Shape-controlled synthesis of III-V colloidal nanocrystals

Abstract

The present invention provides a method for producing a III-V nanocrystal composition, the method comprising: forming a first mixture containing a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent; adding at least one pnictogen-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 removal reagent and a composition containing III-V clusters to the first mixture at the growth temperature for a total growth time of at least 6 hours to obtain a III-V nanocrystal composition. The present invention also provides cuboctahedral III-V nanocrystals that can be formed by the method of the present invention.

Description

[Technical Field]

[0001] The present invention relates generally to nanocrystals. In particular, the present invention relates to a method for producing a III-V nanocrystal composition, the method comprising: forming a first mixture containing a first indium-containing compound and / or a first gallium-containing compound, a first ligand, and a first solvent; adding at least one pnictogen-containing compound to the first mixture; heating the first mixture to a growth temperature in the range of 200°C to 350°C; and adding an oxide removal reagent and a composition containing III-V clusters to the first mixture at the growth temperature for a total growth time of at least 6 hours to obtain a 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 technology]

[0002] Nanocrystals are useful in a wide range of applications, for example, because their optical properties can be finely tuned to provide desired properties. The optical properties (e.g., light absorption and emission characteristics) of nanocrystals can be finely tuned by controlling their size. The largest nanocrystals produce the longest wavelengths (and lowest frequencies), while the smallest nanocrystals produce shorter wavelengths (and higher frequencies). The size of nanocrystals can be controlled by leveraging the method by which they are produced. This ability to finely tune their optical properties by controlling their size makes nanocrystals suitable for use in a wide range of applications, including, for example, photodetectors, sensors, solar cells, bioimaging and biosensing, photovoltaics, displays, lighting, security and counterfeiting, batteries, wired high-speed communications, quantum dot (QD) lasers, photocatalysis, spectrometers, injectable compositions, field-effect transistors, light-emitting diodes, lasers, photonic or optical switching devices, hydrogen generation, and metamaterials.

[0003] Although lead and other heavy metal nanocrystals have been shown to exhibit good performance, their use can be problematic in some industries due to their toxicity. There is a need in the industry to provide alternative quantum dot systems that avoid the use of toxic heavy metals such as lead.

[0004] III-V nanocrystals represent promising candidates to replace heavy metal-based nanocrystals, which were first synthesized over a decade ago. Of particular interest are InAs and InSb nanocrystals. However, so far, III-V nanocrystals have not been able to reproduce the desirable performance of lead-based nanocrystals.

[0005] InAs synthesis can be broadly divided into two categories depending on the arsenic precursor used in the synthesis: 1. Tris(trimethylsilyl)arsine Route—Alivisatos et al. (Appl. Phys. Lett. 1996, 69, 1432) reported the synthesis of InAs quantum dots using a dehalosilylation reaction in the presence of InCl3 + As[Si(CH3)3] at temperatures ranging from 240 to 265 °C, using the coordinating solvent trioctylphosphine (TOP), which acts as both a solvent and a ligand. Recently, Bawendi et al. (Nat. Comms. 2016, 7, 12749) and Jeong et al. (Nat. Comms. 2018, 9, 1) further developed a route in the presence of indium carboxylate, octadecene, and a sequential injection approach to synthesize InAs QDs. These InAs QDs have been utilized to synthesize core / shell QDs and for biological labeling and solar cells, among other uses. Recently, Sargent et al. (Nano. Lett., 2021, 21, 6057) developed an InAs photodetector with an EQE of 40% at a wavelength of 940 nm. 2. Aminoarsine Route—Inspired by the success of aminophosphines in developing InP QDs, 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) replaced In(III)Cl3 with In(I)Cl, which acts as a reducing agent, eliminating the need for an external reducing agent, and also serves as an indium source. Hens et al. (J. Am. Chem. Soc. 2021, 143, 4290) developed In(P)As QDs using a similar approach, replacing the hydride with an aminophosphine as the reducing agent. Photodetectors developed using this approach have an EQE of approximately 1% at 1400 nm.

[0006] However, prior art methods for producing III-V nanocrystals, including the approaches described above, lead to III-V nanocrystals with low charge transport capabilities, which limits their use in devices such as solar cells and photodetectors. DISCLOSURE OF THE INVENTION

[0007] Thus, there is an unmet need for III-V nanocrystals with improved charge transport capabilities.

[0008] Summary of the Invention According to a first aspect, the present invention provides a method for producing a III-V nanocrystal composition, comprising the steps of: 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 hydroxyl functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid; 24 an organic compound; b) adding at least one pnictogen-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 removal reagent 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 obtain a III-V nanocrystal composition; The present invention provides a method comprising:

[0009] According to a second aspect, the present invention provides a substantially cuboctahedral III-V nanocrystal.

