Blue-emitting nanocrystals with cubic shape and group IV metal fluoride passivation

Abstract

The present disclosure relates to the field of nanotechnology. The present disclosure provides a method for producing nanostructures using Group IV metal halides. These nanostructures have high quantum yield, narrow emission peak width, tunable emission wavelength, and colloidal stability. Nanostructures produced using the method are also provided. Additionally, nanostructured films and molded articles comprising the nanostructures are also provided.

Description

[Technical Field]

[0001]

[0001] The present disclosure relates to the field of nanotechnology. The present disclosure provides a method for producing nanostructures using Group IV metal fluorides. Nanostructures produced using the method are also provided. The nanostructures have high quantum yield, narrow emission peak width, tunable emission wavelength, and colloidal stability. Additionally, nanostructured films and molded articles comprising the nanostructures are also provided. [Background technology]

[0002]

[0002] Semiconductor nanostructures can be incorporated into various electronic and optical devices. The electrical and optical properties of such nanostructures vary, for example, depending on their composition, shape, and size. For example, the size-tunable nature of semiconductor nanoparticles is of interest for applications such as light-emitting diodes (LEDs) and liquid crystal displays (LCDs). Highly luminescent nanostructures are particularly desirable for such applications.

[0003]

[0003] The steric bulkiness of long-chain alkyl ligands can limit packing and result in insufficient ligand coverage on the surface of semiconductor nanocrystals. Similarly, rounded particle surfaces can exhibit steps, pits, and kinks that can make passivation by ligands difficult. Such unpassivated sites on the surface of quantum dots can create mid-gap states that function as hole traps when a potential is applied to the quantum dots. Holes accumulate at the HTL-QD interface, thereby increasing the operating voltage and causing irreversible electrochemical degradation.

[0004] There is a need to fabricate nanostructures with high quantum yield, narrow emission peak width, tunable emission wavelength, and colloidal stability. Summary of the Invention

[0005]

[0005] The present disclosure provides a nanostructure comprising a nanocrystalline core and at least one shell, wherein the at least one shell has formula (I): MF4(I) (M=Zr, Hf, or Ti) The present invention provides a nanostructure comprising at least one metal fluoride of the formula:

[0006] In some embodiments, the core is selected from the group consisting of InP, InAs, ZnSe, ZnTe, and ZnSe. 1-x Te x (0≦x<1).

[0007] In some embodiments, the core is ZnSe or ZnSe 1-x Te x (0≦x<1).

[0008]

[0008] In some embodiments, at least one shell is selected from the group consisting of CdS, CdSe, CdO, CdTe, ZnS, ZnO, ZnSe, ZnTe, MgTe, GaAs, GaSb, GaN, HgO, HgS, HgSe, HgTe, InAs, InSb, InN, AlAs, AlN, AlSb, AlS, PbS, PbO, PbSe, PbTe, MgO, MgS, MgSe, MgTe, CuCl, Ge, Si, and alloys thereof.

[0009] In some embodiments, at least one shell comprises ZnSe or ZnS.

[0010]

[0010] In some embodiments, the at least one metal fluoride is HfF4 or ZrF4.

[0011] In some embodiments, the molar ratio of the at least one metal fluoride to zinc in the nanostructures is from about 1:1 to about 1:8.

[0012] In some embodiments, the nanostructures are: (a) comprising a core comprising ZnSe, at least one shell comprising ZnS, and at least one shell comprising HfF4; or (b) ZnSe 1-x Te x (where 0≦x<1), at least one shell comprising ZnSe, at least one shell comprising ZnS, and at least one shell comprising HfF4.

[0013] In some embodiments, the nanostructures are quantum dots.

[0014] In some embodiments, the nanostructures exhibit a photoluminescence quantum yield of between about 60% and about 100%.

[0015] In some embodiments, the nanostructures exhibit a full width at half maximum of between about 10 nm and about 40 nm.

[0016] In some embodiments, the nanostructure composition comprises: (a) a nanostructure as described herein; (b) at least one organic resin; Includes.

[0017] The present disclosure provides a method for producing nanostructures, comprising: (a) providing a nanocrystalline core; (b) optionally mixing the core in (a) with a zinc source and a selenium source to obtain a core having a ZnSe shell; (c) The core in (a) or the core having a ZnSe shell in (b) is reacted with a zinc source, a sulfur source, and a compound of formula (I): MF4(I) (M=Zr, Hf, or Ti) to obtain a nanostructure; and Also provided is a method comprising:

[0018] In some embodiments, the core is InP, InAs, ZnSe, ZnTe, or ZnSe. 1-x Te x (0≦x<1).

[0019] In some embodiments, the core is ZnSe or ZnSe 1-x Te x (0≦x<1).

[0020]

[0019] In some embodiments, the zinc source in (b) is selected from the group consisting of 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 peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof.

[0021]

[0020] In some embodiments, the zinc source in (c) is selected from the group consisting of 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 peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof.

[0022]

[0021] In some embodiments, the selenium source in (b) is selected from the group consisting of 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 combinations thereof.

[0023]

[0022] In some embodiments, the sulfur source in (c) is selected from the group consisting of elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide, and combinations thereof.

[0024] In some embodiments, the temperature in (b) is increased, decreased, or maintained between about 200°C and about 310°C.

[0025] In some embodiments, the temperature in (c) is increased, decreased, or maintained between about 280°C and about 310°C.

[0026] In some embodiments, the nanostructures exhibit a photoluminescence quantum yield of between about 60% and about 100%.

[0027] In some embodiments, the nanostructures have a full width at half maximum between about 10 nm and about 40 nm.

[0028] The present disclosure provides a lighting device comprising: (a) a first conductive layer; (b) a second conductive layer; (c) a light-emitting layer comprising at least one population of nanostructures comprising a core and at least one shell, wherein the at least one shell comprises a Group IV metal fluoride; Also provided is a lighting device including:

[0029] In some embodiments, the core of the nanostructure is InP, InAs, ZnSe, ZnTe, or ZnSe. 1-x Te x (0≦x<1).

[0030] In some embodiments, the core of the nanostructure is ZnSe or ZnSe 1-x Te x (0≦x<1).

[0031]

[0030] In some embodiments, at least one shell of a nanostructure selected from the group consisting of CdS, CdSe, CdO, CdTe, ZnS, ZnO, ZnSe, ZnTe, MgTe, GaAs, GaSb, GaN, HgO, HgS, HgSe, HgTe, InAs, InSb, InN, AlAs, AlN, AlSb, AlS, PbS, PbO, PbSe, PbTe, MgO, MgS, MgSe, MgTe, CuCl, Ge, Si, and alloys thereof.

[0032] In some embodiments, at least one shell of the nanostructure comprises ZnSe or ZnS.

[0033] In some embodiments, at least one metal fluoride of the nanostructures is HfF4 or ZrF4.

[0034] In some embodiments, the device is stable for at least 7 days when stored at room temperature.

[0035] In some embodiments, the device is stable for at least 14 days when stored at room temperature.

[0036] In some embodiments, the lighting device further comprises an electron transport layer.

[0037] In some embodiments, the lighting device is a light emitting diode.

[0038]

[0037] In some embodiments, the first conductive layer comprises indium tin oxide, indium zinc oxide, tin dioxide, zinc oxide, magnesium, aluminum, aluminum-lithium, calcium, magnesium-indium, magnesium-silver, silver, gold, or a mixture thereof.

[0039] In some embodiments, the first conductive layer comprises indium tin oxide.

[0040] In some embodiments, the second conductive layer comprises indium tin oxide, indium zinc oxide, titanium dioxide, tin oxide, zinc sulfide, silver, or a mixture thereof.

[0041] In some embodiments, the second conductive layer comprises aluminum.

[0042] In some embodiments, the second conductive layer comprises gold.

[0043] In some embodiments, the lighting device further comprises a semiconducting polymer layer.

[0044]

[0043] In some embodiments, the semiconducting polymer layer comprises copper phthalocyanine, 4,4',4''-tris[(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4''-tris(diphenylamino)triphenylamine (TDATA), 4,4',4''-tris[2-naphthyl(phenyl)amino]triphenylamine (2T-NATA), polyaniline / dodecylbenzenesulfonic acid, poly(3,4-ethylenedioxythiophene) / polystyrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid, or polyaniline / poly(4-styrenesulfonate).

[0045] In some embodiments, the semiconductive polymer layer comprises PEDOT / PSS.

[0046] In some embodiments, the lighting device further comprises a first transport layer.

[0047]

[0046] In some embodiments, the first transport layer comprises N,N'-di(naphthalen-1-yl)-N,N'-bis(4-vinylphenyl)-4,4'-diamine, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], or poly(9-vinylcarbazole).

[0048] In some embodiments, the first transport layer comprises N,N'-di(naphthalen-1-yl)-N,N'-bis(4-vinylphenyl)-4,4'-diamine. [Brief explanation of the drawings]

[0049] [Figure 1]

[0048] Figure 1 shows a density of states diagram representing the states that can be occupied by the system with mid-gap trap states, denoted "trap states." Covering the entire surface with halide ions reduces the mid-gap trap states, allowing for the formation of quantum dots with better electronic balance. [Figure 2]

[0049] This table compares the solution quantum yield, maximum external quantum efficiency, and device lifetime of control ZnSe quantum dots, ZnSe quantum dots containing ZnF2 only in the shell layer, ZnSe quantum dots containing HfF4 only in the shell layer, and ZnSe quantum dots containing ZrF4 only in the shell layer. [Figure 3]

[0050] 1 is a transmission electron microscopy (TEM) image showing the quasi-spherical morphology characteristic of ZnSe / ZnS core / shell structured quantum dots. [Figure 4]

[0051] TEM images showing an increase in the ratio of tetrahedral and cubic particles for the synthesis of ZnSe / ZnS core / shell quantum dots using HfF4. [Figure 5]

[0052] TEM images showing the characteristic quasi-spherical morphology of ZnSeTe / ZnSe / ZnS core / shell / shell structured quantum dots. [Figure 6]

[0053] TEM images showing an increase in the proportion of tetrahedral and cubic particles for the synthesis of ZnSeTe / ZnSe / ZnS core / shell / shell structured quantum dots using HfF4. [Figure 7]

[0054] Scatter plot of external quantum efficiency versus luminance for devices fabricated with quantum dots having standard ligands (■), ZrF4 ligands (●), and HfF4 ligands (♦). [Figure 8]

[0055] Scatter plot of voltage versus time for hole-only devices fabricated with quantum dots fabricated with standard ligand (●), ZrF4 ligand (■), and HfF4 ligand (◆). All devices had comparable quantum dot thickness and were driven with a hole current density of 0.1 J. DETAILED DESCRIPTION OF THE INVENTION

[0050] definition

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The following definitions supplement those in the art and are directed to this application, regardless of whether they are related or unrelated, for example, to any co-owned patents or applications. Although any methods and materials similar or equivalent to those described herein can be used to test the present invention, the preferred materials and methods are described herein. Therefore, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0051]

[0057] 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, and so forth.

[0052]

[0058] As used herein, the term "about" means that a particular quantity value varies by ±10% of the value. For example, "about 100 nm" includes a range of sizes from 90 nm to 110 nm, inclusive.

