Synthesis of shape-controlled III-V colloidal nanocrystals

Abstract

A method of preparing a Group III-V nanocrystalline composition, the method comprising forming a first mixture comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent, adding to the first mixture at least one compound comprising a nitrogen group element, heating the first mixture to a growth temperature in the range of 200 DEG C to 350 DEG C; and adding an oxide remover and a composition comprising Group III-V clusters to the first mixture at a growth temperature for a total growth time of at least 6 hours to provide the Group III-V nanocrystalline composition. The invention also provides cubic octahedral III-V group nanocrystals, which can be formed by the method of the invention.

Description

Technical Field

[0001] The present invention generally relates to nanocrystals. In particular, the present invention relates to a method for preparing a III-V nanocrystal composition, comprising forming a first mixture comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent; adding at least one nitrogen-containing compound to the first mixture and heating the first mixture to a growth temperature in the range of 200°C to 350°C; and adding an oxide remover and a composition comprising a III-V cluster to the first mixture at the growth temperature for a total growth time of at least 6 hours to provide the III-V nanocrystal composition. The present invention also relates to cuboctahedral III-V nanocrystals that can be formed by the method of the present invention. Background Art

[0002] Nanocrystal is useful in a wide range of applications, for example, because their optical properties can be finely tuned to provide required properties. The optical properties (such as light absorption and emission characteristics) of nanocrystal can be finely tuned by controlling the size of nanocrystal. The largest nanocrystal produces the longest wavelength (and the lowest frequency), while the smallest nanocrystal produces shorter wavelength (and higher frequency). The size of nanocrystal can be controlled by its preparation method. This ability of finely tuning its optical properties by controlling the size of nanocrystal makes nanocrystal suitable for a wide range of applications, including photodetectors, sensors, solar cells, bioimaging and biosensing, photovoltaics, displays, lighting, security and anti-counterfeiting, batteries, wired high-speed communications, quantum dot (QD) lasers, photocatalysts, spectrometers, injectable compositions, field effect transistors, light emitting diodes, lasers, photon or optical switching devices, hydrogen production and metamaterials.

[0003] While lead and other heavy metal nanocrystals have demonstrated promising properties, their use in certain industries can be problematic due to their toxicity. The industry needs to provide alternative quantum dot systems that avoid the use of toxic heavy metals like lead.

[0004] First synthesized over a decade ago, III-V nanocrystals are promising candidates to replace heavy metal-based nanocrystals. InAs and InSb nanocrystals are of particular interest. However, to date, III-V nanocrystals have been unable to replicate the desirable properties of lead-based nanocrystals.

[0005] InAs synthesis can generally be divided into two categories depending on the arsenic precursor used in the synthesis:

[0006] 1. Tris(trimethylsilyl)arsine route - Alivisatos et al. (Appl. Phys. Lett. 1996, 69, 1432) reported the synthesis of InAs quantum dots by dehalogenation silylation reaction in the presence of InCl3 + As[Si(CH3)3] in the temperature range of 240 to 265°C, using the coordinating solvent trioctylphosphine (TOP) as solvent and ligand. Recently, Bawendi et al. (Nat. Comms. 2016, 7, 12749) and Jeong et al. (Nat. Comms. 2018, 9, 1) further developed a route for synthesizing InAs quantum dots in the presence of indium carboxylate and octadecene by a continuous injection method. These InAs quantum dots have been used to synthesize core / shell quantum dots, as well as for applications such as biomarkers and solar cells. Recently, Sargent et al. (Nano. Lett., 2021, 21, 6057) developed an InAs photodetector with an EQE of 40% at a wavelength of 940 nm.

[0007] 2. Aminopsine route - Inspired by the successful development of InP quantum dots by aminophosphine, Talapin et al. (Chem.Mater.2016,28,6797) introduced InCl3+aminoarsine in the presence of oleylamine and a reducing agent. Bawendi et al. (J.Am.Chem.Soc., 2020,142,4088) have replaced In(III)Cl3 with In(I)Cl as a reducing agent, eliminating the need for an external reducing agent and also acting as an indium source. Hens et al. (J.Am.Chem.Soc.2021,143,4290) used a similar method to develop In(P)As quantum dots using aminophosphine instead of hydride as a reducing agent. The photodetector developed using this method has an EQE of approximately 1% at 1400nm.

[0008] However, prior art methods for producing III-V nanocrystals, including the above-mentioned methods, result in III-V nanocrystals with low charge transfer capabilities, which limits their use in devices such as solar cells and photodetectors.

[0009] Therefore, there is an unmet need for III-V nanocrystals with improved charge transfer capabilities. Summary of the Invention

[0010] According to a first aspect, the present invention provides a method for preparing a III-V nanocrystalline composition, the method comprising:

[0011] a) forming a first mixture comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent, wherein the first ligand is a C6-C 24an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group;

[0012] b) adding at least one nitrogen-containing compound to the first mixture and heating the first mixture to a growth temperature in the range of 200° C. to 350° C.;

[0013] c) adding an oxide remover and a composition comprising III-V clusters to the first mixture at the growth temperature for a total growth time of at least 6 hours to provide a III-V nanocrystalline composition.

[0014] According to a second aspect, the present invention provides a substantially cubooctahedral Group III-V nanocrystal.

[0015] According to a third aspect, the present invention provides a III-V nanocrystal composition comprising a plurality of nanocrystals according to the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the ultraviolet-visible spectrum of InAs nanocrystals having an absorption peak at 1400 nm prepared according to the method of the first aspect of the present invention (Example 2).

[0017] Figure 2 This is the ultraviolet-visible spectrum of InAs nanocrystals having an absorption peak at 1100 nm prepared according to the method of the first aspect of the present invention (Example 2).

[0018] Figure 3 An electron micrograph of InAs nanocrystals having an absorption peak at 1400 nm prepared according to the method of the present invention (Example 2) is shown.

[0019] Figure 4 A further selection of electron micrographs of InAs nanocrystals having an absorption peak at 1400 nm prepared according to the method of the present invention (Example 2) is shown. Figure 4 (a) and (b) show InAs nanocrystals containing oleic acid as a ligand compound, and Figure 4 (c) and (d) show InAs nanocrystals containing InBr3 as ligands. Figure 4 (b) Used to calculate the average size of nanocrystals with an absorption peak at 1400 nm.

[0020] Figure 5 An electron micrograph of InAs nanocrystals having an absorption peak at 1100 nm prepared according to the method of the present invention (Example 2) is shown. Figure 5 (i) Used to calculate the average size of nanocrystals with an absorption peak at 1100 nm.

[0021] Figure 6 The UV-visible spectra of InAs nanocrystals having absorption peaks at 1100 nm and 1400 nm are shown. Both nanocrystals are prepared according to the method of the first aspect of the present invention (Example 4).

[0022] Figure 7 The electron micrograph of InAs nanocrystals having absorption peaks at 1100 nm and 1400 nm prepared according to the method of the first aspect of the present invention (Example 4) is shown. Figure 7 (b)(v) is used to calculate the average size of nanocrystals with an absorption peak at 1100 nm.

[0023] Figure 8 The electron micrograph image of InAs nanocrystals prepared according to the method of the present invention (Example 4) is shown, which has an absorption peak at 1400 nm. This image is used to calculate the average size of the nanocrystals. DETAILED DESCRIPTION

[0024] When describing aspects of the present invention, the terms used are to be interpreted in accordance with the following definitions, unless the context indicates otherwise.

[0025] As used in the specification and appended claims, the singular forms "a," "an," and "the" include both singular and plural references unless the context clearly dictates otherwise. For example, "a nanocrystal" refers to one or more nanocrystals. For example, "an indium-containing compound" refers to one indium-containing compound or a plurality of indium-containing compounds. When used in conjunction with inclusive language, a reference to a number includes combinations including that number or more than that number.

[0026] As used herein, the terms "comprising," "comprised of," and "comprised of" are synonymous with "comprising," and "includes," "containing," and "contains" are inclusive or open-ended and do not exclude other unrecited members, elements, or method steps. The terms "comprising," "comprises," and "comprised of" encompass the term "consisting of."

[0027] As used herein, when the term "and / or" is used in connection with a list of two or more items, it means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a list is described as including groups A, B, and / or C, the list may include A alone, B alone, C alone, A and B combined, A and C combined, B and C combined, or A, B, and C combined.

[0028] As used herein, unless expressly specified otherwise, all numbers, such as those expressing values, ranges, percentage amounts, are to be understood as if preceded by the word "about," even if the term does not expressly appear.

[0029] As used herein, the term "about" when referring to a measurable value such as a parameter, amount, time duration, etc., indicates that the value includes the standard deviation of error for the device or method employed to determine the value. The term "about" is meant to encompass variations of + / - 10% or less, + / - 5% or less, or + / - 0.1% or less from the specified value, provided such variations are suitable for implementation within the present disclosure. It should be understood that the value to which the modifier "about" refers is itself also specifically disclosed.

[0030] Numerical ranges expressed by endpoints include all integers and, where appropriate, fractions contained within the range (e.g., when referring to, for example, a plurality of elements, 1 to 5 may include 1, 2, 3, and 4, and when referring to, for example, a measurement, 1.5, 2, 2.75, and 3.80 may also be included). The expression of endpoints also includes the endpoint values ​​themselves (e.g., from 1.0 to 5.0 includes 1.0 and 5.0). Any numerical range described herein is intended to include all subranges contained therein.

[0031] Unless otherwise defined, all terms used in this disclosure, including technical and scientific terms, have the meanings commonly understood by those skilled in the art to which this disclosure belongs. Further guidance, including definitions of terms used in the specification, is provided to better understand the teachings of this disclosure. All publications cited herein are incorporated herein by reference.

[0032] As used herein, unless otherwise defined, the term "composition" can be open or closed. For example, a "composition" includes a specified material, i.e., a nanocrystal, and other unspecified materials or may consist of the specified materials, i.e., substantially excludes the unspecified materials.

[0033] method

[0034] According to a first aspect, the present invention provides a method for preparing a III-V nanocrystalline composition, the method comprising:

[0035] a) forming a first mixture comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent, wherein the first ligand is a C6-C 24 an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group;

[0036] b) adding at least one nitrogen-containing compound to the first mixture and heating the first mixture to a growth temperature in the range of 200° C. to 350° C.;

[0037] c) adding an oxide remover and a composition comprising III-V clusters to the first mixture at the growth temperature for a total growth time of at least 6 hours to provide a III-V nanocrystalline composition.

[0038] Any suitable indium-containing compound, gallium-containing compound, and nitrogen group element-containing compound may be used.

[0039] As mentioned earlier, heavy-metal-free nanocrystals are highly sought after in the quantum dot industry due to their lower toxicity. III-V nanocrystals offer a promising alternative to heavy-metal-based materials but have not been fully utilized because their performance and optical properties have yet to match those of lead-based nanocrystals.

[0040] The performance of colloidal quantum dots (CQDs) and optoelectronic devices containing quantum dots depends largely on the order and interaction of nanocrystals in solid films. It is generally understood in the art that shape control of nanocrystal synthesis may affect the order and interaction of nanocrystals, and therefore, if controlled, may improve the optical properties of the resulting nanocrystals. For example, Pietryga et al. (J.Am.Chem.Soc.2008,130,14,4879-4885) reported the synthesis of large lead selenide (PbSe) nanocrystals in the shape of cubes at room temperature. Lee et al. (Adv.Mater.2003,15(5),441) reported the control of the shapes of different colloidal inorganic nanocrystals from nanorods to cubes by changing different growth parameters.

[0041] Solid films containing colloidal quantum dots with sufficient surface passivation, high packing density, and coupling strength along specific facets should show enhanced charge carrier mobility and transport.

[0042] A common approach for increasing the packing density of colloidal quantum dots involves replacing the natural long-chain organic ligands on the synthesized quantum dots with short conductive ligands. This is typically achieved by a ligand exchange step after the initial synthesis, using natural long-chain organic ligands to control the growth of nanocrystals. For example, Biondi et al. (Adv. Mater. 2021, 2101056) exchanged the natural ligands attached to PbS-colloidal quantum dots to increase (100): (100) facet coupling, resulting in a tenfold increase in hole mobility and a faster device response.