[0010] 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 explanation of the drawings]

[0011] [Figure 1] FIG. 2 shows the UV-visible spectrum of InAs nanocrystals prepared according to the method of the first aspect of the present invention (Example 2), with an absorbance peak at 1400 nm. [Figure 2] FIG. 2 shows the UV-visible spectrum of InAs nanocrystals prepared according to the method of the first aspect of the present invention (Example 2), with an absorbance peak at 1100 nm. [Figure 3] FIG. 1 shows a selection of electron micrographs of InAs nanocrystals with an absorbance peak at 1400 nm, prepared according to the method of the present invention (Example 2). [Figure 4] Figure 4 shows a further selection of electron micrographs of InAs nanocrystals with an absorbance peak at 1400 nm prepared according to the method of the present invention (Example 2). Figures 4(a) and (b) show InAs nanocrystals with oleic acid as the ligand compound, while Figures 4(c) and (d) show InAs nanocrystals with InBr as the ligand. Figure 4(b) was used to calculate the average size of the nanocrystals with an absorbance peak at 1400 nm. [Figure 5] Figure 5(i) shows a selection of electron micrographs of InAs nanocrystals with an absorbance peak at 1100 nm prepared according to the method of the present invention (Example 2). Figure 5(i) was used to calculate the average size of the nanocrystals with an absorbance peak at 1100 nm. [Figure 6] FIG. 1 shows the UV-visible spectra of InAs nanocrystals with absorbance peaks at 1100 nm and 1400 nm, both prepared according to the method of the first aspect of the present invention (Example 4). [Figure 7] 7(b)(v) shows a selection of electron micrographs of InAs nanocrystals with absorbance peaks at 1100 nm and 1400 nm, both prepared according to the method of the first aspect of the present invention (Example 4). Figure 7(b)(v) was used to calculate the average size of the nanocrystals with an absorption peak at 1100 nm. [Figure 8] 1 shows an electron micrograph image of InAs nanocrystals with an absorbance peak at 1400 nm prepared according to the method of the present invention (Example 4), which was used to calculate the average size of the nanocrystals. DETAILED DESCRIPTION OF THE INVENTION

[0012] Detailed Description When describing embodiments of the present invention, the terms used should be construed in accordance with the following definitions, unless the context dictates otherwise.

[0013] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise. By way of example, a "nanocrystal" means one nanocrystal or more than one nanocrystal. By way of example, an "indium-containing compound" means one indium-containing compound or more than one indium-containing compound. Reference to a number used in conjunction with comprising language includes compositions containing that number or more than that number.

[0014] The terms "comprising," "comprises," and "comprised of," as used herein, are synonymous with "including," "includes," or "containing," "contains," and are inclusive or open-ended and do not exclude any additional, unrecited members, elements, or method steps. The terms "comprising," "comprises," and "comprised of" also include the term "consisting of."

[0015] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be used alone, or any combination of two or more of the listed items can be used.For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone; B alone; C alone; A and B combined; A and C combined, B and C combined; or A, B, and C combined.

[0016] As used herein, unless expressly stated otherwise, all numbers expressing values, ranges, percentage quantities, etc. can be read as if preceded by the word "about" even if the word "about" does not explicitly appear.

[0017] 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 being employed to determine the value. The term "about" is intended to encompass variations of no more than + / - 10%, no more than + / - 5%, or no more than + / - 0.1% from the specified value, where such variations are appropriate for practice in this disclosure. It is to be understood that the value to which the modifier "about" refers is also that which is specifically disclosed.

[0018] The recitation of numerical ranges by endpoints includes all integers and, where appropriate, fractions subsumed within that range (e.g., 1 to 5, e.g., when referring to the number of elements, can include 1, 2, 3, 4; e.g., when referring to a measurement, can also include 1.5, 2, 2.75, and 3.80). The recitation of endpoints also includes the endpoint values ​​themselves (e.g., 1.0 to 5.0 includes both 1.0 and 5.0). Every numerical range recited herein is intended to include all subranges subsumed therein.

[0019] Unless otherwise defined, all terms used in this disclosure, including technical and scientific terms, have the meanings that are commonly understood by those skilled in the art to which this disclosure belongs.In order to utilize further guidance and better understand the teachings of this disclosure, definitions are included for the terms used in the description.All publications referred to in this specification are incorporated herein by reference.

[0020] As used herein, unless otherwise defined, the term "composition" may be open-ended or closed-ended. For example, a "composition" may comprise the specified materials, i.e., nanocrystals, and additional unspecified materials, or may consist of the specified materials, i.e., to the substantial exclusion of unspecified materials.

[0021] method According to a first aspect, the present invention provides a method for producing a III-V nanocrystal composition, comprising the steps of: 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 hydroxyl functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid; 24 an organic compound; b) adding at least one pnictogen-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 removal reagent 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 obtain a III-V nanocrystal composition; The present invention provides a method comprising:

[0022] Any suitable indium-, gallium-, and pnictogen-containing compounds may be used.

[0023] As previously mentioned, heavy-metal-free nanocrystals are highly desirable in the quantum dot industry due to their lower toxicity. III-V nanocrystals offer a promising alternative to heavy-metal-based materials, but are still underutilized because their performance and optical properties are not yet comparable to those of lead-based nanocrystals.