[0053]

[0059] A "nanostructure" is a structure having at least one region or characteristic dimension that is less than about 500 nm. 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. Typically, the region or characteristic dimension is along the shortest axis of the structure. Examples of such structures include nanowires, nanorods, nanotubes, branched nanostructures, nanotetrapods, nanotripods, nanobipods, nanocrystals, nanodots, quantum dots, nanoparticles, and the like. A nanostructure can be, for example, substantially crystalline, substantially monocrystalline, polycrystalline, amorphous, or a combination 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.

[0054]

[0060] When used in reference to nanostructures, the term "heterostructure" refers to a nanostructure characterized by at least two different and / or distinguishable material types. Typically, one region of the nanostructure comprises a first material type, while a second region of the nanostructure comprises a second material type. In certain embodiments, the nanostructure comprises 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, e.g., relative to the long axis of a nanowire, the long axis of an arm of a branched nanowire, or the center of a nanocrystal. A shell can, but need not, completely cover an adjacent material to be considered a shell or for the nanostructure to be considered a heterostructure; for example, a nanocrystal characterized by one material covered with small islands of a second material is a heterostructure. In other embodiments, the different material types are distributed at different locations within the nanostructure, e.g., along the major (long) axis of a nanowire or along the long axis of an arm of a branched nanowire. Different regions within a heterostructure can comprise entirely different materials, or the different regions can comprise a base material (eg, silicon) with different dopants or different concentrations of the same dopant.

[0055]

[0061] As used herein, the "diameter" of a nanostructure refers to the diameter of a cross section perpendicular to the first axis of the nanostructure, the first axis having the greatest difference in length from the second and third axes (the second and third axes being the two axes closest in length to each other). The first axis is not necessarily the longest axis of the nanostructure; for example, in the case of a disk-shaped nanostructure, the cross section is a substantially circular cross section perpendicular to the short longitudinal 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 or high aspect ratio nanostructures such as nanowires, 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 side to the other through the center of the sphere.

[0056]

[0062] The terms "crystalline" or "substantially crystalline," when used in connection with a nanostructure, mean that the nanostructure typically exhibits long-range order across one or more dimensions of the structure. Those skilled in the art will understand that the term "long-range order" depends on the absolute size of a particular nanostructure, since the order of a crystal cannot extend beyond the boundaries of the crystal. In this case, "long-range order" refers to substantial order across at least most of the dimensions of the nanostructure. In some cases, the nanostructure may have an oxide or other coating, or may be composed of a core and at least one shell. In such cases, it will be recognized that the oxide, shell, or other coating may, but need not, exhibit such order (e.g., it may be amorphous, polycrystalline, etc.). In such cases, the phrases "crystalline," "substantially crystalline," "substantially monocrystalline," or "monocrystalline" refer to the central core of the nanostructure (excluding coating layers and shells). As used herein, the terms "crystalline" or "substantially crystalline" are intended to encompass structures containing various defects, stacking faults, atomic substitutions, and the like, so long as the structure exhibits 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 recognized that the interface between the core and the exterior of the nanostructure, or between the core and an adjacent shell, or between a shell and a second adjacent shell, may comprise a non-crystalline region or may even be amorphous. This does not prevent a nanostructure from being crystalline or substantially crystalline as defined herein.

[0057]

[0063] When used in reference to a nanostructure, the term "monocrystalline" indicates that the nanostructure is substantially crystalline and comprises substantially one crystal. When used in reference to a nanostructure heterostructure comprising a core and one or more shells, the term "monocrystalline" indicates that the core is substantially crystalline and comprises substantially one crystal.

[0058]

[0064] A "nanocrystal" is 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 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. The term "nanocrystal" is intended to include substantially monocrystalline nanostructures that contain various defects, stacking faults, atomic substitutions, etc., as well as substantially monocrystalline nanostructures that are free of such defects, stacking faults, and substitutions. In the case of nanocrystal heterostructures that include 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 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.

[0059]

[0065] 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 some embodiments, 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 appropriate optical tests available in the art. The ability to tune nanocrystal size, e.g., within a range between about 1 nm and about 15 nm, allows for a photoemission range across the optical spectrum, providing great flexibility in color rendering.

[0060]

[0066] A "ligand" is a molecule capable of interacting (either weakly or strongly) with one or more faces of a nanostructure, for example, through covalent interactions, ionic interactions, van der Waals interactions, or other molecular interactions with the surface of the nanostructure.

[0061]

[0067] "Photoluminescence quantum yield" (QY) is the ratio of photons emitted to photons absorbed, e.g., 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.

[0062]

[0068] As used herein, the term "monolayer" is a measure of shell thickness derived from the bulk crystal structure of the shell material as the shortest distance between related lattice planes. For example, for a cubic lattice structure, the thickness of one monolayer is defined as the distance between adjacent lattice planes in the

[0111] direction. For example, one monolayer of cubic ZnSe corresponds to a thickness of 0.33 nm, and one monolayer of cubic ZnS corresponds to a thickness of 0.31 nm. The thickness of a monolayer of an alloy material can be determined from the composition of the alloy by Vegard's law.

[0063]

[0069] As used herein, the term "shell" refers to a material deposited on a core or on a previously deposited shell of the same or different composition, resulting from a single deposition of the shell material. The exact shell thickness depends on the material and the precursor input and conversion rate, and can 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 well known in the art. For example, the actual shell thickness can be determined by comparing the particle size determined from TEM images of nanocrystals before and after shell synthesis.

[0064]

[0070] As used herein, the term "full width at half maximum" (FWHM) is a measure of the size distribution of quantum dots. The emission spectrum of quantum dots generally has the shape of a Gaussian curve. The width of the Gaussian curve is defined as the FWHM and provides an understanding of the particle size distribution. A smaller FWHM corresponds to a narrower quantum dot nanocrystal size distribution. The FWHM also depends on the emission wavelength maximum.

[0065]

[0071] "Peak emission wavelength" (PWL) is the wavelength at which the radiative emission spectrum of a light source reaches its maximum.

[0066]

[0072] As used herein, the term "external quantum efficiency" (EQE) is the ratio of the number of photons emitted from a light-emitting diode (LED) to the number of electrons passing through the device. EQE measures how efficiently an LED converts electrons into photons and emits them. EQE is calculated using the formula: EQE = [Injection efficiency] × [Solid state quantum yield] × [Extraction efficiency] can be evaluated using Injection efficiency = fraction of electrons injected through the device into the active region; Solid quantum yield = the ratio of all electron-hole recombinations in the activated region that are radiative and therefore generate photons; Extraction efficiency = the fraction of photons generated in the active region that are emitted from the device.

[0067]

[0073] Unless expressly stated otherwise, ranges recited herein are inclusive of both endpoints.

[0068]

[0074] Various additional terms are defined or otherwise characterized herein.

[0069]

[0075] Core / shell nanoparticles are typically synthesized in a mixture of long alkyl-chain compounds, such as trioctylphosphine, lauric acid, and zinc oleate, to bind to and passivate the surface of quantum dots. However, the limited packing density of the alkyl chains prevents complete surface passivation, so small ligands are used for synergistic passivation. The present disclosure provides a method for incorporating Group IV metal fluorides, such as zirconium fluoride and / or hafnium fluoride, into the shell growth reaction as a fluorine source, which results in better surface ligand coverage and passivation of hole traps formed by dangling bonds. The resulting quantum dots are more stable in electroluminescent devices without significantly compromising maximum external quantum efficiency. The resulting quantum dots remain colloidally stable in nonpolar solvents, such as octane, which is favorable for solution processing of quantum dots into electroluminescent devices.

[0070] nanostructure

[0076] In some embodiments, the present disclosure provides a nanostructure comprising a core and at least one shell, wherein the at least one shell comprises a Group IV metal fluoride.

[0071]

[0077] In some embodiments, the present disclosure provides a nanostructure comprising a core comprising zinc and at least one shell, wherein the at least one shell comprises zinc and a Group IV metal halide.

[0072]

[0078] In some embodiments, the nanostructures are quantum dots.

[0073] Nanostructured Composition

[0079] In some embodiments, the present disclosure provides: (a) at least one population of nanostructures, the nanostructures comprising a core and at least one shell, the at least one shell comprising a Group IV metal fluoride; (b) at least one organic resin; A nanostructure composition comprising:

[0074]

[0080] In some embodiments, the present disclosure provides: (a) at least one population of nanostructures, the nanostructures comprising a core comprising zinc and at least one shell, the at least one shell comprising zinc and a Group IV metal halide; (b) at least one organic resin; A nanostructure composition comprising:

[0075]

[0081] In some embodiments, the nanostructures are quantum dots.

[0076] Nanocrystalline Core

[0082] In some embodiments, the nanostructures are made of InP, InAs, ZnSe, ZnTe, or ZnSe 1-x Te x In some embodiments, the nanostructures comprise a ZnSe core and a ZnS shell. In some embodiments, the nanostructures comprise a ZnSe core and a ZnS shell. 1-x Te x In some embodiments, the nanostructure comprises a ZnSe core, a ZnSe shell, and a ZnS shell. In some embodiments, the nanostructure is a ZnSe / ZnS core / shell nanostructure. In some embodiments, the nanostructure comprises a ZnSe 1-x Te x / ZnSe / ZnS core / shell nanostructure.

[0077]

[0083] As used herein, the term "nucleation stage" refers to the formation of a core nucleus. As used herein, the term "growth stage" refers to the growth process of adding additional inorganic material to the nanostructure.

[0078]

[0084] The diameter of the nanocrystal core can be controlled by varying the amount of precursor provided. The diameter of the nanocrystal can be determined using techniques known to those skilled in the art. In some embodiments, the diameter of the nanocrystal core is determined using transmission electron microscopy (TEM).

[0079]

[0085] In some embodiments, the nanocrystalline core has a diameter between about 1.0 nm and about 7.0 nm, between about 1.0 nm and about 6.0 nm, between about 1.0 nm and about 5.0 nm, between about 1.0 nm and about 4.0 nm, between about 1.0 nm and about 3.0 nm, between about 1.0 nm and about 2.0 nm, between about 2.0 nm and about 7.0 nm, between about 2.0 nm and about 6.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 4.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 6.0 nm, between about 2.0 nm and about 7.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 4.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 6.0 nm, between about 2.0 nm and about 7.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 4.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 6.0 nm, between about 2.0 nm and about 7.0 nm, between about 2.0 nm and about 5.0 nm, between about 2.0 nm and about 6 ...6.0 nm, between about 2. In some embodiments, the nanocrystalline core has a diameter between about 3.0 nm and about 3.0 nm, between about 3.0 nm and about 7.0 nm, between about 3.0 nm and about 6.0 nm, between about 3.0 nm and about 5.0 nm, between about 3.0 nm and about 4.0 nm, between about 4.0 nm and about 7.0 nm, between about 4.0 nm and about 6.0 nm, between about 4.0 nm and about 5.0 nm, between about 5.0 nm and about 7.0 nm, between about 5.0 nm and about 6.0 nm, or between about 6.0 nm and about 7.0 nm. In some embodiments, the nanocrystalline core has a diameter between about 3.0 nm and about 6.0 nm.