[0043] However, there is a significant lack of understanding in the art of how to achieve beneficial shape control using III-V nanocrystals. To the best of the inventors' knowledge, there is no work in the literature on controlling the shape and faceting of short-wave infrared (SWIR) InAs and InSb quantum dots while maintaining the spatial confinement effects of the nanocrystals and a sufficient degree of surface passivation. This lack of understanding of how to control the shape of InAs or InSb colloidal quantum dots to promote specific end-face coupling in solid films may have limited the performance of prior art devices. In fact, as recently reported by Hens and colleagues, 1400nm InAs colloidal quantum dot photodiodes showed only 1% EQE and high dark current.

[0044] However, the present inventors have discovered a method to control the shape of III-V nanocrystals, thereby improving the optical properties of the resulting nanocrystals.

[0045] The method of the first aspect of the present invention provides a nanocrystal composition comprising substantially cuboctahedral Group III-V nanocrystals by controlling the thermodynamic and reaction conditions for nanocrystal growth. Specifically, the method of the first aspect controls the growth of the nanocrystals by selecting a suitable growth temperature within the range of 200° C. to 350° C., adding an oxide remover to the first mixture, and selecting a suitable total growth time of at least 6 hours. Without intending to be bound by theory, when these conditions are met, the method of the first aspect produces substantially cuboctahedral Group III-V nanocrystals.

[0046] Without intending to be bound by theory, it is believed that the cuboctahedral shape of the III-V family nanocrystal causes an improvement in the arrangement of the nanocrystal facets. The better arrangement of the nanocrystal faces causes the charge transfer of the nanocrystal to be improved, as shown in the following examples. In addition, the nanocrystal prepared by the method for the first aspect of the present invention is stable and highly monodisperse. Method of the present invention provides a method for regulating the nanocrystal band gap, and provides high crystallinity and high uniformity.

[0047] The nanocrystals prepared by the first method readily transfer from a nonpolar solvent phase to a polar solvent phase during inorganic ligand exchange in solution, forming high-quality quantum dot inks. The resulting unique shape facilitates the accumulation of the nanocrystals into highly ordered quantum dot films with well-aligned end faces, enhancing charge transfer and thus improving device performance.

[0048] The nanocrystals prepared by the method of the first aspect are usually semiconductor nanocrystals, in particular quantum dots.

[0049] As used herein, the term "nanocrystalline" is used to refer to a crystalline particle having at least one dimension measuring less than 100 nanometers (nm).

[0050] As used herein, the term "semiconductor nanocrystal" is used to refer to a semiconductor crystalline material that exhibits quantum confinement effects that enable it to mimic the properties of atoms, where at least one dimension measures less than 100 nm.

[0051] As used herein, the term "quantum dot" is used to refer to spherical semiconductor nanocrystals. Quantum dots are also known as zero-dimensional nanocrystals.

[0052] As used herein, the term "Group III-V semiconductor nanocrystal" is used to refer to a semiconductor nanocrystal containing a Group III element and a Group V element.

[0053] As used herein, the term "Group III element" is used to refer to elements in Group 13 of the periodic table. For example, the Group III element may be boron, aluminum, gallium, indium, or thallium. Preferably, the Group III element is indium.

[0054] As used herein, the terms "Group V elements" and "nitrogen group elements" are used to refer to elements in Group 15 of the periodic table. For example, the Group V element may be nitrogen, phosphorus, arsenic, antimony, or bismuth. Preferably, the Group V element is arsenic.

[0055] As used herein, the term "ligand" is used to refer to a compound that can form a complex with a nanocrystal by coordinating with the nanocrystal surface. Preferably, a plurality of ligands at least partially cover the surface of the nanocrystal. More preferably, a plurality of ligands cover the surface of the nanocrystal. Nanocrystals typically include a crystal nucleus of a size of several tens of nanometers. Nanocrystals are typically stabilized as colloidal solutions by surface-capped ligands, and these ligands coordinate to the crystal nucleus with Lewis acidic (Z-type), Lewis basic (L-type) or anionic (X-type) species.

[0056] As used herein, the term "organic compound" is used to refer to a compound that contains carbon atoms covalently bonded to other atoms. x -C y"Organic compound," where x and y are integers, is used to refer to an organic compound containing at least x carbon atoms and not more than y carbon atoms.

[0057] As used herein, the term "inorganic compound" is used to refer to compounds other than organic compounds.

[0058] As used herein, the terms "median particle size" and "average particle size" are used to refer to the Feret diameter of a particle. The Feret diameter is a measure of the size of a particle along a specified direction and is defined as the distance between two parallel tangent lines to the particle. This value can be obtained using standard imaging software or manually determined from micrographs (e.g., those obtained by TEM).

[0059] An oxide remover and a composition comprising a III-V group cluster (step c) reagent) are added to the first mixture at a growth temperature for a total growth time of at least 6 hours to provide a III-V group nanocrystal composition. The oxide remover can be added to the first mixture together with the composition comprising a III-V group cluster or separately. The oxide remover can be added to the first mixture simultaneously with or sequentially from the composition comprising a III-V group cluster. Prior to addition, they can be part of the same solution or separate solutions. Preferably, the step c) reagents are added simultaneously and separately.

[0060] The step c) reagent can be added in any suitable manner, such as by injection. The step c) reagent can be added continuously throughout the growth time, in a single injection, or a combination of these techniques. The step c) reagent can be added at the growth temperature (a temperature in the range of 200°C to 350°C), at a temperature higher or lower than that of the step c) reagent. Preferably, the step c) reagent is added at the growth temperature.

[0061] The first mixture may include an indium-containing compound and / or a gallium-containing compound. Thus, the first mixture may include an indium-containing compound but not a gallium-containing compound. Alternatively, the first mixture may include a gallium-containing compound but not an indium-containing compound. Alternatively, the first mixture may include both an indium-containing compound and a gallium-containing compound. In a particularly preferred embodiment, the first mixture includes an indium-containing compound.

[0062] By selecting a preferred indium precursor, further control of the reaction can be achieved. Preferred indium-containing compounds and preferred features associated with indium-containing compounds are applicable to all indium-containing compounds in the present invention, including the second indium-containing compound discussed further below. Preferably, the first mixture comprises a first indium-containing compound. Preferably, the first indium-containing compound is selected from indium acetate, indium triformate, indium nitrate, hydrated indium nitrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, hydrated indium perchlorate and mixtures thereof. More preferably, the first indium-containing compound is indium acetate.

[0063] In some embodiments, the first mixture includes a first gallium-containing compound. When using a gallium-containing compound, further control over shape and reactivity can be achieved by selecting a preferred gallium precursor. Preferably, the first gallium-containing compound is selected from gallium acetate, gallium nitrate, gallium sulfate, gallium hydroxide, gallium trifluoromethanesulfonate, gallium trifluoroacetylacetonate, gallium acetylacetonate, gallium trifluoroacetate, gallium phosphate, and hydrated gallium perchlorate. Preferably, the first gallium-containing compound is gallium acetate.

[0064] In some embodiments, the first mixture includes a first indium-containing compound and a first gallium-containing compound, and the resulting nanocrystals are ternary or quaternary. The preferred indium-containing compounds and gallium-containing compounds described above are also applicable to this embodiment.

[0065] The reaction is carried out in a solvent in which the components of the first mixture are soluble. Indium-containing compounds, gallium-containing compounds, and nitrogen-containing compounds are generally soluble in polar and non-polar solvents. Typically, a non-polar solvent is used because long-chain organic ligands are used in the initial synthesis. Therefore, the first solvent is preferably a non-polar solvent. Preferably, the first solvent has a relative dielectric constant at 20°C of less than 3, more preferably less than 2.5. As used herein, the term "relative dielectric constant" refers to the ratio of the dielectric constant of a substance to the dielectric constant of a vacuum; it is a dimensionless number. As defined in Christian Wohlfarth's book "Permittivity (Dielectric Constant) of Liquids," the dielectric constant of a substance (commonly referred to as the dielectric constant) is the ratio of the electric displacement D to the electric field strength E when an external electric field is applied to the substance. The relative dielectric constant is measured using a BI-870 dielectric constant meter from Brookhaven Instruments, with a sensitivity range of 1 to 200. The instrument can be calibrated with liquids of known relative dielectric constants. Polar solvents generally have higher relative dielectric constants, while non-polar solvents generally have lower relative dielectric constants.

[0066] Preferably, the first solvent is selected from the group consisting of n H 2n+2 Hydrocarbons of formula C n H 2n+1 NH2-alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary and secondary phosphines, wherein n is in the range of 6 to 20.

[0067] The components in the first mixture can be combined in any suitable amounts and in any suitable order, and based on common knowledge, these suitable amounts are obvious to those skilled in the art based on common knowledge. Preferably, the molar ratio of the at least one nitrogen-containing compound to the first indium-containing compound and the first gallium-containing compound is in the range of 0.5:1 to 1:0.5, preferably in the range of 0.5:1 to 1:1. The molar ratio (MR1) of the at least one nitrogen-containing compound to the first indium-containing compound and the first gallium-containing compound is defined as the ratio of the total moles of all nitrogen-containing compounds in the first mixture to the sum of the total moles of all indium-containing compounds and the total moles of all gallium-containing compounds in the first mixture, as shown in the following formula:

[0068]

[0069] The indium-containing compound and the first gallium-containing compound are each a Group III precursor, meaning that they are compounds containing a Group III element as described above. The ratio of the Group V element (nitrogen-containing element) to the Group III element (MR2) in the first mixture is typically the same as MR1. MR2 is preferably in the range of 0.5:1 to 1:0.5, more preferably in the range of 0.5:1 to 1:1, and more preferably in the range of 0.6:1 to 1:1. The Group V element may be present in the first mixture as part of the nitrogen-containing compound, and the Group III element may be present in the first mixture as part of the Group III precursor.

[0070] In one embodiment, step b) comprises adding a nitrogen-containing compound, wherein the nitrogen-containing compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds, and antimony-containing compounds. By adding a nitrogen-containing compound, the resulting nanocrystals will contain a nitrogen-containing element in the crystal nucleus. Thus, this embodiment can produce InAs nanocrystals, InSb nanocrystals, InP nanocrystals, InGaAs nanocrystals, InGaSb nanocrystals, InGaP nanocrystals, GaAs nanocrystals, GaSb nanocrystals, and GaP nanocrystals.

[0071] In one embodiment, step b) includes adding two nitrogen-containing compounds, wherein the first nitrogen-containing compound is an arsenic-containing compound and the second nitrogen-containing compound is a phosphorus-containing compound or an antimony-containing compound. By adding two nitrogen-containing compounds, the resulting nanocrystal will contain both nitrogen-containing elements in the crystal nucleus. Therefore, this embodiment can produce InAsSb nanocrystals, InAsP nanocrystals, InGaAsSb nanocrystals, and InGaAsP nanocrystals.

[0072] Preferably, the arsenic-containing compound is selected from tris(trialkylsilyl)arsine, wherein the alkyl group is methyl, ethyl, propyl, butyl, or substituted alkyl; tris(trimethylgermyl)arsine; tris(triphenylsilyl)arsine; triphenylarsine; aminoarsine (R2N)3As, wherein R is an alkyl or aryl group; arsenic halides; alkyl or aryl arsenious acids, and mixtures thereof. Preferably, the arsenic-containing compound is selected from tris(trimethylsilyl)arsine, tris(trimethylgermyl)arsine, tris(dimethylamino)arsine, and mixtures thereof. A particularly preferred arsenic-containing compound is tris(trimethylsilyl)arsine.

