TWI891954B - Films comprising bright silver based quaternary nanostructures - Google Patents

Abstract

Disclosed are films comprising Ag, In, Ga, and S (AIGS) nanostructures and at least one ligand bound to the nanostructures. In some embodiment, the AIGS nanostructures have a photon conversion efficiency of greater than 32% and a peak wavelength emission of 480-545 nm. In some embodiments, the nanostructures have an emission spectrum with a FWHM of 24-38 nm.

Description

Quaternary nanostructured membrane comprising a bright silver substrate

The present invention relates to the field of nanotechnology. More specifically, the present invention provides thin, heavy metal-free nanostructured color conversion films that exhibit a high photon conversion efficiency (PCE) greater than 32% at a peak emission wavelength of 480-545 nm when excited by a blue light source with a wavelength of approximately 450 nm.

Efficient color conversion is crucial for lighting and display applications. In display applications, blue light sources with a wavelength of approximately 450 nm are most commonly used for backlighting. Most applications require materials that are free of heavy metals such as Cd and Pb.

Improved efficiency results in less wasted power and increased emission. Color conversion films are characterized by their photon conversion efficiency (PCE), defined as the number of emitted photons divided by the number of source photons. Green, heavy-metal-free QD color conversion films used in displays typically have poor performance due to their limited absorption of the blue light that excites them. Blue absorption is often inherently limited by the material system used, requiring thicker films to absorb sufficient 450 nm light.

Thin films formed by deposition of QD inks are typically cured by UV irradiation. In many cases, this is followed by heat treatment at 180°C for up to one hour in the presence of air. The photon conversion efficiency of these films is limited by a combination of poor absorption and poor light conversion due to instability during these processing steps.

There remains a need for Ag/In/Ga/S (AIGS) nanostructures with high band-edge emission (BE), narrow full-width at half-maximum (FWHM), high quantum yield (QY), and reduced red shift, and which can be used to prepare films with high (greater than 32%) photon conversion efficiency (PCE) at peak emission wavelengths between 480 nm and 545 nm using an excitation wavelength of approximately 450 nm.

The present invention provides thin, heavy-metal-free, nanostructured color-conversion films that exhibit high photon conversion efficiencies (PCEs) greater than 32% at peak emission wavelengths of 480-545 nm when excited with a blue light source having a wavelength of approximately 450 nm. This is achieved by using Ag/In/Ga/S (AIGS) nanostructures in an ink formulation containing one or more ligands, wherein all handling of the ink, subsequent deposition, film processing, and measurement are performed in an oxygen-free environment prior to exposure to blue or UV light. In some embodiments, the AIGS nanostructures have a FWHM of 28-38 nm. In other embodiments, the AIGS nanostructures have a FWHM of less than 32 nm. This narrow FWHM was achieved by adding at least one polyamine-based ligand to the AIGS nanostructures and preparing the films, where all handling of the nanostructure ink, ink deposition, film processing, and measurements were performed in an oxygen-free environment.

The thin film formed by deposition of the QD ink is typically cured by UV irradiation. In many cases, this is followed by a heat treatment at 180°C for up to one hour in the presence of air. It has been found that poor absorption and poor light conversion due to instability during these treatment steps can reduce photon conversion efficiency.

Disclosed herein are films comprising AIGS nanostructures in an ink formulation comprising at least one ligand that achieve a PCE greater than (>) 32% after heat treatment. In some embodiments, films comprising AIGS nanostructures, at least one ligand, and exhibiting a PCE greater than 32% at a peak emission wavelength of 480-545 nm when excited with a blue light source having a wavelength of 450 nm are provided. The PCE is calculated by integrating the emission spectrum from 484 nm to 700 nm, where the green portion is defined as 484-588 nm. In some embodiments, the film is a thin (5-15 µm) color-converting film.

The films prepared in this way have good (>95%) blue light absorption at approximately 450 nm, but have moderate emission properties. However, when treated in the absence of oxygen and/or light and/or encapsulated before exposing the films to UV or blue light, the emission properties of the films are significantly improved.

In some embodiments, the film further comprises at least one monomer incorporated into the ligand coating the AIGS surface. In some embodiments, the at least one monomer is an acrylate. In some embodiments, the monomer is at least one of ethyl acrylate, hexamethylene diacrylate (HDDA), tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate.

A method for preparing an AIGS film is provided, comprising: (a) providing an AIGS nanostructure and at least one ligand coating the nanostructure; (b) mixing at least one organic resin with the AIGS nanostructure of (a); and (c) preparing a first film comprising the mixed AIGS nanostructure, at least one ligand coating the nanostructure, and at least one organic resin on a first barrier layer; (d) curing the film by UV irradiation and/or baking; and (e) encapsulating the first film between the first barrier layer and a second barrier layer; wherein the encapsulated film exhibits a power conversion efficiency (PCE) greater than 32% at a peak emission wavelength of 480-545 nm when excited by a blue light source having a wavelength of approximately 450 nm.

In some embodiments, the AIGS nanostructure further comprises at least one monomer incorporated into at least one ligand coating the AIGS surface.

Also provided is a method further comprising: (f) adding at least one oxygen-reactive material to the mixture of the AIGS nanostructure and the ligand in (a), adding at least one oxygen-reactive material to the mixture in (b), and/or forming a second film comprising at least one oxygen-reactive material on top of the first film prepared in (c); and/or (g) forming a sacrificial barrier layer on the first film prepared in (c) to temporarily block oxygen and/or water, measuring the PCE of the film, and then removing the sacrificial barrier layer.

Also provided are methods comprising: (a) encapsulating the film prior to heat treatment and/or measurement; (b) using an oxygen-reactive material as part of the formulation during heat treatment or light exposure; and/or (c) temporarily blocking oxygen through the use of a sacrificial barrier layer.

In some embodiments, the nanostructure has an emission spectrum with a FWHM of less than 40 nm. In some embodiments, the nanostructure has an emission spectrum with a FWHM of 24-38 nm. In some embodiments, the nanostructure has an emission spectrum with a FWHM of 27-32 nm. In some embodiments, the nanostructure has an emission spectrum with a FWHM of 29-31 nm.

In some embodiments, the nanostructures have a QY of 80-99.9%. In some embodiments, the nanostructures have a QY of 85-95%. In some embodiments, the nanostructures have a QY of about 86-94%. In some embodiments, the nanostructures have an OD ₄₅₀ /mass ( ^{mL.mg -1.cm -1} ) greater than or equal to 0.8, where OD is optical density. In some embodiments, the nanostructures have an OD ₄₅₀ /mass ( ^{mL.mg -1.cm -1} ) within the inclusive range of 0.8-2.5. In some embodiments, the nanostructures have an OD ₄₅₀ /mass ( ^mL.mg - ^{1.cm -1} ) within the inclusive range of 0.87-1.9. In some embodiments, the nanostructures have an average diameter of less than 10 nm as determined by transmission electron microscopy (TEM). In some embodiments, the average diameter is about 5 nm.

In some embodiments, at least about 80% of the emission is band-edge emission. In some embodiments, at least about 90% of the emission is band-edge emission. In some embodiments, 92-98% of the emission is band-edge emission. In some embodiments, 93-96% of the emission is band-edge emission.

In some embodiments, the AIGS nanostructure has a peak emission wavelength (PWL) of approximately 450 nm.

In some embodiments, the AIGS nanostructure comprises a gradient of increasing gallium at the surface of the nanostructure to decreasing gallium in the center of the nanostructure.

In some embodiments, at least one ligand is an amine-based ligand, a polyamine-based ligand, a ligand containing a hydroxyl group, or a ligand containing a silane group. It was unexpectedly discovered that the use of polyamine-based ligands resulted in AIGS-containing films with a FWHM greater than 32 nm.

In some embodiments, at least one polyamino ligand is a polyaminoalkane, a polyamino-cycloalkane, a polyamino heterocyclic compound, a polyamino-functionalized polysiloxane, or a polyamino-substituted glycol. In some embodiments, the polyamino ligand is a _C2-20 alkane or _C2-20 cycloalkane substituted with two or three amine groups, optionally containing one or two amine groups in place of a carbon group. In some embodiments, the polyamino ligand is 1,3-cyclohexanebis(methylamine), 2,2-dimethyl-1,3-propanediamine, or tris(2-aminoethyl)amine.

In some embodiments, the ligand is a compound of formula I: wherein: x is 1 to 100; y is 0 to 100; and R ² is a C _1-20 alkyl group.

In some embodiments, x = 19, y = 3, and R ² = -CH ₃ .

In some embodiments, at least one ligand is (3-aminopropyl)trimethoxy-silane); (3-benzylpropyl)triethoxysilane; DL-α-lipoic acid; 3,6-dioxa-1,8-octanedithiol; 6-benzyl-1-hexanol; methoxypolyethylene glycol amine (about m.w. 500); poly(ethylene glycol) methyl ether thiol (about m.w. 800); diethyl phenylphosphinate; N,N-diisopropyl dibenzyl phosphinate; N,N-diisopropyl di-tert-butyl phosphinate; tris(2-carboxyethyl)phosphine hydrochloride; poly(ethylene glycol) methyl ether thiol (about m.w. 2000); methoxypolyethylene glycolamine (approximately m.w. 750); acrylamide; or polyethyleneimine. The M.w. of the polymer was determined by mass spectrometry.

In some embodiments, at least one ligand is a combination of: amino-polyepoxyalkylene oxide (m.w. approximately 1000) and methoxypolyethylene glycol amine (m.w. approximately 500); amino-polyepoxyalkylene oxide (m.w. approximately 1000) and 6-benzyl-1-hexanol; amino-polyepoxyalkylene oxide (m.w. approximately 1000) and (3-benzylpropyl)triethoxysilane; and 6-benzyl-1-hexanol and methoxypolyethylene glycol amine (m.w. approximately 500).

In some embodiments, the AIGS nanostructure further comprises at least one monomer incorporated into at least one ligand coating the AIGS surface.

Also provided is a nanostructure composition comprising: (a) an AIGS nanostructure exhibiting a PCE greater than 32%, and (b) at least one organic resin.

In some embodiments, at least one organic resin is cured.

Also provided is a method for preparing the nanostructure composition described herein, comprising: (a) providing an AIGS nanostructure and at least one ligand coating the nanostructure; (b) mixing at least one organic resin with the nanostructure of (a); (c) preparing a first film comprising the mixed AIGS nanostructure, at least one ligand coating the nanostructure, and at least one organic resin on a first barrier layer; (d) curing the film by UV irradiation and/or baking; and (e) encapsulating the first film between the first barrier layer and a second barrier layer, wherein the encapsulated film exhibits a power conversion efficiency (PCE) greater than 32% at a peak emission wavelength of 480-545 nm when excited using a blue light source having a wavelength of approximately 450 nm.

In some embodiments, the nanostructure of (a) further comprises at least one monomer incorporated into the ligand coating the AIGS surface. In some embodiments, the at least one monomer is an acrylate. In some embodiments, the monomer is at least one of ethyl acrylate, HDDA, tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate.

In some embodiments, the method is performed before exposing the encapsulated film to air to measure the emission spectrum of the AIGS nanostructure. In some embodiments, the method is performed under an inert atmosphere.

In some embodiments, the method further comprises: (f) adding at least one oxygen-reactive material to the mixture of the AIGS nanostructure and the ligand in (a); (g) adding at least one oxygen-reactive material to the mixture in (b); and/or (h) forming a second film comprising at least one oxygen-reactive material on top of the first film prepared in (c); and/or (i) forming a sacrificial barrier layer on the first film prepared in (c) to temporarily block oxygen and/or water, measuring the PCE of the film, and then removing the sacrificial barrier layer.

In some embodiments, both barrier layers exclude oxygen and/or water.

In some embodiments, 92-98% of the emission is band-edge emission. In some embodiments, 93-96% of the emission is band-edge emission.

Also provided is a method for preparing a composition comprising: (a) providing a composition comprising an AIGS nanostructure and at least one ligand coating the surface of the nanostructure; and (b) mixing the composition obtained in (a) with at least one second ligand.

In some embodiments, the composition of (a) further comprises an organic resin. In some embodiments, the composition of (a) further comprises at least one monomer that is incorporated into a ligand that coats the AIGS surface. In some embodiments, the method further comprises inkjet printing the composition.

In some embodiments, the method further comprises preparing a film comprising the composition obtained in (b). In some embodiments, the method further comprises curing the film. In some embodiments, the film is cured by heating. In some embodiments, the film is cured by exposure to electromagnetic radiation.

Also provided is a device comprising the above-described membrane.

Also provided is a nanostructure molded article comprising: (a) a first conductive layer; (b) a second conductive layer; and (c) a film comprising an AIGS nanostructure layer between the first conductive layer and the second conductive layer, wherein the nanostructure layer comprises an AIGS nanostructure having a PCE greater than 32%.

A nanostructured color converter is also provided, comprising: a baseboard; a display panel disposed on the baseboard; and a film comprising an AIGS nanostructure layer, wherein the nanostructure layer comprises AIGS nanostructures having a PCE greater than 32%, the nanostructure layer being disposed on the display panel.

In some embodiments, the nanostructure layer comprises a patterned nanostructure layer. In some embodiments, the backplane comprises an LED, an LCD, an OLED, or a micro-LED.

The following detailed description of other features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, is provided with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific embodiments described herein. These embodiments are presented herein for illustrative purposes only. Additional embodiments will be readily apparent to those skilled in the art based on the teachings contained herein.

Definition

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. The following definitions supplement those in the industry and are specific to the present application and are not attributed to any related or unrelated circumstances, such as any commonly owned patents or applications. Although any methods and materials similar or equivalent to those described herein can be used in the practice of the testing of the present invention, the preferred materials and methods are described herein. Therefore, the terminology used herein is used only for the purpose of describing particular embodiments and is not intended to be limiting.

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 those nanostructures, and so forth.

As used herein, the term "about" indicates that the value of a given quantity varies by +/- 10% of that value. For example, "about 100 nm" encompasses a size range of 90 nm to 110 nm, inclusive.

A "nanostructure" is a structure having at least one region or feature dimension less than about 500 nm. In some embodiments, the nanostructure has a dimension 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 feature dimension will be along the smallest axis of the structure. Examples of such structures include nanowires, nanorods, nanotubes, branched nanostructures, nanotetrapods, tripods, diploids, nanocrystals, nanodots, quantum dots, nanoparticles, and the like. The nanostructure can be, for example, substantially crystalline, substantially single crystalline, polymorphic, amorphous, or combinations thereof. In some embodiments, each of the three dimensions of the nanostructure has a dimension 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.

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, wherein the different material types are distributed radially around the long axis of a nanowire, the long axis of an arm of a branched nanowire, or the center of a nanocrystal, for example. The shell may, but need not, completely cover adjacent materials for the nanostructure to be considered a shell or a heterostructure; for example, a nanocrystal characterized by a core of one material covered by islands of a second material is a heterostructure. In other embodiments, different material types are distributed at different locations within the nanostructure, for example, along the major axis of a nanowire or along the long axis of an arm of a branched nanowire. Different regions within a heterostructure can contain completely different materials, or different regions can contain a base material (e.g., silicon) with different dopants or different concentrations of the same dopant.

As used herein, the "diameter" of a nanostructure refers to the diameter of a cross-sectional plane orthogonal to the first axis of the nanostructure, where the first axis has the largest length difference relative to the second and third axes (the second and third axes being the two axes most nearly equal in length). The first axis is not necessarily the longest axis of the nanostructure; for example, for a disk-shaped nanostructure, the cross-sectional plane would be a substantially circular cross-sectional plane orthogonal to the short longitudinal axis of the disk. When the cross-sectional plane is non-circular, the diameter is the average of the long and short axes of the cross-sectional plane. For long 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 through the center of the sphere to the other side.

When used with respect to nanostructures, the term "crystalline" or "substantially crystalline" refers to the fact 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" will depend on the absolute size of the particular nanostructure, as the order of a single crystal cannot extend beyond the boundaries of the crystal. In this context, "long-range order" will mean substantial order across at least most dimensions of the nanostructure. In some cases, the nanostructure may have an oxide or other coating, or may comprise a core and at least one shell. In such cases, it will be understood that the oxide, shell, or other coating may, but need not, exhibit such order (e.g., it may be amorphous, polycrystalline, or other). In these cases, the phrases "crystalline," "substantially crystalline," "substantially single-crystalline," or "single-crystalline" refer to the central core of the nanostructure (excluding coatings or shells). As used herein, the terms "crystalline" or "substantially crystalline" are intended to encompass structures that include various defects, stacking defects, 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 should be understood 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 contain non-crystalline regions and may even be amorphous. This does not preclude the nanostructure from being crystalline or substantially crystalline as defined herein.

When used with respect to a nanostructure, the term "single crystal" indicates that the nanostructure is substantially crystalline and comprises substantially a single crystal. When used with respect to a nanostructure heterostructure comprising a core and one or more shells, "single crystal" indicates that the core is substantially crystalline and comprises substantially a single crystal.

A "nanocrystal" is a nanostructure that is substantially single crystalline. Thus, a nanocrystal has at least one region or characteristic dimension that is less than about 500 nm. In some embodiments, the 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 encompass substantially single crystalline nanostructures that include various defects, stacking defects, atomic substitutions, and the like, as well as substantially single crystalline nanostructures that are free of such defects, defects, or substitutions. In the case of a nanocrystalline heterostructure comprising a core and one or more shells, the core of the nanocrystal is typically substantially single crystalline, but the shell need not be single crystalline. In some embodiments, each of the three dimensions of the nanocrystals has a dimension 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.

The term "quantum dot" (or "dot") refers to a nanocrystal that exhibits quantum confinement or exciton confinement. Quantum dots can be substantially uniform in their material properties or, in certain embodiments, can be heterogeneous, for example, comprising a core and at least one shell. The optical properties of quantum dots can be influenced by their particle size, chemical composition, and/or surface composition and can be determined by suitable optical tests available in the industry. The ability to tailor the size of the nanocrystals, for example, to a range between about 1 nm and about 15 nm, enables photoemission coverage across the entire optical spectrum, providing tremendous versatility in color rendering.