[0080]

[0086] In some embodiments, the nanocrystalline core is doped with at least one metal ion or another element. Doping is the intentional introduction of impurities into a nanostructure to change its optical, electrical, chemical, and / or magnetic properties. Yim, K., et al., Scientific Reports 7:40907 (January 2017). Doping uses very small amounts of metal ions that cause negligible distortion in the nanostructure's lattice. In some embodiments, the dopant concentration is about 10 15 atoms / cm 3 ~about 10 20 atoms / cm 3 It is between.

[0081]

[0087] In some embodiments, the nanocrystalline core is doped with at least one metal ion or another element selected from the group consisting of lithium, boron, carbon, nitrogen, fluorine, sodium, aluminum, silicon, chlorine, potassium, scandium, selenium, titanium, vanadium, chromium, manganese, nickel, gallium, arsenic, palladium, gold, cadmium, indium, tin, antimony, lead, and combinations thereof. In some embodiments, the nanocrystalline core is doped with at least one metal ion or another element selected from the group consisting of indium, gallium, aluminum, selenium, titanium, tin, chlorine, fluorine, and combinations thereof.

[0082]

[0088] In some embodiments, the nanocrystalline core is alloyed with at least one metal ion or other element. An alloy is a combination of at least two metals or at least one metal ion with at least one other element. In forming an alloy, high concentrations of the metal ion or other element often result in properties different from those of the pure material. In some embodiments, the concentration of the alloyed metal ion or other element is between about 0.1% and about 50% by weight.

[0083]

[0089] In some embodiments, the nanocrystalline core is alloyed with at least one metal or another element selected from the group consisting of magnesium, cadmium, mercury, sulfur, tellurium, and selenium, hi some embodiments, the ZnSe nanocrystalline core is alloyed with tellurium.

[0084]

[0090] In some embodiments, the cores are purified prior to depositing the shell, hi some embodiments, the cores are filtered to remove precipitates from the core solution.

[0085]

[0091] In some embodiments, the core is subjected to an acid etching step before depositing the shell.

[0086]

[0092] In some embodiments, the core diameter is determined by measuring the lowest-energy electronic transition using absorbance spectroscopy and modeling the corresponding quantum dot size based on quantum confinement principles. Quantum confinement in zero-dimensional nanocrystallites, such as quantum dots, arises from the spatial confinement of electrons within the crystallite boundaries. Quantum confinement can be observed when the diameter of a material is as large as the de Broglie wavelength of the wave function. The electronic and optical properties of nanoparticles deviate substantially from those of bulk materials. When the confinement dimensions are larger than the particle's wavelength, the particle behaves as if it were free. During this state, the band gap remains at its original energy due to the continuous energy states. However, as the confinement dimensions decrease, reaching a certain limit, typically the nanoscale, the energy spectrum becomes discrete. As a result, the band gap becomes size-dependent.

[0087] Nanostructured Shell Layer

[0093] The shell can, for example, increase the quantum yield and / or stability of the nanostructure. In some embodiments, the core and shell comprise different materials. In some embodiments, the nanostructure comprises multiple shells of different shell materials.

[0088]

[0094] In some embodiments, a shell comprising a mixture of Group II and Group VI elements is deposited on the core or core / shell structure. In some embodiments, the shell is deposited with 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 deposited with 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 deposited with 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 composed of zinc and sulfur; zinc and selenium; zinc, sulfur, and selenium; zinc and tellurium; zinc, tellurium, and sulfur; zinc, tellurium, and selenium; zinc, cadmium, and sulfur; zinc, cadmium, and selenium; cadmium and sulfur; cadmium and selenium; cadmium, selenium, and sulfur; cadmium, zinc, and sulfur; cadmium, zinc, and selenium; or cadmium, zinc, sulfur, and selenium.

[0089]

[0095] In some embodiments, at least one shell comprises CdS, CdSe, CdO, CdTe, ZnS, ZnO, ZnSe, ZnTe, MgTe, GaAs, GaSb, GaN, HgO, HgS, HgSe, HgTe, InAs, InSb, InN, AlAs, AlN, AlSb, AlS, PbS, PbO, PbSe, PbTe, MgO, MgS, MgSe, MgTe, CuCl, Ge, Si, or an alloy thereof. In some embodiments, at least one shell comprises ZnSe. In some embodiments, at least one shell comprises ZnS. In some embodiments, at least one shell comprises a first shell comprising ZnSe and a second shell comprising ZnS.

[0090]

[0096] In some embodiments, the shell comprises more than one monolayer of shell material. The number of monolayers is an average across all nanostructures, and therefore the number of monolayers in a shell may be a fraction. In some embodiments, the number of monolayers in the shell is between 0.25 and 10, between 0.25 and 8, between 0.25 and 7, between 0.25 and 6, between 0.25 and 5, between 0.25 and 4, between 0.25 and 3, between 0.25 and 2, between 2 and 10, between 2 and 8, between 2 and 7, between 2 and 6, between 2 and 5, between 2 and 4, between 2 and 3, between 3 and 10, between 3 and 8, between 3 and 7, between 3 and 6, between 3 and 5, between 3 and 4, between 4 and 10, between 4 and 8, between 4 and 7, between 4 and 6, between 4 and 5, between 5 and 10, between 5 and 8, between 5 and 7, between 5 and 6, between 6 and 10, between 6 and 8, between 6 and 7, between 7 and 10, between 7 and 8, or between 8 and 10. In some embodiments, the shell comprises between 3 and 5 monolayers.

[0091]

[0097] The thickness of each shell can be determined using techniques known to those skilled in the art. In some embodiments, the thickness of each shell is determined by comparing the average diameter of the nanostructures before and after adding each shell. In some embodiments, the average diameter of the nanostructures before and after adding each shell is determined by TEM.

[0092]

[0098] In some embodiments, each shell has a thickness between about 0.05 nm and about 3.5 nm, between about 0.05 nm and about 2 nm, between about 0.05 nm and about 0.9 nm, between about 0.05 nm and about 0.7 nm, between about 0.05 nm and about 0.5 nm, between about 0.05 nm and about 0.3 nm, between about 0.05 nm and about 0.1 nm, between about 0.1 nm and about 3.5 nm, between about 0.1 nm and about 2 nm, between about 0.1 nm and about 0.9 nm, between about 0.1 nm and about 0.7 nm, between about 0.1 nm and about 0.5 nm, between about 0.1 nm and about 0.3 nm, or between about 0. The thickness is between 3 nm and about 3.5 nm, between about 0.3 nm and about 2 nm, between about 0.3 nm and about 0.9 nm, between about 0.3 nm and about 0.7 nm, between about 0.3 nm and about 0.5 nm, between about 0.5 nm and about 3.5 nm, between about 0.5 nm and about 2 nm, between about 0.5 nm and about 0.9 nm, between about 0.5 nm and about 0.7 nm, between about 0.7 nm and about 3.5 nm, between about 0.7 nm and about 2 nm, between about 0.7 nm and about 0.9 nm, between about 0.9 nm and about 3.5 nm, between about 0.9 nm and about 2 nm, or between about 2 nm and about 3.5 nm.

[0093] Method for producing nanostructures containing group IV fluoride passivation in the shell

[0099] In some embodiments, the present disclosure provides a method for producing nanostructures, comprising: (a) providing a nanocrystalline core; (b) optionally mixing the core in (a) with a zinc source and a selenium source to obtain a core having a ZnSe shell; (c) mixing the core in (a) or the core with a ZnSe shell in (b) with a zinc source, a sulfur source, and a group IV fluoride; Obtaining a nanostructure; The present invention provides a manufacturing method comprising the steps of:

[0094]

[0100] In some embodiments, the present disclosure provides a method for producing nanostructures, comprising: (a) providing a nanocrystalline core; (b) mixing the core in (a) with a zinc source and a selenium source to obtain a core having a ZnSe shell; (c) mixing the core with the ZnSe shell in (b) with a zinc source, a sulfur source, and a group IV fluoride; Obtaining a nanostructure; The present invention provides a manufacturing method comprising the steps of:

[0095]

[0101] In some embodiments, the present disclosure provides a method for producing nanostructures, comprising: (a) providing a nanocrystalline core; (b) mixing the core in (a) with a zinc source, a sulfur source, and a Group IV fluoride; Obtaining a nanostructure; The present invention provides a manufacturing method comprising the steps of:

[0096]

[0102] In some embodiments, the nanocrystalline core is ZnSe, ZnSe 1-x Te x , InP, or InAs. In some embodiments, the nanocrystalline core comprises ZnSe. In some embodiments, the nanocrystalline core comprises ZnSe. 1-x Te x Includes.

[0097]

[0103] 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 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 dioleate, 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 dioleate. In some embodiments, the zinc source is in situ generated zinc dioleate.

[0098]

[0104] 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 combinations 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.

[0099]

[0105] In some embodiments, the sulfur source is selected from the group consisting of elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide, and combinations thereof. In some embodiments, the sulfur source is an alkyl-substituted zinc dithiocarbamate. In some embodiments, the sulfur source is octanethiol. In some embodiments, the sulfur source is tributylphosphine sulfide.

[0100]

[0106] In some embodiments, the molar ratio of the nanocrystalline core to the zinc source is between 1:2 and 1:1000, between 1:2 and 1:100, between 1:2 and 1:50, between 1:2 and 1:25, between 1:2 and 1:15, between 1:2 and 1:10, between 1:2 and 1:5, between 1:5 and 1:1000, between 1:5 and 1:100, between 1:5 and 1:50, between 1:5 and 1:25, between 1:5 and 1:15, between 1:5 and 1:10, between 1:10 and 1:1000 between 1:10 and 1:100, between 1:10 and 1:50, between 1:10 and 1:25, between 1:10 and 1:15, between 1:15 and 1:1000, between 1:15 and 1:100, between 1:15 and 1:50, between 1:15 and 1:25, between 1:25 and 1:1000, between 1:25 and 1:100, between 1:25 and 1:50, between 1:50 and 1:100, between 1:50 and 1:100, or between 1:100 and 1:1000.

[0101]

[0107] In some embodiments, the zinc source is zinc dioleate. In some embodiments, the zinc source is in situ prepared zinc dioleate. In some embodiments, the molar ratio of nanocrystalline core to zinc dioleate is between 1:2 and 1:1000, between 1:2 and 1:100, between 1:2 and 1:50, between 1:2 and 1:25, between 1:2 and 1:15, between 1:2 and 1:10, between 1:2 and 1:5, between 1:5 and 1:1000, between 1:5 and 1:100, between 1:5 and 1:50, between 1:5 and 1:25, between 1:5 and 1:15, between 1:5 and 1:10, between 1:10 and 1:1 The molar ratio of the nanocrystalline core to zinc dioleate is between 1:20 and 1:50. In some embodiments, the molar ratio of the nanocrystalline core to zinc dioleate is between 1:20 and 1:50. In some embodiments, the molar ratio of the nanocrystalline core to zinc dioleate is between 1:20 and 1:30.