[0073] Preferably, the antimony-containing compound is selected from tris(trialkylsilyl)antimony, wherein the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl; tris(trimethylgermyl)antimony and aminoantimony (R2N)3Sb, wherein R is an alkyl or aryl group; antimony halides; dialkylantimony amides; dialkylsilylamides; stibine; antimony aziridinides; antimony thiolates; antimony carbamates; guanidine antimony and mixtures thereof. Preferably, the antimony-containing compound is selected from tris(trimethylsilyl)antimony, tris(trimethylgermyl)antimony, tris(dimethylamino)antimony and mixtures thereof.

[0074] Preferably, the phosphorus-containing compound is selected from tris(trialkylsilyl)phosphine, wherein the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl; tris(trimethylgermyl)phosphine; tris(triphenylsilyl)phosphine; triphenylphosphine; aminophosphine (R2N)3P; wherein R is an alkyl or aryl group; phosphine halides; alkyl or aryl phosphonic acids and mixtures thereof. Preferably, the phosphorus-containing compound is selected from tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine and mixtures thereof. A particularly preferred phosphorus-containing compound is tris(trimethylsilyl)phosphine.

[0075] The ligands of the present invention (e.g., first and second ligands) are typically provided in the form of multiple ligands. The term "first ligand" is used to refer to the ligand component of the first mixture, and it is readily understood that the first ligand component will include multiple ligands. Similarly, this applies to the second ligand in the second mixture, as described below.

[0076] The first ligand is C6-C 24 An organic compound comprising a functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid.The first ligand may be any such compound capable of forming a complex with the nanocrystal by coordinating to the surface of the nanocrystal.

[0077] The molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound can be any suitable molar ratio, and such suitable values ​​will be apparent to those skilled in the art, taking into account common knowledge. The molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound can be sufficient to coordinate the ligand to the nucleus of the developing nanocrystal to stabilize the growth of the nanocrystal. Preferably, the molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound is at least 2:1, and more preferably at least 2.5:1.

[0078] Preferably, the first ligand is selected from the group consisting of n H 2n+1 NH2 alkylamine, formula C n H 2n+1 Alkyl carboxylic acid of COOH, formula C n H 2n+ 1PO3H2, an alkylphosphonic acid, an aromatic phosphonic acid, an alkyl or aryl thiol, an alkyl or aryl arsenious acid, and mixtures thereof, wherein n is in the range of 6 to 20. Preferably, the first ligand is selected from aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkanes, dithioalkanes, thiocarboxylic acids, thioglycolic acid, polyethylene glycol, bis(3-aminopropyl)-capped polyethylene glycol, didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, and alkylamines. Preferably, the first ligand is selected from mercaptopropionic acid, mercaptobenzoic acid, mercaptoacetic acid, polyethylene glycol, bis(3-aminopropyl)-terminated polyethylene glycol, dodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, and bis(diphenylphosphino)methane.

[0079] The growth temperature can be any temperature at which the nanocrystals grow. Maintaining the mixture at the growth temperature may include maintaining the temperature of the mixture at a specific suitable temperature. However, it should be understood that the temperature may vary during the total growth time and during the first and second growth times, as described below. Thus, maintaining the first mixture at the growth temperature may include maintaining the temperature of the first mixture within a suitable growth temperature range, for example, within a range of 200° C. to 350° C.

[0080] Preferably, the growth temperature is in the range of 220°C to 340°C, preferably in the range of 240°C to 330°C, preferably in the range of 260°C to 320°C, preferably in the range of 270°C to 300°C.

[0081] The growth temperature can be varied to produce nanocrystals of different sizes. For example, a lower growth temperature (e.g., 200°C to 250°C) may result in smaller nanocrystals, while a higher growth temperature (e.g., above 270°C) may result in larger nanocrystals. Therefore, if smaller nanocrystals are desired, a lower growth temperature may be preferred.

[0082] The growth time refers to the length of time that the first mixture is at a suitable growth temperature. For example, the growth time can be the length of time that the first mixture is at a temperature range of 200°C to 350°C. The total growth time refers to the total time that the first mixture is at the growth temperature during the synthesis process. The total growth time can be a period of time without any interruptions, that is, a period of time when the temperature of the first mixture is not higher or lower than the suitable growth temperature range. Alternatively, the total growth time can be divided into two sections, such as a first growth time and a second growth time, between which the temperature of the first mixture can be lower or higher than the suitable growth temperature range. For example, the first mixture can be maintained at a suitable growth temperature for a first growth time of 4 hours, cooled, and then heated again to a suitable growth temperature for a second growth time of 8 hours. In this example, the total growth time would be 12 hours.

[0083] Preferably, the total growth time is in the range of 6 hours to 30 hours, preferably in the range of 8 hours to 26 hours, preferably in the range of 7 hours to 24 hours, preferably in the range of 9 hours to 23 hours, preferably in the range of 10 hours to 22 hours.

[0084] Contrary to previous ideas in the literature, the inventors have found that the slow growth of nanocrystals, and the long total growth time required by the method of the first aspect of the present invention, allows for more thermodynamic control of the nanocrystal end faces. Longer total growth times typically produce cuboctahedral nanocrystals.

[0085] The total growth time can be varied to adjust the band gap of the resulting nanocrystals. For example, a shorter total growth time (e.g., in the range of 6 to 10 hours) may result in an InAs nanocrystal with an absorption peak around 1400 nm, while a longer total growth time (e.g., greater than 12 hours) may result in an InAs nanocrystal with an absorption peak around 1600 nm. This tunability is very advantageous and allows the production of a variety of nanocrystals for various purposes.

[0086] Where a smaller band gap is desired, the total growth time is preferably in the range of 8 hours to 19 hours, preferably in the range of 9 hours to 18 hours, preferably in the range of 10 hours to 17 hours, and preferably in the range of 11 hours to 16 hours.

[0087] Where a larger band gap is desired, the total growth time is preferably in the range of 14 to 28 hours, preferably in the range of 15 to 26 hours, preferably in the range of 16 to 24 hours, and preferably in the range of 17 to 22 hours.

[0088] Preferably, the nanocrystal composition comprises a III-V nanocrystal, wherein the nanocrystal comprises a crystal nucleus and a plurality of first ligands coordinated to the surface of the crystal nucleus. The crystal nucleus typically comprises indium and / or gallium introduced by an indium-containing compound and / or a gallium-containing compound. The crystal nucleus typically comprises a nitrogen-containing element introduced by a nitrogen-containing compound. Therefore, various nanocrystal systems can be prepared by the method of the first aspect.

[0089] As the nanocrystal grows, the first ligand coordinates with the surface of the nanocrystal core, thereby stabilizing the nanocrystal and helping it grow.

[0090] In the method of the first aspect, an oxide remover is used to at least partially remove any surface oxidation that may occur on the surface of the crystal nucleus during the nanocrystal growth process. For example, Chaudret et al. (Journal of American Chemical Society, 2010, 18147-18157, 132 (51)) hypothesize that the surface of the crystal nucleus may be oxidized during the nanocrystal synthesis process. Without intending to be bound by theory, it is believed that the oxide layer around the nanocrystal produced by surface oxidation will prevent and / or hinder the further growth of the nanocrystal. Therefore, surface oxidation is undesirable.

[0091] Oxide remover of the present invention can be any suitable compound or composition, and in view of common general knowledge, those skilled in the art will recognize these suitable oxide removers.Preferably, oxide remover is a compound that can react with the oxide on the crystal nucleus surface to remove oxide from the crystal nucleus surface.Preferably, oxide remover is an organic acid, an organic base or a metal halide.Preferably, oxide remover is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halide, indium halide and metal halide, wherein metal is bismuth, lead or cadmium.In a particularly preferred embodiment, oxide remover is hydrobromic acid.

[0092] The oxide remover is preferably added in a small amount, for example 10 ppm. Preferably, the molar ratio of the oxide remover to the sum of the first indium-containing compound and / or the first gallium-containing compound is in the range of 1:100 to 1:1,000,000, preferably in the range of 1:1,000 to 1:100,000, more preferably in the range of 1:000 to 1:50,000. Preferably, the amount of the oxide remover in the first mixture is in the range of 0.0001 mmol to 0.005 mmol, preferably in the range of 0.00025 mmol to 0.0025 mmol. This can correspond to a concentration in the first mixture immediately after the addition of the oxide remover, which is in the range of 5 μM to 1,000 μM, preferably in the range of 50 μM to 500 μM.

[0093] Preferably, steps a), b) and c) are carried out under inert conditions. For example, steps a), b) and c) can be carried out under nitrogen, argon or another inert gas.

[0094] In a preferred embodiment, step a) further comprises degassing the first mixture under vacuum (about 0.1 mbar) at a degassing temperature of 50°C to 150°C for 5 to 180 minutes. Preferably, the degassing time is in the range of 20 minutes to 160 minutes, preferably in the range of 40 minutes to 140 minutes, preferably in the range of 60 minutes to 120 minutes, preferably in the range of 80 minutes to 100 minutes. Preferably, the degassing temperature is in the range of 70°C to 150°C, preferably in the range of 80°C to 140°C, preferably in the range of 90°C to 130°C, preferably in the range of 100°C to 120°C.

[0095] Preferably, step a) further comprises heating the first mixture to a first temperature in the range of 50° C. to 150° C. Preferably, the first temperature is in the range of 60° C. to 140° C., preferably in the range of 70° C. to 130° C., preferably in the range of 80° C. to 120° C., more preferably in the range of 90° C. to 110° C.

[0096] In the case of degassing and heating the first mixture to the first temperature, degassing occurs before cooling the first mixture to the first temperature.

[0097] Preferably, step c) comprises:

[0098] i) adding a first oxide remover and a composition comprising a III-V cluster to the first mixture at a growth temperature for a first growth time of 2 hours to 8 hours to provide a plurality of nanocrystals in the first mixture;

[0099] ii) cooling the first mixture;

[0100] iii) heating the first mixture to a growth temperature;

[0101] iv) adding a third oxide remover and a composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time of 6 hours to 20 hours to provide a III-V nanocrystalline composition.

[0102] When step c) comprises steps i) to iv) as described above, the method of the first aspect essentially comprises the following steps:

[0103] A first mixture is formed comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent, wherein the first ligand is a C6-C 24 an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group;

[0104] adding at least one nitrogen-containing compound to the first mixture, and heating the first mixture to a growth temperature in a range of 200° C. to 350° C.;

[0105] adding a first oxide remover and a composition comprising a III-V cluster to the first mixture at a growth temperature for a first growth time of 2 hours to 8 hours to provide a plurality of nanocrystals in the first mixture;

[0106] allowing the first mixture to cool;

[0107] heating the first mixture to a growth temperature;

[0108] A third oxide remover and a composition comprising III-V clusters are added to the first mixture at the growth temperature for a second growth time of 6 hours to 20 hours to provide a III-V nanocrystalline composition.

[0109] Preferably, step iii) further comprises adding a second oxide remover to the first mixture before heating the first mixture to the growth temperature.

[0110] Preferably, step i) further comprises heating the first mixture to a third temperature in the range of 50° C. to 150° C., preferably in the range of 60° C. to 140° C., preferably in the range of 70° C. to 130° C., more preferably in the range of 80° C. to 120° C., preferably in the range of 90° C. to 110° C. When the first mixture is at the third temperature, the second oxide-removing agent is preferably added.

[0111] The multiple nanocrystals prepared by step i) generally exhibit a relatively low absorption peak. For example, for the multiple InAs nanocrystals prepared by step i), the absorption peak may be around 1100 nm. This absorption peak then increases over the total growth time.

[0112] Preferably, the first growth time is in the range of 2.5 hours to 7 hours, preferably in the range of 3 hours to 6 hours, preferably in the range of 3.5 hours to 5.5 hours, preferably in the range of 4 hours to 5 hours.

[0113] Preferably, the second growth time is in the range of 6 hours to 18 hours, preferably in the range of 6.5 hours to 16 hours, preferably in the range of 7 hours to 15 hours.

[0114] As mentioned above, the total growth time here will be the sum of the first growth time and the second growth time.