The term "oxygen-free ligand" refers to a coordinating molecule that does not contain an oxygen atom capable of coordinating or reacting with a metal ion as used herein.

A "ligand" is a molecule capable of interacting (whether weakly or strongly) with one or more faces of a nanostructure, such as through covalent, ionic, van der Waals, or other molecular interactions with the surface of the nanostructure.

The photoluminescence quantum yield (QY) is the ratio of photons emitted by a nanostructure or group of nanostructures to the photons absorbed. As is known in the industry, the quantum yield is typically determined by the absolute change in photon counts when illuminating a sample within an integrating sphere, or by comparison with a well-characterized standard sample with a known quantum yield value.

Peak emission wavelength (PWL) is the wavelength at which the measured emission spectrum of a light source reaches its maximum value.

As used herein, the term "full width at half maximum" (FWHM) is a measure of the size distribution of nanostructures. The emission spectrum of a nanostructure typically has a Gaussian curve shape. The width of this Gaussian curve is defined as the FWHM and provides an idea of the particle size distribution. A smaller FWHM corresponds to a narrower size distribution of the nanostructure or nanocrystals. The FWHM also depends on the maximum emission wavelength.

Compared to the corresponding defect emission, band-edge emission is centered at higher energies (lower wavelengths) and has a smaller offset from the absorption onset energy. Furthermore, band-edge emission has a narrower wavelength distribution than defect emission. Both band-edge and defect emission follow a normal (approximately Gaussian) wavelength distribution.

Optical density (OD) is a common method for quantifying the concentration of solutes or nanoparticles. According to the Beer-Lambert law, the absorbance (also known as "extinction") of a given sample is directly proportional to the concentration of the solute that absorbs light of a specific wavelength.

Optical density is the light attenuation per centimeter of material, as measured using a standard spectrometer, and is typically specified per 1 cm path length. Nanostructured solutions are often measured by their optical density rather than mass or molarity because it is proportional to concentration and is a more convenient way to express the amount of light absorption occurring in the nanostructured solution at the wavelength of interest. A nanostructured solution with an OD of 100 is 100 times more concentrated (and contains 100 times more particles per mL) than a product with an OD of 1.

Optical density can be measured at any wavelength of interest, such as the wavelength chosen to excite the fluorescent nanostructures. Optical density is a measure of the intensity of light lost when passing through a nanostructure solution at a specific wavelength and is calculated using the following formula: OD = log ₁₀ * (I _OUT / I _IN ) where: I _OUT = the intensity of radiation entering the cell; and I _IN = the intensity of radiation transmitted through the cell.

The optical density of a nanostructure solution can be measured using a UV-VIS spectrometer. Therefore, by using a UV-VIS spectrometer, the optical density can be calculated to determine the amount of nanostructures present in the sample.

Unless expressly indicated otherwise, the ranges listed herein are inclusive.

Various additional terms are defined or otherwise used herein. AIGS Nanostructures

A nanostructure comprising Ag, In, Ga, and S is provided, wherein the nanostructure has a peak emission wavelength (PWL) between 480 and 545 nm. In some embodiments, at least about 80% of the emission is band-edge emission. The percentage of band-edge emission is calculated by fitting the Gaussian peaks (typically two or more) of the nanostructure's emission spectrum and comparing the area of the peak with energy closer to the nanostructure's band gap (representing band-edge emission) to the sum of all peak areas (band-edge emission + defect emission).

In one embodiment, the nanostructure has an emission spectrum with a FWHM of less than 40 nm. In another embodiment, the nanostructure has an emission spectrum with a FWHM of 36-38 nm. In some embodiments, the nanostructure has an emission spectrum with a FWHM of 27-32 nm. In some embodiments, the nanostructure has an emission spectrum with a FWHM of 29-31 nm.

In another embodiment, the nanostructure has a QY of about 80% to 99.9%. In another embodiment, the nanostructure has a QY of 85-95%. In another embodiment, the nanostructure has a QY of about 86% to about 94%. In some embodiments, at least 80% of the emission framing emits at the band edge. In other embodiments, at least 90% of the emission framing emits at the band edge. In other embodiments, at least 95% of the emission framing emits at the band edge. In some embodiments, 92-98% of the emission framing emits at the band edge. In some embodiments, 93-96% of the emission framing emits at the band edge.

AIGS nanostructures provide high blue light absorption. As a predictor of blue light absorption efficiency, the optical density at 450 nm (OD _{450 /mass) was calculated by measuring the optical density of a nanostructure solution in a 1 cm pathlength cuvette and dividing it by the dry mass per mL (mg/mL) of the same solution after all volatiles were removed under vacuum (<200} mTorr). In one embodiment, the nanostructures provided herein have an OD ₄₅₀ /mass ( ^mL.mg - ^{1.cm -1} ) of at least 0.8. In another embodiment, the nanostructures have an OD ₄₅₀ /mass (mL.mg ^{- 1.cm -1} ) of 0.8-2.5. In another embodiment, the nanostructures have an OD ₄₅₀ /mass ( ^{mL.mg -1.cm -1} ) of 0.87-1.9.

In one embodiment, the nanostructure is treated with gallium ions such that ion exchange of gallium for indium occurs throughout the AIGS nanostructure. In another embodiment, the nanostructure has Ag, In, Ga, and S in the core and is treated by ion exchange with gallium ions and S. In another embodiment, the nanostructure has Ag, In, Ga, and S in the core and is treated by ion exchange with silver ions, gallium ions, and S. In some embodiments, the ion exchange treatment results in a gradient of gallium, silver, and/or sulfur throughout the nanostructure.

In one embodiment, the average diameter of the nanostructures is less than 10 nm as measured by TEM. In another embodiment, the average diameter is about 5 nm. AIGS nanostructures are prepared using GaX ₃ (X = F, Cl or Br) precursors and oxygen-free ligands.

The reports on the preparation of AIGS in the literature do not attempt to exclude oxygen-containing ligands. In the coating of AIGS with gallium, oxygen-containing ligands are often used to stabilize the Ga precursor. Gallium(III) acetylacetonate is often used as a precursor that is easy to handle in air, while Ga(III) chloride needs to be handled carefully due to its sensitivity to moisture. For example, in Kameyama et al . ACS Appl. Mater. Interfaces 10: 42844-42855 (2018), gallium(III) acetylacetonate was used as a precursor for core and core/shell structures. Since gallium has a high affinity for oxygen, when Ga and S precursors are used to produce nanostructures with a significant gallium content, oxygen-containing ligands and the use of gallium precursors that are not prepared under oxygen-free conditions can produce unwanted side reactions, such as gallium oxidation. These side reactions may lead to defects in the nanostructure and result in lower quantum yield.

In some embodiments, oxygen-free GaX ₃ (X = F, Cl, or Br) is used as a precursor in the preparation of AIGS cores to prepare AIGS nanostructures. In some embodiments, GaX ₃ (X = F, Cl, or Br) is used as a precursor and an oxygen-free ligand in the preparation of Ga-rich AIGS nanostructures to prepare AIGS nanostructures. In some embodiments, GaX ₃ (X = F, Cl, or Br) is used as a precursor and an oxygen-free ligand in the preparation of AIGS cores to prepare AIGS nanostructures. In some embodiments, GaX ₃ (X = F, Cl, or Br) is used as a precursor and an oxygen-free ligand in the preparation of AIGS cores and the ion exchange treatment of AIGS cores to prepare AIGS nanostructures.

A nanostructure comprising Ag, In, Ga, and S is provided, wherein the nanostructure has a peak emission wavelength (PWL) between 480 nm and 545 nm, and wherein the nanostructure is prepared using a GaX ₃ (X=F, Cl, or Br) precursor and an oxygen-free ligand.

In some embodiments, nanostructures prepared using GaX ₃ (X = F, Cl, or Br) precursors and oxygen-free ligands exhibit a FWHM emission spectrum of 35 nm or less. In some embodiments, nanostructures prepared using GaX ₃ (X = F, Cl, or Br) precursors and oxygen-free ligands exhibit a FWHM of 30-38 nm. In some embodiments, nanostructures prepared using GaX ₃ (X = F, Cl, or Br) precursors and oxygen-free ligands have a QY of at least 75%. In some embodiments, nanostructures prepared using GaX ₃ (X = F, Cl, or Br) precursors and oxygen-free ligands have a QY of 75-90%. In some embodiments, nanostructures prepared using GaX ₃ (X = F, Cl, or Br) precursors and oxygen-free ligands have a QY of approximately 80%.

The AIGS nanostructures prepared herein provide high blue light absorption. In some embodiments, the nanostructures have an OD ₄₅₀ /mass (mL·mg ^{-1 ·} cm ^-1 ) of at least 0.8. In some embodiments, the nanostructures have an OD ₄₅₀ /mass (mL ^· mg ^{-1 ·} cm ^-1 ) of 0.8-2.5. In another embodiment, the nanostructures have an OD ₄₅₀ /mass (mL ^· mg ^{-1 ·} cm ^-1 ) of 0.87-1.9.

In some embodiments, the nanostructure is treated with gallium ions, causing ion exchange of gallium for indium throughout the AIGS nanostructure. In some embodiments, the nanostructure comprises Ag, In, Ga, and S in the core, with a gallium gradient between the surface and the center of the nanostructure. In some embodiments, the nanostructure is an AIGS core treated with AGS, and a _GaX3 (X = F, Cl, or Br) precursor and an oxygen-free ligand are used in the core. In some embodiments, the nanostructure is an AIGS nanostructure prepared using a _GaX3 (X = F, Cl, or Br) precursor and an oxygen-free ligand. In some embodiments, the AIGS nanostructure is prepared by reacting a preformed In-Ga reagent with an Ag ₂ S nanostructure to obtain an AIGS nanostructure, which is then reacted with an oxygen-free Ga salt to exchange ions with Ga to form the AIGS nanostructure.

A method for fabricating an AIGS nanostructure is provided, comprising: (a) preparing a mixture comprising an AIGS core, a sulfur source, and a ligand; (b) adding the mixture obtained in (a) to a mixture of gallium carboxylate and the ligand at a temperature of 180-300°C to obtain an ion-exchanged nanostructure having a gallium gradient from the surface to the center of the nanostructure; and (c) isolating the nanostructure.

In some embodiments, the nanostructure has a PWL of 480-545 nm, wherein at least about 60% of the emission is band-edge emission.

Also provided is a method for fabricating an AIGS nanostructure, comprising: (a) reacting Ga(acetylpyruvate) ₃ , InCl ₃ , and optionally a ligand in a solvent at a temperature sufficient to produce an In-Ga reagent; (b) reacting the In-Ga reagent with an Ag ₂ S nanostructure at a temperature sufficient to produce an AIGS nanostructure; and (c) reacting the AIGS nanostructure with an oxygen-free Ga salt in a solvent containing a ligand at a temperature sufficient to produce an ion-exchanged nanostructure having a gallium gradient from the surface to the center of the nanostructure.

In some embodiments, the nanostructure has a PWL of 480-545 nm, wherein at least about 60% of the emission is band-edge emission.

In some embodiments, the ligand is an alkylamine. In some embodiments, the alkylamine ligand is oleylamine. In some embodiments, the ligand is used in excess and serves as a solvent, and the solvent is not present in the reaction. In some embodiments, a solvent is present in the reaction. In some embodiments, the solvent is a high-boiling solvent. In some embodiments, the solvent is octadecene, squalane, dibenzyl ether, or xylene. In some embodiments, the sufficient temperature in (a) is 100°C to 280°C; the sufficient temperature in (b) is 150°C to 260°C; and the sufficient temperature in (c) is 170°C to 280°C. In some embodiments, the sufficient temperature in (a) is about 210°C, the sufficient temperature in (b) is about 210°C, and the sufficient temperature in (c) is about 240°C.

In some embodiments, at least 80% of the emissions are edge-on emissions. In other embodiments, at least 90% of the emissions are edge-on emissions. In other embodiments, at least 95% of the emissions are edge-on emissions. In some embodiments, 92-98% of the emissions are edge-on emissions. In some embodiments, 93-96% of the emissions are edge-on emissions.

Examples of ligands are disclosed in U.S. Patent Nos. 7,572,395, 8,143,703, 8,425,803, 8,563,133, 8,916,064, 9,005,480, 9,139,770, and 9,169,435, and U.S. Patent Application Publication No. 2008/0118755. In one embodiment, the ligand is an alkylamine. In some embodiments, the ligand is an alkylamine selected from the group consisting of dodecylamine, oleylamine, hexadecylamine, dioctylamine, and octadecylamine.

In some embodiments, the sulfur source in (a) comprises trioctylphosphine sulfide, elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl)sulfide, trioctylphosphine sulfide, or a combination thereof. In some embodiments, the sulfur source in (a) is derived from S ₈ .

In one embodiment, the sulfur source is from S ₈ .

In one embodiment, the temperature in (a) and (b) is about 270°C.

In some embodiments, the mixture in (b) further comprises a solvent. In some embodiments, the solvent is trioctylphosphine, dibenzyl ether, or squalane.

In some embodiments, the gallium carboxylate is a _C2-24 gallium carboxylate. Examples of _C2-24 carboxylates include acetate, propionate, butyrate, valerate, hexanoate, heptanoate, octanoate, nonanoate, decanoate, undecanoate, tridecanoate, tetradecanoate, pentadecanoate, hexadecanoate, octadecanoate (oleate), nonadecanoate, and tricosanoate. In one embodiment, the gallium carboxylate is gallium oleate.

In some embodiments, the ratio of gallium carboxylate to AIGS core is 0.008-0.2 mmol gallium carboxylate/mg AIGS. In one embodiment, the ratio of gallium carboxylate to AIGS core is about 0.04 mmol gallium carboxylate/mg AIGS.

In another embodiment, the AIGS nanostructures are isolated, for example, by precipitation. In some embodiments, the AIGS nanostructures are precipitated by adding a non-solvent for the AIGS nanostructures. In some embodiments, the non-solvent is a toluene/ethanol mixture. The precipitated nanostructures can be further isolated by centrifugation and washing with a non-solvent for the nanostructures.

Also provided is a method for fabricating a nanostructure, comprising: (a) preparing a mixture comprising AIGS nuclei and gallium halide in a solvent, and maintaining the mixture for a time sufficient to obtain an ion-exchanged nanostructure having a gallium gradient from the surface to the center of the nanostructure; and (b) isolating the nanostructure.

In some embodiments, the nanostructure has a PWL of 480-545 nm, and at least about 60% of the emission is band-edge emission.

In some embodiments, at least 80% of the emission is band-edge emission. In other embodiments, at least 90% of the emission is band-edge emission. In other embodiments, at least 95% of the emission is band-edge emission.

In some embodiments, the gallium halide is a chloride, bromide, or iodide of gallium. In one embodiment, the gallium halide is gallium iodide.

In some embodiments, the solvent comprises trioctylphosphine. In some embodiments, the solvent comprises toluene.

In some embodiments, the sufficient time in (a) is 0.1-200 hours. In some embodiments, the sufficient time in (a) is about 20 hours.

In some embodiments, the mixture is maintained at 20° C. to 100° C. In one embodiment, the mixture is maintained at about room temperature (20° C. to 25° C.).

In some embodiments, the molar ratio of gallium halide to AIGS core is from about 0.1 to about 30.

In another embodiment, the AIGS nanostructures are isolated, for example, by precipitation. In some embodiments, the AIGS nanostructures are precipitated by adding a non-solvent for the AIGS nanostructures. In some embodiments, the non-solvent is a toluene/ethanol mixture. The precipitated nanostructures can be further isolated by centrifugation and/or washing with a non-solvent for the nanostructures.

Also provided is a method for fabricating a nanostructure, comprising: (a) preparing a mixture comprising an AIGS nanostructure, a sulfur source, and a ligand; (b) adding the mixture obtained in (a) to a mixture of GaX ₃ (X = F, Cl, or Br) and an oxygen-free ligand at a temperature of 180-300° C. to obtain an ion-exchanged nanostructure having a gallium gradient from the surface to the center of the nanostructure; and (d) isolating the nanostructure.

In some embodiments, the nanostructures have a PWL of 480-545 nm.

In some embodiments, the preparation in (a) is carried out under oxygen-free conditions. In some embodiments, the preparation in (a) is carried out in a glove box.

In some embodiments, the addition in (b) is performed under anaerobic conditions. In some embodiments, the addition in (b) is performed in a glove box.

In some embodiments, at least 80% of the emission is band-edge emission. In other embodiments, at least 90% of the emission is band-edge emission. In other embodiments, at least 95% of the emission is band-edge emission.

Examples of ligands are disclosed in U.S. Patent Nos. 7,572,395, 8,143,703, 8,425,803, 8,563,133, 8,916,064, 9,005,480, 9,139,770, and 9,169,435, and U.S. Patent Application Publication No. 2008/0118755. In some embodiments, the ligand in (a) is an oxygen-free ligand. In some embodiments, the ligand in (b) is an oxygen-free ligand. In some embodiments, the ligands in (a) and (b) are alkylamines. In some embodiments, the ligand is an alkylamine selected from the group consisting of dodecylamine, oleylamine, hexadecylamine, dioctylamine, and octadecylamine. In some embodiments, the ligand in (a) is oleylamine. In some embodiments, the ligand in (b) is oleylamine. In some embodiments, the ligand in (a) and (b) is oleylamine.

In one embodiment, the sulfur source is from S ₈ .

In one embodiment, the temperature in (a) and (b) is about 270°C.

In some embodiments, the mixture in (b) further comprises a solvent. In some embodiments, the solvent is trioctylphosphine, dibenzyl ether, or squalane.