[0102]

[0108] In some embodiments, the molar ratio of nanocrystalline core to sulfur source is between 1:2 and 1:1000, between 1:2 and 1:100, between 1:2 and 1:50, between 1:2 and 1:25, between 1:2 and 1:15, between 1:2 and 1:10, between 1:2 and 1:5, between 1:5 and 1:1000, between 1:5 and 1:100, between 1:5 and 1:50, between 1:5 and 1:25, between 1:5 and 1:15, between 1:5 and 1:10, between 1:10 and 1:1000 between 1:10 and 1:100, between 1:10 and 1:50, between 1:10 and 1:25, between 1:10 and 1:15, between 1:15 and 1:1000, between 1:15 and 1:100, between 1:15 and 1:50, between 1:15 and 1:25, between 1:25 and 1:1000, between 1:25 and 1:100, between 1:25 and 1:50, between 1:50 and 1:100, between 1:50 and 1:100, or between 1:100 and 1:1000.

[0103]

[0109] In some embodiments, the temperature of the reaction mixture after combining the zinc source and the selenium source is between 200° C. and 310° C., between 200° C. and 280° C., between 200° C. and 250° C., between 200° C. and 220° C., between 220° C. and 310° C., between 220° C. and 280° C., between 220° C. and 250° C., between 250° C. and 310° C., between 250° C. and 280° C., or between 280° C. and 310° C. In some embodiments, the temperature of the reaction mixture in (d) is between 250° C. and 310° C.

[0104]

[0110] In some embodiments, the time required to reach the above temperature after mixing the zinc source and the selenium source is between 2 and 240 minutes, between 2 and 200 minutes, between 2 and 100 minutes, between 2 and 60 minutes, between 2 and 40 minutes, between 5 and 240 minutes, between 5 and 200 minutes, between 5 and 100 minutes, between 5 and 60 minutes, between 5 and 40 minutes, between 10 and 240 minutes, between 10 and 200 minutes, between 10 and 100 minutes, between 10 and 60 minutes, between 10 and 40 minutes, between 40 and 240 minutes, between 40 and 200 minutes, between 40 and 100 minutes, between 40 and 60 minutes, between 60 and 240 minutes, between 60 and 200 minutes, between 60 and 100 minutes, between 100 and 240 minutes, between 100 and 200 minutes, or between 200 and 240 minutes.

[0105]

[0111] In some embodiments, the temperature after combining the zinc source and the selenium source is maintained for 2 to 240 minutes, 2 to 200 minutes, 2 to 100 minutes, 2 to 60 minutes, 2 to 40 minutes, 5 to 240 minutes, 5 to 200 minutes, 5 to 100 minutes, 5 to 60 minutes, 5 to 40 minutes, 10 to 240 minutes, 10 to 200 minutes, 10 to 100 minutes, 10 to 60 minutes, 10 to 40 minutes, 40 to 240 minutes, 40 to 200 minutes, 40 to 100 minutes, 40 to 60 minutes, 60 to 240 minutes, 60 to 200 minutes, 60 to 100 minutes, 100 to 240 minutes, 100 to 200 minutes, or 200 to 240 minutes. In some embodiments, after combining the core, or the core with a ZnSe shell, with the zinc source, sulfur source, and Group IV fluoride, the temperature of the reaction mixture is maintained for 30 to 120 minutes.

[0106]

[0112] In some embodiments, the temperature after combining the core, or the core having a ZnSe shell, with the zinc source, sulfur source, and Group IV fluoride is between 200°C and 310°C, between 200°C and 280°C, between 200°C and 250°C, between 200°C and 220°C, between 220°C and 310°C, between 220°C and 280°C, between 220°C and 250°C, between 250°C and 310°C, between 250°C and 280°C, or between 280°C and 310°C. In some embodiments, the temperature in (f) is between 250°C and 100°C.

[0107]

[0113] In some embodiments, the time to reach the above temperature after mixing the core or the core having a ZnSe shell with the zinc source, the sulfur source, and the Group IV fluoride is between 2 and 240 minutes, between 2 and 200 minutes, between 2 and 100 minutes, between 2 and 60 minutes, between 2 and 40 minutes, between 5 and 240 minutes, between 5 and 200 minutes, between 5 and 100 minutes, between 5 and 60 minutes, between 5 and 40 minutes, between 1 and 240 minutes, between 1 and 200 minutes, between 1 and 100 minutes, between 1 and 2 ... Between 0 and 240 minutes, between 10 and 200 minutes, between 10 and 100 minutes, between 10 and 60 minutes, between 10 and 40 minutes, between 40 and 240 minutes, between 40 and 200 minutes, between 40 and 100 minutes, between 40 and 60 minutes, between 60 and 240 minutes, between 60 and 200 minutes, between 60 and 100 minutes, between 100 and 240 minutes, between 100 and 200 minutes, or between 200 and 240 minutes.

[0108]

[0114] In some embodiments, the temperature after combining the core, or the core having a ZnSe shell, with the zinc source, the sulfur source, and the Group IV fluoride is maintained for 2 to 240 minutes, 2 to 200 minutes, 2 to 100 minutes, 2 to 60 minutes, 2 to 40 minutes, 5 to 240 minutes, 5 to 200 minutes, 5 to 100 minutes, 5 to 60 minutes, 5 to 40 minutes, 10 to 240 minutes, 10 to 200 minutes, 10 to 100 minutes, 10 to 60 minutes, 10 to 40 minutes, 40 to 240 minutes, 40 to 200 minutes, 40 to 100 minutes, 40 to 60 minutes, 60 to 240 minutes, 60 to 200 minutes, 60 to 100 minutes, 100 to 240 minutes, 100 to 200 minutes, or 200 to 240 minutes.

[0109]

[0115] In some embodiments, the number of monolayers in the ZnSe shell is between 0.25 and 10, between 0.25 and 8, between 0.25 and 7, between 0.25 and 6, between 0.25 and 5, between 0.25 and 4, between 0.25 and 3, between 0.25 and 2, between 2 and 10, between 2 and 8, between 2 and 7, between 2 and 6, between 2 and 5, between 2 and 4, between 2 and 3, between 3 and 10, between 3 and 8, between 3 and 7, between 3 and 6, between 3 and 5, between 3 and 4, between 4 and 10, between 4 and 8, between 4 and 7, between 4 and 6, between 4 and 5, between 5 and 10, between 5 and 8, between 5 and 7, between 5 and 6, between 6 and 10, between 6 and 8, between 6 and 7, between 7 and 10, between 7 and 8, or between 8 and 10. In some embodiments, the ZnSe shell comprises between 2 and 6 monolayers. In some embodiments, the ZnSe shell comprises between 3 and 5 monolayers.

[0110]

[0116] In some embodiments, the ZnSe monolayer has a thickness of about 0.328 nm.

[0111]

[0117] In some embodiments, the ZnSe shell has a thickness between 0.08 nm and 3.5 nm, between 0.08 nm and 2 nm, between 0.08 nm and 0.9 nm, between 0.08 nm and 0.7 nm, between 0.08 nm and 0.5 nm, between 0.08 nm and 0.2 nm, between 0.2 nm and 3.5 nm, between 0.2 nm and 2 nm, between 0.2 nm and 0.9 nm, between 0.2 nm and 0.7 nm, between 0.2 nm and 0.5 nm, between 0.5 nm and 3.5 nm, between 0.5 nm and 2 nm, between 0.5 nm and 0.9 nm, between 0.5 nm and 0.7 nm, between 0.7 nm and 3.5 nm, between 0.7 nm and 2 nm, between 0.7 nm and 0.9 nm, between 0.9 nm and 3.5 nm, between 0.9 nm and 2 nm, or between 2 nm and 3.5 nm.

[0112]

[0118] In some embodiments, the number of monolayers in the ZnS shell is between 0.25 and 10, between 0.25 and 8, between 0.25 and 7, between 0.25 and 6, between 0.25 and 5, between 0.25 and 4, between 0.25 and 3, between 0.25 and 2, between 2 and 10, between 2 and 8, between 2 and 7, between 2 and 6, between 2 and 5, between 2 and 4, between 2 and 3, between 3 and 10, between 3 and 8, between 3 and 7, between 3 and 6, between 3 and 5, between 3 and 4, between 4 and 10, between 4 and 8, between 4 and 7, between 4 and 6, between 4 and 5, between 5 and 10, between 5 and 8, between 5 and 7, between 5 and 6, between 6 and 10, between 6 and 8, between 6 and 7, between 7 and 10, between 7 and 8, or between 8 and 10. In some embodiments, the ZnS shell comprises between 2 and 12 monolayers. In some embodiments, the ZnS shell comprises between 4 and 6 monolayers.

[0113]

[0119] In some embodiments, the ZnS monolayer has a thickness of about 0.31 nm.

[0114]

[0120] In some embodiments, the ZnS shell has a thickness between 0.08 nm and 3.5 nm, between 0.08 nm and 2 nm, between 0.08 nm and 0.9 nm, between 0.08 nm and 0.7 nm, between 0.08 nm and 0.5 nm, between 0.08 nm and 0.2 nm, between 0.2 nm and 3.5 nm, between 0.2 nm and 2 nm, between 0.2 nm and 0.9 nm, between 0.2 nm and 0.7 nm, between 0.2 nm and 0.5 nm, between 0.5 nm and 3.5 nm, between 0.5 nm and 2 nm, between 0.5 nm and 0.9 nm, between 0.5 nm and 0.7 nm, between 0.7 nm and 3.5 nm, between 0.7 nm and 2 nm, between 0.7 nm and 0.9 nm, between 0.9 nm and 3.5 nm, between 0.9 nm and 2 nm, or between 2 nm and 3.5 nm.

[0115] Group IV metal fluorides

[0121] The present disclosure provides methods for fabricating nanostructures comprising a core comprising nanocrystals and at least one shell disposed on the core, wherein at least one shell comprises at least one Group IV metal fluoride. In some embodiments, the nanostructures comprise a core comprising nanocrystals and at least two shells disposed on the core, wherein at least one shell comprises at least one Group IV metal fluoride. In some embodiments, the nanostructures comprise a core comprising nanocrystals and at least two shells disposed on the core, wherein at least two shells comprise at least one Group IV metal fluoride.

[0116]

[0122] In some embodiments, at least one shell comprises one, two, or three Group IV metal fluorides. In some embodiments, at least one shell comprises one Group IV metal fluoride. In some embodiments, at least one shell comprises two Group IV metal fluorides. In some embodiments, at least one shell comprises three Group IV metal fluorides.

[0117]

[0123] In some embodiments, the Group IV metal fluoride has the formula (I): MF4(I) are group IV metal fluorides, M=Zr, Hf, or Ti.

[0118]

[0124] In some embodiments, the Group IV metal fluoride is selected from the group consisting of ZrF4, HfF4, and TiF4. In some embodiments, the Group IV metal fluoride is ZrF4. In some embodiments, the Group IV metal fluoride is HfF4.