[0115] Preferably, the nanocrystal composition comprises a Group III-V nanocrystal, wherein the nanocrystal comprises a core and a plurality of first ligands coordinated to a surface of the core, and wherein the first oxide remover, the second oxide remover, and the third oxide remover are each independently a compound capable of reacting with an oxide on a surface of the core to remove the oxide from the surface of the core.

[0116] The first oxide remover, the second oxide remover and the third oxide remover are each independently selected with the same preferences as explained above with respect to the oxide removers in step c).

[0117] In one embodiment, the first oxide remover, the second oxide remover, and the third oxide remover are the same compound or different compounds. Preferably, the first oxide remover, the second oxide remover, and the third oxide remover are the same compound. Preferably, the first oxide remover, the second oxide remover, and the third oxide remover are hydrobromic acid.

[0118] Preferably, the first mixture comprises a compound selected from the group consisting of secondary amines, zinc carboxylates, and mixtures thereof, wherein the compound is preferably dioctylamine. This compound is used to further enhance the shape control of the nanocrystals by complexing with the nitrogen-containing compound. In this way, the reactivity of the nitrogen-containing compound can be reduced, thereby better controlling the size and size distribution of the nanocrystals. Preferably, when the nitrogen-containing compound is tris(trimethylsilyl)arsine or tris(trimethylsilyl)antimony, this compound is used because these compounds are particularly reactive.

[0119] The method of the first aspect involves adding a III-V cluster to the first mixture. As defined herein, a III-V cluster is an amorphous particle comprising a Group III element and a Group V element, wherein the particle diameter as measured by TEM is less than 2 nm. Occasionally, these particles are referred to as magic-sized particles (MSCs). The composition comprising the III-V cluster used in the method of the first aspect of the invention can be prepared in advance or as part of the method of the first aspect of the invention.

[0120] In one embodiment, the method further comprises preparing a composition comprising a III-V cluster, the composition comprising:

[0121] A) adding a second indium-containing compound and / or a second gallium-containing compound and a second ligand to a second solvent to form a second mixture, wherein the second ligand is a C6-C 24 an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group;

[0122] B) adding at least one nitrogen group element compound to the second mixture under continuous stirring to provide a III-V cluster.

[0123] Preferably, the III-V cluster comprises phosphorus, arsenic, antimony, or mixtures thereof. Preferably, the III-V cluster is an amorphous cluster exhibiting an absorption peak in the range of 250 nm to 1200 nm, preferably in the range of 300 nm to 700 nm. Typically, InP clusters exhibit characteristic absorption peak characteristics around 330-400 nm. InAs clusters exhibit these absorption characteristics in the range of 370-570 nm. InSb clusters exhibit characteristic absorption peak characteristics around 380-650 nm. InGaAs clusters exhibit characteristic absorption peak characteristics around 300-400 nm.

[0124] The second mixture generally corresponds to the first mixture. For example, if the first mixture includes a first indium-containing compound, the second mixture should generally include a second indium-containing compound. Furthermore, the first indium-containing compound and the second indium-containing compound are preferably the same, i.e., the second indium-containing compound is preferably any of the indium-containing compounds specified above for the first indium-containing compound, in particular indium acetate. The first indium-containing compound and the second indium-containing compound may be the same or different. Preferably, the first indium-containing compound and the second indium-containing compound are the same.

[0125] Preferably, the second mixture includes a second indium-containing compound.

[0126] In one embodiment, the second mixture includes a second gallium-containing compound. Furthermore, the first gallium-containing compound and the second gallium-containing compound are preferably the same. That is, the second gallium arsenide-containing compound is preferably any of the gallium-containing compounds specified above for the first gallium-containing compound, particularly gallium acetate. The first gallium-containing compound and the second gallium-containing compound may be the same or different. Preferably, the first gallium-containing compound and the second gallium-containing compound are the same.

[0127] In one embodiment, the second mixture includes a second indium-containing compound and a second gallium-containing compound.

[0128] The first solvent and the second solvent are preferably the same, that is, the second solvent is preferably any solvent mentioned above in relation to the first solvent. The first solvent and the second solvent may be the same or different. Preferably, the first solvent and the second solvent are the same. Preferably, the second solvent is a non-polar solvent. Preferably, the relative dielectric constant of the second solvent at 20°C is less than 3, more preferably less than 2.5. Preferably, the second solvent is selected from the group consisting of: n H 2n+2 Hydrocarbons of formula C n H 2n+1 NH2 alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary phosphines and secondary phosphines, wherein n is in the range of 6 to 20. Preferably, the second solvent is the same as the first solvent.

[0129] The molar ratios specified above for the first indium-containing compound and / or the first gallium-containing compound also apply to the preferred ratios in the method for preparing a III-V cluster.

[0130] The components in the second mixture can be combined in any suitable amounts and in any suitable order, and these suitable amounts will be apparent to those skilled in the art based on common knowledge. Preferably, the molar ratio of the at least one nitrogen-containing compound to the second indium-containing compound and the second gallium-containing compound is in the range of 0.5:1 to 1:0.5, preferably in the range of 0.5:1 to 1:1, and in the range of 0.6:1 to 1:1. The molar ratio (MR3) of the at least one nitrogen-containing compound to the second indium-containing compound and the second gallium-containing compound is defined as the sum of the total moles of all nitrogen-containing compounds in the second mixture and the total moles of all indium-containing compounds and the total moles of all gallium-containing compounds in the first mixture, as shown in the following formula:

[0131]

[0132] The second indium-containing compound and the second gallium-containing compound are both Group III precursors. The ratio of Group V elements (nitrogen group elements) to Group III elements (MR4) in the second mixture is typically the same as MR3. MR4 is preferably in the range of 0.5:1 to 1:0.5, more preferably in the range of 0.5:1 to 1:1, and more preferably in the range of 0.6:1 to 1:1. The Group V element can be present in the second mixture as part of the nitrogen group compound, and the Group III element can be present in the second mixture as part of the Group III precursor.

[0133] Preferably, the molar ratio of the at least one nitrogen-containing compound to the second indium-containing compound and the second gallium-containing compound is in the range of 0.5:1 to 1:0.5, preferably in the range of 0.5:1 to 1:1, preferably in the range of 0.6:1 to 1:1.

[0134] In one embodiment, step B) comprises adding a nitrogen-containing compound, wherein the nitrogen-containing compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds, and antimony-containing compounds.

[0135] In one embodiment, step B) comprises adding two nitrogen-containing compounds, wherein the first nitrogen-containing compound is an arsenic-containing compound, and the second nitrogen-containing compound is a phosphorus-containing compound or an antimony-containing compound.

[0136] The first phosphorus-containing compound and the second phosphorus-containing compound are preferably the same, that is, the second phosphorus-containing compound is preferably any phosphorus-containing compound specified above for the first phosphorus-containing compound. The first phosphorus-containing compound and the second phosphorus-containing compound may be the same or different. Preferably, the first phosphorus-containing compound and the second phosphorus-containing compound are the same.

[0137] The first arsenic-containing compound and the second arsenic-containing compound are preferably the same, i.e., the second arsenic-containing compound is preferably any of the arsenic-containing compounds specified above for the first arsenic-containing compound. The first arsenic-containing compound and the second arsenic-containing compound may be the same or different. Preferably, the first arsenic-containing compound and the second arsenic-containing compound are the same.

[0138] The first antimony-containing compound and the second antimony-containing compound are preferably the same, i.e., the second antimony-containing compound is preferably any antimony-containing compound specified above for the first antimony-containing compound. The first antimony-containing compound and the second antimony-containing compound may be the same or different. Preferably, the first antimony-containing compound and the second antimony-containing compound are the same.

[0139] As described above, the molar ratio of the second ligand to the second indium-containing compound can be any suitable ratio, preferably at least 2:1, preferably at least 2.5:1.

[0140] Preferably, the first ligand and the second ligand are the same, i.e., the second ligand is preferably any ligand specified above for the first ligand. The first ligand and the second ligand may be the same or different. Preferably, the first ligand and the second ligand are the same.

[0141] The III-V nanocrystalline composition obtained by the method of the first aspect of the present invention can be easily distinguished from the nanocrystalline composition prepared by the method of the prior art because the nanocrystals produced by the method of the present invention are cuboctahedral.

[0142] product

[0143] According to a second aspect, the present invention provides a substantially cubooctahedral III-V nanocrystal. Preferably, the nanocrystal is a cubooctahedron. To the best of the inventor's knowledge, no cubooctahedral III-V nanocrystal has been disclosed, and this shape results in improved optoelectronic properties as described above.

[0144] As used herein, the term "cuboctahedron" is used to refer to the supramolecular structure of crystalline materials, and the 3D shape of the material is similar to a cuboctahedron. A cuboctahedron is a polyhedron with 8 triangular faces and 6 square faces. The cuboctahedron has 12 identical vertices, each of which has 2 triangles and 2 squares connected, and 24 identical edges, with each edge separating the triangle from the square. Shape and structure are well known to those skilled in the art, and can be analyzed by TEM. Usually, the shape of nanocrystals is determined from TEM and HR TEM images by the human eye or by image analysis software (such as imageJ) that needs user input.

[0145] High-resolution TEM (HRTEM) can be used to image nanocrystals and determine their shape. HRTEM micrographs can be subjected to fast Fourier transform (FFT) analysis. If the nanocrystal is a cuboctahedron, it will typically appear in a TEM image viewed along the

[110] zone axis with six boundary facets (four {111} faces and two {002} faces). These features correspond to single-crystalline fcc nanoparticles with a cuboctahedral shape. HRTEM images of single particles provide more detail for accurate shape determination.

[0146] In cuboctahedral III-V nanocrystals, the atoms forming the cubic octahedral faces are typically Group III elements and Group V elements. Preferably, the nanocrystal comprises a nucleus comprising indium and / or gallium, and a nitrogen group element. Preferably, the nitrogen group element is phosphorus, arsenic, antimony, or a mixture thereof. Preferably, the nitrogen group element is arsenic, antimony, or a mixture thereof.

[0147] In one embodiment, the surface coordination of a plurality of parts and the nanocrystalline nucleus.Preferably, the part is an organic compound, an inorganic compound or its mixture.The preferred version of the part of the second aspect and the part of the first aspect is identical, and the part of the second aspect is preferably any part specified above for the first aspect.

[0148] The absorption peak exhibited by nanocrystals varies significantly depending on the composition of the nanocrystal nucleus. Typically, nanocrystal compositions exhibit absorption peaks in the range of 500nm to 3000nm. The absorption peak can be adjusted to any position within the known limitations of each nanocrystal system according to the desired function of the nanocrystal. For example, the absorption peak position of InAs can be in the range of 500nm to 1700nm. For InAs / Sb nanocrystals, the absorption peak can be in the range of 700nm to 2200nm, and can also be changed by changing the composition, reaction conditions, temperature and growth time of antimony. For InSb, the absorption peak may be in the range of 700nm to 3000nm.

[0149] When the crystal core is composed of indium and arsenic, the absorption peak is preferably in the range of 1300nm to 1700nm, preferably in the range of 1320nm to 1680nm, preferably in the range of 1340nm to 1660nm, preferably in the range of 1360nm to 1640nm, preferably in the range of 1380nm to 1620nm, preferably in the range of 1400nm to 1600nm. Preferably, the InAs nanocrystalline composition exhibits an emission peak in the range of 1300nm to 1900nm, preferably in the range of 1320nm to 1880nm, preferably in the range of 1340nm to 1860nm, preferably in the range of 1360nm to 1840nm, preferably in the range of 1380nm to 1820nm, preferably in the range of 1400nm to 1800nm.

[0150] The industry's goal is to scale up InAs quantum dots to push their absorption further into the short-wave infrared (SWIR) region. Absorption peaks above the "eye-safe threshold" of 1350nm are particularly interesting for light sensing applications. However, despite progress in the synthesis of colloidal InPn quantum dots, previous attempts in the art to push the lowest-energy electronic transition (LEET) beyond 1400nm have resulted in a concomitant loss of synthetic control and severe peak broadening.