In some embodiments, GaX ₃ is gallium chloride, gallium fluoride, or gallium iodide. In some embodiments, GaX ₃ is gallium chloride. In some embodiments, GaX ₃ is Ga(III) chloride.

In some embodiments, the ratio of GaX ₃ to AIGS cores is 0.008-0.2 mmol GaX ₃ / mg AIGS. In some embodiments, the molar ratio of GaX ₃ to AIGS cores is about 0.1 to about 30. In some embodiments, the ratio of GaX ₃ to AIGS cores is about 0.04 mmol GaX ₃ / mg AIGS.

In some embodiments, the AIGS nanostructures are isolated, for example, by precipitation. In some embodiments, the AIGS nanostructures are precipitated by adding a non-solvent for the AIGS nanostructures. In some embodiments, the non-solvent is a toluene/ethanol mixture. The precipitated nanostructures can be further isolated by centrifugation and/or washing with a non-solvent for the nanostructures.

In some embodiments, the mixture in (a) is maintained at 20° C. to 100° C. In some embodiments, the mixture in (a) is maintained at about room temperature (20° C. to 25° C.).

In some embodiments, the mixture in (b) is maintained at 200°C to 300°C for 0.1 to 200 hours. In some embodiments, the mixture in (b) is maintained at 200°C to 300°C for approximately 20 hours. Doped AIGS Nanostructures

In some embodiments, the AIGS nanostructure is doped. In some embodiments, the dopant in the nanocrystal core comprises a metal, including one or more transition metals. In some embodiments, the dopant is a transition metal selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, and combinations thereof. In some embodiments, the dopant comprises a non-metal. In some embodiments, the dopant is ZnS, ZnSe, ZnTe, CdSe, CdS, CdTe, HgS, HgSe, HgTe, _CuInS2 , _CuInSe2 , AlN, AlP, AlAs, GaN, GaP, or GaAs.

In some embodiments, the core is purified by precipitation from a non-solvent. In some embodiments, the AIGS nanostructures are filtered to remove precipitates from the core solution. Nanostructure Compositions

In some embodiments, the present invention provides a nanostructure composition comprising: (a) at least one population of AIGS nanostructures; and (b) at least one organic resin.

In some embodiments, the nanostructure has a PWL between 480-545 nm.

In some embodiments, at least 80% of the nanostructures emit at the band-edge. In other embodiments, at least 90% of the nanostructures emit at the band-edge. In other embodiments, at least 95% of the nanostructures emit at the band-edge. In some embodiments, 92-98% of the nanostructures emit at the band-edge. In some embodiments, 93-96% of the nanostructures emit at the band-edge.

In some embodiments, the nanostructure composition further comprises at least one second population of nanostructures. Nanostructures having a wavelength (PWL) between 480 and 545 nm emit green light. Additional populations of nanostructures emitting in the green, yellow, orange, and/or red regions of the spectrum may be added. These nanostructures have a PWL greater than 545 nm. In some embodiments, the nanostructures have a PWL between 550 and 750 nm. The size of the nanostructures determines the emission wavelength. The at least one second population of nanostructures may comprise a III-V nanocrystal selected from the group consisting of BN, BP, BAs, BSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, and InSb. In some embodiments, the core of the second population of nanostructures is an InP nanocrystal. Organic resin

In some embodiments, the organic resin is a thermosetting resin or an ultraviolet (UV) curable resin. In some embodiments, the organic resin is cured by a method that is conducive to roll-to-roll processing.

Thermosetting resins require curing, during which they undergo irreversible molecular crosslinking, rendering the resin infusible. In some embodiments, the thermosetting resin is an epoxy resin, a phenolic resin, a vinyl resin, a melamine resin, a urea resin, an unsaturated polyester resin, a polyurethane resin, an allyl resin, an acrylic resin, a polyamide resin, a polyamide-imide resin, a phenolamine polycondensate resin, a urea-melamine polycondensate resin, or a combination thereof.

In some embodiments, the thermosetting resin is an epoxy resin. Epoxy resins cure easily without producing volatiles or byproducts associated with various chemicals. Epoxy resins are also compatible with most substrates and tend to wet surfaces easily. See Boyle, M.A. et al., “Epoxy Resins,” Composites, Vol. 21, ASM Handbook, pp. 78-89 (2001).

In some embodiments, the organic resin is a silicone thermosetting resin. In some embodiments, the silicone thermosetting resin is OE6630A or OE6630B (Dow Corning Corporation, Auburn, MI).

In some embodiments, a thermal initiator is used. In some embodiments, the thermal initiator is AIBN [2,2'-azobis(2-methylpropionitrile)] or benzoyl peroxide.

UV-curable resins are polymers that cure and harden rapidly when exposed to specific wavelengths of light. In some embodiments, the UV-curable resin is a resin having free radical polymerizable groups (e.g., (meth)acryloxy, vinyloxy, styryl, or vinyl) or cationic polymerizable groups (e.g., epoxy, thioepoxy, vinyloxy, or cyclobutyloxy) as functional groups. In some embodiments, the UV-curable resin is a polyester resin, a polyether resin, a (meth)acrylate resin, an epoxy resin, a urethane resin, an alkyd resin, a spiroaldehyde resin, a polybutadiene resin, or a polythiol polyene resin.

In some embodiments, the UV curable resin is selected from the group consisting of isobornyl acrylate, isobornyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, urethane acrylate, allyloxylated cyclohexyl diacrylate, bis(acryloyloxyethyl)hydroxy isocyanurate, bis(acryloyloxyneopentyl glycol) adipate, bisphenol A diacrylate, bisphenol A dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, Acrylates, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, dicyclopentyl diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, dipentatriol hexaacrylate, dipentatriol monohydroxypentaacrylate, di(trihydroxymethylpropane) tetraacrylate, ethylene glycol dimethacrylate, glycerol methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol dimethacrylate Hydroxyl neopentanoate diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, phosphoric acid dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, tetraethylene glycol diacrylate, tetrabromobisphenol A diacrylate, triethylene glycol divinyl ether, triglycerol diacrylate, trihydroxymethylpropane triacrylate, tripropylene glycol diacrylate, tris(acryloyloxyethyl) isocyanurate, phosphoric acid triacrylate, phosphoric acid diacrylate, propargyl acrylate, ethylene Terminated polydimethylsiloxane, vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymer, vinyl-terminated polyphenylmethylsiloxane, vinyl-terminated trifluoromethylsiloxane-dimethylsiloxane copolymer, vinyl-terminated diethylsiloxane-dimethylsiloxane copolymer, vinyl methylsiloxane, monomethacryloxypropyl-terminated polydimethylsiloxane, monovinyl-terminated polydimethylsiloxane, monoallyl-monotrimethylsiloxy-terminated polyethylene oxide, and combinations thereof.

In some embodiments, the UV curable resin is a hydroxy-functional compound that can crosslink with isocyanates, epoxies, or unsaturated compounds under UV curing conditions. In some embodiments, the polythiol is pentaerythritol tetrakis(3-butyl-propionate) (PETMP); trihydroxymethyl-propane tris(3-butyl-propionate) (TMPMP); diol di(3-butyl-propionate) (GDMP); tris[25-(3-butyl-propionyloxy)ethyl]isocyanurate (TEMPIC); di-pentaerythritol hexa(3-butyl-propionate) (Di-PETMP); ethoxylated trihydroxymethylpropane tris(3-butyl-propionate) (ETTMP 1300 and ETTMP 700); polycaprolactone tetrakis(3-butyl-propionate) (PCL4MP); 1350); pentaerythritol tetrahedral acetate (PETMA); trihydroxymethyl-propane trihedral acetate (TMPMA); or glycol dihedral acetate (GDMA). These compounds are sold under the trade name ^THIOCURE® by Bruno Bock, Marschacht, Germany.

In some embodiments, the UV-curable resin is a polythiol. In some embodiments, the UV-curable resin is a polythiol selected from the group consisting of ethylene glycol bis(butyl acetate), ethylene glycol bis(3-butyl propionate), trihydroxymethylpropane tris(butyl acetate), trihydroxymethylpropane tris(3-butyl propionate), pentaerythritol tetra(butyl acetate), pentaerythritol tetra(3-butyl propionate) (PETMP), and combinations thereof. In some embodiments, the UV-curable resin is PETMP.

In some embodiments, the UV-curable resin comprises a thiol-ene formulation of polythiol and 1,3,5-triallyl-1,3,5-triazine-2,4,6 (1H,3H,5H)-trione (TTT). In some embodiments, the UV-curable resin comprises a thiol-ene formulation of PETMP and TTT.

In some embodiments, the UV curable resin further comprises a photoinitiator. The photoinitiator initiates the crosslinking and/or curing reaction of the photosensitive material during exposure. In some embodiments, the photoinitiator is acetophenone-based, benzoin-based, or sulfhydryl-based. .

In some embodiments, the photoinitiator is a vinyl acrylate-based resin. In some embodiments, the photoinitiator is MINS-311RM (Minuta Technology Co., Ltd, Korea).

In some embodiments, the photoinitiator is IRGACURE ^® 127, IRGACURE ^® 184, IRGACURE ^® 184D, IRGACURE ^® 2022, IRGACURE ^® 2100, IRGACURE ^® 250, IRGACURE ^® 270, IRGACURE ^® 2959, IRGACURE ^® 369, IRGACURE ^® 369 EG, IRGACURE ^® 379, IRGACURE ^® 500, IRGACURE ^® 651, IRGACURE ^® 754, IRGACURE ^® 784, IRGACURE ^® 819, IRGACURE ^® 819Dw, IRGACURE ^® 907, IRGACURE ^® 907 FF, IRGACURE ^® OxeOl, ^IRGACURE® TPO-L, IRGACURE® 1173, IRGACURE® 1173D, IRGACURE® 4265, IRGACURE® BP, or IRGACURE® MBF (BASF Corporation, Wyandotte, MI). In some embodiments, the photoinitiator is TPO (2,4,6-trimethylbenzyl-diphenyl-phosphine oxide) or MBF (methyl benzoylformate).

In some embodiments, the weight % of at least one organic resin in the nanostructure composition is between about 5% and about 99%, about 5% and about 95%, about 5% and about 90%, about 5% and about 80%, about 5% and about 70%, about 5% and about 60%, about 5% and about 50%, about 5% and about 40%, about 5% and about 30%, about 5% and about 20%, about 5% and about 10%, about 10% and about 99%, about 10% and about 95%, about 10% and about 90%, about 10% and about 8 ...0%, about 10% and about 80%, about 10% and about 50%, about 5% and about 40%, about 5% and about 30%, about 5% and about 20%, about 5% and about 10%, about 10% and about 99 about 10% and about 70%, about 10% and about 60%, about 10% and about 50%, about 10% and about 40%, about 10% and about 30%, about 10% and about 20%, about 20% and about 99%, about 20% and about 95%, about 20% and about 90%, about 20% and about 80%, about 20% and about 70%, about 20% and about 60%, about 20% and about 50%, about 20% and about 40%, about 20% and about 30%, about 30% and about 99%, about 30% and about 95%, about 30% and about 90%, about 30% and about 80%, about 30% and about 70%, about 30% and about 60%, about 30% and about 50%, about 30% and about 40%, about 40% and about 99%, about 40% and about 95%, about 40% and about 90%, about 40% and about 80%, about 40% and about 70%, about 40% and about 60%, about 40% and about 50%, about 50% and about 99%, about 50% and about 95%, about 50% and about 90%, about 50% and about 80%, about 5 In some embodiments, the present invention provides an amount between about 0% and about 70%, about 50% and about 60%, about 60% and about 99%, about 60% and about 95%, about 60% and about 90%, about 60% and about 80%, about 60% and about 70%, about 70% and about 99%, about 70% and about 95%, about 70% and about 90%, about 70% and about 80%, about 80% and about 99%, about 80% and about 95%, about 80% and about 90%, about 90% and about 99%, about 90% and about 95%, or about 95% and about 99%.

In some embodiments, the nanostructure composition further comprises at least one monomer incorporated into the ligand coating the AIGS surface. AIGS nanostructures containing at least one monomer incorporated into the ligand coating the AIGS surface have been found to exhibit high QY, good compatibility with HDDA (a common monomer used in inkjet printable inks), and good blue light absorption.

In some embodiments, at least one monomer is an acrylate. Examples of acrylate monomers include, but are not limited to, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, tridecyl methacrylate, stearyl methacrylate, decyl methacrylate, dodecyl methacrylate, methoxydiethylene glycol methacrylate, polypropylene glycol monomethacrylate, phenyl methacrylate, phenylmethyl methacrylate, tetrahydrofurfuryl methacrylate, t-butylcyclohexyl methacrylate, behenyl methacrylate, dicyclopentyl methacrylate, dicyclopentenyloxyethyl methacrylate, methyl 2-Ethylhexyl acrylate, octyl methacrylate, isooctyl methacrylate, n-decyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, benzyl methacrylate, 2-phenylethyl methacrylate, 2-phenoxyethyl acrylate, ethyl acrylate, methyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, 2-carboxyethyl acrylate, acrylic acid, ethylene glycol diacrylate, 1,3-propylene glycol diacrylate, 1,4-bis(acryloyloxy)butane, isobornyl acrylate, tetrahydrofurfuryl acrylate, cyclotrihydroxymethylpropane formaldehyde acrylate, cyclohexyl methacrylate, and 4-tert-butylcyclohexyl acrylate.

In some embodiments, the monomer is at least one of ethyl acrylate, HDDA, tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate. Method for Preparing AIGS Nanostructure Compositions

The present invention provides a method for preparing a nanostructure composition, comprising: (a) Providing at least one population of AIGS nanostructures; and (b)    Mixing at least one organic resin with the composition of (a).

In some embodiments, the nanostructure has a PWL between 480-545 nm, and at least about 80% of the emission is band-edge emitting. In some embodiments, at least 80% of the emission is band-edge emitting. In other embodiments, at least 90% of the emission is band-edge emitting. In other embodiments, at least 95% of the emission is band-edge emitting. In some embodiments, 92-98% of the emission is band-edge emitting. In some embodiments, 93-96% of the emission is band-edge emitting.

The present invention also provides a method for preparing a nanostructure composition, comprising: (a) providing at least one population of AIGS nanostructures, wherein the nanostructures are prepared using a GaX ₃ (X = F, Cl, or Br) precursor and an oxygen-free ligand; and (b) mixing at least one organic resin with the composition of (a).

In some embodiments, the nanostructure has a PWL between 480-545 nm and at least about 60% of the emission is band-edge emission.

The present invention also provides a method for preparing a nanostructure composition, the method comprising: (a) providing at least one population of AIGS nanostructures, wherein the nanostructures have a PWL between 480-545 nm, wherein at least about 80% of the emission is band-edge emission, and wherein the nanostructures exhibit a QY of 80-99%; and (b) mixing at least one organic resin with the composition of (a).

In some embodiments, at least one population of nanostructures is mixed with at least one organic resin at a speed between about 100 rpm and about 10,000 rpm, about 100 rpm and about 5,000 rpm, about 100 rpm and about 3,000 rpm, about 100 rpm and about 1,000 rpm, about 100 rpm and about 500 rpm, about 500 rpm and about 10,000 rpm, about 500 rpm and about 5,000 rpm, about 500 rpm and about 3,000 rpm, about 500 rpm and about 1,000 rpm, about 1,000 rpm and about 10,000 rpm, about 1,000 rpm and about 5,000 rpm, about 1,000 rpm and about 3,000 rpm, about 3,000 rpm and about 10,000 rpm. rpm, about 3,000 rpm and about 10,000 rpm, or about 5,000 rpm and about 10,000 rpm.

In some embodiments, at least one population of nanostructures is mixed with at least one organic resin for a period of time between about 10 minutes and about 24 hours, about 10 minutes and about 20 hours, about 10 minutes and about 15 hours, about 10 minutes and about 10 hours, about 10 minutes and about 5 hours, about 10 minutes and about 1 hour, about 10 minutes and about 30 minutes, about 30 minutes and about 24 hours, about 30 minutes and about 20 hours, about 30 minutes and about 15 hours, about 30 minutes and about 10 hours, about 30 minutes and about 5 hours, about 30 minutes and about about 1 hour, about 1 hour and about 24 hours, about 1 hour and about 20 hours, about 1 hour and about 15 hours, about 1 hour and about 10 hours, about 1 hour and about 5 hours, about 5 hours and about 24 hours, about 5 hours and about 20 hours, about 5 hours and about 15 hours, about 5 hours and about 10 hours, about 10 hours and about 24 hours, about 10 hours and about 20 hours, about 10 hours and about 15 hours, about 15 hours and about 24 hours, about 15 hours and about 20 hours, or a time between about 20 hours and about 24 hours.

In some embodiments, at least one population of nanostructures is mixed with at least one organic resin at a temperature between about -5°C and about 100°C, about -5°C and about 75°C, about -5°C and about 50°C, about -5°C and about 23°C, about 23°C and about 100°C, about 23°C and about 75°C, about 23°C and about 50°C, about 50°C and about 100°C, about 50°C and about 75°C, or about 75°C and about 100°C. In some embodiments, at least one organic resin is mixed with at least one population of nanostructures at a temperature between about 23°C and about 50°C.

In some embodiments, if more than one organic resin is used, the organic resins are added and mixed together. In some embodiments, the first organic resin and the second organic resin are mixed at a speed between about 100 rpm and about 10,000 rpm, about 100 rpm and about 5,000 rpm, about 100 rpm and about 3,000 rpm, about 100 rpm and about 1,000 rpm, about 100 rpm and about 500 rpm, about 500 rpm and about 10,000 rpm, about 500 rpm and about 5,000 rpm, about 500 rpm and about 3,000 rpm, about 500 rpm and about 1,000 rpm, about 1,000 rpm and about 10,000 rpm, about 1,000 rpm and about 5,000 rpm, about 1,000 rpm and about 3,000 rpm, about 3,000 rpm and about 10,000 rpm. rpm, about 3,000 rpm and about 10,000 rpm, or about 5,000 rpm and about 10,000 rpm.

