in a dark place at 85℃. Storage at 60°C and 90% relative humidity.

[0148] Figures 12A-12D show the emission power from the sheet over 500 hours. The sheet was found to retain more than 90% of the emission power under 1 and 10 times flux at 50°C (Figure 12B) and 1 times flux at 80°C (Figure 12D), indicating satisfactory stability / reliability as product requirements. However, under very harsh conditions (68 times flux at 50°C (Figure 12B) and 10 times flux at 80°C (Figure 12D)), the stability of the film was found to be insufficient. Also, no significant change was observed in the emission power of the sheet upon storage in the dark at 85°C (Figure 12A) and at 60°C / 90% relative humidity (Figure 12C). This indicates that the QDEF film exhibited good stability.

[0149] Example 5 Process 4: Calcium silicate encapsulated QD microparticles:

[0150] A typical process is summarized in Figure 13. The details of the process are as follows: To 2 ml of the QD solution, 3 ml of water was added and the resulting solution was heated to 60°C. · 0.15ml of MPTMS was added to the above solution and kept at 60℃ for 5 minutes under stirring condition (500 rpm). This solution was mixed with 3 ml of LiSil solution under stirring for 10 minutes. · In the next step, 24 ml of Span80 / ODE (3 wt%) was added to the QD / LiSil solution to make a microemulsion, and the microemulsion was homogenized by passing it through a 5 μm syringe filter. The homogenized microemulsion was heated in air at 100°C for 60 minutes under stirring conditions (range 500-750 rpm) to remove water. 1.4 gm of calcium chloride was dissolved in 6 ml of water. A microemulsion was prepared by mixing calcium chloride solution with 24 ml of ODE / Span 80 (3 t%) and homogenizing it through a 5 μm filter. This microemulsion was added to the above microemulsion. The resulting microemulsion was kept at 100°C for an additional 45 minutes to complete the crosslinking reaction. Finally, the particles were isolated by centrifugation and purified by acetone and ethanol washing. The powder was dried and stored in a carrier solvent.

[0151] Scanning electron microscopy was used to characterize the QD-calcium silicate particles, as shown in Figures 14A-14D. The QD-calcium silicate particles were found to have a very rough surface texture (Figures 14A-14C) with sizes ranging from 4 to 15 microns (Figure 14D).

[0152] Figures 15A-15D show the emission power from the sheet over 1600 hours. The sheet was found to retain over 90% of its emission power under 1 and 10x flux at 50°C (Figure 15A) and 1x flux at 80°C (Figure 15B), indicating stability / reliability. However, under very harsh conditions (68x flux at 50°C (Figure 15A) and 10x flux at 80°C (Figure 15B)), the film was found to be insufficiently stable. Also, no significant change in the emission power of the sheet was observed upon storage in the dark at 85°C (Figure 15C) and at 60°C / 90% relative humidity (Figure 15D). This indicates good stability of QDEF.

[0153] Example 6 In this example, silicate-containing microparticles are obtained from ammonium silicate instead of lithium silicate in Example 4. As shown in Figures 16A and 16B, microparticles with various sizes ranging from submicron to about 10 μm were obtained. As shown in Figure 16C, the composition of the nanoparticles consisted of CdSe / ZnSe nanostructures and silica.

[0154] Example 7 In this example, silicate-containing microparticles are obtained from ammonium silicate using an emulsion process. As shown in Figures 17A and 17B, microparticles of various sizes ranging from submicron to about 10 μm were obtained. As shown in Figure 17C, the composition of the nanoparticles consisted of CdSe / ZnSe nanostructures and calcium silicate.

[0155] Example 8 In this example, silicate-containing microparticles are obtained from lithium silicate using an emulsion process. As shown in Figures 18A and 18B, microparticles of various sizes ranging from submicron to about 6 μm were obtained. As shown in Figure 18C, the composition of the nanoparticles consisted of CdSe / ZnSe nanostructures and calcium silicate.

[0156] While various embodiments have been described above, it should be understood that they have been presented by way of example and not limitation. It will be apparent to those skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the present invention. Thus, the breadth and scope should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

[0157] All publications, patents, and patent applications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains, and are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing a composition comprising a group of nanostructures including a nanocrystalline core, wherein the nanostructures are embedded in silica microparticles, (a) Mixing nanostructures and metal silicates or ammonium silicates in water, (b) Add the mixture obtained in (a) to a solution containing a nonionic surfactant in a nonpolar aprotic solvent and mix to obtain a first microemulsion. (c) Remove water from the first microemulsion obtained in (b), (d) Mix acetic acid, a nonionic surfactant, and a nonpolar aprotic solvent to obtain a second microemulsion. (e) Mixing the first and second microemulsions to obtain silica fine particles containing nanostructures, and (f) Isolating the fine particles obtained in (e), A method for producing the composition comprising the above.

2. A method for producing the composition according to claim 1, wherein the first and second microemulsions are passed through a filter having pores of less than 10 μm before mixing in (e).

3. A method for producing the composition according to claim 1 or claim 2, wherein the nonpolar aprotic solvent comprises 1-octadecene, 1-hexadecene, 1-eicosene, eicosan, octadecane, hexadecane, tetradecane, squalene, or squalane, or a combination thereof.

4. The nanocrystal core includes Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, C dSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, Ge Se, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si 3N4, Ge3N4, Al A method for producing the composition according to claim 1 or claim 2, selected from the group consisting of 2O3, Al2CO, AgInGaS, and combinations thereof.

5. (a) A composition comprising a collection of nanostructures including a nanocrystalline core, wherein the nanostructures are embedded in silica microparticles, and (b) at least one organic resin, A nanostructure film containing this material.

6. The nanostructured film according to claim 5, wherein the silica microparticles are embedded in the at least one organic resin that forms the film.

7. A cured nanostructure film according to claim 5.

8. The nanostructured film according to claim 5, wherein the film does not include a barrier layer adjacent to the film that has low oxygen and moisture permeability.

9. The nanostructured film according to claim 5, wherein the at least one organic resin is poly(methyl methacrylate) (PMMA), polyethylene terephthalate (PET), or a combination thereof.

10. The nanocrystal core includes Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, C dSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, Ge Se, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si 3N4, Ge3N4, Al The nanostructure film according to claim 5, selected from the group consisting of 2O3, Al2CO, AgInGaS, and combinations thereof.

11. The nanostructure film according to claim 5, wherein the nanocrystalline core is selected from the group consisting of Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, AgInGaS, and combinations thereof.

12. The nanostructure film according to claim 5, wherein the nanostructure comprises InP in the nanocrystalline core and further comprises at least one shell, the at least one shell comprising ZnS or ZnSe.

13. A nanostructured molded article comprising a nanostructured film according to any one of claims 5 to 12.

14. A display device comprising a nanostructured film according to any one of claims 5 to 12.

15. A backlight unit comprising a nanostructured film according to any one of claims 5 to 12.

Images