[0151] Extending the first exciton transition energy to above 1400 nm while maintaining a uniform size distribution remains a major challenge. As quantum dots grow beyond approximately 7 nm, key optical metrics such as the peak-to-valley ratio (P / V) and the exciton full width at half maximum (FWHM) tend to decrease and widen, respectively. While this can be partially explained by the morphology-dependent absorbance of InPn quantum dots, which varies as the dots grow, the loss of synthetic control often results in nonspecific absorbance profiles.

[0152] The present invention provides the ability to push the lowest energy electron transition (LEET) to above 1400 nm and as high as above 1600 nm as shown in the examples below. This is another advantage of the present invention.

[0153] For other systems, such as InAs / Sb and InSb, the absorption peak may be higher than that of InAs nanocrystals. For the InAs / Sb system, the absorption peak is preferably in the range of 700nm to 2200nm, preferably in the range of 1000nm to 2000nm, and more preferably in the range of 1200nm to 1800nm. For the InSb system, the absorption peak is preferably in the range of 700nm to 3000nm, preferably in the range of 1000nm to 2500nm, and more preferably in the range of 1300nm to 2200nm.

[0154] According to a third aspect, the present invention provides a III-V nanocrystal composition comprising a plurality of nanocrystals according to the second aspect.

[0155] The nanocrystals present in the nanocrystal composition of the third aspect may additionally include non-cuboctahedral nanocrystals. Preferably, at least 50% of the nanocrystals present in the nanocrystal composition are cuboctahedral, preferably at least 60%, preferably at least 70%, preferably at least 80%, preferably 90%. This can be determined by TEM.

[0156] Preferably, the median particle size of the nanocrystals is in the range of 2 nm to 20 nm, preferably 2.5 nm to 15 nm, preferably 3 nm to 12 nm, preferably 4 nm to 10 nm, as measured by TEM.

[0157] Preferably, the nanocrystalline composition exhibits an absorption full width at half maximum (FWHM) value of less than 250 nm, preferably less than 225 nm, preferably less than 200 nm, preferably less than 175 nm.

[0158] Preferably, the nanocrystalline composition exhibits an emission full width at half maximum (FWHM) value of less than 250 nm, preferably less than 225 nm, preferably less than 200 nm, preferably less than 175 nm.

[0159] Preferably, the nanocrystalline composition exhibits a peak to valley ratio in the range of 1 to 4, preferably in the range of 1 to 3.5, preferably in the range of 1 to 3, preferably in the range of 1.1 to 2.5, preferably in the range of 1.2 to 2.5.

[0160] Preferably, the nanocrystals exhibit a relative size dispersion of less than 25%, preferably less than 15%, preferably less than 10%, preferably in the range of 1% to 25%, preferably in the range of 1% to 20%, preferably in the range of 2% to 15%, preferably in the range of 3% to 10%.

[0161] Relative size dispersion is a measure of the variance in nanocrystal size. It is determined by measuring the particle size of a specific batch of nanoparticles and determining the variance around the average size. This can be expressed as a specific average size x, plus or minus a particle size range. Relative size dispersion is measured using TEM.

[0162] According to a fourth aspect, the present invention provides an ink comprising the Group III-V nanocrystal composition of the third aspect. Formation of the ink typically includes a ligand exchange step, wherein long-chain organic ligands are replaced with conductive ligands, such as inorganic ligands or short-chain organic ligands. The nanocrystals are optionally dissolved in a polar solvent after washing with acetone. The polar solvent may be selected from 2,6-difluoropyridine, propylene carbonate, dimethylformamide, and combinations thereof.

[0163] According to a fifth aspect, the present invention provides a film comprising the III-V nanocrystalline composition of the third aspect.

[0164] According to a sixth aspect, the present invention provides a device selected from the group consisting of an infrared sensor, a photodetector, a sensor, a solar cell, a bioimaging or biosensing composition, a photovoltaic system, a display, a battery, a laser, a photocatalyst, a spectrometer, an injectable composition, a field effect transistor, a light emitting diode, a photonic or optical switching device or a metamaterial, a fiber amplifier, an optical gain medium, an optical fiber, an infrared LED, a laser, and an electroluminescent device, comprising the nanocrystalline composition of the present invention. Preferably, the infrared sensor or photodetector is modified to be used in a 3D camera and a 3D time-of-flight camera for mobile and consumer, automotive, medical, industrial, defense, or aerospace applications. Preferably, the bioimaging or biosensing composition is modified for use as a biomarker or biotag in in vitro or ex vivo applications. Preferably, the infrared LED and electroluminescent device are modified for use in telecommunications equipment, night vision equipment, solar energy conversion, monitoring equipment, thermoelectric or energy production applications.

[0165] Example

[0166] The examples described below illustrate methods according to the present disclosure.

[0167] While specific examples of the present invention are described below for purposes of illustration, it will be apparent to those skilled in the art that various changes can be made in the details of the invention without departing from the invention as defined in the appended claims.

[0168] Unless otherwise indicated, all parts and percentages in the following examples and throughout the specification are by weight.

[0169] The absorption spectra of colloidal quantum dots or quantum dot films were obtained on a JASCO V-770 UV-visible / NIR spectrometer, which can measure in the wavelength range of 400 to 3200 nm.

[0170] At room temperature, using Cu Ka1 X-ray radiation XRD data were collected on a Panalytical X'Pert PRO MPD diffractometer in the range 10 < 2q < 90°. In each case, a few drops of dispersed sample were placed on a glass microscope slide and allowed to evaporate. Data were analyzed using Rigaku SmartLab Studio II software, and searches and matches were performed using the Crystallographic Open Database.

[0171] TEM and high-resolution transmission electron microscopy (HRTEM) images were acquired using a FEI Talos F200X microscope equipped with an X-FEG electron source. Experiments were performed using an accelerating voltage of 200 kV and a beam current of approximately 5 nA. Images were recorded with a FEI CETA4kx 4k CMOS camera. In each case, a few drops of quantum dots dispersed in a solvent were placed on a carbon-coated copper grid and allowed to evaporate. Prior to imaging, the samples were either used directly or treated with acetone and methanol to remove unwanted organic matter.

[0172] Example 1 - Preparation of amorphous InAs clusters

[0173] In a 250 mL three-necked flask, 3.0 mmol In(OAc)3, 9.2 mmol oleic acid and 15 mL heptadecane were taken and degassed under vacuum (about 0.1 mbar) at 110° C. for 90 minutes. In this step, indium oleate was formed and 9 mmol acetic acid was collected in a cold trap.

[0174] In(OAc)3+R-COOH(R=C 17 H 33 )->In COOR+CH3COOH

[0175] The flask was switched to a nitrogen atmosphere and slowly cooled to room temperature. The flask was transferred to a glove box. In the glove box, 0.96 mmol of tris(trimethylsilyl)arsine ((TMSi)3As), 1.98 mmol of dioctylamine, and 2.5 mL of degassed heptadecane were placed in a 10 mL vial and vortexed thoroughly. Under continuous stirring, the indium oleate solution was mixed with the TMSi-As solution to provide a composition containing InAs clusters.

[0176] The composition containing InAs clusters prepared according to Example 1 was used as the composition containing III-V clusters in Example 2.

[0177] Example 2 - Preparation of Cubo-octahedral InAs Nanocrystals with an Absorption Peak of approximately 1400 nm

[0178] In this embodiment, the preparation of InAs nanocrystals is divided into two crystal growth stages. First, InAs nanocrystals showing an absorption peak at about 1100nm are formed (the first growth time is 4.5 hours). The UV-visible spectra of these nanocrystals are as follows: Figure 2 Second, these nanocrystals were used to prepare nanocrystals showing an absorption peak at about 1400 nm (the second growth time was 8 hours). The UV-visible spectra of these nanocrystals are shown in FIG. Figure 1 Total growth time was 12.5 hours.

[0179] 1100nm quantum dots

[0180] In a 250 mL three-necked flask, 0.4 mmol In(OAc) 3 , 1.2 mmol oleic acid and 6 mL heptadecane were taken and degassed under vacuum (about 0.1 mbar) at 110° C. for 90 minutes. In this step, indium oleate was formed and 1.2 mmol acetic acid was collected in a cold trap.

[0181] In(OAc)3+R-COOH(R=C 17 H 33 )->In COOR+CH3COOH

[0182] The flask was switched to a nitrogen atmosphere and the temperature was maintained at 100°C. In the glove box, 0.32mmol (TMSi)3As, 0.56mmol dioctylamine and 1mL degassed heptadecane were loaded into a syringe. This solution was added to the indium oleate solution at 100°C. The color changed immediately after the injection of the arsenic precursor solution. The solution was simply heated to 287°C (*), and once the temperature reached 287°C (*), growth continued for 15 minutes. 10mL of the amorphous cluster solution of Example 1 was loaded into a syringe (20mm diameter) and added at an injection rate of 2.230mL / hour for nearly 4 hours and 30 minutes. After all the amorphous cluster solution was injected, the solution was kept at 287°C (*) for another 10 minutes. While the clusters were being added, 270μL of a diluted HBr acetone solution was added over 4 hours and 30 minutes (the diluted HBr solution was prepared by diluting 40μL HBr in 2mL acetone solution). The heating was turned off and the solution cooled naturally. The quantum dots were transferred to a glove box for further use. The growth of the colloidal quantum dots was monitored by taking an aliquot and measuring the absorption spectrum.

[0183] The average size of the nanocrystals with maximum absorption at approximately 1100 nm was measured by TEM image analysis to be 5.9 ± 0.1 nm with a standard deviation of 0.76 nm.

[0184] 1400nm quantum dots

[0185] In a 250 mL three-necked flask connected to a vacuum, 6 mL of InAs colloidal quantum dots (50 mg / mL) (maximum absorption wavelength approximately 1100 nm) and 4 mL of degassed heptadecane were added. The contents of the flask were degassed at 100°C under vacuum (approximately 0.1 mbar) for 30 minutes. The flask was then switched to nitrogen. 200 μL of diluted HBr solution was added to the flask and maintained at 100°C for 10 minutes. Subsequently, the temperature was raised to 285°C (*). When the temperature reached approximately 285°C (*), amorphous InAs clusters were loaded into a syringe and added using a syringe pump at a rate of 1.16 mL / h for approximately 8 hours. Simultaneously with the addition of the clusters, 120 μL of diluted HBr was added over 8 hours. The heat was turned off and the solution was allowed to cool naturally. The colloidal quantum dots were transferred to a glove box for further use. The growth of the colloidal quantum dots was monitored by taking aliquots and measuring the absorption spectrum. After this step, the nanocrystals were cuboctahedral.

[0186] purification

[0187] Transfer the contents of the flask to a glove box. Add 5 mL of hexane to the quantum dots, followed by 40 mL of acetone. Aliquot the solution into centrifuge tubes and centrifuge at 6000 RPM for 10 minutes. Discard the clear supernatant and redisperse the colloidal quantum dot precipitate in hexane. Add acetone and isopropyl alcohol (IPA) in a volume ratio of 2:1 and centrifuge the dots again at 6000 RPM for 10 minutes. Discard the supernatant and redisperse the colloidal quantum dot precipitate in n-octane. Centrifuge the colloidal quantum dots in octane at 6000 RPM for 10 minutes to remove any solid impurities. Discard the precipitate and filter the clarified quantum dot solution through 0.1 μm PTFE to obtain the product.

[0188] The obtained nanocrystals showed an absorption peak at about 1400 nm, as shown in Figure 1 As shown, and is a cuboctahedron, as Figure 3 and Figure 4 As shown in the TEM image in Figure 2, after inorganic ligand exchange, these dots aggregate together to form a dense solid film, which plays an important role in improving device performance.

[0189] Without wishing to be bound by theory, the improved facet alignment in the cuboctahedral nanocrystals results in improved charge transfer.