In some embodiments, the first organic resin and the second organic resin are mixed for between about 10 minutes and about 24 hours, about 10 minutes and about 20 hours, about 10 minutes and about 15 hours, about 10 minutes and about 10 hours, about 10 minutes and about 5 hours, about 10 minutes and about 1 hour, about 10 minutes and about 30 minutes, about 30 minutes and about 24 hours, about 30 minutes and about 20 hours, about 30 minutes and about 15 hours, about 30 minutes and about 10 hours, about 30 minutes and about 5 hours, about 30 minutes and about 1 hour. , about 1 hour and about 24 hours, about 1 hour and about 20 hours, about 1 hour and about 15 hours, about 1 hour and about 10 hours, about 1 hour and about 5 hours, about 5 hours and about 24 hours, about 5 hours and about 20 hours, about 5 hours and about 15 hours, about 5 hours and about 10 hours, about 10 hours and about 24 hours, about 10 hours and about 20 hours, about 10 hours and about 15 hours, about 15 hours and about 24 hours, about 15 hours and about 20 hours, or a time between about 20 hours and about 24 hours.

In some embodiments, the AIGS nanostructure is combined with at least one monomer incorporated into the ligand coating the AIGS surface prior to incorporation with the resin. In some embodiments, the monomer is an acrylate. In some embodiments, the monomer is at least one of ethyl acrylate, HDDA, tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate. Properties of AIGS Nanostructures

In some embodiments, the AIGS nanostructures exhibit high photoluminescence quantum yields. In some embodiments, the nanostructures exhibit between about 50% and about 99%, about 50% and about 95%, about 50% and about 90%, about 50% and about 85%, about 50% and about 80%, about 50% and about 70%, about 50% and about 60%, 60% and about 99%, about 60% and about 95%, about 60% and about 90%, about 60% and about 85%, about 60% and about 80%, about 60% and about 70%, about 70% and about 99%, about 70% and about 95%, about 95% and about 60%, about 90% and about 85%, about 60% and about 80%, about 60% and about 70%, about 70% and about 99%, about 70% and about 95%, about 95% and about 60%, about 90% and about 85%, about 90% and about 80%, about 90% and about 70%, about 90% and about 95%, about 95% and about 60%, about 90% and about 85%, about 90% and about 80%, about 90% and about 70%, about 90% and about 95%, about 95% and about 60%, about 90% and about 95 ...95%, about 90% and about 85%, about 90% and about 80%, about 90% and about 70%, about 90% and about 95 In some embodiments, the nanostructures exhibit a photoluminescence quantum yield between about 82% and about 96%, between about 85% and about 96%, and between about 93% and about 94%.

The photoluminescence spectrum of the nanostructure can cover a wide desired portion of the spectrum. In some embodiments, the photoluminescence spectrum of the nanostructure has an emission maximum between 300 nm and 750 nm, 300 nm and 650 nm, 300 nm and 550 nm, 300 nm and 450 nm, 450 nm and 750 nm, 450 nm and 650 nm, 450 nm and 550 nm, 450 nm and 750 nm, 450 nm and 650 nm, 450 nm and 550 nm, 550 nm and 750 nm, 550 nm and 650 nm, or 650 nm and 750 nm. In some embodiments, the photoluminescence spectrum of the nanostructure has an emission maximum between 450 nm and 550 nm.

The size distribution of the nanostructures can be relatively narrow. In some embodiments, the photoluminescence spectrum of a population of nanostructures can have a full width at half maximum (FWHM) between 10 nm and 60 nm, 10 nm and 40 nm, 10 nm and 30 nm, 10 nm and 20 nm, 20 nm and 60 nm, 20 nm and 40 nm, 20 nm and 30 nm, 25 nm and 60 nm, 25 nm and 40 nm, 25 nm and 30 nm, 30 nm and 60 nm, 30 nm and 40 nm, or 40 nm and 60 nm. In some embodiments, the photoluminescence spectrum of a population of nanostructures can have a FWHM between 24 nm and 50 nm.

In some embodiments, the nanostructure emits light having a peak emission wavelength (PWL) between about 400 nm and about 650 nm, about 400 nm and about 600 nm, about 400 nm and about 550 nm, about 400 nm and about 500 nm, about 400 nm and about 450 nm, about 450 nm and about 650 nm, about 450 nm and about 600 nm, about 450 nm and about 550 nm, about 450 nm and about 500 nm, about 500 nm and about 650 nm, about 500 nm and about 600 nm, about 500 nm and about 550 nm, about 550 nm and about 650 nm, about 550 nm and about 600 nm, or about 600 nm and about 650 nm. In some embodiments, the nanostructure emits light having a PWL between about 500 nm and about 550 nm.

As a predictor of blue light absorption efficiency, the optical density at 450 nm (OD 450 /mass) was calculated by measuring the optical density of a nanostructure solution in a 1 cm pathlength cuvette and dividing it by the dry mass per mL (mg/mL) of the same solution after all volatiles were removed under vacuum (< ₂₀₀ mTorr). In some embodiments, the nanostructures have an optical density at 450 nm by mass (OD450/mass) between about 0.28/mg and about 0.5/mg, about 0.28/mg and about 0.4/mg, about 0.28/mg and about 0.35/mg, about 0.28/mg and about 0.32/mg, about 0.32/mg and about 0.5/mg, about 0.32/mg and about 0.4/mg, about 0.32/mg and about 0.35/mg, about 0.35/mg and about 0.5/mg, about 0.35/mg and about 0.4/mg, or about _0.4 /mg and about 0.5/mg.

The nanostructures of the present invention can be embedded in a polymeric matrix using any suitable method. As used herein, the term "embedded" is used to indicate that the nanostructures are surrounded or encapsulated by the polymer that constitutes the majority of the matrix. In some embodiments, at least one population of nanostructures is uniformly distributed throughout the matrix. In some embodiments, at least one population of nanostructures is distributed according to an application-specific distribution. In some embodiments, the nanostructures are mixed in a polymer and applied to the surface of a substrate.

In some embodiments, the present invention provides a nanostructured film layer comprising: (a) a composition comprising at least one population of AIGS nanostructures and at least one ligand bound to the nanostructures; and (b) at least one organic resin.

In some embodiments, a portion of the ligand is bound to the nanostructure. In other embodiments, the surface of the nanostructure is saturated with the ligand.

In some embodiments, the nanostructure has a PWL between 480 nm and 545 nm.

In some embodiments, the composition comprising at least one population of AIGS nanostructures further comprises at least one monomer incorporated into the ligand coating the AIGS surface. In some embodiments, the at least one monomer is an acrylate. In some embodiments, the monomer is at least one of ethyl acrylate, HDDA, tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate.

The present invention also provides a method for preparing a nanostructured film, comprising: (a) Providing at least one population of AIGS nanostructures; and (b) Mixing at least one organic resin with the composition of (a). In some embodiments, the nanostructures have a PWL between 480 and 545 nm.

In some embodiments, at least 80% of the emissions are edge-on emissions. In other embodiments, at least 90% of the emissions are edge-on emissions. In other embodiments, at least 95% of the emissions are edge-on emissions. In some embodiments, 92-98% of the emissions are edge-on emissions. In some embodiments, 93-96% of the emissions are edge-on emissions.

In some embodiments, the nanostructure composition further comprises an amino ligand having Formula I: (I) wherein: x is 1 to 100; y is 0 to 100; and R ² is a C _1-20 alkyl group.

In some embodiments, x is 1 to 100, 1 to 50, 1 to 20, 1 to 10, 1 to 5, 5 to 100, 5 to 50, 5 to 20, 5 to 10, 10 to 100, 10 to 50, 10 to 20, 20 to 100, 20 to 50, or 50 to 100. In some embodiments, x is 10 to 50. In some embodiments, x is 10 to 20. In some embodiments, x is 1. In some embodiments, x is 19. In some embodiments, x is 6. In some embodiments, x is 10.

In some embodiments, R ² is C _1-20 alkyl. In some embodiments, R ² is C _1-10 alkyl. In some embodiments, R ² is C _1-5 alkyl. In some embodiments, R ² is -CH ₂ CH ₃ .

In some embodiments, the compound of Formula I is an amine-terminated polymer commercially available from Huntsman Petrochemical Corporation. In some embodiments, the amine-terminated polymer of Formula (VI) has x = 1, y = 9, and ^R = _-CH and is JEFFAMINE M-600 (Huntsman Petrochemical Corporation, Texas). JEFFAMINE M-600 has a molecular weight of approximately 600. In some embodiments, the amine-terminated polymer of Formula (III) has x = 19, y = 3, and ^R = _-CH and is JEFFAMINE M-1000 (Huntsman Petrochemical Corporation, Texas). JEFFAMINE M-1000 has a molecular weight of approximately 1,000. In some embodiments, the amine-terminated polymer of formula (III) has x = 6, y = 29, and ^R = _-CH and is JEFFAMINE M-2005 (Huntsman Petrochemical Corporation, Texas). JEFFAMINE M-2005 has a molecular weight of about 2,000. In some embodiments, the amine-terminated polymer of formula (III) has x = 31, y = 10, and ^R = -CH and is JEFFAMINE M- ₂₀₇₀ (Huntsman Petrochemical Corporation, Texas). JEFFAMINE M-2070 has a molecular weight of about 2,000. In another embodiment, the ligand is a polyethylene glycol amine, such as PEG550-amine and PEG350-amine, available from CreativePEGWorks.

In some embodiments, the nanostructured film layer is a color conversion layer.

The nanostructured composition can be deposited by any suitable method known in the art, including, but not limited to, painting, spraying, solvent spraying, wet coating, adhesive coating, spin coating, tape coating, roll coating, shower coating, inkjet vapor jetting, drop casting, doctor blade coating, mist deposition, or combinations thereof. In some embodiments, the nanostructured composition is cured after deposition. Suitable curing methods include light curing (e.g., UV curing) and thermal curing. Conventional lamination processes, tape coating methods, and/or roll-to-roll production methods can be used to form the nanostructured films of the present invention. The nanostructured composition can be directly coated onto the desired layer of the substrate. Alternatively, the nanostructure composition can be formed as a solid layer as a standalone element and subsequently applied to a substrate. In some embodiments, the nanostructure composition can be deposited on one or more barrier layers. Spin-on coating

In some embodiments, the nanostructure composition is deposited onto a substrate using spin coating. In spin coating, a small amount of material is typically deposited onto the center of a substrate mounted on a machine (called a spin coater) that is held in place by a vacuum. High-speed rotation is applied to the substrate via the spin coater, which causes a centripetal force to diffuse the material from the center of the substrate to the edges. Although most of the material is stripped off, a certain amount of material remains on the substrate, and as the rotation continues, a thin film of material forms on the surface. In addition to the parameters selected for the spin coating process (such as spin speed, acceleration, and spin time), the final thickness of the film is also determined by the properties of the deposited material and the substrate. For typical films, a spin speed of 1500 to 6000 rpm is used, with a spin time of 10-60 seconds. In some embodiments, the film is deposited at a very low speed (e.g., less than 1000 rpm). In some embodiments, the film is poured at about 300, about 400, about 500, about 600, about 700, about 800, or about 900 rpm. Mist Deposition

In some embodiments, the nanostructured composition is deposited onto the substrate using mist deposition. Mist deposition is performed at room temperature and atmospheric pressure, and the film thickness can be precisely controlled by varying the process conditions. During mist deposition, the liquid source material is converted into a very fine mist and carried into the deposition chamber by nitrogen. The mist is then attracted to the wafer surface by a high voltage potential between the field screen and the wafer holder. Once the droplets coalesce on the wafer surface, the wafer is removed from the chamber and thermally cured to evaporate the solvent. The liquid precursor is a mixture of a solvent and the material to be deposited. It is carried to the atomizer by pressurized nitrogen. Price, S.C. et al., "Formation of Ultra-Thin Quantum Dot Films by Mist Deposition," ESC Transactions 11:89-94 (2007). Spraying

In some embodiments, the nanostructured composition is deposited onto a substrate using spray coating. Typical spray coating equipment includes a nozzle, an atomizer, a precursor solution, and a carrier gas. During the spray deposition process, the precursor solution is pulverized into micron-sized droplets with the aid of a carrier gas or by atomization (e.g., ultrasound, air blast, or electrostatics). The droplets from the atomizer are accelerated through the nozzle across the substrate surface with the help of a carrier gas, which is controlled and regulated as needed. To achieve full coverage of the substrate, the relative motion between the nozzle and the substrate is determined by the design.

In some embodiments, the application of the nanostructure composition further comprises a solvent. In some embodiments, the solvent used to apply the nanostructure composition is water, an organic solvent, an inorganic solvent, a halogenated organic solvent, or a mixture thereof. Exfoliative solvents include, but are not limited to, water, D ₂ O, acetone, ethanol, dioxane, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, anisole, γ-butyrolactone, dimethylformamide, N-methylpyrrolidone, dimethylacetamide, hexamethylphosphatide, toluene, dimethylsulfoxide, cyclopentanone, tetramethylenesulfoxide, xylene, ε-caprolactone, tetrahydrofuran, tetrachloroethylene, chloroform, chlorobenzene, dichloromethane, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, or a mixture thereof. Inkjet printing

Solvents suitable for inkjet printing of nanostructures are known to those skilled in the art. In some embodiments, the organic solvent is a substituted aromatic or heteroaromatic solvent as described in U.S. Patent Application Publication No. 2018/0230321, which is incorporated herein by reference in its entirety.

In some embodiments, the organic solvent used in the nanostructure composition used as an inkjet printing formulation is defined by its boiling point, viscosity, and surface tension. The properties of organic solvents suitable for inkjet printing formulations are shown in Table 1. Table 1: Properties of organic solvents used in inkjet printing formulations solvent Boiling point (℃) Viscosity (mPa·s) Surface tension (dyne/cm) 1-Methylnaphthalene 240 3.3 38 1-Methoxynaphthalene 270 7.2 43 3-Phenoxytoluene 271 4.8 37 Dibenzyl ether 298 8.7 39 Benzyl benzoate 324 10.0 44 Butyl benzoate 249 2.7 34 Hexyl benzoate 272 — — Octylbenzene 265 2.6 31 Cyclohexylbenzene 240 2.0 34 Hexadecane 287 3.4 28 4-Methylanisole 179 — 29

In some embodiments, the boiling point of the organic solvent at 1 atmosphere is between about 150° C. and about 350° C. In some embodiments, the boiling point of the organic solvent at 1 atmosphere is between about 150° C. and about 350° C., about 150° C. and about 300° C., about 150° C. and about 250° C., about 150° C. and about 200° C., about 200° C. and about 350° C., about 200° C. and about 300° C., about 200° C. and about 250° C., about 250° C. and about 350° C., about 250° C. and about 300° C., or about 300° C. and about 350° C.

In some embodiments, the organic solvent has a viscosity between about 1 ^mPa.s and about 15 ^mPa.s. In some embodiments, the organic solvent has a velocity between about 1 ^mPa.s and about 15 ^mPa.s , about 1 ^mPa.s and about 10 ^mPa.s , about 1 mPa.s and about 8 ^mPa.s , about 1 ^mPa.s and about 6 ^mPa.s , about 1 ^mPa.s and about 4 mPa.s, about 1 ^mPa.s and about 2 ^mPa.s , about 2 ^mPa.s and about 15 ^mPa.s , about 2 ^mPa.s and about 10 ^mPa.s , about 2 ^mPa.s and about 8 ^mPa.s , about 2 ^mPa.s and about 6 ^mPa.s , about 2 ^mPa.s and about ^{4 mPa.s} , about 4 ^mPa.s and about 15 ^mPa.s , about ^{4 mPa.s.} s and about 10 ^mPa.s , about 4 mPa.s and about 8 ^mPa.s , about 4 ^mPa.s and about 6 ^mPa.s , about 6 ^mPa.s and about 15 ^mPa.s , about 6 mPa.s and about 10 ^mPa.s , about 6 ^mPa.s and about 8 ^mPa.s , about 8 ^mPa.s and about 15 ^mPa.s , about 8 ^{mPa.s and} about 10 ^mPa.s , or about 10 ^{mPa.s and} about 15 ^mPa.s.

In some embodiments, the organic solvent has a surface tension between about 20 dynes/cm and about 50 dynes/cm. In some embodiments, the organic solvent has a surface tension between about 20 dynes/cm and about 50 dynes/cm, about 20 dynes/cm and about 40 dynes/cm, about 20 dynes/cm and about 35 dynes/cm, about 20 dynes/cm and about 30 dynes/cm, about 20 dynes/cm and about 25 dynes/cm, about 25 dynes/cm and about 50 dynes/cm, about 25 dynes/cm and about 40 dynes/cm, about 25 dynes/cm /cm and about 35 dynes/cm, about 25 dynes/cm and about 30 dynes/cm, about 30 dynes/cm and about 50 dynes/cm, about 30 dynes/cm and about 40 dynes/cm, about 30 dynes/cm and about 35 dynes/cm, about 35 dynes/cm and about 50 dynes/cm, about 35 dynes/cm and about 40 dynes/cm, or about 40 dynes/cm and about 50 dynes/cm.

In some embodiments, the organic solvent used in the nanostructure composition is alkylnaphthalene, alkoxynaphthalene, alkylbenzene, aryl, alkyl-substituted benzene, cycloalkylbenzene, C ₉ -C ₂₀ alkane, diaryl ether, alkyl benzoate, aryl benzoate, or alkoxy-substituted benzene.