[0119] Group IV metal fluoride concentrations

[0125] The concentration of at least one group IV metal fluoride in the nanostructures can be determined by optical density (OD) measurements. OD can be measured at 450 nm using a 1 cm path length cuvette. 450For 100 μL of nanostructures with a pH of 1.5, the concentration of at least one group IV metal fluoride in the solution may be between about 0.01 mM and about 40 mM, between about 0.01 mM and about 20 mM, between about 0.01 mM and about 10 mM, between about 0.01 mM and about 5 mM, between about 0.01 mM and about 2.5 mM, between about 0.01 mM and about 1.5 mM, between about 0.01 mM and about 1 mM, between about 0.01 mM and about 0.5 mM, between about 0.01 mM and about 0.25 mM between about 0.25 mM and about 40 mM, between about 0.25 mM and about 20 mM, between about 0.25 mM and about 10 mM, between about 0.25 mM and about 5 mM, between about 0.25 mM and about 2.5 mM, between about 0.25 mM and about 1.5 mM, between about 0.25 mM and about 1.5 mM, between about 0.25 mM and about 1 mM, between about 0.25 mM and about 0.5 mM, between about 0.25 mM and about 0.25 mM, between about 0.5 mM and about 40 mM, between about 0.5 mM and about between about 20 mM, between about 0.5 mM and about 10 mM, between about 0.5 mM and about 5 mM, between about 0.5 mM and about 2.5 mM, between about 0.5 mM and about 1.5 mM, between about 0.5 mM and about 1 mM, between about 1 mM and about 40 mM, between about 1 mM and about 20 mM, between about 1 mM and about 10 mM, between about 1 mM and about 5 mM, between about 1 mM and about 2.5 mM, between about 1 mM and about 1.5 mM, between about 1.5 mM and about 40 mM, between about 1.5 mM and about 20 mM, Between about 1.5 mM and about 10 mM, between about 1.5 mM and about 5 mM, between about 1.5 mM and about 2.5 mM, between about 2.5 mM and about 40 mM, between about 2.5 mM and about 20 mM, between about 2.5 mM and about 10 mM, between about 2.5 mM and about 5 mM, between about 5 mM and about 40 mM, between about 5 mM and about 20 mM, between about 5 mM and about 10 mM, between about 10 mM and about 40 mM, between about 10 mM and about 20 mM, or between about 20 mM and about 40 mM. 450 For a 100 μL nanostructure with a pH of 1.5, the concentration of the at least one metal fluoride is between about 1 mM and about 2.5 mM.

[0120] Ratio of group IV metal fluoride to zinc-containing core

[0126] In some embodiments, the molar ratio of the at least one Group IV metal fluoride to the zinc-containing core is between about 1:1 and about 8:1, between about 1:1 and about 7:1, between about 1:1 and about 6:1, between about 1:1 and about 5:1, between about 1:1 and about 4:1, between about 1:1 and about 3:1, between about 1:1 and about 2:1, between about 2:1 and about 8:1, between about 2:1 and about 7:1, between about 2:1 and about 6:1, between about 2:1 and about 5:1, between about 2:1 and about 4:1, between about 2:1 and about 3:1, between about 3:1, between about 3:1 and about 8:1, between about 3:1 and about 7:1, between about 3:1 and about 6:1, between about 3:1 and about 5:1, between about 3:1 and about 4:1, between about 4:1 and about 8:1, between about 4:1 and about 7:1, between about 4:1 and about 6:1, between about 4:1 and about 5:1, between about 5:1 and about 8:1, between about 5:1 and about 7:1, between about 5:1 and about 6:1, between about 6:1 and about 8:1, between about 6:1 and about 7:1, or between about 7:1 and about 8:1. In some embodiments, the molar ratio of at least one Group IV metal fluoride to zinc core is between about 1:1 and about 3:1.

[0121] Core / shell nanostructures

[0127] In some embodiments, the core / shell nanostructure is a ZnSe / ZnS nanostructure. In some embodiments, the core / shell nanostructure is a ZnSe 1-x Te x In some embodiments, the core / shell nanostructure is a ZnSe / ZnS nanostructure with HfF4 in the ZnS shell. In some embodiments, the core / shell nanostructure is a ZnSe / ZnS nanostructure with ZrF4 in the ZnS shell. In some embodiments, the core / shell nanostructure is a ZnSe / ZnS nanostructure with HfF4 in the ZnS shell. 1-x Te x / ZnSe / ZnS nanostructure.

[0122] solvent

[0128] In some embodiments, the method for producing a nanostructure comprising a zinc core and at least two shells, wherein at least two shells comprise zinc, further comprises a solvent.

[0123]

[0129] In some embodiments, the solvent is selected from the group consisting of chloroform, acetone, hexane, heptane, butanone, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, 1,4-butanediol diacetate, diethylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether acetate, glyceryl triacetate, heptyl acetate, hexyl acetate, pentyl acetate, butyl acetate, ethyl acetate, diethylene glycol butyl methyl ether, diethylene glycol monobutyl ether, di(propylene glycol) dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, methyl ethyl ketone, methyl isobutyl ketone, monomethyl ether glycol esters, gamma-butyrolactone, methyl acetate-3-ethyl ether, butyl carbitol, butyl carbitol acetate, propanediol monomethyl ether, propanediol monomethyl ether acetate, cyclohexane, toluene, xylene, isopropyl alcohol, and combinations thereof. In some embodiments, the solvent is hexane, heptane, toluene, or chloroform.

[0124] Improved properties of nanostructures

[0130] In some embodiments, the core / shell nanostructures produced using the methods described herein exhibit high photoluminescence quantum yields. In some embodiments, the core / shell nanostructures can have a photoluminescence quantum yield of between 60% and 100%, between 60% and 95%, between 60% and 90%, between 60% and 85%, between 60% and 80%, between 60% and 70%, between 70% and 100%, between 70% and 95%, between 70% and 90%, between 70% and 85%, between 70% and 80%, between 80% and 100%, between 80% and 95%, between 80% and 90%, between 80% and 85%, between 85% and 100%, between 85% and 95%, between 80% and 85%, between 85% and 100%, between 85% and 90%, between 90% and 100%, between 90% and 95%, or between 95% and 100%. In some embodiments, core / shell nanostructures produced using the methods described herein have a photoluminescence quantum yield of between 60% and 80%.

[0125]

[0131] The photoluminescence spectrum of core / shell nanostructures produced using the methods described herein can span virtually any desired portion of the spectrum. In some embodiments, the photoluminescence spectrum of the core / shell nanostructure has an emission maximum between 300 nm and 750 nm, between 300 nm and 650 nm, between 300 nm and 550 nm, between 300 nm and 450 nm, between 450 nm and 750 nm, between 450 nm and 650 nm, between 450 nm and 550 nm, between 450 nm and 750 nm, between 450 nm and 650 nm, between 450 nm and 550 nm, between 550 nm and 750 nm, between 550 nm and 650 nm, or between 650 nm and 750 nm. In some embodiments, the photoluminescence spectrum of the core / shell nanostructure has an emission maximum between 500 nm and 550 nm. In some embodiments, the photoluminescence spectrum of the core / shell nanostructures produced using the methods described herein has an emission maximum between 430 nm and 460 nm.

[0126]

[0132] The size distribution of core / shell nanostructures produced using the methods described herein can be relatively narrow. In some embodiments, the photoluminescence spectrum of a population or core / shell nanostructure produced using the methods described herein has a full width at half maximum of between 10 nm and 60 nm, between 10 nm and 40 nm, between 10 nm and 30 nm, between 10 nm and 20 nm, between 20 nm and 60 nm, between 20 nm and 40 nm, between 20 nm and 30 nm, between 30 nm and 60 nm, between 30 nm and 40 nm, or between 40 nm and 60 nm. In some embodiments, the photoluminescence spectrum of a population or core / shell nanostructure produced using the methods described herein has a full width at half maximum of between 10 nm and 40 nm.

[0127]

[0133] In some embodiments, the nanostructures of the present invention are cubic. The shape of the nanostructures can be determined by visual inspection. In some embodiments, the cubic shape of the nanostructures is observed by visual inspection of TEM images.

[0128]

[0134] In some embodiments, a population of nanostructures that are cubic is a population in which at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% of the nanostructures are cubic, hi some embodiments, a population of nanostructures that are cubic is a population in which at least 85% of the nanostructures are cubic.

[0129] Nanostructured Film

[0135] In some embodiments, the core / shell nanostructures prepared by the methods described herein are incorporated into nanostructured films, hi some embodiments, the nanostructured films are incorporated into quantum dot-enhanced films (QDEFs).

[0130]

[0136] In some embodiments, the present disclosure provides a nanostructured film comprising: (a) at least one population of nanostructures, the nanostructures comprising a core and at least one shell, the at least one shell comprising a Group IV metal fluoride; (b) at least one organic resin; The present invention provides a nanostructured film comprising:

[0131]

[0137] In some embodiments, the nanostructures are quantum dots.

[0132]

[0138] In some embodiments, the present disclosure provides a nanostructured film comprising: (a) at least one population of nanostructures, the nanostructures comprising a core comprising zinc and at least one shell, the at least one shell comprising zinc and a Group IV metal fluoride; (b) at least one organic resin; The present invention provides a nanostructured film comprising:

[0133]

[0139] In some embodiments, the nanostructures are quantum dots.

[0134]

[0140] In some embodiments, the core / shell nanostructures are embedded in a matrix. As used herein, the term "embedded" is used to indicate that the nanostructures are enclosed or encased in a matrix material that constitutes the majority component of the matrix. In some embodiments, the nanostructures are uniformly distributed throughout the matrix material. In some embodiments, the nanostructures are distributed according to a uniform distribution function that is application specific.

[0135]

[0141] In some embodiments, the nanostructures can comprise a uniform population having sizes that emit in the blue visible wavelength spectrum, the green visible wavelength spectrum, or the red visible wavelength spectrum, hi some embodiments, the nanostructures can comprise a first population of nanostructures having sizes that emit in the blue visible wavelength spectrum, a second population of nanostructures having sizes that emit in the green visible wavelength spectrum, and a third population of nanostructures having sizes that emit in the red visible wavelength spectrum.

[0136]

[0142] The matrix material may be any suitable host matrix material capable of accommodating the nanostructures. Suitable matrix materials may be chemically and optically compatible with the nanostructures and any surrounding packaging materials or layers used to attach the nanostructure film to the device. Suitable matrix materials 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. Matrix materials may include polymers and organic and inorganic oxides. Suitable polymers for use in the matrix material may be any polymer known to those skilled in the art that can be used for such purposes. These polymers 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, such as, but not limited to, aminosilicones (AMS), polyphenylmethylsiloxanes, polyphenylalkylsiloxanes, polydiphenylsiloxanes, polydialkylsiloxanes, silsesquioxanes, fluorinated silicones, and vinyl- and hydride-substituted silicones; acrylic polymers and copolymers derived from monomers such as, but not limited to, methyl methacrylate, butyl methacrylate, and lauryl methacrylate; styrenic polymers, such as polystyrene, aminopolystyrene (APS), and poly(acrylonitrile ethylene styrene) (AES); polymers that crosslink with difunctional monomers such as divinylbenzene; crosslinkers suitable for crosslinking ligand materials, such as epoxides that combine with ligand amines (e.g., APS or polyethyleneimine ligand amines) to form epoxies.