[0190] The average size of the nanocrystals with maximum absorption at approximately 1400 nm was measured by TEM image analysis to be 9.0 ± 0.1 nm with a standard deviation of 2.22 nm.

[0191] Example 3 - Preparation of Cubo-octahedral InAs Nanocrystals with an Absorption Peak of approximately 1600 nm

[0192] The method was the same as Example 2 except that a second growth time of 14 hours was required and the amorphous cluster solution was added at a rate of 1.1.6 mL / hour.

[0193] In the TEM images, it can be seen that the nanocrystals are cubic octahedrons.

[0194] Example 4 - Further preparation of cubic octahedral InAs nanocrystals with an absorption peak of approximately 1400 nm using 240°C and ZnBr2 additives

[0195] The method was the same as in Example 2, and amorphous clusters were prepared using the same method as described in Example 1, with the following differences:

[0196] i) ZnBr2 was added to the cluster preparation, so the first section of the method in Example 1 was modified as follows: In a 250 mL three-necked flask, 0.4 mmol in(OAc)3, 0.2 mmol ZnBr2, 1.2 mmol oleic acid, and 6 mL heptadecane were degassed at 110°C under vacuum (approximately 0.1 mbar) for 90 minutes. During this step, indium oleate was formed, and 1.2 mmol acetic acid was collected in the cold trap. ii) The nanocrystals were grown at a temperature of 240°C, rather than the growth temperature indicated by an asterisk (*).

[0197] The average size of the nanocrystals having a maximum absorption at approximately 1100 nm was 5.85 ± 0.4 nm as measured by TEM image analysis. The average size of the nanocrystals having a maximum absorption at approximately 1400 nm was 8.9 ± 0.6 nm as measured by TEM image analysis.

[0198] The absorption spectra of these nanocrystals are Figure 6 shown.

[0199] exist Figure 7 The TEM images show that the nanocrystals are cubic octahedrons.

[0200] Implementation Plan

[0201] 1. A method for preparing a III-V nanocrystal composition, the method comprising:

[0202] a) forming a first mixture comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent, wherein the first ligand is a C6-C 24 an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group;

[0203] b) adding at least one nitrogen-containing compound to the first mixture and heating the first mixture to a growth temperature in the range of 200° C. to 350° C.;

[0204] c) adding an oxide remover and a composition comprising III-V clusters to the first mixture at the growth temperature for a total growth time of at least 6 hours to provide a III-V nanocrystalline composition.

[0205] 2. The method of embodiment 1, wherein the first mixture comprises the first indium-containing compound.

[0206] 3. The method according to embodiment 2, wherein the first indium-containing compound is selected from indium acetate, indium triformate, indium nitrate, hydrated indium nitrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, hydrated indium perchlorate, and mixtures thereof.

[0207] 4. The method of embodiment 3, wherein the first indium-containing compound is indium acetate.

[0208] 5. The method according to any one of the preceding embodiments, wherein the first mixture comprises the first gallium-containing compound.

[0209] 6. The method according to embodiment 5, wherein the first gallium-containing compound is selected from gallium acetate, gallium nitrate, gallium sulfate, gallium hydroxide, gallium trifluoromethanesulfonate, gallium trifluoroacetylacetonate, gallium acetylacetonate, gallium trifluoroacetate, gallium phosphate, and hydrated gallium perchlorate.

[0210] 7. The method of embodiment 6, wherein the first gallium-containing compound is gallium acetate.

[0211] 8. The method of any one of the preceding embodiments, wherein the first mixture comprises the first indium-containing compound and the first gallium-containing compound.

[0212] 9. The method according to any one of the preceding embodiments, wherein the first solvent is a non-polar solvent.

[0213] 10. The method according to any one of the preceding embodiments, wherein the first solvent has a relative dielectric constant at 20°C of less than 3, more preferably less than 2.5.

[0214] 11. The method according to any one of the preceding embodiments, wherein the first solvent is selected from the group consisting of formula C n H 2n+2 Hydrocarbons of formula C n H 2n+1NH2-alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary and secondary phosphines, wherein n is in the range of 6 to 20.

[0215] 12. The method according to any one of the preceding embodiments, wherein the molar ratio of the at least one nitrogen-containing compound to the first indium-containing compound and the first gallium-containing compound is in the range of 0.5:1 to 1:0.5, preferably in the range of 0.5:1 to 1:1, and preferably in the range of 0.6:1 to 1:1.

[0216] 13. The method according to any one of the preceding embodiments, wherein step b) comprises adding a nitrogen group element compound, wherein the nitrogen group element compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds and antimony-containing compounds.

[0217] 14. The method according to any one of embodiments 1 to 12, wherein step b) comprises adding two nitrogen-containing compounds, wherein the first nitrogen-containing compound is an arsenic-containing compound, and wherein the second nitrogen-containing compound is a phosphorus-containing compound or an antimony-containing compound.

[0218] 15. The method of embodiment 13 or embodiment 14, wherein the arsenic-containing compound is selected from tris(trialkylsilyl)arsine, where the alkyl group is methyl, ethyl, propyl, butyl, or substituted alkyl; tris(trimethylgermyl)arsine; tris(triphenylsilyl)arsine; triphenylarsine; aminoarsine (R2N)3As, where R is an alkyl or aryl group; arsenic halides; alkyl or aryl arsenious acids, and mixtures thereof.

[0219] 16. The method of embodiment 15, wherein the arsenic-containing compound is selected from tris(trimethylsilyl)arsine, tris(trimethylgermyl)arsine, tris(dimethylamino)arsine, and mixtures thereof.

[0220] 17. A method according to any one of embodiments 13 to 16, wherein the antimony-containing compound is selected from tris(trialkylsilyl)antimony, where the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl; tris(trimethylgermyl)antimony and aminoantimony (R2N)3Sb, where R is alkyl or aryl; antimony halides; dialkylantimony amides; dialkylsilicamides; stibine; antimony aziridines; antimony thiols; antimony carbamates; antimony guanidines and mixtures thereof.

[0221] 18. The method of embodiment 17, wherein the antimony-containing compound is selected from the group consisting of tris(trimethylsilyl)antimony, tris(trimethylgermyl)antimony, tris(dimethylamino)antimony, and mixtures thereof.

[0222] 19. A method according to embodiment 18, wherein the phosphorus-containing compound is selected from tris(trialkylsilyl)phosphine, wherein the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl; tris(trimethylgermyl)phosphine; tris(triphenylsilyl)phosphine; triphenylphosphine; aminophosphine (R2N)3P, wherein R is alkyl or aryl; phosphine halides; alkyl or aryl phosphonic acids and mixtures thereof, preferably wherein the phosphorus-containing compound is selected from tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine and mixtures thereof, preferably wherein the phosphorus-containing compound is tris(trimethylsilyl)phosphine.

[0223] 20. The method according to any one of the preceding embodiments, wherein the molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound is at least 2:1, preferably at least 2.5:1.

[0224] 21. The method according to any one of the preceding embodiments, wherein the first ligand is selected from the group consisting of formula C n H 2n+1 NH2 alkylamine, formula C n H 2n+1 Alkyl carboxylic acid of COOH, formula C n H 2n+1 Alkylphosphonic acids, aromatic phosphonic acids, alkyl or aryl thiols, alkyl or aryl arsenious acids of PO3H2, wherein n is in the range of 6 to 20, and mixtures thereof.

[0225] 22. A method according to embodiment 21, wherein the first ligand is selected from aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkanes, dithioalkanes, thiocarboxylic acids, thioglycolic acid, polyethylene glycol, bis(3-aminopropyl)-terminated polyethylene glycol, didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane and alkylamines.

[0226] 23. A method according to embodiment 22, wherein the first ligand is selected from mercaptopropionic acid, mercaptobenzoic acid, mercaptoacetic acid, polyethylene glycol, bis(3-aminopropyl)-capped polyethylene glycol, dodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, preferably oleic acid, oleylamine, mercaptopropionic acid or a mixture thereof.

[0227] 24. The method according to any one of the preceding embodiments, wherein the growth temperature is in the range of 220°C to 340°C, preferably in the range of 240°C to 330°C, preferably in the range of 260°C to 320°C, preferably in the range of 270°C to 300°C.

[0228] 25. The method according to any one of the preceding embodiments, wherein the total growth time is in the range of 6 hours to 30 hours, preferably in the range of 8 hours to 26 hours, preferably in the range of 8 hours to 24 hours, preferably in the range of 9 hours to 23 hours, preferably in the range of 10 hours to 22 hours.

[0229] 26. The method according to embodiment 25, wherein the total growth time is 8 hours to 19 hours, preferably 9 hours to 18 hours, preferably 10 hours to 17 hours, preferably 11 hours to 16 hours.

[0230] 27. The method according to embodiment 25, wherein the total growth time is 14 hours to 28 hours, preferably 15 hours to 26 hours, preferably 16 hours to 24 hours, preferably 17 hours to 22 hours.

[0231] 28. The method according to any one of the preceding embodiments, wherein the nanocrystal composition comprises a Group III-V nanocrystal, wherein the nanocrystal comprises a core and a plurality of first ligands coordinated to a surface of the core.

[0232] 29. The method according to embodiment 28, wherein the oxide remover is a compound capable of reacting with the oxide on the surface of the crystal nucleus to remove the oxide from the surface of the crystal nucleus.

[0233] 30. The method according to any one of the preceding embodiments, wherein the oxide removal agent is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halide, indium halide and metal halide, wherein the metal is bismuth, lead or cadmium.

[0234] 31. The method of embodiment 30, wherein the oxide removal agent is hydrobromic acid.

[0235] 32. The method according to any of the preceding embodiments, wherein the molar ratio of the oxide remover to the sum of the first indium-containing compound and / or the first gallium-containing compound is in the range of 1:100 to 1:1000000, preferably in the range of 1:1000 to 1:100000, more preferably in the range of 1:000 to 1:50000.

[0236] 33. The method according to any one of the preceding embodiments, wherein the concentration of the oxide remover in the first mixture is in the range of 5 μM to 1000 μM, preferably in the range of 50 μM to 500 μM.

[0237] 34. The method according to any one of the preceding embodiments, wherein steps a), b) and c) are performed under inert conditions.

[0238] 35. The method according to any one of the preceding embodiments, wherein step a) further comprises heating the first mixture to a first temperature in the range of 50°C to 150°C.

[0239] 36. The method according to embodiment 35, wherein the first temperature is in the range of 60°C to 140°C, preferably in the range of 70°C to 130°C, preferably in the range of 80°C to 120°C, preferably in the range of 90°C to 110°C.

[0240] 37. The method according to any one of the preceding embodiments, wherein step c) comprises:

[0241] i) adding a first oxide remover and a composition comprising a III-V cluster to the first mixture at a growth temperature for a first growth time of 2 hours to 8 hours to provide a plurality of nanocrystals in the first mixture;

[0242] ii) cooling the first mixture;

[0243] iii) adding a second oxide remover to the first mixture and heating the first mixture to a growth temperature;

[0244] iv) adding a third oxide remover and a composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time of 6 hours to 20 hours to provide a III-V nanocrystalline composition.

[0245] 38. The method according to embodiment 37, wherein step iii) further comprises adding a second oxide remover to the first mixture before heating the first mixture to the growth temperature.

[0246] 39. The method according to embodiment 37 or embodiment 38, wherein step i) further comprises heating the first mixture to a third temperature in the range of 50°C to 150°C, preferably in the range of 60°C to 140°C, preferably in the range of 70°C to 130°C, preferably in the range of 80°C to 120°C and preferably in the range of 90°C to 110°C.

[0247] 40. The method according to any one of embodiments 37 to 39, wherein the first growth time is in the range of 2.5 hours to 7 hours, preferably in the range of 3 hours to 6 hours, preferably in the range of 3.5 hours to 5.5 hours, preferably in the range of 4 hours to 5 hours.

[0248] 41. The method according to any one of embodiments 37 to 40, wherein the second growth time is in the range of 6 hours to 18 hours, preferably in the range of 6.5 hours to 16 hours, preferably in the range of 7 hours to 15 hours.