In some embodiments, the organic solvent used in the nanostructured composition is 1-tetrahydronaphthalenone, 3-phenoxytoluene, acetophenone, 1-methoxynaphthalene, n-octylbenzene, n-nonylbenzene, 4-methylanisole, n-decylbenzene, p-diisopropylbenzene, pentylbenzene, tetrahydronaphthalene, cyclohexylbenzene, chloronaphthalene, 1,4-dimethylnaphthalene, 3-isopropylbiphenyl, p-methylisopropylbenzene, dipentylbenzene, o-diethylbenzene, m-dimethylnaphthalene, -diethylbenzene, p-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, butylbenzene, dodecylbenzene, 1-methylnaphthalene, 1,2,4-trichlorobenzene, diphenyl ether, diphenylmethane, 4-isopropylbiphenyl, benzyl benzoate, 1,2-bi(3,4-dimethylphenyl)ethane, 2-isopropylnaphthalene, dibenzyl ether, or a combination thereof. In some embodiments, the organic solvent used in the nanostructured composition is 1-methylnaphthalene, n-octylbenzene, 1-methoxynaphthalene, 3-phenoxytoluene, cyclohexylbenzene, 4-methylanisole, n-decylbenzene, or a combination thereof.

In some embodiments, the organic solvent is an anhydrous organic solvent. In some embodiments, the organic solvent is a substantially anhydrous organic solvent.

In some embodiments, the organic solvent is a non-volatile monomer or a combination of monomers selected from the list provided above.

In some embodiments, the weight % of the organic solvent in the nanostructure composition is between about 70% and about 99%. In some embodiments, the weight % of the organic solvent in the nanostructure composition is between about 70% and about 99%, about 70% and about 98%, about 70% and about 95%, about 70% and about 90%, about 70% and about 85%, about 70% and about 80%, about 70% and about 75%, about 75% and about 99%, about 75% and about 98%, about 75% and about 95%, about 75% and about 90%, about 75% and about 85%, about 75% and about 80 %, about 80% and about 99%, about 80% and about 98%, about 80% and about 95%, about 80% and about 90%, about 80% and about 85%, about 85% and about 99%, about 85% and about 98%, about 85% and about 95%, about 85% and about 90%, about 90% and about 99%, about 90% and about 98%, about 90% and about 95%, about 95% and about 99%, about 95% and about 98%, or about 98% and about 99%. In some embodiments, the weight % of the organic solvent in the nanostructure composition is between about 95% and about 99%.

In some embodiments, the composition for inkjet printing further comprises a monomer incorporated into the ligand coating the AIGS surface. In some embodiments, the monomer is an acrylate. In some embodiments, the monomer is at least one of ethyl acrylate, HDDA, tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate. It has been found that the use of the monomer in the inkjet composition provides better compatibility of the AIGS nanostructures in the inkjet composition, improves QY, and improves blue light absorption. Film Curing

In some embodiments, the composition is thermally cured to form the nanostructured layer. In some embodiments, UV light is used to cure the composition. In some embodiments, the nanostructured composition is applied directly onto the barrier layer of the nanostructured film, and an additional barrier layer is subsequently deposited onto the nanostructured layer to produce the nanostructured film. A supporting substrate may be used beneath the barrier film to increase strength, stability, and coating uniformity, and to prevent material inconsistencies, bubble formation, and wrinkling or folding of the barrier layer material or other materials. Additionally, one or more barrier layers may be deposited onto the nanostructured layer to seal the material between the top and bottom barrier layers. Suitably, the barrier layer can be deposited as a laminate film and optionally sealed or further processed before the nanostructured film is incorporated into a specific lighting device. As will be understood by those skilled in the art, the nanostructured composition deposition process can include additional or varying components. Such embodiments will allow for in-line process adjustment of nanostructured emission characteristics, such as brightness and color (e.g., to adjust the quantum film white point), as well as nanostructured film thickness and other characteristics. Furthermore, such embodiments will allow for periodic testing of nanostructured film characteristics during production, as well as any necessary switching to achieve precise nanostructured film characteristics. Such testing and adjustments can also be accomplished without changing the mechanical configuration of the production line, since the individual amounts of the mixture used in forming the nanostructured membrane can be electronically varied using a computer program.

We have discovered that nanostructured films with high PCEs can be obtained when the films are processed without exposing the AIGS nanocrystals to blue or UV light before providing an oxygen-free environment for the nanostructures. The oxygen-free environment can be provided by: (a) encapsulating the film with an oxygen barrier before thermal treatment and/or exposure to blue light for PCE measurement; (b) using an oxygen-reactive material as part of the formulation during thermal treatment or light exposure; and/or (c) temporarily blocking oxygen through the use of a sacrificial barrier layer.

In some embodiments, PCE improvement can be achieved by any method capable of forming an oxygen barrier on the AIGS layer. In high-volume production of devices containing such AIGS-CC layers, encapsulation can be performed using vapor deposition methods. In this case, a typical process flow involves inkjet printing the AIGS layer, followed by UV curing, baking at 180°C to remove volatiles, deposition of an organic planarization layer, and then deposition of an inorganic barrier layer. Techniques used to deposit the inorganic layer can include atomic layer deposition (ALD), molecular layer deposition (MLD), chemical vapor deposition (CVD) (with or without plasma enhancement), pulsed vapor deposition (PVD), sputtering, or metal evaporation. Other potential encapsulation methods include solution-processed or printed organic layers, UV- or heat-curable adhesives, and lamination using barrier films.

In some embodiments, the membrane is encapsulated in an inert atmosphere. In some embodiments, the membrane is encapsulated in a nitrogen or argon atmosphere.

Oxygen-reactive materials include any material that reacts more readily with oxygen than the AIGS nanostructure. Examples of oxygen-reactive materials include, but are not limited to, phosphines, phosphites, metal-organic precursors, titanium nitride, and tantalum nitride. In some embodiments, the phosphine can be any C _1-20 trialkylphosphine. In one embodiment, the phosphine is trioctylphosphine. In some embodiments, the phosphite can be a trialkylphosphite, an alkylarylphosphite, or a triarylphosphite. In some embodiments, the metal-organic precursor can be a trialkylaluminum, a trialkylgallium, a trialkylindium, a dialkylzinc, or the like.

Examples of sacrificial barrier layers include polymer layers that can be dissolved in a solvent and washed off. Examples of such polymers include (but are not limited to) polyvinyl alcohol, polyvinyl acetate, and polyethylene glycol. Other examples of sacrificial barrier layers include inorganic compounds or salts, such as lithium silicate, lithium fluoride, etc. Examples of solvents that can be used to wash off the sacrificial layer include water and organic solvents, such as alcohols (such as ethanol, methanol), halogenated hydrocarbons (such as dichloromethane and vinyl chloride), aromatic hydrocarbons (such as toluene, xylene), aliphatic hydrocarbons (such as hexane, octane, octadecene), tetrahydrofuran, C _4-20 ethers (such as diethyl ether), and C _2-20 esters (such as ethyl acetate). Nanostructured membrane characteristics and embodiments

In some embodiments, the nanostructured films of the present invention are used to form display devices. As used herein, a display device refers to any system with an illuminated display. Such devices include, but are not limited to, liquid crystal displays (LCDs), televisions, computers, mobile phones, smartphones, personal digital assistants (PDAs), gaming devices, electronic reading devices, digital cameras, augmented reality/virtual reality (AR/VR) glasses, light projection systems, heads-up displays, and the like.

In some embodiments, the nanostructured film is part of a nanostructured color conversion layer.

In some embodiments, a display device includes a nanostructured color converter. In some embodiments, the display device includes a backplane; a display panel disposed on the backplane; and a nanostructured layer. In some embodiments, the nanostructured layer is disposed on the display panel. In some embodiments, the nanostructured layer includes a patterned nanostructured layer.

In some embodiments, the backplane includes blue LEDs, LCDs, OLEDs, or micro-LEDs.

In some embodiments, the nanostructure layer is disposed on the light source element. In some embodiments, the nanostructure layer comprises a patterned nanostructure layer. The patterned nanostructure layer can be prepared by any method known in the industry. In one embodiment, the patterned nanostructure layer is prepared by inkjet printing of a nanostructure solution. Solvents suitable for the solution include (but are not limited to) dipropylene glycol monomethyl ether acetate (DPMA), polyglycidyl methacrylate (PGMA), diethylene glycol monoethyl ether acetate (EDGAC), and propylene glycol methyl ether acetate (PGMEA). Volatile solvents can also be used for inkjet printing because they allow for rapid drying. Volatile solvents include ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and tetrahydrofuran. Alternatively, "solvent-free" inks, in which AIGS nanostructures are dispersed in an ink monomer, can be used for inkjet printing.

In some embodiments, AIGS nanostructures are inkjet-printed using a composition that also includes at least one monomer incorporated into a ligand coating the AIGS surface. In some embodiments, the at least one monomer is an acrylate. In some embodiments, the acrylate is at least one of ethyl acrylate, tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, or isobornyl acrylate. It has been discovered that AIGS nanostructures treated with the at least one monomer during ligand exchange provide improved compatibility with HDDA (a common monomer used in inkjet-printable inks), resulting in improved QY and blue light absorption.

In some embodiments, the nanostructure layer has a thickness between about 1 μm and about 25 μm. In some embodiments, the nanostructure layer has a thickness between about 5 μm and about 25 μm. In some embodiments, the nanostructure layer has a thickness between about 10 μm and about 12 μm.

In some embodiments, the nanostructured display device exhibits a PCE of at least 32%. In some embodiments, the nanostructured molded article exhibits a PCE of 32-40%. In some embodiments, the nanostructured molded article exhibits a PCE of 33-40%, 34-40%, 35-40%, 36-40%, 37-40%, 38-40%, 39-40%, 33-39%, 34-39%, 35-39%, 36-39%, 37-39%, 38-39%, 33-38%, 34-38%, 35-38%, 36-38%, 37-38%, 33-37%, 34-37%, 35-37%, 36-37%, 33-36%, 34-36%, 35-36%, 33-35%, or 34-35%.

In some embodiments, the optical film comprising the nanostructure layer is substantially free of cadmium. As used herein, the term "substantially free of cadmium" is intended to mean that the nanostructure composition contains less than 100 ppm by weight of cadmium. RoHS compliance requires that no more than 0.01% (100 ppm) by weight of cadmium be present in the raw homogeneous precursor material. Cadmium concentration can be measured by inductively coupled plasma mass spectrometry (ICP-MS) analysis and is measured at the parts per billion (ppb) level. In some embodiments, the "substantially free of cadmium" optical film contains 10 to 90 ppm of cadmium. In other embodiments, the substantially free of cadmium optical film contains less than about 50 ppm, less than about 20 ppm, less than about 10 ppm, or less than about 1 ppm of cadmium. Nanostructured molded products

In some embodiments, the present invention provides a nanostructured molded article comprising: (a) a first barrier layer; (b) a second barrier layer; and (c) a nanostructure layer between the first barrier layer and the second barrier layer, wherein the nanostructure layer comprises a nanostructure cluster comprising AIGS nanostructures; and at least one organic resin.

In some embodiments, the nanostructure has a PWL between 480-545 nm.

In some embodiments, at least 80% of the emission is band-edge emission. In other embodiments, at least 90% of the emission is band-edge emission. In other embodiments, at least 95% of the emission is band-edge emission. In some embodiments, 92-98% of the emission is band-edge emission. In some embodiments, 93-96% of the emission is band-edge emission. In some embodiments, the nanostructure molded article exhibits a PCE of at least 32%. In some embodiments, the nanostructure molded article exhibits a PCE of 32-40%. In some embodiments, the nanostructured molded article exhibits a PCE of 33-40%, 34-40%, 35-40%, 36-40%, 37-40%, 38-40%, 39-40%, 33-39%, 34-39%, 35-39%, 36-39%, 37-39%, 38-39%, 33-38%, 34-38%, 35-38%, 36-38%, 37-38%, 33-37%, 34-37%, 35-37%, 36-37%, 33-36%, 34-36%, 35-36%, 33-35%, or 34-35%. Barrier Layer

In some embodiments, the nanostructured molded article includes one or more barrier layers disposed on one or both sides of the nanostructured layer. Suitable barrier layers protect the nanostructured layer and the nanostructured molded article from environmental conditions such as high temperature, oxygen, and moisture. Suitable barrier materials include non-yellowing, transparent, hydrophobic, chemically and mechanically compatible materials, exhibiting optical and chemical stability, and capable of withstanding high temperatures. In some embodiments, the one or more barrier layers are refractive index matched to the nanostructured molded article. In some embodiments, the matrix material of the nanostructured molded article and one or more adjacent barrier layers are index-matched to have similar refractive indices, so that a majority of light transmitted through the barrier layers toward the nanostructured molded article is transmitted through the barrier layers into the nanostructured layers. This index matching reduces optical loss at the interface between the barrier layers and the matrix material.

The barrier layer is suitably a solid material and can be a solidified liquid, gel, or polymer. Depending on the specific application, the barrier layer can include flexible or inflexible materials. The barrier layer is typically a planar layer and, depending on the specific lighting application, can include any suitable shape and surface area configuration. In some embodiments, one or more barrier layers are compatible with lamination processing techniques, wherein a nanostructured layer is disposed on at least a first barrier layer and at least a second barrier layer is disposed on the nanostructured layer on an opposite side of the nanostructured layer to form a nanostructured molded article according to an embodiment of the present invention. Suitable barrier materials include any suitable barrier material known in the industry. For example, suitable barrier materials include glass, polymers, and oxides. Suitable barrier layer materials include, but are not limited to, polymers such as polyethylene terephthalate (PET); oxides such as silicon oxide, titanium oxide, or aluminum oxide (e.g., SiO ₂ , Si ₂ O ₃ , TiO ₂ , or Al ₂ O ₃ ); and suitable combinations thereof. In some embodiments, each barrier layer of the nanostructured molded article comprises at least two layers comprising different materials or compositions, such that the multiple barrier layers eliminate or reduce the alignment of pinhole defects in the barrier layer, thereby providing effective resistance to oxygen and moisture permeation into the nanostructured layer. The nanostructured layer may include any suitable material or combination of materials and any suitable number of barrier layers on either or both sides of the nanostructured layer. The material, thickness, and number of barrier layers will depend on the specific application and are appropriately selected to maximize barrier protection and brightness of the nanostructure layer while minimizing the thickness of the nanostructure molded article. In some embodiments, each barrier layer comprises a laminate, and in some embodiments, a double-laminated film, where the thickness of each barrier layer is sufficiently thick to eliminate wrinkling during roll-to-roll or laminate manufacturing. In embodiments where the nanostructures contain heavy metals or other toxic materials, the number or thickness of the barriers may further depend on regulatory toxicity guidelines, which may require more or thicker barrier layers. Additional considerations for the barriers include cost, availability, and mechanical strength.

In some embodiments, the nanostructured film comprises two or more barrier layers adjacent to each side of the nanostructured layer, for example, two or three layers on each side of the nanostructured layer, or two barrier layers on each side. In some embodiments, each barrier layer comprises a thin glass sheet, for example, a glass sheet having a thickness of about 100 μm, 100 μm or less, or 50 μm or less.

As those skilled in the art will appreciate, each barrier layer of the nanostructured film of the present invention can have any suitable thickness, depending on the specific requirements and characteristics of the lighting device and application, as well as the individual film components, such as the barrier layer and the nanostructured layer. In some embodiments, each barrier layer can have a thickness of 50 µm or less, 40 µm or less, 30 µm or less, 25 µm or less, 20 µm or less, or ₁₅ µm or less. In certain embodiments, the barrier layer comprises an oxide coating, which can include materials such as silicon oxide, titanium oxide, and _aluminum oxide (e.g., _SiO2 , _Si2O3 , _TiO2 , or _Al2O3 ). The oxide coating may have a thickness of about 10 μm or less, 5 μm or less, 1 μm or less, or 100 nm or less. In some embodiments, the barrier comprises a thin oxide coating having a thickness of about 100 nm or less, 10 nm or less, 5 nm or less, or 3 nm or less. The top and/or bottom barrier may consist of a thin oxide coating, or may comprise a thin oxide coating and one or more additional material layers. Display device with nanostructured color conversion layer

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

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 and emit red light, white light, green light, and/or blue light, respectively. In some embodiments, the color filter is described in U.S. Patent No. 9,971,076, which is incorporated herein by reference in its entirety.

In some embodiments, each pixel region includes a color conversion layer. In some embodiments, the color conversion layer includes a nanostructure described herein configured to convert incident light into light of a first color. In some embodiments, the color conversion layer includes a nanostructure described herein configured to convert incident light into blue light.

In some embodiments, a display device includes 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 color conversion layers. In some embodiments, a display device includes 1 color conversion layer including the nanostructures described herein. In some embodiments, a display device includes 2 color conversion layers including the nanostructures described herein. In some embodiments, a display device includes 3 color conversion layers including the nanostructures described herein. In some embodiments, a display device includes 4 color conversion layers including the nanostructures described herein. In some embodiments, a display device includes at least one red conversion layer, at least one green conversion layer, and at least one blue conversion layer.

In some embodiments, the color conversion layer has a thickness between about 3 μm and about 10 μm, about 3 μm and about 8 μm, about 3 μm and about 6 μm, about 6 μm and about 10 μm, about 6 μm and about 8 μm, or about 8 μm and about 10 μm. In some embodiments, the color conversion layer has a thickness between about 3 μm and about 10 μm.

The nanostructured color conversion layer can be deposited by any suitable method known in the art, including, but not limited to, painting, spraying, solvent spraying, wet coating, adhesive coating, spin coating, tape coating, roll coating, shower coating, inkjet printing, photoresist patterning, droplet dispensing, doctor blade coating, mist deposition, or combinations 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. Compositions comprising AIGS nanostructures and ligands

In some embodiments, the AIGS nanostructure composition further comprises one or more ligands, including amine ligands, polyamine ligands, hydroxyl ligands, phosphine ligands, silane ligands, and polymeric or oligomeric chains, such as polyethylene glycol with amine and silane groups.