[0137]

[0143] In some embodiments, the matrix material includes scattering microbeads, such as TiO microbeads, ZnS microbeads, or glass microbeads, which can improve the light conversion efficiency of the nanostructured film. In some embodiments, the matrix material can include light blocking elements.

[0138]

[0144] In some embodiments, the matrix material can have low oxygen and moisture permeability, can exhibit high photostability and chemical stability, can exhibit advantageous refractive index, and can adhere to the exterior surfaces of the nanostructures, thereby forming a hermetic seal to protect the nanostructures. In another embodiment, the matrix material can be curable using UV or thermal curing methods to facilitate roll-to-roll processing.

[0139]

[0145] In some embodiments, nanostructured films can be formed by mixing nanostructures in a polymer (e.g., photoresist) and casting the nanostructure-polymer mixture onto a substrate, by mixing nanostructures with monomers and polymerizing them together, by mixing nanostructures in a sol-gel to form an oxide, or by any other method known to one skilled in the art.

[0140]

[0146] In some embodiments, forming the nanostructured film can include a film extrusion process. The film extrusion process can include forming a homogeneous mixture of a matrix material and core / shell nanostructures coated with a barrier layer, such as nanostructures functionalized with a Group IV metal fluoride, and introducing the homogeneous mixture into a top-mounted hopper to feed the homogeneous mixture into an extruder. In some embodiments, the homogeneous mixture can be in the form of pellets. The film extrusion process can 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 can have a thickness of less than about 75 μm, for example, 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 can optionally include a secondary process prior to the film extrusion process. Secondary processes can include processes such as coextrusion, thermoforming, vacuum forming, plasma treating, molding, and / or embossing to create a texture on the top surface of the nanostructured film layer. The textured top surface of the nanostructured film can help, for example, improve the defined light diffusion and / or defined angular optical emission properties of the nanostructured film.

[0141] Quantum dot-on-glass LCD display

[0147] In some embodiments, the nanostructured film is incorporated into a quantum dot-on-glass LCD display. The LCD display can include a nanostructured film formed directly on a light guide plate (LGP) without the need for an intermediate substrate or barrier layer. In some embodiments, the nanostructured film can be a thin film. In some embodiments, the nanostructured film can have a thickness of 500 μm or less, 100 μm or less, or 50 μm or less. In some embodiments, the nanostructured film is a thin film having a thickness of about 15 μm or less.

[0142]

[0148] The LGP can include an optical cavity having one or more surfaces, including at least a top surface, that comprises 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 LGP can be formed at least in part from glass to provide a substrate with sufficient barrier and structural properties.

[0143]

[0149] In some embodiments, a nanostructured film can be formed on an LGP. In some embodiments, the nanostructured film comprises a population of nanostructures embedded in a matrix material, such as a resin. The nanostructured film can be formed on an LGP by any method known in the art, such as wet coating, painting, spin coating, or screen printing. After deposition, the resin of the nanostructured film can be cured. In some embodiments, one or more nanostructured film resins can be partially cured, further processed, and then finally cured. The nanostructured film can be deposited as a single layer or as separate layers, and the separate layers can include various properties. The width and height of the nanostructured film can be any desired dimension depending on the size of the display panel of the display device. For example, the nanostructured film can have a relatively small surface area for small display embodiments such as watches and phones, or the nanostructured film can have a large surface area for large display embodiments such as TVs and computer monitors.

[0144]

[0150] In some embodiments, an optically transparent substrate is formed on the nanostructured film by any method known in the art, such as vacuum deposition, vapor deposition, or the like. The optically transparent substrate can be configured to environmentally seal the nanostructured film from underlying layers and / or structures. In some embodiments, a light-blocking element can be included in the optically transparent substrate. In some embodiments, a light-blocking element can be included in a second polarizing filter, which can be disposed between the substrate and the nanostructured film. In some embodiments, the light-blocking element can be, for example, a dichroic filter that can reflect primary light (e.g., blue light, UV light, or a combination of UV and blue light) while transmitting secondary light. The light-blocking element can include a specialized UV light filtering element to filter out unconverted UV light from the red and green subpixels and / or UV light from the blue subpixels.

[0145] On-chip and near-chip placement of quantum dots

[0151] In some embodiments, the nanostructures are incorporated into the display device by "on-chip" placement. As used herein, "on-chip" refers to placing the nanostructures in the LED cup. In some embodiments, the nanostructures are dissolved in a resin or fluid that fills the LED cup.

[0146]

[0152] In some embodiments, the nanostructures are incorporated into the display device in a "near-chip" configuration. As used herein, "near-chip" refers to coating the nanostructures on top of the LED assembly so that the emitted light passes through the nanostructure film.

[0147] Display device with nanostructured color conversion layer

[0153] In some embodiments, the present invention provides a method for producing a pharmaceutical composition comprising: (a) a display panel for emitting a first light; (b) a backlight unit configured to provide a first light to the display panel; (c) a color filter including at least one pixel region including a color conversion layer; The present invention provides a display device including:

[0148]

[0154] In some embodiments, the color filter includes 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, it can pass through the pixel regions to emit red light, white light, green light, and / or blue light, respectively. In some embodiments, the color filter is described in U.S. Patent Application Publication No. 2017 / 153366, which is incorporated herein by reference in its entirety.

[0149]

[0155] 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 light of a first color. In some embodiments, the color conversion layer includes nanostructures described herein configured to convert incident light to blue light.

[0150]

[0156] In some embodiments, the display device includes 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 color conversion layers. In some embodiments, the display device includes one color conversion layer comprising the nanostructures described herein. In some embodiments, the display device includes two color conversion layers comprising the nanostructures described herein. In some embodiments, the display device includes three color conversion layers comprising the nanostructures described herein. In some embodiments, the display device includes four color conversion layers comprising the nanostructures described herein. In some embodiments, the display device includes at least one red conversion layer, at least one green conversion layer, and at least one blue conversion layer.

[0151]

[0157] 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.

[0152]

[0158] The nanostructured 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 a combination thereof. In some embodiments, the nanostructured color conversion layer is deposited by photoresist patterning. In some embodiments, the nanostructured color conversion layer is deposited by inkjet printing.

[0153] Inkjet printing

[0159] 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 forming thin films over large areas and do not provide a means for patterning the deposited layers, thus limiting their use. Inkjet printing allows for precisely patterned deposition of thin films on a large scale at low cost. Inkjet printing also allows for precise patterning of nanostructured layers, allowing for the printing of display pixels, eliminating the need for photopatterning. Therefore, inkjet printing is very attractive for industrial applications, especially for displays.

[0154]

[0160] 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 frequently used for 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 highly hydrophilic nature of nanostructures containing poly(alkylene oxide) ligands increases their solubility in these solvents.

[0155]

[0161] In some embodiments, the nanostructures 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 a combination thereof. In some embodiments, the nanostructures described herein including poly(alkylene oxide) ligands 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 a combination thereof.

[0156]

[0162] For application by inkjet printing or microdispensing, the inkjet composition containing the nanostructures should be dissolved in a suitable solvent, which must be capable of dispersing the nanostructure composition and must not have any adverse effects on the selected printhead.

[0157]

[0163] In some embodiments, the inkjet composition further comprises one or more additional ingredients such as surfactants, lubricants, wetting agents, dispersants, hydrophobizing agents, adhesives, flow improvers, defoamers, deaerators, diluents, adjuvants, colorants, dyes, pigments, sensitizers, stabilizers, and suppressors.

[0158]

[0164] In some embodiments, the nanostructure composition described herein comprises between about 0.01% and about 20% by weight of the ink jet composition. In some embodiments, the nanostructures comprising poly(alkylene oxide) ligands are present in an amount, by weight of the ink jet composition, between about 0.01% and about 20%, between about 0.01% and about 15%, between about 0.01% and about 10%, between about 0.01% and about 5%, between about 0.01% and about 2%, between about 0.01% and about 1%, between about 0.01% and about 0.1%, between about 0.01% and about 0.05%, between about 0.05% and about 20%, between about 0.05% and about 15%, between about 0.05% and about 10%, between about 0.05% and about 5%, between about 0.05% and about 2%, between about 0.05% and about 1%, between about 0.05% and about 0.1%, between about 0.1% and about 20%, between about 0.1% and about 15%, or between about 0.05% and about 0.1%. Between 0.1% and about 10%, Between 0.1% and about 5%, Between 0.1% and about 2%, Between 0.1% and about 1%, Between 0.5% and about 20%, Between 0.5% and about 15%, Between 0.5% and about 10%, Between 0.5% and about 5%, Between 0.5% and about 2%, Between 0.5% and about 1%, Between 1% and about 20%, Between 1% and about 15%, Between 1% and about 1 % to about 10%, between about 1% to about 5%, between about 1% to about 2%, between about 2% to about 20%, between about 2% to about 15%, between about 2% to about 10%, between about 2% to about 5%, between about 5% to about 20%, between about 5% to about 15%, between about 5% to about 10%, between about 10% to about 20%, between about 10% to about 15%, or between about 15% to 20%.

[0159]

[0165] In some embodiments, inkjet compositions comprising the nanostructures or nanostructure compositions described herein are used to form electronic devices. In some embodiments, inkjet compositions comprising the nanostructures or nanostructure compositions described herein are used to form electronic devices selected from the group consisting of nanostructured films, displays, lighting devices, backlight units, color filters, surface emitting devices, electrodes, magnetic storage devices, and batteries. In some embodiments, inkjet compositions comprising the nanostructure compositions described herein are used to form light emitting devices.

[0160] lighting equipment

[0166] In some embodiments, nanoparticles comprising zinc oxide can be used in the electron transport layer of a lighting device.

[0161]

[0167] The lighting device can be used in a wide variety of applications, such as flexible electronics, touchscreens, monitors, televisions, mobile phones, and any high-resolution display. In some embodiments, the lighting device is a light-emitting diode. In some embodiments, the lighting device is a quantum dot light-emitting diode (QD-LED). An example of a QD-LED is disclosed in U.S. Patent Application No. 15 / 824,701, the entire contents of which are incorporated herein by reference.

[0162]

[0168] In some embodiments, the present disclosure provides a lighting device comprising: (a) a first conductive layer; (b) a second conductive layer; (c) a light-emitting layer comprising at least one population of nanoparticles comprising a core and at least one shell disposed on the core, the at least one shell comprising zinc and a Group IV metal fluoride; The present invention provides a lighting device comprising:

[0163]

[0169] In some embodiments, the lighting device comprises: (a) a first conductive layer; (b) a second conductive layer; (c) an electron transport layer, the electron transport layer comprising at least one population of nanostructures; (d) a light-emitting layer comprising at least one population of nanoparticles comprising a core comprising zinc and at least one shell, the at least one shell comprising zinc and a Group IV metal fluoride; Includes.

[0164]

[0170] In some embodiments, the nanostructures are quantum dots.

[0165]

[0171] In some embodiments, the lighting device includes a first conductive layer, a second conductive layer, and an electron transport layer, the electron transport layer being disposed between the first conductive layer and the second conductive layer, hi some embodiments, the electron transport layer is a thin film.