[0249] 42. The method of any one of embodiments 37 to 41, wherein the nanocrystal composition comprises a Group III-V nanocrystal, wherein the nanocrystal comprises a core and a plurality of first ligands coordinated to a surface of the core, and wherein the first oxide remover, the second oxide remover, and the third oxide remover are each independently a compound capable of reacting with an oxide on a surface of the core to remove the oxide from the surface of the core.

[0250] 43. The method of any one of embodiments 37 to 42, wherein the first oxide remover, the second oxide remover, and the third oxide remover are each independently a compound selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halide, indium halide, and a metal halide, wherein the metal is bismuth, lead, or cadmium.

[0251] 44. The method according to any one of embodiments 37 to 43, wherein the first oxide remover, the second oxide remover, and the third oxide remover are the same compound.

[0252] 45. The method of any one of embodiments 37 to 44, wherein the first oxide remover, the second oxide remover, and the third oxide remover are hydrobromic acid.

[0253] 46. ​​The method according to any one of the preceding embodiments, wherein the first mixture comprises a compound selected from the group consisting of secondary amines, zinc carboxylates, and mixtures thereof, preferably wherein the compound is dioctylamine.

[0254] 47. The method according to any one of the preceding embodiments, wherein the III-V clusters are amorphous particles comprising Group III elements and Group V elements, the particles having a diameter less than 2 nm.

[0255] 48. The method of embodiment 48, wherein the III-V cluster comprises phosphorus, arsenic, antimony, or a mixture thereof.

[0256] 49. The method according to embodiment 48 or embodiment 49, wherein the III-V cluster is an amorphous cluster exhibiting an absorption peak in the range of 900 nm to 1200 nm, preferably in the range of 1000 nm to 1200 nm.

[0257] 50. The method of any one of the preceding embodiments, further comprising preparing a composition comprising a III-V cluster, the method comprising:

[0258] A) adding a second indium-containing compound and / or a second gallium-containing compound and a second ligand to a second solvent to form a second mixture, wherein the second ligand is a C6-C 24 an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group;

[0259] B) adding at least one nitrogen-containing compound to the second mixture under continuous stirring to provide a III-V cluster.

[0260] 51. The method of embodiment 50, wherein the second mixture comprises the second indium-containing compound.

[0261] 52. The method of embodiment 51, wherein the second indium-containing compound is selected from the group consisting of indium acetate, indium triformate, indium nitrate, hydrated indium nitrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, hydrated indium perchlorate, and mixtures thereof.

[0262] 53. The method of embodiment 52, wherein the second indium-containing compound is indium acetate.

[0263] 54. The method of any one of embodiments 50 to 53, wherein the second mixture comprises the second gallium-containing compound.

[0264] 55. The method of embodiment 54, wherein the second gallium-containing compound is selected from the group consisting of gallium acetate, gallium nitrate, gallium sulfate, gallium hydroxide, gallium trifluoromethanesulfonate, gallium trifluoroacetylacetonate, gallium acetylacetonate, gallium trifluoroacetate, gallium phosphate, and hydrated gallium perchlorate.

[0265] 56. The method of embodiment 55, wherein the second gallium-containing compound is gallium acetate.

[0266] 57. The method of any one of embodiments 50 to 56, wherein the second mixture comprises the second indium-containing compound and the second gallium-containing compound.

[0267] 58. The method of any one of embodiments 50 to 57, wherein the second solvent is a non-polar solvent.

[0268] 59. The method of any one of embodiments 50 to 58, wherein the second solvent has a relative dielectric constant at 20°C of less than 3, more preferably less than 2.5.

[0269] 60. The method according to any one of embodiments 50 to 59, wherein the second solvent is selected from the group consisting of formula C n H 2n+2 Hydrocarbons of formula C n H2n+1 NH2-alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary and secondary phosphines, wherein n is in the range of 6 to 20.

[0270] 61. The method of any one of embodiments 50 to 60, wherein the second solvent is the same as the first solvent.

[0271] 62. A method according to any one of embodiments 50 to 61, wherein the molar ratio of the at least one nitrogen-containing compound to the second indium-containing compound and the second gallium-containing compound is in the range of 0.5:1 to 1:0.5, preferably in the range of 0.5:1 to 1:1, and preferably in the range of 0.6:1 to 1:1.

[0272] 63. The method according to any one of embodiments 50 to 62, wherein step B) comprises adding a nitrogen group element compound, wherein the nitrogen group element compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds, and antimony-containing compounds.

[0273] 64. The method according to any one of embodiments 50 to 62, wherein step B) comprises adding two nitrogen-containing compounds, wherein the first nitrogen-containing compound is an arsenic-containing compound, and wherein the second nitrogen-containing compound is a phosphorus-containing compound or an antimony-containing compound.

[0274] 65. The method of embodiment 63 or embodiment 64, wherein the arsenic-containing compound is selected from tris(trialkylsilyl)arsine, where the alkyl group is methyl, ethyl, propyl, butyl, or substituted alkyl; tris(trimethylgermyl)arsine; tris(triphenylsilyl)arsine; triphenylarsine; aminoarsine (R2N)3As, where R is alkyl or aryl; arsenic halides; alkyl or aryl arsenious acids, and mixtures thereof.

[0275] 66. The method of embodiment 65, wherein the arsenic-containing compound is tris(trimethylsilyl)arsine.

[0276] 67. A method according to any one of embodiments 63 to 66, wherein the antimony-containing compound is selected from tris(trialkylsilyl)antimony, where the alkyl group is methyl, ethyl, propyl, butyl, or substituted alkyl; tris(trimethylgermyl)antimony and aminoantimony (R2N)3Sb, where R is alkyl or aryl; antimony halides; antimony dialkylamides; dialkylsilicamides; stibine; antimony aziridines; antimony thiolates; antimony carbamates, and antimony guanidines.

[0277] 68. The method of embodiment 67, wherein the antimony-containing compound is tris(trimethylsilyl)antimony.

[0278] 69. The method of any one of embodiments 63 to 68, wherein the phosphorus-containing compound is selected from...

[0279] 70. The method of any one of embodiments 50 to 69, wherein the molar ratio of the second ligand to the second indium-containing compound is at least 2:1, preferably at least 2.5:1.

[0280] 71. The method according to any one of embodiments 50 to 70, wherein the second ligand is selected from the group consisting of formula C n H 2n+ 1NH2 alkylamine, formula C n H 2n+1 Alkyl carboxylic acid of COOH, formula C n H 2n+1 Alkylphosphonic acids, aromatic phosphonic acids, alkyl or aryl thiols, alkyl or aryl arsenious acids of PO3H2, wherein n is in the range of 6 to 20, and mixtures thereof.

[0281] 72. A method according to embodiment 71, wherein the second ligand is selected from aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkanes, dithioalkanes, thiocarboxylic acids, thioglycolic acid, polyethylene glycol, bis(3-aminopropyl)-capped polyethylene glycol, dodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane and alkylamines.

[0282] 73. A method according to embodiment 72, wherein the second ligand is selected from mercaptopropionic acid, mercaptobenzoic acid, mercaptoacetic acid, polyethylene glycol, bis(3-aminopropyl)-terminated polyethylene glycol, dodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, and bis(diphenylphosphino)methane.

[0283] 74. The method of any one of embodiments 50 to 73, wherein the second ligand is the same as the first ligand.

[0284] 75. A III-V nanocrystalline composition obtainable by any of the preceding embodiments.

[0285] 76. A substantially cuboctahedral III-V nanocrystal.

[0286] 77. The nanocrystal of embodiment 76, wherein the nanocrystal is a cuboctahedron.

[0287] 78. The nanocrystal of embodiment 76 or embodiment 77, wherein the nanocrystal comprises a crystalline core comprising indium and / or gallium and a nitrogen group element.

[0288] 79. The nanocrystal of embodiment 78, wherein the nitrogen group element is phosphorus, arsenic, antimony, or a mixture thereof.

[0289] 80. The nanocrystal of embodiment 79, wherein the nitrogen group element is arsenic, antimony, or a mixture thereof.

[0290] 81. The nanocrystal of any one of embodiments 78 to 80, wherein a plurality of ligands are coordinated to the surface of the core.

[0291] 82. The nanocrystal of embodiment 81, wherein the ligand is an organic compound, an inorganic compound, or a mixture thereof.

[0292] 83. The nanocrystal of any one of embodiments 76 to 82, wherein the nanocrystal composition exhibits an absorption peak in the range of 500 nm to 3000 nm, preferably in the range of 1300 nm to 1700 nm, preferably in the range of 1320 nm to 1680 nm, preferably in the range of 1340 nm to 1660 nm, preferably in the range of 1360 nm to 1640 nm, preferably in the range of 1380 nm to 1620 nm, preferably in the range of 1400 nm to 1600 nm.

[0293] 84. The nanocrystal of any one of embodiments 76 to 83, wherein the nanocrystal composition exhibits an emission peak in the range of 1300 nm to 1900 nm, preferably in the range of 1320 nm to 1880 nm, preferably in the range of 1340 nm to 1860 nm, preferably in the range of 1360 nm to 1840 nm, preferably in the range of 1380 nm to 1820 nm, preferably in the range of 1400 nm to 1800 nm.

[0294] 85. A Group III-V nanocrystal composition comprising a plurality of nanocrystals according to any one of Embodiments 76 to 84.

[0295] 86. The nanocrystalline composition of embodiment 85, wherein the nanocrystals have a median particle size in the range of 2 nm to 20 nm, preferably 2.5 nm to 15 nm, preferably 3 nm to 12 nm, preferably 4 nm to 10 nm.

[0296] 87. The nanocrystalline composition of embodiment 85 or embodiment 86, wherein the nanocrystalline composition exhibits an absorption full width at half maximum (FWHM) value of less than 250 nm, preferably less than 225 nm, preferably less than 200 nm, preferably less than 175 nm.

[0297] 88. The nanocrystalline composition of any one of embodiments 85 to 87, wherein the nanocrystalline composition exhibits an emission full width at half maximum (FWHM) value of less than 250 nm, preferably less than 225 nm, preferably less than 200 nm, preferably less than 175 nm.

[0298] 89. The nanocrystalline composition of any one of embodiments 85 to 88, wherein the nanocrystalline composition exhibits a peak-to-valley ratio in the range of 1 to 4, preferably in the range of 1 to 3.5, preferably in the range of 1 to 3, preferably in the range of 1.1 to 2.5, preferably in the range of 1.2 to 2.5.

[0299] 90. The nanocrystal composition of any one of embodiments 85 to 89, wherein the nanocrystals exhibit a relative size dispersion of less than 25%, preferably less than 15%, preferably less than 10%, preferably in the range of 1% to 25%, preferably in the range of 1%-20%, preferably in the range of 2% to 15%, preferably in the range of 3% to 10%.

[0300] 91. An ink comprising the Group III-V nanocrystalline composition of any one of Embodiments 85 to 90.

[0301] 92. A film comprising the Group III-V nanocrystalline composition of any one of Embodiments 85 to 90.

[0302] References

[0303] 1. Alivisatos et al.Appl.Phys.Lett.1996,69,1432.

[0304] 2.Bawendi et al.Nat.Comms.2016,7,12749).

[0305] 3.Jeong et al.Nat.Comms.2018,9,1.

[0306] 4.Sargent et al Nano.Lett.,2021,21,6057.

[0307] 5.Talapin et al.Chem.Mater.2016,28,6797.

[0308] 6.Bawendi et al.J.Am.Chem.Soc.,2020,142,4088.

[0309] 7.Hens et al.J.Am.Chem.Soc.2021,143,4290.

[0310] 8.Pietryga et alJ.Am.Chem.Soc.2008,130,14,4879-4885.

[0311] 9.Lee et alAdv.Mater.2003,15(5),441.

[0312] 10.Biondi et alAdv.Mater.2021,2101056.