In some embodiments, the amine-ligand has Formula I: (I) wherein: x is 1 to 100; y is 0 to 100; and R ² is a C _1-20 alkyl group.

In some embodiments, the polyamino ligand is a polyaminoalkane, a polyamine-cycloalkane, a polyamino heterocyclic compound, a polyamino-functionalized polysiloxane, or a polyamino-substituted glycol. In some embodiments, the polyamino ligand is a _C2-20 alkane or _C2-20 cycloalkane substituted with two or three amine groups, optionally containing one or two amine groups in place of a carbon group. In some embodiments, the polyamine ligand is ethylenediamine, 1,2-diaminopropane, 1,2-diamino-2-methylpropane, N-methyl-ethylenediamine, N-ethyl-ethylenediamine, N-isopropyl-ethylenediamine, N-cyclohexyl-ethylenediamine, N-cyclohexyl-ethylenediamine, N-octyl-ethylenediamine, N-decyl-ethylenediamine, N-dodecyl-ethylenediamine, N,N-dimethyl-ethylenediamine, Diamine, N,N-diethyl-ethylenediamine, N,N'-diethyl-ethylenediamine, N,N'-diisopropylethylenediamine, N,N,N'-trimethyl-ethylenediamine, diethylenetriamine, N-isopropyl-diethylenetriamine, N-(2-aminoethyl)-1,3-propanediamine, triethylenetetramine, N,N'-bis(3-aminopropyl)ethylenediamine, N,N'-bis(2- 1,3-propanediamine, tris(2-aminoethyl)amine, tetraethylenepentamine, pentaethylenehexamine, 2-(2-amino-ethylamino)ethanol, N,N-bis(hydroxyethyl)ethylenediamine, N-(hydroxyethyl)diethylenetriamine, N-(hydroxyethyl)triethylenetetramine, hexahydropyrazine, 1-(2-aminoethyl)hexahydropyrazine, 4-(2-aminoethyl) 1,3-diaminopropane, 1,4-diaminobutane, 1,3-diaminopentane, 1,5-diaminopentane, 2,2-dimethyl-1,3-propanediamine, hexamethylenediamine, 2-methyl-1,5-diaminopropane, 1,7-diaminoheptane, 1,8-diaminooctane, 2,2,4-trimethyl-1,6-hexanediamine, 2, 4,4-trimethyl-1,6-hexanediamine, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, N-methyl-1,3-propanediamine, N-ethyl-1,3-propanediamine, N-isopropyl-1,3-propanediamine, N,N-dimethyl-1,3-propanediamine, N,N'-dimethyl-1,3-propanediamine, N , N'-diethyl-1,3-propanediamine, N,N'-diisopropyl-1,3-propanediamine, N,N,N'-trimethyl-1,3-propanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, N,N'-dimethyl-1,6-hexanediamine, 3,3'-diamino-N-methyl-dipropylamine, N-(3-aminopropyl)-1,3-propanediamine , spermidine, bis(hexamethylene)triamine, N,N',N''-trimethyl-bis(hexamethylene)triamine, 4-amino-1,8-octanediamine, N,N'-bis(3-aminopropyl)-1,3-propanediamine, spermine, 4,4'-methylenebis(cyclohexylamine), 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-cyclohexanebis(methylamine) , 1,4-cyclohexanebis(methylamine), 1,2-bis(aminoethoxy)ethane, 4,9-dioxado-1,12-dodecanediamine, 4,7,10-trioxado-1,13-tridecanediamine, 1,3-diamino-hydroxy-propane, 4,4-methylenedihexahydropyridine, 4-(aminomethyl)hexahydropyridine, 3-(4-aminobutyl)hexahydropyridine, or polyallylamine. In some embodiments, the polyamino ligand is 1,3-cyclohexanebis(methylamine), 2,2-dimethyl-1,3-propanediamine, or tris(2-aminoethyl)amine.

In some embodiments, the polyamino ligand is a polyamino heterocyclic compound. In some embodiments, the polyamino heterocyclic compound is 2,4-diamino-6-phenyl-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4-diamino-6-diethylamino-1,3,5-triazine, 2-N,4-N,6-N-tripropyl-1,3,5-triazine-2,4,6-triamine, 2,4-diaminopyrimidine, 2,4,6-triaminopyrimidine, 2,5-diaminopyridine, 2,4,5,6-tetraaminopyrimidine, pyridine-2,4,5-triamine, 1-(3-aminopropyl)imidazole, 4-phenyl-1H-imidazole-1,2 -diamine, 1H-imidazole-2,5-diamine, 4-phenyl-N(1)-[(E)-phenylmethylene]-1H-imidazole-1,2-diamine, 2-phenyl-1H-imidazole-4,5-diamine, 1H-imidazole-2,4,5-triamine, 1H-pyrrole-2,5-diamine, 1,2,4,5-tetrazine-3,6-diamine, N,N'-dicyclohexyl-1,2,4,5-tetrazine-3,6-diamine, N3-propyl-1H-1,2,4-triazole-3,5-diamine or N,N'-bis(2-methoxybenzyl)-1H-1,2,4-triazole-3,5-diamine.

In some embodiments, the polyamine ligand is a polyamine-functionalized polysiloxane. In some embodiments, the polyamine-functionalized polysiloxane is one of the following: 、 、 、 、 、 or .

In some embodiments, the polyamino ligand is a polyamino-substituted ethylene glycol. In some embodiments, the polyamino-substituted ethylene glycol is 2-[3-amino-4-[2-[2-amino-4-(2-hydroxyethyl)phenoxy]ethoxy]phenyl]ethanol, 1,5-diamino-3-oxopentan, 1,8-diamino-3,6-dioxooctane, bis[5-chloro-1H-indol-2-yl-carbonyl-aminoethyl]-ethylene glycol, amino-PEG8-t-Boc-hydrazide, or 2-(2-(2-ethoxyethoxy)ethoxy)ethylamine.

In some embodiments, the alkyl-ligand is (3-alkylpropyl)triethoxysilane, 3,6-dioxa-1,8-octanedithiol; 6-alkyl-1-hexanol; alkylsuccinic acid, alkylundecanoic acid, alkylhexanoic acid, alkylpropionic acid, alkylacetic acid, cysteine, methionine, and alkylpoly(ethylene glycol).

In some embodiments, the silane-ligand is an aminoalkyltrialkoxysilane or a thioalkyltrialkoxysilane. In some embodiments, the aminoalkyltrialkoxysilane is (3-aminopropyl)triethoxysilane or (3-hydroxypropyl)triethoxysilane.

In some embodiments, the ligand includes, but is not limited to, amino-polyepoxyalkylene (e.g., about m.w. 1000); (3-aminopropyl)trimethoxysilane; (3-benzylpropyl)triethoxysilane; DL-α-lipoic acid; 3,6-dioxa-1,8-octanedithiol; 6-benzyl-1-hexanol; methoxypolyethylene glycolamine (about m.w. 500); poly(ethylene glycol) methyl ether thiol (about m.w. 800); diethyl phenylphosphinate; N,N-diisopropyl dibenzyl phosphinate; N,N-diisopropyl di-tert-butyl phosphinate; tris(2-carboxyethyl)phosphine hydrochloride; poly(ethylene glycol) methyl ether thiol (about m.w. 2000); methoxypolyethylene glycolamine (approximately m.w. 750); acrylamide; and polyethyleneimine.

Specific combinations of ligands include amino-polyepoxyalkylene oxide (m.w. approximately 1000) and methoxypolyethylene glycol amine (m.w. approximately 500); amino-polyepoxyalkylene oxide (m.w. approximately 1000) and 6-benzene-1-hexanol; amino-polyepoxyalkylene oxide (m.w. approximately 1000) and (3-benzenepropyl)triethoxysilane; and 6-benzene-1-hexanol and methoxypolyethylene glycol amine (m.w. approximately 500); these provide excellent dispersibility and thermal stability. See Example 9.

Compared to AIGS films without polyamine ligands and films containing monoamine ligands, films containing AIGS nanostructures and polyamine ligands exhibited higher photoconversion efficiencies (PCEs), less wrinkling, and less delamination. Therefore, AIGS-polyamine ligand compositions are uniquely suited for nanostructured color conversion layers.

The following examples illustrate and do not limit the products and methods described herein. Suitable modifications and adaptations of various conditions, formulations, and other parameters commonly encountered in the art and apparent to those skilled in the art in light of this disclosure are within the spirit and scope of the present invention. Examples Example 1: AIGS Nucleosynthesis

Sample ID 1 was prepared using the following typical synthesis of the AIGS core: 4 mL of 0.06 M CH₃CO₂Ag in oleylamine, 1 mL of 0.2 M _InCl₃ in ethanol, 1 mL of 0.95 M sulfur in oleylamine, and 0.5 mL of dodecanethiol were injected into a flask containing 5 mL of degassed octadecene, 300 mg of trioctylphosphine oxide, and 170 mg of gallium acetylacetonate. The mixture was heated to 40°C for 5 minutes, then the temperature was raised to 210°C and held for 100 minutes. After cooling to 180°C, 5 mL of trioctylphosphine was added. The reaction mixture was transferred to a glove box and diluted with 5 mL of toluene. The final AIGS product was precipitated by adding 75 mL of ethanol, centrifuged, and redispersed in toluene. Sample IDs 2 and 3 were also prepared using this method. The optical properties of the AIGS cores were measured and summarized in Table 2. The size and morphology of the AIGS cores were characterized by transmission electron microscopy (TEM). Table 2 Sample ID QY (%) PWL (nm) FWHM (nm) Ag/(Ag+In+Ga) by ICP In/(In+Ga) by ICP Notes 1 44 519.5 47 0.39 0.44 50 mL flask scale 2 30 514 50 0.37 0.41 10x magnification sample ID 1 3 40 518 52 0.38 0.45 10x magnification sample ID 1 Example 2: AIGS nanostructures subjected to ion exchange treatment

Sample ID 4 was prepared using the following typical ion exchange treatment: 2 mL of a 0.3 M solution of gallium oleate in octadecene and 12 mL of oleylamine were introduced into a flask and degassed. The mixture was heated to 270°C. A total of 1 mL of a 0.95 M solution of sulfur in oleylamine and 1 mL of a premixed solution of isolated AIGS cores (15 mg/mL) were injected. The reaction was stopped after 30 minutes. The final product was transferred to a glove box, washed with toluene/ethanol, centrifuged, and redispersed in toluene. Samples ID 4-8 were also prepared using this method. The optical properties of the resulting AIGS nanostructures are summarized in Table 3. Ion exchange with gallium ions results in almost complete band-edge emission. An increase in the average particle size was observed by TEM. Table 3 Sample ID PWL (nm) FWHM (nm) QY (%) OD ₄₅₀ /mass (mL ^. mg ^{-1 .} cm ^-1 ) 4 516 38 61 - 5 517 36 58 0.87 6 520 37 53 1.04 7 514 38 64 0.72 8 514 38 65 1.15 Example 3: Ion exchange treatment of gallium halide and trioctylphosphine

Room-temperature ion exchange reactions with AIGS nanostructures were performed by adding a solution of _GaI3 in trioctylphosphine (0.01-0.25 M) to AIGS QDs and maintaining them at room temperature for 20 hours. This treatment resulted in a significant enhancement of the band-edge emission, as summarized in Table 4, while substantially maintaining the peak wavelength (PWL).

The composition changes before and after the addition of GaI ₃ were monitored by inductively coupled plasma atomic emission spectroscopy (ICP-AE) and energy dispersive X-ray spectroscopy (EDS), as summarized in Table 4. The composite images of the In and Ga elemental distribution before and after the GaI ₃ /TOP treatment show a radial distribution from In to Ga, indicating that the ion exchange treatment leads to a gradient with a higher amount of gallium near the surface and a lower amount of gallium in the center of the nanostructure. Table 4 ID PWL (nm) FWHM (nm) QY (%) Marginal contribution Ag/(Ag+In+Ga) by ICP In/(In+Ga) by ICP Ag/(Ag+In+Ga) by EDS In/(In+Ga) by EDS 9 542 38 11 <45% 0.41 0.11 0.45 0.16 10 543 37 twenty four >80% 0.38 0.09 0.44 0.14 Example 4: AIGS ion exchange treatment using an oxygen-free gallium source

Samples ID 14 and 15 were prepared using the following typical treatment of AIGS nanoparticles using an oxygen-free Ga source: 400 mg of GaCl ₃ dissolved in 400 μL of toluene was added to 8 mL of degassed oleylamine, followed by 40 mg of AIGS cores, and then 1.7 mL of 0.95 M sulfur in oleylamine. After heating to 240°C, the reaction was held for 2 hours and then cooled. The final product was transferred to a glove box, washed with toluene/ethanol, centrifuged, and dispersed in toluene. Samples ID 15 and 16 were also prepared using this method. Samples ID 11-13 were prepared using the method of Example 2. The optical properties of the treated AIGS materials are shown in Table 5. Table 5 Sample ID PWL (nm) FWHM (nm) QY (%) BE% Gallium Source 11 525 43 25 Not determined acetylopyruvate) Ga(III) 12 516 34 73 90 Gallium oleate 13 522 35 72 87 Gallium oleate 14 521 35 85 86 Ga(III) chloride 15 521 35 80 89 Ga(III) chloride 16 Not determined Undetermined Not determined Undetermined Ga(III) iodide

As shown in Table 5, the quantum yield of the treated AIGS nanostructures can be improved by using Ga(III) chloride instead of Ga(III) acetylacetonate or gallium oleate when oleylamine is used as the solvent. The final material subjected to ion exchange using Ga(III) chloride produces similar sizes and similar band-edge to trap emission properties as the starting nanostructure. Therefore, the increase in quantum yield (QY) is not solely due to an increase in the trapped emission component. Furthermore, it was unexpectedly discovered that when Ga(III) iodide was used instead of Ga(III) chloride, the AIGS nanostructures appeared to dissolve in the reaction mixture, and no ion exchange occurred.

High-resolution TEM with energy-dispersive X-ray spectroscopy (EDS) of sample 14 showed that the nanostructure may contain a slight gradient of decreasing In from the center of the AIGS nanostructure to the surface, indicating that the treatment under these conditions resulted in In being exchanged out of the AIGS structure and replaced by Ga, with Ag present throughout the structure rather than growing a distinct GS layer. This may also help improve the quantum yield of the nanostructure due to the lower strain. Example 5: AIGS cores from hot injection of preformed _Ag2S nanostructures mixed with preformed In-Ga reagents

To prepare _Ag2S nanostructures, add 0.5 g of AgI and 2 mL of oleylamine to a 20 mL vial under a _N2 atmosphere and stir at 58°C until a clear solution is obtained. In a separate 20 mL vial, combine 5 mL of DDT and 9 mL of 0.95 M sulfur in oleylamine. Add the DDT and S-OYA mixture to the AgI solution and stir at 58°C for 10 minutes. Use the resulting _Ag2S nanoparticles without washing.

To prepare the In-Ga reagent mixture, a 100 mL flask was charged with 1.2 g of Ga(acetylpyruvate) ₃ , 0.35 g of InCl ₃ , 2.5 mL of oleylamine, and 2.5 mL of ODE. The mixture was heated to 210°C under a _nitrogen atmosphere for 10 minutes. An orange, viscous product was obtained.

To form AIGS nanoparticles, 1.75 g of TOPO, 23 mL of oleylamine, and 25 mL of ODE were added to a 250 mL flask under _N2 . After degassing under vacuum, the solvent mixture was heated to 210°C over 40 minutes. In a 40 mL vial, the above _Ag2S and In-Ga reagent mixtures were mixed at 58°C and transferred to a syringe. The Ag-In-Ga mixture was then injected into the solvent mixture at 210°C and maintained for 3 hours. After cooling to 180°C, 5 mL of trioctylphosphine was added. The reaction mixture was transferred to a glove box and diluted with 50 mL of toluene. The final product was precipitated by adding 150 mL of ethanol, centrifuged, and redispersed in toluene. The AIGS nanostructures were then ion exchanged using the method described in Example 4. The optical properties of materials prepared by this method at a scale 24 times larger than that described above are shown in Table 6. Sample ID PWL (nm) FWHM (nm) BE% QY (%) OD ₄₅₀ / mass (mL ^. mg ^{-1 .} cm ^-1 ) 17 510 34 96 86 - 18 524 38 93 94 1.1 19 520 38 93 88 1.3 20 517 38 94 86 1.3 twenty one 518 38 94 89 1.4 twenty two 528 37 93 93 1.9 Example 7: Improved Photoluminescence Stability of AIGS Nanostructures by Repeated Gallium Ion Exchange 7.1 First Ion Exchange Process

Oleylamine (OYA, 2.5 L) was degassed under vacuum at 40 °C for 40 min. AIGS nanostructures (25.4 g in toluene) were added, followed by GaCl ₃ (127 g in minimal toluene) and sulfur (0.95 M, 570 mL) dissolved in OYA. The mixture was heated to 240 °C over 40 min and maintained for 4 hours. After cooling, the mixture was diluted with 1 volume of toluene. After centrifugation to remove some by-products, the material was washed with 2 volumes of ethanol, collected by centrifugation, and redissolved in toluene. After the second wash, the nanostructures were dissolved in heptane for storage. 7.2 Second ion exchange process

Oleylamine (OYA, 960 mL) was degassed under vacuum at 40°C for 20 min. To the OYA was added an AIGS ion-exchanged nanostructure (12 g in heptane), such as that from Example 7.1, followed by _GaCl₃ (22.5 g in a minimal volume of toluene) and then sulfur (0.95 M, 100 mL) dissolved in the OYA. The mixture was heated to 240°C over 40 min and held for 3 hr. After cooling, the mixture was diluted with 1 volume of toluene, then washed (precipitated with 1.6 volumes of ethanol, centrifuged), and redispersed in toluene or heptane, as needed. When the ink formulation was subjected to ligand exchange, a further ethanol wash was applied, and the QDs were redispersed in heptane. 7.3 Alternative Second Ion Exchange Process

Oleylamine (15 mL) is degassed under vacuum at 60°C for 20 min. _GaCl3 (360 mg in a minimum volume of toluene) is added to OYA, followed by AIGS (200 mg in heptane) such as from Example 7.1, and then sulfur (0.95 M, 1.6 mL) dissolved in OYA. The mixture is heated to 240°C over 40 min and maintained for 3 hr. After cooling, the mixture is washed as described in Example 7.1. 7.4 Alternative Second Ion Exchange Process

This example is implemented as described in Example 7.3, but at a scale three times greater. 7.5 Alternative Second Ion Exchange Process

Oleylamine (10 mL) and oleic acid (5 mL) are degassed under vacuum at 90° C. for 20 min. (Ga(NMe ₃ ) ₃ ) ₂ (206 mg) and GaCl ₃ (180 mg in a minimal volume of toluene) are added, followed by AIGS (200 mg in heptane) such as from Example 7.1. After heating to 130° C., TMS ₂ S (0.65 mL of a 50% solution in ODE) is added over 20 min, and the mixture is maintained for 2.5 hr. After cooling, the mixture is washed as described in Example 7.1. 7.6 Results

AIGS nanostructures were subjected to an ion exchange process, where In was replaced by Ga. The higher temperature used in this process (240°C versus 210°C) compared to core growth results in maturation, resulting in a larger average size than untreated nanostructures. The nanostructures lack a well-defined shell structure, as observed in cross-sectional TEM elemental images. The lack of a high-bandgap shell is expected to limit the retention of photoluminescence in these materials during film processing.