[0166]

[0172] In some embodiments, the lighting device includes additional layers between the first conductive layer and the second conductive layer, such as a hole injection layer, a hole transport layer, an electron transport layer, and an emissive layer. In some embodiments, the hole injection layer, the hole transport layer, the electron transport layer, and the emissive layer are thin films. In some embodiments, these layers are laminated on a substrate.

[0167]

[0173] When a voltage is applied to the first conductive layer and the second conductive layer, holes injected in the first conductive layer move to the light-emitting layer via the hole injection layer and / or the hole transport layer, and electrons injected from the second conductive layer move to the light-emitting layer via the electron transport layer. The holes and electrons recombine in the light-emitting layer to generate excitons.

[0168] substrate

[0174] The substrate can be any substrate commonly used in the manufacture of lighting devices. In some embodiments, the substrate is a transparent substrate such as glass. In some embodiments, the substrate is a flexible substrate such as polyimide, or a flexible transparent material such as polyethylene terephthalate. In some embodiments, the substrate has a thickness between about 0.1 mm and about 2 mm. In some embodiments, the substrate is a glass substrate, a plastic substrate, a metal substrate, or a silicon substrate.

[0169] First Conductive Layer

[0175] In some embodiments, the first conductive layer is disposed on a substrate. In some embodiments, the first conductive layer is a stack of conductive layers. In some embodiments, the first conductive layer has a thickness between about 50 nm and about 250 nm. In some embodiments, the first conductive layer is deposited as a thin film using any known deposition technique, such as, for example, sputtering or electron beam evaporation. In some embodiments, the first conductive layer comprises indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO), zinc oxide (ZnO), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), silver (Ag), gold (Au), or a mixture thereof. In some embodiments, the first conductive layer is an anode.

[0170] Second Conductive Layer

[0176] In some embodiments, additional layers can be sandwiched between the first and second conductive layers. In some embodiments, the first conductive layer functions as the anode of the device, while the second conductive layer functions as the cathode of the device. In some embodiments, the second conductive layer is a metal such as aluminum. In some embodiments, the second conductive layer has a thickness between about 100 nm and about 150 nm. In some embodiments, the second conductive layer is a stack of conductive layers. For example, the second conductive layer can include one layer of silver sandwiched between two layers of ITO (ITO / Ag / ITO).

[0171]

[0177] In some embodiments, the second conductive layer comprises indium tin oxide (ITO), indium zinc oxide (IZO), titanium dioxide, tin oxide, zinc sulfide, silver (Ag), or a mixture thereof.

[0172] Semiconducting polymer layer

[0178] In some embodiments, the lighting device further comprises a semiconducting polymer layer. In some embodiments, the semiconducting polymer functions as a hole injection layer. In some embodiments, the semiconducting polymer layer is deposited on the first conductive layer. In some embodiments, the semiconducting polymer layer is deposited by vacuum deposition, spin coating, printing, casting, slot-die coating, or Langmuir-Blodgett (LB) deposition. In some embodiments, the semiconducting polymer layer has a thickness between about 20 nm and about 60 nm.

[0173]

[0179] In some embodiments, the semiconducting polymer layer comprises copper phthalocyanine, 4,4',4''-tris[(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4''-tris(diphenylamino)triphenylamine (TDATA), 4,4',4''-tris[2-naphthyl(phenyl)amino]triphenylamine (2T-NATA), polyaniline / dodecylbenzenesulfonic acid, poly(3,4-ethylenedioxythiophene) / polystyrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid, or polyaniline / poly(4-styrenesulfonate).

[0174] First Transport Layer

[0180] In some embodiments, the lighting device further includes a transport layer to facilitate transport of electrons and holes due to an electric field generated between the first conductive layer and the second conductive layer. In some embodiments, the lighting device further includes a first transport layer associated with the first conductive layer. In some embodiments, the first transport layer functions as a hole transport layer (and electron and / or exciton blocking layer). In some embodiments, the first transport layer is deposited on the first conductive layer. In some embodiments, the first transport layer is deposited on the semiconducting polymer layer. In some embodiments, the first transport layer has a thickness between about 20 nm and about 50 nm. In some embodiments, the first transport layer is substantially transparent to visible light.

[0175]

[0181] In some embodiments, the first transport layer comprises a material selected from the group consisting of amines, triarylamines, thiophenes, carbazoles, phthalocyanines, porphyrins, or mixtures thereof. In some embodiments, the first transport layer comprises N,N'-di(naphthalen-1-yl)-N,N'-bis(4-vinylphenyl)-4,4'-diamine, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], and poly(9-vinylcarbazole).

[0176] Second Transport Layer

[0182] In some embodiments, the lighting device further comprises a second transport layer. In some embodiments, the second transport layer functions as an electron transport layer (and hole and / or exciton blocking layer). In some embodiments, the second transport layer is in contact with the light-emitting layer. In some embodiments, the second transport layer is disposed between the light-emitting layer and the second conductive layer. In some embodiments, the second transport layer has a thickness between about 20 nm and about 50 nm. In some embodiments, the second transport layer is substantially transparent to visible light.

[0177]

[0183] In some embodiments, the second transport layer is an electron transport layer.

[0178]

[0184] If the polarity of the first conductive layer and the second conductive layer is reversed, the roles of the first transport layer and the second transport layer are reversed.

[0179] electron transport layer

[0185] In some embodiments, the lighting device includes at least one electron transport layer. In some embodiments, the lighting device is a quantum dot light emitting diode.

[0180]

[0186] In some embodiments, the electron transport layer has a thickness of about 20 nm to about 50 nm, about 20 nm to about 50 nm, about 20 nm to about 40 nm, about 20 nm to about 30 nm, about 30 nm to about 50 nm, about 30 nm to about 40 nm, or about 40 nm to about 50 nm.

[0181]

[0187] In some embodiments, the electron transport layer comprises zinc oxide, hi some embodiments, the electron transport layer comprises zinc magnesium oxide.

[0182] Lighting device with improved properties

[0188] In some embodiments, lighting devices fabricated using the nanostructures of the present disclosure have a refractive index of between about 1.5% and about 20%, between about 1.5% and about 15%, between about 1.5% and about 12%, between about 1.5% and about 10%, between about 1.5% and about 8%, between about 1.5% and about 4%, between about 1.5% and about 3%, between about 3% and about 20%, between about 3% and about 15%, between about 3% and about 1 2%, between about 3% and about 10%, between about 3% and about 8%, between about 8% and about 20%, between about 8% and about 15%, between about 8% and about 12%, between about 8% and about 10%, between about 10% and about 20%, between about 10% and about 15%, between about 10% and about 12%, between about 12% and about 20%, between about 12% and about 15%, or between about 15% and about 20%. In some embodiments, lighting devices fabricated using the nanostructures of the present disclosure exhibit an EQE of between about 2% and about 6%. In some embodiments, the lighting device is a light emitting diode.

[0183]

[0189] In some embodiments, lighting devices fabricated with the nanostructures of the present disclosure exhibit improved lifetime. In some embodiments, a lighting device fabricated using the nanostructures of the present disclosure may achieve 500 nits (cd / m) illumination for about 1 second to about 100 seconds, about 1 second to about 60 seconds, about 1 second to about 40 seconds, about 1 second to about 30 seconds, about 1 second to about 20 seconds, about 1 second to about 10 seconds, about 10 seconds to about 100 seconds, about 10 seconds to about 60 seconds, about 10 seconds to about 40 seconds, about 10 seconds to about 30 seconds, about 10 seconds to about 20 seconds, about 20 seconds to about 100 seconds, about 20 seconds to about 50 seconds, about 20 seconds to about 40 seconds, about 20 seconds to about 30 seconds, about 30 seconds to about 40 seconds, about 40 seconds to about 100 seconds, about 40 seconds to about 60 seconds, or about 60 seconds to about 100 seconds. 2 ) of the initial brightness (T 50 In some embodiments, lighting devices fabricated using the nanostructures of the present disclosure reach 500 nits (cd / m) in between about 20 seconds and about 60 seconds. 2 ) of the initial brightness (T 50 ) is reached. [Example]

[0184] Example

[0190] The following examples are illustrative, but not limiting, of the products and processes described herein. Suitable modifications and adaptations of the variety of conditions, formulations, and other parameters normally encountered in the art and which will become apparent to those skilled in the art in light of this disclosure are within the spirit and scope of the invention.

[0185] Example 1 ZnSe using TOPTe precursor 1-x Te x Nanocrystal synthesis

[0191] Preparation of TOPTe precursor: A Te precursor mixture was prepared by first diluting trioctylphosphine telluride (1 M Te, 230 μL) with 2.5 mL of dry, distilled oleylamine. To this solution was added lithium triethylborohydride (1 M in THF, 230 μL), resulting in a deep purple solution. Finally, zinc oleate (0.5 M in trioctylphosphine (TOP), 460 μL) was added, resulting in a colorless, opaque, viscous gel that could be drawn into a syringe.

[0186]

[0192] A 100 mL three-neck flask was charged with oleylamine (15 mL) and degassed under vacuum at 110 °C for 30 minutes. The mixture was then heated to 300 °C under a nitrogen flow. After reaching this temperature, a solution of trioctylphosphine selenide (TOPSe, 2.7 mmol) and diphenylphosphine (225 μL) in TOP (2.9 mL total) was added to the flask. After the temperature returned to 300 °C, the TOPTe precursor and a solution of diethylzinc (295 μL) in TOP (1 mL total) were rapidly injected from separate syringes. The temperature was set to 280 °C, and after 5 minutes, injection of a solution of diethylzinc (294 μL) and TOPSe (4.4 mmol) in TOP (3.8 mL total) was initiated at a rate of 0.5 mL / min and continued until all 3.8 mL had been added. After the precursor injection was complete, the reaction mixture was maintained at 280 °C for 5 minutes and then cooled to room temperature. The growth solution was diluted with an equal volume of toluene (40 mL), and the nanocrystals were precipitated by adding ethanol (120 mL). After centrifugation, the supernatant was discarded, and the nanocrystals were redispersed in hexane (5 mL). The concentration was measured as the dry weight by evaporating the solvent of an aliquot. The dried material was further subjected to thermogravimetric analysis to determine the ZnSe content.

[0187] Example 2 Synthesis of ZnSe nanocrystals

[0193] ZnSe nanocrystals were produced using the method of Example 1 without injecting the TOPTe precursor.

[0188] Example 3 ZnSe1-x Te x Synthesis of ZnSe nanocrystals

[0194] ZnSe with an average diameter of 4.0 nm 1-x Te x A ZnSe buffer layer was formed on top of the nanocrystals with a target shell thickness of 4 monolayers (ML) of ZnSe.