[0313] 11.Chaudret et al.Journal ofAmerican ChemicalSociety,2010,18147-18157,132(51).

Claims

1. A method for preparing a III-V nanocrystal composition, the method comprising: a) forming a first mixture comprising a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent, wherein the first ligand is a C6-C 24 an organic compound comprising a functional group selected from the group consisting of an amino group, a thiol group, a hydroxyl group, and a carboxylic acid group; b) adding at least one nitrogen-containing compound to the first mixture, and heating the first mixture to a growth temperature in the range of 200° C. to 350° C.; c) adding an oxide remover and a composition comprising III-V clusters to the first mixture at a growth temperature for a total growth time of at least 6 hours to provide a III-V nanocrystalline composition.

2. The method of claim 1, wherein the first mixture comprises the first indium-containing compound, Preferably, the first indium-containing compound is selected from indium acetate, indium triformate, indium nitrate, hydrated indium nitrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, hydrated indium perchlorate, and mixtures thereof. Preferably, the first indium-containing compound is indium acetate.

3. The method according to claim 1 or 2, wherein the first mixture comprises the first gallium-containing compound, Preferably, the first gallium-containing compound is selected from gallium acetate, gallium nitrate, gallium sulfate, gallium hydroxide, gallium trifluoromethanesulfonate, gallium trifluoroacetylacetonate, gallium acetylacetonate, gallium trifluoroacetate, gallium phosphate, hydrated gallium perchlorate, Preferably, the first gallium-containing compound is gallium acetate.

4. The method according to any one of the preceding claims, wherein the first solvent is a non-polar solvent, Preferably, the relative dielectric constant of the first solvent at 20° C. is less than 3, more preferably less than 2.5, Preferably, the first solvent is selected from the group consisting of formula C n H 2n+2 Hydrocarbons of formula C n H 2n+1 NH2-alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary and secondary phosphines, wherein n is in the range of 6 to 20.

5. The method according to any one of the preceding claims, wherein the molar ratio of the at least one nitrogen group element compound to the first indium containing compound and the first gallium containing compound is in the range of 0.5:1 to 1:0.5, preferably in the range of 0.5:1 to 1:1, preferably in the range of 0.6:1 to 1:

1.

6. The method according to any one of the preceding claims, wherein step b) comprises adding a nitrogen-containing compound, wherein the nitrogen-containing compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds and antimony-containing compounds, or Step b) includes adding two nitrogen-containing element compounds, wherein the first nitrogen-containing element compound is an arsenic-containing compound, and the second nitrogen-containing element compound is a phosphorus-containing compound or an antimony-containing compound.

7. The method of claim 6, wherein the arsenic-containing compound is selected from tris(trialkylsilyl)arsine, wherein the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl; tris(trimethylgermyl)arsine; tris(triphenylsilyl)arsine; triphenylarsine; aminoarsine (R2N)3As, wherein R is an alkyl or aryl group; arsenic halides; alkyl or aryl arsenious acids and mixtures thereof, Preferably, the arsenic-containing compound is selected from tris(trimethylsilyl)arsine, tris(trimethylgermyl)arsine, tris(dimethylamino)arsine and mixtures thereof.

8. The method according to claim 6 or 7, wherein the antimony-containing compound is selected from tris(trialkylsilyl)antimony, wherein the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl; tris(trimethylgermyl)antimony and aminoantimony (R2N)3Sb, wherein R is an alkyl or aryl group; antimony halides; antimony dialkylamides; dialkylsilicamides; stibine; antimony aziridines; antimony thiols; antimony carbamates; antimony guanidines and mixtures thereof, Preferably, the antimony-containing compound is selected from tris(trimethylsilyl)antimony, tris(trimethylgermyl)antimony, tris(dimethylamino)antimony and mixtures thereof.

9. The process according to claim 6 , wherein the phosphorus-containing compound is selected from tris(trialkylsilyl)phosphine, wherein the alkyl group is methyl, ethyl, propyl, butyl or substituted alkyl, tris(trimethylgermyl)phosphine, tris(triphenylsilyl)phosphine, triphenylphosphine, aminophosphine (RN)P, wherein R is alkyl or aryl, phosphine halides, alkyl or aryl phosphonic acids and mixtures thereof, preferably wherein the phosphorus-containing compound is selected from tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine and mixtures thereof, more preferably wherein the phosphorus-containing compound is tris(trimethylsilyl)phosphine.

10. The method according to any one of the preceding claims, wherein the molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound is at least 2:1, preferably at least 2.5:

1.

11. The method according to any one of the preceding claims, wherein the first ligand is selected from the group consisting of formula C n H 2n+1 NH2 alkylamine, formula C n H 2n+1 Alkyl carboxylic acid of COOH, formula C n H 2n+1 PO3H2, wherein n is in the range of 6 to 20, an alkylphosphonic acid, an aromatic phosphonic acid, an alkyl or aryl thiol, an alkyl or aryl arsenious acid, and mixtures thereof, Preferably, the first ligand is selected from the group consisting of aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkanes, dithioalkanes, thiocarboxylic acids, thioglycolic acid, polyethylene glycol, bis(3-aminopropyl)-terminated polyethylene glycol, didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, and alkylamines, Preferably, the first ligand is selected from mercaptopropionic acid, mercaptobenzoic acid, mercaptoacetic acid, polyethylene glycol, bis(3-aminopropyl)-capped polyethylene glycol, dodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, preferably oleic acid, oleylamine, mercaptopropionic acid or a mixture thereof.

12. The method according to any of the preceding claims, wherein the growth temperature is in the range of 220°C to 340°C, preferably in the range of 240°C to 330°C, preferably in the range of 260°C to 320°C, preferably in the range of 270°C to 300°C.

13. The method according to any one of the preceding claims, wherein the total growth time is in the range of 6 hours to 30 hours, preferably in the range of 8 hours to 26 hours, preferably in the range of 8 hours to 24 hours, preferably in the range of 9 hours to 23 hours, preferably in the range of 10 hours to 22 hours, Optionally, wherein the total growth time is in the range of 8 hours to 19 hours, preferably in the range of 9 hours to 18 hours, preferably in the range of 10 hours to 17 hours, preferably in the range of 11 hours to 16 hours, or Optionally, wherein the total growth time is in the range of 14 hours to 28 hours, preferably in the range of 15 hours to 26 hours, preferably in the range of 16 hours to 24 hours, preferably in the range of 17 hours to 22 hours.

14. The method of any one of the preceding claims, wherein the nanocrystal composition comprises a Group III-V nanocrystal, wherein the nanocrystal comprises a core and a plurality of first ligands coordinated to a surface of the core, Preferably, the oxide remover is a compound capable of reacting with oxides on the surface of the crystal nucleus to remove the oxides from the crystal surface, Preferably, the oxide remover is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halide, indium halide and metal halide, wherein the metal is bismuth, lead or cadmium, Preferably, the oxide removing agent is hydrobromic acid.

15. The method according to any one of the preceding claims, wherein the molar ratio of the oxide remover to the sum of the first indium-containing compound and / or the first gallium-containing compound is in the range of 1:100 to 1:1000000, preferably in the range of 1:1000 to 1:100000, more preferably in the range of 1:000 to 1:50000 and / or The concentration of the oxide remover in the first mixture is in the range of 5 μM to 1000 μM, preferably in the range of 50 μM to 500 μM.

16. The method according to any one of the preceding claims, wherein step a) further comprises heating the first mixture to a first temperature in the range of 50°C to 150°C, Preferably, the first temperature is in the range of 60°C to 140°C, preferably in the range of 70°C to 130°C, preferably in the range of 80°C to 120°C, preferably in the range of 90°C to 110°C.

17. The method according to any one of the preceding claims, wherein step c) comprises: i) adding a first oxide remover and a composition comprising a III-V cluster to the first mixture at a growth temperature for a first growth time of 2 hours to 8 hours to provide a plurality of nanocrystals in the first mixture; ii) cooling the first mixture; iii) heating the first mixture to a growth temperature; iv) adding a third oxide remover and a composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time of 6 hours to 20 hours to provide a III-V nanocrystalline composition, Preferably, step iii) further comprises adding a second oxide remover to the first mixture before heating the first mixture to the growth temperature, Preferably, step i) further comprises heating the first mixture to a third temperature in the range of 50°C to 150°C, preferably in the range of 60°C to 140°C, preferably in the range of 70°C to 130°C, preferably in the range of 80°C to 120°C and preferably in the range of 90°C to 110°C.

18. The method according to claim 17, wherein the first growth time is in the range of 2.5 hours to 7 hours, preferably in the range of 3 hours to 6 hours, preferably in the range of 3.5 hours to 5.5 hours, preferably in the range of 4 hours to 5 hours, and / or The second growth time is in the range of 6 hours to 18 hours, preferably in the range of 6.5 hours to 16 hours, and more preferably in the range of 7 hours to 15 hours.

19. The method according to claim 17 or 18, wherein the first oxide remover, the second oxide remover and the third oxide remover are the same compound, It is preferred that the first oxide remover, the second oxide remover and the third oxide remover are hydrobromic acid.

20. The method of any one of the preceding claims, wherein the III-V clusters are amorphous particles comprising a Group III element and a Group V element, wherein the particles have a diameter of less than 2 nm, Preferably, the III-V cluster comprises phosphorus, arsenic, antimony or a mixture thereof.

21. A III-V nanocrystalline composition obtainable by any one of the preceding claims.

22. A substantially cuboctahedral III-V nanocrystal.

23. The nanocrystal of claim 22, wherein the nanocrystal comprises a core comprising indium and / or gallium and a nitrogen group element, Preferably, the nitrogen group element is phosphorus, arsenic, antimony or a mixture thereof, Preferably, the nitrogen group element is arsenic, antimony or a mixture thereof.

24. The nanocrystal of claim 22 or 23, wherein a plurality of ligands are coordinated to the surface of the core. Preferably, the ligand is an organic compound, an inorganic compound or a mixture thereof.

25. The nanocrystal according to any one of claims 22 to 24, wherein the nanocrystal composition exhibits an absorption peak in the range of 500 nm to 3000 nm, preferably in the range of 1300 nm to 1700 nm, preferably in the range of 1320 nm to 1680 nm, preferably in the range of 1340 nm to 1660 nm, preferably in the range of 1360 nm to 1640 nm, preferably in the range of 1380 nm to 1620 nm, preferably in the range of 1400 nm to 1600 nm, and / or Wherein the nanocrystalline composition exhibits an emission peak in the range of 1300nm to 1900nm, preferably in the range of 1320nm to 1880nm, preferably in the range of 1340nm to 1860nm, preferably in the range of 1360nm to 1840nm, preferably in the range of 1380nm to 1820nm, and preferably in the range of 1400nm to 1800nm.

26. A III-V nanocrystal composition comprising a plurality of nanocrystals according to any one of claims 22 to 25.

27. The nanocrystalline composition of claim 26, wherein the nanocrystalline composition exhibits an absorption full width at half maximum (FWHM) value of less than 250 nm, preferably less than 225 nm, preferably less than 200 nm, preferably less than 175 nm, and / or wherein the nanocrystalline composition exhibits an emission full width at half maximum (FWHM) value of less than 250 nm, preferably less than 225 nm, preferably less than 200 nm, preferably less than 175 nm.

28. The nanocrystalline composition of claim 26 or 27, wherein the nanocrystalline composition exhibits a peak-to-valley ratio in the range of 1 to 4, preferably in the range of 1 to 3.5, preferably in the range of 1 to 3, preferably in the range of 1.1 to 2.5, preferably in the range of 1.2 to 2.5, and / or wherein the nanocrystals exhibit a relative size dispersion of less than 25%, preferably less than 15%, preferably less than 10%, preferably in the range of 1% to 25%, preferably in the range of 1% to 20%, preferably in the range of 2% to 15%, preferably in the range of 3% to 10%.

29. An ink or film comprising the Group III-V nanocrystalline composition of any one of claims 26 to 28.

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