After the second ion exchange process, the average TEM size did not increase (Figures 2A-2C), but the TEM elemental maps showed a more pronounced gradient toward Ga-rich (higher bandgap) regions in the QDs.

The elemental compositions of the single and multiple ion exchange processes are shown in Table 7. The values are the averages of 10-20 samples from Examples 7.1 and 7.2. Sample type PWL (nm) FWHM (nm) Ag/(Ag+In+Ga) In/(In+Ga) Single ion exchange treatment 523 34.5 0.39 0.27 Double ion exchange treatment 523 34.1 0.40 0.24

The properties of the ion-exchanged AIGS nanostructures are shown in Table 8. The metal ratio is the molar ratio determined by ICP. Table 8 Sample ID PWL , nm FWHM , nm BE , % QY , % Ag/ (Ag+In+Ga) In/ (In+Ga) Example 7.1 524.2 34.8 90 83 0.41 0.27 Example 7.2 523.6 34.4 90 89 0.40 0.24 Example 7.3 525.1 34.4 90 87 0.42 0.23 Example 7.4 525.9 34.3 90 88 0.42 0.24 Example 7.5 524.4 33.5 90 62 0.28 0.12 Example 7.6 521.0 24.5 92 89 0.41 0.18

As shown in Table 9, the film PCE retained after UV curing and 180°C baking is significantly improved by the second ion exchange process. This is believed to be due to the process increasing the Ga concentration in the outer layer of the nanostructure, resulting in a gradient of higher band gap regions introduced by ion exchange. Table 9 Sample ID Blue absorption (%) Green PCE % after UV Green PCE % after baking Retained QY % Example 7.1 91.5 25.6 9.7 37.9 Example 7.2 91.9 25.8 16.3 63.3 Example 7.3 88.1 23.1 14.7 63.8 Example 7.4 88.5 23.7 14.9 62.8 Example 7.5 95.0 26.4 17.3 64.7 Example 7.6 91.0 31.4 19.7 62.8 Example 8 - Compositions containing AIGS nanostructures and polyamine-based ligands

Abbreviations • Jeffamine - Jeffamine M-1000 • HDDA - 1-6-Hexanediol Diacrylate • DMA - 1,3-cyclohexanedimethylamine • PCE - Photon Conversion Efficiency

The crude AIGS QD growth solution (Solution 1) was purified by washing with ethanol and redispersing in heptane. To Solution 1, 6-benzyl-1-hexanol was added, heated at 50°C for 30 minutes, washed with ethanol, and redispersed in heptane (Solution 2). 2 µL of 6-benzyl-1-hexanol was added per 100 mg of QD inorganic solid. Jeffamine and HDDA were added to Solution 2 for the ligand exchange step, heated at 80°C for 1 hour, precipitated with heptane, and redispersed in HDDA (Solution 3). 83 mg of Jeffamine was added per 100 mg of QD inorganic solid. 0.42 g of HDDA was added per 100 mg of QD inorganic solid. Solution 3 and HDDA were added to an inkjet ink composition containing 10 wt% _TiO₂ and 90 wt% monomer. The inkjet formulation consists of 10 wt% QD inorganic material, 4 wt% TiO ₂ , and the remaining 86 wt% is a combination of ligands (bound and unbound), HDDA, monomers, photoinitiators, and other organic materials remaining from the QD solution. This ink formulation is Solution 4.

The polyamine-based ligand dimethylamine (50 mg dimethylamine/100 mg QD inorganic solid) was added to Solution 4, and the composition was then cast into a film. Membrane Casting

Solution 4 was spin-coated onto a 2" x 2" glass substrate. The film was cured using a UV LED curing lamp. The film's light conversion efficiency (PCE), a measure of brightness, was then tested. The film was then baked on a hot plate set at 180°C for 30 minutes, slightly elevated above the hot plate. Alternatively, the film was baked on a hot plate set at 180°C for 10 minutes, in direct contact with the hot surface.

The film PCE was then measured. A 1" x 1" masked array of blue 448 nm LEDs provided excitation for the film. An integrating sphere was placed on top of the film and connected to a fluorimeter (see Figures 3A and 3B). The collected spectrum was analyzed to obtain the PCE.

PCE is the ratio of the number of green photons emitted in the forward direction to the number of blue photons generated by the test platform. Although the emission spectrum from 484 nm to 700 nm was used to calculate the PCE, the peak wavelength of the green emission is expected to be between 484 nm and 545 nm, with the main part of the emission below 588 nm. The PCE, LRR, and film morphology are reported in Table 10. Unexpectedly, the presence of the ligands 1,3-cyclohexanebis(methylamine), tris(2-aminoethyl)amine, and 2,2-dimethyl-1,3-propanediamine resulted in high retention of PCE, high LRR, and no wrinkling after baking at 180°C compared to the film without ligands. Table 10 additives PCE after UV curing PCE after baking at 180℃ LRR Membrane morphology No additives 28.4% 14.1% 49.7% wrinkles 1,3-cyclohexanebis(methylamine) 21.0% 20.4% 96.8% No wrinkles Tris(2-aminoethyl)amine 12.0% 12.1% 100.7% No wrinkles 2,2-Dimethyl-1,3-propanediamine 21.2% 21.1% 99.2% No wrinkles

Figure 1 shows the effect of diamine addition on film morphology. The films in Figure 1, from left to right, contain: no additive (wrinkling); 2,2-dimethyl-1,3-propanediamine (diamine, no wrinkling); cyclohexanemethylamine (monoamine, wrinkling); and tris(2-aminoethyl)amine (triamine, no wrinkling). From left to right, the first and third films without diamine exhibit extensive wrinkling. In contrast, the second and fourth films exhibit no wrinkling. Surprisingly, the use of diamine-based ligands in AIGS films significantly reduces film wrinkling. Example 9 - Testing of Additional Ligands in AIGS Nanostructures

In this experiment, we tested the enhanced QY, high compatibility, and good thermal stability of additional ligands added to AIGS nanoparticles. Furthermore, we evaluated the ability of these ligands to protect the AIGS nanostructure from degradation and oxidation. We also tested combinations of ligands that could be formulated into AIGS ink compositions.

Ligand exchange with these ligands was carried out in organic solvents such as ethyl acetate, PGMEA, acetone, xylene, 1,2-dichlorobenzene (ODCB), butyl acetate, and diethylene glycol monoethyl ether (DGMEE).

The AIGS nanostructures were ligand exchanged with ligands containing polymeric or oligomeric chains (e.g., polyethylene glycol with amine and silane groups) and hydroquinones (e.g., phosphino-, hydroxyl-, and combinations thereof) for copassivation.

FIG4 shows the quantum yield values for a number of individual ligands and AIGS nanostructures subjected to single ion exchange treatment as described herein. In this figure, NG : natural AIGS; NG-NL1 : amino-polyepoxy, about mw 1000; NG-NL2 : (3-aminopropyl)trimethoxysilane; NG-NL3 : (3-butylpropyl)triethoxysilane; NG-NL4 : DL-α-lipoic acid; NG-NL5 : 3,6-dioxa-1,8-octanedithiol; NG-NL6 : 6-butyl-1-hexanol; NG-NL7 : methoxypolyethylene glycolamine 500; NG-NL8 : poly(ethylene glycol) methyl ether thiol Mn 800; NG-NL9 : diethyl phenylphosphinate; NG-NL10 : dibenzyl N,N-diisopropylphosphinate; NG-NL11 : N,N-diisopropylphosphamide di-tert-butyl ester; NG-NL12 : tris(2-carboxyethyl)phosphine hydrochloride; NG-NL13 : poly(ethylene glycol) methyl ether thiol Mn 2000; NG-NL14 : methoxypolyethylene glycol amine 750; NG-NL15 : acrylamide; and NG-NL16 : polyethyleneimine.

As shown in Figure 4, treatment of AIGS nanostructures with (3-butylpropyl)triethoxysilane (NL3), 3,6-dioxa-1,8-octanedithiol (NL5), and 6-butyl-1-hexanol (NL6) resulted in high QYs (73.7%, 72.9%, and 76.1%, respectively). Thus, the present invention provides AIGS nanostructure compositions comprising at least one butyl-substituted ligand that provide improved QYs. It is believed that butyl-substituted ligands provide high QYs by passivating the surface of the AIGS nanostructures and reducing defect emission. Amine-substituted ligands also improve QYs.

In this single ligand test, compared to native AIGS nanostructures, PEGylamine-substituted ligands (L1, L7, L8, and L13), thiol-substituted ligands (L3, L5, and L6), and silane ligand (L2) demonstrated good QY. Furthermore, when dispersed in HDDA, ligands L1, L7, and L8 exhibited improved compatibility with the monomer.

Figure 5 shows the QY% for various 2-ligand combinations that yield improved QY (good combinations) and reduced QY (poor combinations). Surface defects can be reduced by adding thiol ligands. The combination of L6 and L7 yields better stability than other combinations. However, for relatively hydrophilic ink compositions, more optimal ligands are relatively hydrophilic ligands, such as methoxypolyethylene glycol amine and poly(ethylene glycol) methyl ether thiol. These thiols also improve QY by passivating surface defects.

The suitable temperature for ligand exchange is room temperature to 120° C. The total amount of ligand in the composition can be 60% to 150% of the mass of AIGS.

Table 11 shows the relative changes in QY, PWL, and FWHM before and after ligand exchange with various ligands. Table 11 shows that L6 and L7 are the most effective ligand combinations for ink formulations, especially when combined with acrylate monomers. Combinations of L2 and L7, L2 and L6, and L2 and L3, L6 and L7 provide excellent dispersibility and thermal stability. See Figure 6. Table 11 QY before LE (%) QY after LE (%) Previous PWL (nm) Afterwards PWL (nm) Previous FWHM (nm) After FWHM (nm) QY change (%) PWL change (nm) FWHM change (nm) L6, 7 55.3 61.5 531.1 531.6 36.3 36.2 +11.2 -0.1 +0.3 L6, 2 55.3 57.8 531.1 531.3 36.3 36.3 +4.5 -0.1 0.0 L3, 7 55.0 56.6 531.3 531.1 36.2 36.1 +3.0 0.0 +0.1 L5, 7 55.0 57.6 531.3 530.8 36.2 36.1 +4.7 +0.1 +0.3 L13, 7 55.0 57.5 531.3 531.2 36.2 36.1 +4.6 0.0 +0.2 L2, 8 55.0 57.1 531.3 531.9 36.2 36.4 +3.8 -0.1 -0.5 L3, 8 55.0 63.8 531.3 530.8 36.2 36.2 +16.0 +0.1 -0.1 L5, 8 55.0 63.3 531.3 531.8 36.2 36.6 +15.0 -0.1 -1.0 L2, 15 55.3 59.0 531.1 532.1 36.3 36.6 +6.6 -0.2 -0.7 L3, 15 55.3 55.5 531.1 532.4 36.3 37.5 +0.4 -0.3 -3.3 L2, 13 55.3 53.6 531.1 532.5 36.3 36.6 -3.1 -0.3 -0.7 L3, 13 55.3 62.2 531.1 530.0 36.3 38.5 +12.4 +0.2 -5.6 L2, 7 56.6 58.2 530.7 532.0 36.5 36.1 +2.8 -0.3 +0.9 L2, 3 54.6 58.7 530.6 531.3 36.2 36.8 +7.5 -0.1 -1.7

Further investigation revealed ligand combinations that exhibited good thermal stability when heated to 180°C for 30 minutes in a glove box. Ligand combinations L6 and L7, L2 and L6, and L2 and L3 demonstrated superior stability compared to L1 alone. See Figure 6.

The effects of different ligand combinations on QY were also investigated. The weight ratio of the ligands was varied, while the total amount of ligands was kept constant. The optimal QY was achieved with a 7:3 ratio of L6 to L7. See Figure 7. All combinations with L6 and L7, with the exception of the 9:1 ratio, showed enhanced QY compared to native AIGS nanostructures. Although these mixtures exhibited high QY, purification was difficult due to the lack of precipitation. Mixtures of L6 and L2, L3 and L7, and L5 and L7 were found to be good ligand mixtures for AIGS nanostructures. These ligand combinations can be used in combination with various monomers, such as tetrahydrofurfuryl acrylate, tri(propylene glycol) diacrylate, 1,4-bis(acryloyloxy)butane, diethylene glycol ethyl ether acrylate, isobornyl acrylate, hydroxypropyl acrylate, 2-(acryloyloxy)ethyl hydrosuccinate, and 1,6-hexanediol diacrylate. Example 10 - Improvement of PCE in AIGS Films

In an _N₂ -filled glove box, AIGS QDs coated with the appropriate ligands were mixed into an ink containing one or more monomers, _TiO₂ scattering particles, and a photoinitiator. The inks were cast into a film by spin coating and then cured using UV irradiation. The film was then baked on a hot plate at 180°C for 30 minutes to remove any remaining volatile components. All processes were performed in an inert atmosphere—in an _N₂ -filled glove box.

Typically at this stage, the film is measured in air by placing it face-up on a blue LED light source. An integrating sphere connected to a spectrophotometer is placed on top of the QD film (see Figures 3A and 3B) to capture the film's emission spectrum. The measurement is repeated using a blank glass substrate (without QDs). The blue light absorption and photon conversion efficiency (PCE) of the QD film are measured using the following formula: Blue absorption = Number of blue photons transmitted through the QD film / Number of incident blue photons PCE = Number of forward-emitted green photons (484-588 nm) / Number of incident blue photons

To investigate the effects of air and moisture during measurement, the baked QD film was encapsulated before removal from the _N₂ glove box. This was done by applying a few drops of UV-curable transparent adhesive onto the QD layer, placing a cover glass, and curing the adhesive via UV irradiation. The QD film, thus encapsulated with glass and adhesive, was measured in air using the aforementioned method.

The results show that encapsulating the QD film before measuring in air is crucial for achieving high photon conversion efficiency (PCE). Table 12 shows the results of a set of films measured with and without encapsulation. For comparison, the PCE values of a typical QDCC film containing InP QDs are also shown. When encapsulated and measured, the film containing the AIGS nanostructure has a higher post-baking PCE value than InP at a much lower QD loading. Further improvement of the PCE is achieved by exposing the film to a blue light source (approximately 6 mW/ ^cm2 ) for a period of 1 hour. In addition, the QDCC film prepared with AIGS QDs exhibits a much narrower emission (FWHM approximately 30 nm) compared to the film prepared with InP QDs (FWHM 36 nm). This is due to the lower FWHM of AIGS QDs in solution (34 nm vs. 39 nm) and the use of monoamine and polyamine ligands, which allow for good dispersion in the ink resin. Table 12 QD Type QD loading in ink Encapsulation Post-encapsulation processing Blue absorption in 10µm film PCE after baking at 180 ℃ PWL FWHM AIGS 12.5% Unencapsulated without >95% 28% 535 30 Glass encapsulation without >95% 35% 535 30 Glass encapsulation Irradiate with blue light for 1 hour >95% 38% 535 30 InP 30% Unencapsulated without 85% 32% 540 36

Figure 8 shows the effects of encapsulation and blue light treatment on a wider range of samples. Surprisingly, the PCE values achieved with encapsulation are significantly higher (greater than 32%) than those achieved without encapsulation.

Figure 9 shows the emission linewidth (FWHM) of the film after a 180°C baking step and subsequent encapsulation. The median FWHM for the film baked at 180°C was 30.5 nm, which further narrowed to 30.1 nm upon encapsulation. This narrowing is likely due to the brightening of the film upon encapsulation.

Although the samples in this study were encapsulated using glass and adhesive, this improvement in PCE can be achieved by any method that can form an oxygen barrier on the QD layer. In the mass production of devices containing these QDCC layers, encapsulation may be implemented using a vapor deposition process. In this case, a typical process flow would include inkjet printing of the QD layer, followed by UV radiation curing, baking at 180°C to remove volatiles, deposition of an organic planarization layer, and then deposition of an inorganic barrier layer. Techniques used to deposit the inorganic layer may include atomic layer deposition (ALD), molecular layer deposition (MLD), chemical vapor deposition (CVD) (with or without plasma enhancement), pulsed vapor deposition (PVD), sputtering, or metal evaporation. Other potential encapsulation methods include solution-processed or printed organic layers, UV- or thermally cured adhesives, and lamination using barrier films. Example 11 - AIGS Ink Comprising Monomers Incorporated into Ligands Coated on an AIGS Surface

They found that ligand exchange (LE) of AIGS nanostructures in the presence of monomers resulted in higher solution QY, more compatible inks, and better film properties compared to LE performed in pure solvents. This was demonstrated through LE and film evaluation using 16 different media.