[0189]

[0195] A 100 mL three-neck flask was charged with zinc oleate (6.23 g), lauric acid (3.96 g), trioctylphosphine oxide (4.66 g), and TOP (9.4 mL). The flask was subjected to three vacuum and nitrogen fill cycles, then heated to 100°C and degassed for 30 minutes. The reaction mixture was placed under a nitrogen blanket and the ZnSe 1-x Te x The core solution (4.0 mL, 28.0 mg / mL in hexane) mixed with TOPSe (1.8 mL of 0.3 M selenium in TOP) was added to the flask. The flask was evacuated for 2 minutes and then heated to 310 °C under a nitrogen stream. After reaching this temperature, a slow injection of TOPSe (10.4 mL, 0.3 M in TOP) was initiated at a rate of 0.325 mL / min. After the selenium injection was terminated, the reaction was maintained at 310 °C for 10 minutes and then cooled to room temperature. The reaction mixture was diluted with toluene (45 mL). The core / shell nanocrystals were precipitated by adding ethanol (135 mL) and then isolated by centrifugation, decanting the supernatant, and redispersing the nanocrystals in hexane (5 mL). The solution was filtered through a PTFE 0.22 μm syringe filter, and the concentration was measured as the dry weight by evaporating the solvent of an aliquot. The dried material was further subjected to thermogravimetric analysis to determine the ZnSe content.

[0190] Example 4 Synthesis of ZnSe / ZnS nanocrystals

[0196] A ZnS buffer layer was formed on ZnSe nanocrystals with an average diameter of 4.0 nm, with a target shell thickness of 4 monolayers (ML) of ZnS.

[0191]

[0197] A 500 mL three-neck flask was charged with zinc oleate (27.63 g), lauric acid (17.54 g), trioctylphosphine oxide (18.00 g), and TOP (36.0 mL). The flask was subjected to three vacuum and nitrogen fill cycles, then heated to 100 °C and degassed for 30 minutes. The reaction mixture was placed under a nitrogen blanket, and a solution of ZnSe cores (2.0 mL, 216.0 mg / mL in hexane) was added to the flask. The flask was evacuated for 2 minutes and then heated to 310 °C under a nitrogen stream. Once at temperature, a slow injection of TOPS (25.3 mL of 2.0 M sulfur in TOP) was initiated at a rate of 0.720 mL / min. After the sulfur injection was terminated, the reaction was held at 310 °C for 10 minutes and then cooled to room temperature. The reaction mixture was diluted with toluene (95 mL). The core / shell nanocrystals were precipitated by adding ethanol (190 mL) and then isolated by centrifugation, decanting the supernatant, and redispersing the nanocrystals in hexane (7 mL). The solution was filtered through a PTFE 0.22 μm syringe filter, and the concentration was determined as the dry weight by evaporating the solvent of an aliquot.

[0192] Example 5 ZnSe 1-x Te x Synthesis of ZnSe / ZnS nanocrystals

[0198] ZnSe with an average diameter of 6.1 nm 1-x Te x A ZnS shell was formed on the ZnSe nanocrystals with a target shell thickness of 4 monolayers (ML).

[0193]

[0199] A 25 mL three-neck flask was charged with zinc oleate (375 mg), lauric acid (240 mg), trioctylphosphine oxide (281 mg), and TOP (0.566 mL). The flask was subjected to three vacuum and nitrogen fill cycles, then heated to 100°C and degassed for 30 minutes. The reaction mixture was placed under a nitrogen blanket and the ZnSe 1-x Te xA solution of cores (0.30 mL, 216.0 mg / mL in hexane) mixed with zinc oleate / TOPS (0.064 mL of 2.0 M sulfur in TOP + 0.254 mL of 0.5 M zinc oleate in TOP) was added to the flask. The flask was evacuated for 2 minutes and then heated to 310 °C under a nitrogen stream. After reaching this temperature, a slow injection of zinc oleate / TOPS (9.5 mL, 0.3 M in TOP) was initiated at a rate of 0.103 mL / min. After the sulfur injection was terminated, the reaction was maintained at 310 °C for 10 minutes and then cooled to room temperature. The reaction mixture was diluted with toluene (5 mL). The core / shell nanocrystals were precipitated by adding ethanol (10 mL) and then isolated by centrifugation, decanting the supernatant, and redispersing the nanocrystals in hexane (5 mL). The precipitation was repeated once with ethanol (10 mL), and finally the nanocrystals were redispersed in octane (3 mL). The solution was filtered through a PTFE 0.22 μm syringe filter, and the dry weight of an aliquot was measured before adjusting the concentration to 18 mg / mL.

[0194] Example 6 Synthesis of ZnSe / ZnS nanocrystals with hafnium fluoride passivation

[0200] The procedure was the same as that outlined in Example 4, except that anhydrous hafnium fluoride (242 mg) was also charged to the flask before the first three vacuum and nitrogen fill cycles.

[0195] Example 7 Synthesis of ZnSe / ZnS nanocrystals with zirconium fluoride passivation

[0201] The procedure was the same as that outlined in Example 4, except that anhydrous zirconium fluoride (159 mg) was also charged to the flask before the first three vacuum and nitrogen fill cycles.

[0196] Example 8 ZnSe with hafnium fluoride passivation 1-x Te x Synthesis of ZnSe / ZnS nanocrystals

[0202] The procedure was the same as that outlined in Example 5, except that anhydrous hafnium fluoride (251 mg) was also charged to the flask before the first three vacuum and nitrogen fill cycles.

[0197] Example 9 Photoluminescence properties of nanocrystals prepared using group IV fluorides

[0203] ZnSe / ZnS core / shell and ZnSe prepared in the presence of group IV fluorides 1-x Te x The solution photoluminescence spectra of the ZnSe / ZnS core / shell / shell quantum dots are shown in Table 1. As shown in Table 1, the resulting core / shell quantum dots with well-passivated surfaces exhibit high quantum yields (QY) and narrow full widths at half maximum (FWHM).

[0198]

[0204] The incorporation of group IV fluorides during shell growth also resulted in a change in the morphology of the ZnS-shelled QDs: instead of the quasi-spherical particles synthesized using standard shell growth conditions (Figures 3 and 5), cubic particles were obtained in the presence of HfF (Figures 4 and 6).

[0199] [Table 1]

[0200] Example 10 Electroluminescent devices using nanocrystals fabricated using group IV metal fluorides

[0205] The devices were fabricated by a combination of spin coating and thermal evaporation. First, the hole injection material, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (50 nm), was spin-coated onto a UV-ozone-treated indium tin oxide (ITO) substrate and baked at 200 °C for 15 min. The device was then transferred to an inert atmosphere, and the hole transport material, N,N'-di(naphthalen-1-yl)-N,N'-bis(4-vinylphenyl)biphenyl-4,4'-diamine (VNPB) (20 nm), was deposited by spin coating and baked at 200 °C for 15 min. ZnSe / ZnS or ZnSe 1-x Te x A solution of QDs in either ZnSe or ZnS was deposited by spin-coating (without the resin used in the emissive layer), followed by spin-coating of ZnMgO (20 nm) as an electron transport material, and then an Al cathode (150 nm) was deposited by thermal evaporation. The device was then encapsulated with a cap glass, getter, and epoxy resin.

[0201]

[0206] In electrochemical devices, cubic particles were found to have substantially less roll-off in higher luminescence (Figure 7). This improved roll-off indicates improved surface passivation and electrochemical stability of the Group IV metal fluoride ligands.

[0202] Example 11 Properties of the fabricated electroluminescent devices

[0207] ZnSe / ZnS core / shell and ZnSe prepared in the presence of group IV metal fluorides 1-x Te x The electroluminescence spectra of the device containing ZnSe / ZnS core / shell / shell quantum dots are shown in Table 2. As shown in Table 2, the electroluminescence lifetime (500 cd / m 2 T in 50 ) increased by 2–3 times in quantum dots prepared in the presence of group IV metal fluorides.

[0203] [Table 2]

[0204]

[0208] Furthermore, evidence of hole trap passivation can be seen in hole-only devices fabricated with group IV metal fluorides (Figure 8). Keeping the hole current (0.1 J) and thickness comparable, the output voltage (V o ) and forward voltage (V f ), a lower voltage (60-80 mV lower) was required to pass the applied current. Furthermore, the voltage increase (dV / dt) during the test was found to be small (9-12%), as shown in Table 3. This is direct evidence of an increase in hole conductivity due to an increase in hole trap passivation.

[0205] [Table 3]

[0206]

[0209] While various embodiments have been described above, it should be understood that they are provided by way of example only, and not limitation. Various changes in form and detail therein will be apparent to those skilled in the relevant art without departing from the spirit and scope of the present invention. Accordingly, the breadth and scope thereof should not be limited to the above-described exemplary embodiments, but should be defined only by the following claims and their equivalents.

[0207]

[0210] 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. 1. A lighting device, comprising: (a) a first conductive layer; (b) a second conductive layer; (c) a light-emitting layer comprising at least one population of nanostructures comprising a core and at least one shell, wherein the at least one shell comprises a Group IV metal fluoride; Including, The group IV metal fluoride is HfF 4 or ZrF 4 ; Lighting equipment.

2. The core of the nanostructure is InP, InAs, ZnSe, ZnTe, or ZnSe １－ｘ Te ｘ 10. The lighting device of claim 1, comprising: (0≦x<1).

3. 3. The lighting device of claim 1, wherein the at least one shell of the nanostructure is selected from the group consisting of CdS, CdSe, CdO, CdTe, ZnS, ZnO, ZnSe, ZnTe, MgTe, GaAs, GaSb, GaN, HgO, HgS, HgSe, HgTe, InAs, InSb, InN, AlAs, AlN, AlSb, AlS, PbS, PbO, PbSe, PbTe, MgO, MgS, MgSe, MgTe, CuCl, Ge, Si, and alloys thereof.

4. 4. The lighting device of claim 1, wherein at least one shell of the nanostructure comprises ZnSe or ZnS.

5. 5. The lighting device of claim 1, wherein the lighting device is stable for at least 7 days when stored at room temperature.

6. The lighting device of any one of claims 1 to 5, further comprising an electron transport layer.

7. The lighting device according to any one of claims 1 to 6, wherein the lighting device is a light emitting diode.

8. 8. The lighting device of claim 1, wherein the first conductive layer comprises indium tin oxide, indium zinc oxide, tin dioxide, zinc oxide, magnesium, aluminum, aluminum-lithium, calcium, magnesium-indium, magnesium-silver, silver, gold, or a mixture thereof.

9. 9. The lighting device of claim 1, wherein the second conductive layer comprises indium tin oxide, indium zinc oxide, titanium dioxide, tin oxide, zinc sulfide, silver, gold, or a mixture thereof.

10. 10. The lighting device according to any one of claims 1 to 9, further comprising a semiconducting polymer layer.

11. 11. The lighting device of claim 10, wherein the semiconducting polymer layer comprises copper phthalocyanine, 4,4',4''-tris[(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4''-tris(diphenylamino)triphenylamine (TDATA), 4,4',4''-tris[2-naphthyl(phenyl)amino]triphenylamine (2T-NATA), polyaniline / dodecylbenzenesulfonic acid, poly(3,4-ethylenedioxythiophene) / polystyrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid, or polyaniline / poly(4-styrenesulfonate).

12. 12. The lighting device of claim 1, further comprising a first transport layer.

13. 13. The lighting device of claim 12, wherein the first transport layer comprises N,N'-di(naphthalen-1-yl)-N,N'-bis(4-vinylphenyl)-4,4'-diamine, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], or poly(9-vinylcarbazole).

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