LE of quantum dots (QDs), such as CdSe and InP, can be performed in organic solvents to replace native ligands with desired ligands. The resulting QDs can then be formulated into solvent-free inks by dispersing the QDs in a monomer, removing the original solvent, and adding other ink components such as scattering media and photoinitiators.

This procedure can also be used for the LE of AIGS nanostructures, resulting in high retention of QY. However, this method typically results in poor dispersibility of the nanostructures in the monomer during solvent removal. Good dispersion of the AIGS nanostructures in the ink and effective passivation of the ligands on the nanostructure surface are essential for maintaining film performance under harsh processing conditions (e.g., UV irradiation, high-temperature baking, etc.). Therefore, AIGS nanostructures ligand-exchanged using conventional methods are not suitable for QDCC applications.

Figure 10 shows the PLQY of ligand-exchanged AIGS nanostructures in various organic solvents (e.g., acetone, PGMEA, ethyl acetate, toluene, dichloromethane (DCM), chloroform, dimethylformamide (DMF), and ethanol) at two temperatures: room temperature (25°C) and 80°C. Jeffamine M1000 was used as the ligand at a mass ratio of 0.8:1 relative to the AIGS nanostructure.

After LE, several solvents, including PGMEA, ethyl acetate, toluene, and DCM, were very effective in maintaining QY. Notably, LE at room temperature resulted in higher QY than LE at 80°C. Other solvents tested, such as acetone, chloroform, DMF, and ethanol, resulted in lower QY.

However, as shown in Table 13 (o = clear dispersion; Δ = turbid dispersion), AIGS nanostructures ligand-exchanged in solvent at room temperature have poor compatibility with HDDA (a common monomer used in inkjet printable inks). AIGS nanostructures ligand-exchanged at 80°C have better compatibility with HDDA but have lower QY. Therefore, it is difficult to find effective LE conditions that result in high QY and good compatibility with HDDA. Table 13 acetone PGMEA Ethyl acetate Toluene DCM Chloroform DMF ethanol Comp. w/HDDA O Δ Δ Δ Δ Δ Δ Δ Comp. w/HDDA (80℃ LE) O O O O O - - -

The LE studies were repeated using a series of common monomers (shown in Table 14) instead of organic solvents as the medium. LE was performed by mixing the starting AIGS nanostructures (in heptane) with the monomers, then adding Jeffamine M1000 and heating at 80°C. Table 14 Monomer name M1 Diethylene glycol monomethyl ether methacrylate M2 Ethyl acrylate M3 HDDA M4 Tetrahydrofurfuryl acrylate M5 Tri(propylene glycol) diacrylate M6 1,4-Bis(acryloyloxy)butane M7 Diethylene glycol ethyl ether acrylate M8 Isobornyl acrylate M9 Diethylene glycol diacrylate M10 2-Methoxyethyl acrylate M11 Tetraethylene glycol diacrylate M13 Diethylene glycol divinyl ether M14 Butyl acrylate M15 2-Phenoxyethyl methacrylate M16 1,6-Hexanediol dimethacrylate

Figure 11 shows the QY after LE in the presence of monomers. In all 16 cases, QY increased upon LE and was also higher than the QY achieved via LE in organic solvents.

After LE, the AIGS nanostructures were isolated and purified by precipitation in heptane, and the yield was calculated by recording the initial and final QD masses. Unlike LE in solvent, where only a small mass change was observed, the mass of the ligand-exchanged QDs in monomers increased by 30-100%, depending on the monomer. Since most of the monomers tested were miscible in heptane and removed during QD precipitation, this indicates that a certain amount of monomer was incorporated into the ligand coating the QD surface.

All 16 AIGS samples were dispersed in HDDA and then mixed into an ink containing a scattering medium and a photoinitiator. Unlike nanostructures that undergo ligand exchange in solvent, all 16 samples tested here demonstrated good compatibility with HDDA. Three films were cast from each ink by spin coating at 700, 800, and 900 rpm, followed by UV curing.

As shown in FIG12 , some monomers M2, M3, M4, M5, M6, and M8 exhibit high film EQE and can serve as good LE media for AIGS QDs.

Figure 13 shows the blue absorption of an AIGS nanostructured film spun at 800 RPM. M7, M10, M13, M15, and M16 provide high blue absorption. Example 12: Increasing Blue Absorption Using Polyamine Ligands

A typical film deposition process involves a hard bake at very high temperatures (usually around 200°C) to completely remove any residual solvents and selective components. This hard bake prevents outgassing during the deposition of other layers on top of the QDCC layer. This harsh bake sometimes results in very low EQE. Also, either the nanostructure is destroyed by the high temperature or the ligands separate from the nanostructure, leading to aggregation. Table 15 shows the EQE of a typical AIGS film after UV curing and after a hard bake at 180°C. Although the EQE is good, above 33% after UV curing, it drops to below 19% after a hard bake at 180°C for 30 minutes. The light retention ratio (LRR), which is the ratio of the EQE after baking to the EQE before baking, is very low, below 60%, meaning that the film performance drops by more than 40% after baking. Table 15 After UV After baking LRR No. 1 film 33.7% 18.4% 54.7% No. 2 film 33.1% 18.3% 55.3%

To overcome such a high EQE loss and the resulting low LRR during hard baking, two approaches were tested to improve the LRR.

To keep the AIGS nanostructures uniformly dispersed throughout the film and prevent aggregation, a diamine (1,3-bis(aminomethyl)cyclohexane) was added to the AIGS monomer dispersion before ink formulation. Alternatively, it can be added to the ink formulation after mixing the other ink components (such as scattering media and photoinitiators) in the AIGS monomer dispersion. As seen in Figure 14, adding diamine to the AIGS monomer dispersion before ink formulation increased the EQE after UV curing and POB. When diamine was added at 5% w/w of the AIGS inorganic quality, the EQE after UV curing increased by 3%. Adding more diamine did not further improve the EQE. After POB, the effect of diamine on improving the EQE was even greater. Adding 5% diamine improved the EQE by 5% compared to no diamine in the monomer. With the addition of 30% diamine, the EQE increased from 25% to 32%, and the LRR was 92%, similar to the results observed with InP green QD films. As shown in Figure 15, a side effect of the diamine is an increase in viscosity. However, for monomers such as ethyl acrylate, the ink viscosity drops dramatically to below 20 cP at room temperature.

As an alternative approach to increasing EQE, better AIGS surface passivation with diamine was attempted. As shown in Figure 16, the QY of the AIGS nanostructures that underwent ligand exchange in the presence of diamine immediately after LE was enhanced by more than 12%. It should be noted that the QY of the AIGS nanostructures was also enhanced after heat treatment at 180°C for 30 minutes (simulating a hard bake) in the presence of monomer. For LE, the decrease in QY after 30 minutes at 180°C became smaller as the addition of diamine increased. At 50% w/w diamine in LE, the QY before and after the heat process was almost equal, and when LE was performed using 70% diamine, the QY after the heat process became higher.

The performance of QDCC films using these AIGS nanostructures is plotted in Figure 17. The film EQE is better when LE is performed with diamine compared to without diamine in the LE, and increases even higher with the addition of more diamine up to 50%. The EQE and LE obtained with 70% diamine addition are lower than 30% and 50%. It is suspected that when higher amounts of diamine are used for LE, the amount of diamine incorporated on the AIGS surface increases, but this reduces the amount of ligands and/or monomers on the AIGS surface. The observed decrease in QD quality after LE with diamine may be due to fewer ligands and/or monomers on the QD surface. This also occurs when LE is performed with diamine added to the LE monomer, which results in an increase in ink viscosity.

When using these two methods to improve membrane EQE, as shown in Figure 19, the diamine's effect on membrane EQE was greatest when added to both the ligand exchange and monomer dispersion processes. Viscosity does not necessarily depend on the total amount of diamine in the ink. The sample with the highest diamine content (where diamine was used in both the LE and monomer dispersion) had an intermediate viscosity. This viscosity was lower than when the same amount of diamine was used only in the LE.

EQE enhancement using diamines in LE and/or monomer dispersion was tested using 1,3-bis(aminomethyl)cyclohexane and five other additives listed in Table 16. All additives had similar effects on the initial EQE, and A1, A5, and A6 were slightly better than the other additives when added directly with the monomer. However, after hard baking, A1 and A6 were the two best additives in the final film EQE. In addition, among the amines listed, good EQE was obtained without using the same additive in the LE and monomer addition. Even when the same diamine is used in the LE and monomer addition, its effect in improving EQE can be different. For example, as shown in Figure 23, when used in the monomer addition, A6 is as effective as A1 in preserving EQE, however, it is not as effective as when A1 is used in the LE. Table 16 Additive List A1 1,3-Bis(aminomethyl)cyclohexane A2 1,7-Diaminoheptane A3 Cycloheptylamine A4 4,4'-Methylenebis(2-methylcyclohexylamine) A5 Cyclopentylamine A6 2-Methyl-1,5-diaminopentane A7 4-aminohexahydropyridine

Although various embodiments have been described above, it should be understood that these embodiments have been presented by way of example only and not limitation. Those skilled in the art will readily appreciate that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention. Therefore, the breadth and scope should not be limited by any of the exemplary embodiments described above, but should be defined solely in accordance with the appended patent claims and their equivalents.

All publications, patents, and patent applications mentioned in this specification are indicative of the level of skill in the art to which this invention pertains and are incorporated herein 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.

The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate the present embodiment and, together with the description, further serve to explain the principles of the present embodiment and to enable one skilled in the art to make and use the present embodiment.

Figure 1 is a photograph showing, from left to right, the first and third films without polyamine ligands exhibiting extended wrinkling. The second and fourth films containing polyamine ligands exhibit no wrinkling.

Figures 2A-2C show TEM images of the AIGS nanostructure before ion exchange treatment (Figure 2A), after a single ion exchange treatment (Figure 2B), and after a double ion exchange treatment (Figure 2C).

3A and 3B are schematic diagrams of unencapsulated ( FIG. 3A ) and encapsulated ( FIG. 3B ) membranes.

FIG4 shows a scatter plot of QY% exhibited by a mixture of various ligands.

FIG5 is a scatter plot showing ligand combinations that provide improved QY% (good combinations) and combinations that provide decreased QY% (poor combinations).

Figure 6 shows the QY% of various ligand combinations before ligand exchange (NG), after ligand exchange (LE), and after 30 minutes of thermal testing.

FIG7 is a graph showing the QY% of various ligand combinations at various ligand ratios.

Figure 8 shows two scatter plots of the PCE of an AIGS film measured after normal post-baking (PoB) (left) and after encapsulation before PCE measurement (right).

FIG9 shows two scatter plots of the PCE of AIGS films baked at 180° C. before PCE measurement, without encapsulation (left) and after encapsulation (right).

FIG10 is a bar graph showing the photoluminescence quantum yield (PLQY) of ligand-exchanged AIGS nanostructures in various solvents at room temperature and 80°C.

FIG11 is a bar graph showing the QY of ligand-exchanged AIGS nanostructures in the presence of various monomers.

FIG12 is a line graph showing the film external quantum efficiency (EQE) of AIGS nanostructures that underwent ligand exchange and were treated with various monomers and after UV curing.

FIG13 is a bar graph showing the blue light absorption of AIGS nanostructured inks that were ligand exchanged, treated with various monomers, and spin-coated at 800 rpm.

FIG. 14 is a line graph showing the effect of diamine (1,3-bis(aminomethyl)cyclohexane) on film EQE after UV and post-baking (POB) at 180°C for 30 min.

FIG15 is a line graph showing the effect of added diamine on viscosity, which is an indirect measure of blue light absorption in films after spin coating at 800 RPM.

Figure 16 is a bar graph showing the effect of ligand exchange (LE) with diamine (DA) on solution QY. The graph shows that after heating at 180°C, the decrease in QY decreases with increasing amounts of diamine.

FIG17 is a line graph showing the effect of increasing amounts of DA on the PCE of films after UV curing.

FIG. 18 is a line graph showing the effect of increasing the amount of DA in the film on the blue light absorbance of the film.

FIG19 is a line graph showing the effect of DA addition in the monomer dispersion, in the LE, and in both the monomer dispersion and the LE on the blue light absorbance of the PCE film.

FIG20 is a line graph showing the effect of added DA in monomer dispersion, in LE, and in both monomer dispersion and LE on film viscosity and blue light absorbance.

FIG21 is a line graph showing the effect of various additives on the initial film EQE.

FIG22 is a line graph showing the effect of various additives on the film EQE after POB.

FIG23 is a line graph showing the effect of additional additives on film EQE and blue light absorption.

Features and advantages of the present invention will become more apparent from the detailed description below when taken in conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference characters generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit in the corresponding reference character. Unless otherwise indicated, the drawings provided throughout this disclosure should not be construed as being drawn to scale.

Claims (22)

A color conversion film comprising Ag, In, Ga, and S (AIGS) nanostructures, at least one ligand, and at least one organic resin. The film exhibits a photon conversion efficiency (PCE) greater than 32% at a peak emission wavelength of 480-545 nm when excited by a 450 nm blue light source. The nanostructures have an emission spectrum with a full width at half maximum (FWHM) less than 40 nm, and a quantum yield (QY) of 80-99.9%. The color conversion film of claim 1, wherein the nanostructures have an OD ₄₅₀ /mass (mL·mg ¹ ·cm ^-1 ) greater than or equal to 0.8. The color conversion film of claim 1, wherein the average diameter of the nanostructures is less than 10 nm as measured by TEM. The color conversion film of claim 1, wherein at least 80% of the emission is edge emission. The color conversion film of claim 1, wherein the at least one ligand is an amino ligand, a ligand containing a hydroxyl group, or a ligand containing a silane group. The color conversion film of claim 1, wherein the at least one ligand is a polyamine-based ligand. The color conversion film of claim 6, wherein the at least one polyamine ligand is a polyamine alkane, a polyamine-cycloalkane, a polyamine heterocyclic compound, a polyamine-functionalized polysiloxane, or a polyamine-substituted glycol. The color conversion film of claim 6, wherein the polyamino ligand is a C _2-20 alkane or C _2-20 cycloalkane substituted with two or three amino groups and optionally containing one or two amino groups instead of a carbon group. The color conversion film of claim 8, wherein the polyamine ligand is 1,3-cyclohexanebis(methylamine), 2,2-dimethyl-1,3-propanediamine, tris(2-aminoethyl)amine, or 2-methyl-1,5-diaminopentane. The color conversion film of claim 1, wherein the at least one ligand is a compound of formula I: wherein: x is 1 to 100; y is 0 to 100; and R ² is a C _1-20 alkyl group. The color conversion film of claim 1, wherein the at least one ligand is (3-aminopropyl)trimethoxysilane; (3-benzylpropyl)triethoxysilane; DL-α-lipoic acid; 3,6-dioxa-1,8-octanedithiol; 6-benzyl-1-hexanol; methoxypolyethylene glycol amine; poly(ethylene glycol) methyl ether thiol; diethyl phenylphosphinate; N,N-diisopropyl dibenzyl phosphinate; N,N-diisopropyl di-tert-butyl phosphinate; tris(2-carboxyethyl)phosphine hydrochloride; poly(ethylene glycol) methyl ether thiol; methoxypolyethylene glycol amine; acrylamide; or polyethyleneimine. The color conversion film of claim 1, wherein the at least one ligand is a combination of: amino-polyepoxyalkylene and methoxy polyethylene glycol amine; amino-polyepoxyalkylene and 6-benzene-1-hexanol; amino-polyepoxyalkylene and (3-benzenepropyl)triethoxysilane; and 6-benzene-1-hexanol and methoxy polyethylene glycol amine. The color conversion film of claim 1, wherein the at least one organic resin is cured. The color conversion film of claim 1 exhibits greater than 95% blue light absorption at 450 nm. The color conversion film of claim 1, wherein the AIGS nanostructures comprise a gradient of gallium increasing from the surface of the nanostructures to gallium decreasing in the center of the nanostructures. A method for preparing a color conversion film as claimed in any one of claims 1 to 15, the method comprising: (a) providing AIGS nanostructures and at least one ligand coating the surfaces of the AIGS nanostructures, wherein the AIGS nanostructures are prepared by reacting with an oxygen-free gallium salt to exchange ions with gallium; (b) mixing at least one organic resin with the AIGS nanostructures of (a); (c) preparing on a first barrier layer (d) curing the film; and (e) encapsulating the first film between the first barrier layer and the second barrier layer; wherein the encapsulated film exhibits a photon conversion efficiency (PCE) greater than 32% at a peak emission wavelength of 480-545 nm when excited by a blue light source having a wavelength of 450 nm. The method of claim 16, wherein the method is performed before the encapsulated film is exposed to a blue LED light source in air. The method of claim 16, wherein the method is carried out under an inert atmosphere. The method of claim 16, wherein the method further comprises: adding at least one oxygen-reactive material to the mixture of the AIGS nanostructure and the ligand in (a), adding at least one oxygen-reactive material to the mixture in (b), and/or forming a second film comprising at least one oxygen-reactive material on top of the first film prepared in (c), and/or forming a sacrificial barrier layer that temporarily blocks oxygen and/or water on the first film prepared in (c), measuring the PCE of the film, and then removing the sacrificial barrier layer. The method of claim 16, wherein the two barrier layers exclude oxygen and/or water. The method of claim 16, wherein the gallium salt is gallium halide. The method of claim 16, wherein the ligand is an oxygen-free ligand.