[0024] The performance of colloidal quantum dots (CQDs) and optoelectronic devices containing them strongly depends on the order and interaction of nanocrystals in solid thin films. Generally, it is understood in the art that shape control in nanocrystal synthesis can affect the order and interaction of nanocrystals, and therefore, if controlled, can lead to improved optical properties of the resulting nanocrystals. For example, Pietryga et al. (J. Am. Chem. Soc. 2008, 130, 14, 4879-4885) reported the room-temperature synthesis of large lead selenide (PbSe) nanocrystals exhibiting cubic shapes. Lee et al. (Adv. Mater. 2003, 15(5), 441) reported the shape control of different colloidal inorganic nanocrystals from nanorods to cubic shapes by changing different growth parameters.

[0025] Solid thin films containing colloidal quantum dots with sufficient surface passivation and high packing density and bonding strength along specific facets should exhibit enhanced charge carrier mobility and transport.

[0026] One common approach used to improve the packing density of CQDs involves replacing the natural long-chain organic ligands on as-synthesized quantum dots with short, conductive ligands. This is typically achieved via a ligand exchange step after the initial synthesis, where the natural long-chain organic ligands are used to control nanocrystal growth. For example, Biondi et al. (Adv. Mater. 2021, 2101056) exchanged the natural ligands attached to PbS CQDs to increase the (100):(100) facet bonding, leading to a 10-fold increase in hole mobility and faster device response.

[0027] However, there is a significant lack of understanding in the art regarding how to achieve beneficial shape control with III-V nanocrystals. To the best of our knowledge, there has been no reported work in the literature on controlling the shape and facets of short-wave infrared (SWIR) InAs and InSb quantum dots while maintaining nanocrystal confinement and a sufficient degree of surface passivation. The lack of understanding of controlling InAs or InSb CQD shape to facilitate specific facet bonding in solid thin films can lead to performance limitations in state-of-the-art devices. Indeed, 1400 nm InAs CQD photodiodes, as recently reported by Hens and coworkers, exhibit only a 1% EQE and high dark current.

[0028] Nevertheless, the present inventors have discovered techniques for controlling the shape of III-V nanocrystals, leading to improved optical properties of the resulting nanocrystals.

[0029] The method of the first aspect of the present invention provides a nanocrystal composition comprising substantially cuboctahedral III-V nanocrystals by controlling the thermodynamics and reaction conditions of nanocrystal growth. In particular, the method of the first aspect controls nanocrystal growth by selecting a suitable growth temperature within the range of 200°C to 350°C, adding an oxide removal reagent to the first mixture, and selecting a suitable total growth time of at least 6 hours. Without wishing to be bound by theory, when these conditions are met, the method of the first aspect produces substantially cuboctahedral III-V nanocrystals.

[0030] Without wishing to be bound by theory, it is believed that the cuboctahedral shape of III-V nanocrystals leads to improved alignment of the nanocrystal facets. Better alignment of the nanocrystal facets leads to improved charge transport in the nanocrystals, as shown in the examples below. Furthermore, the nanocrystals produced by the method of the first aspect of the present invention are stable and highly monodisperse. The method of the present invention provides an approach for tuning the band gap of nanocrystals, resulting in high crystallinity and high uniformity.

[0031] The nanocrystals produced by the method of the first embodiment are very easy to phase transfer from nonpolar to polar solvents during solution-inorganic ligand exchange to form high-quality QD inks. The resulting unique shape helps pack the nanocrystals into highly ordered QD thin films with favorable facet alignment, enhancing charge transport and leading to improved device performance.

[0032] The nanocrystals produced by the method of the first aspect are generally semiconductor nanocrystals, particularly quantum dots.

[0033] As used herein, the term "nanocrystal" is used to refer to a crystalline particle having at least one dimension less than 100 nanometers (nm).

[0034] As used herein, the term "semiconductor nanocrystal" is used to refer to a semiconductor crystalline material that exhibits quantum confinement effects that allow it to mimic the properties of an atom, with at least one dimension less than 100 nm.

[0035] As used herein, the term "quantum dot" is used to refer to spherical semiconductor nanocrystals. Quantum dots may also be known as zero-dimensional nanocrystals.

[0036] As used herein, the term "III-V semiconductor nanocrystals" is used to refer to semiconductor nanocrystals that include group III and group V elements.

[0037] As used herein, the term "Group III element" refers to an element in Group 13 of the Periodic Table of Elements. For example, the Group III element may be boron, aluminum, gallium, indium, or thallium. Preferably, the Group III element is indium.

[0038] As used herein, the terms "Group V element" and "pnictogen" are used to refer to elements in Group 15 of the Periodic Table of Elements. For example, the Group V element may be nitrogen, phosphorus, arsenic, antimony, or bismuth. Preferably, the Group V element is arsenic.

[0039] As used herein, the term "ligand" refers to a compound that can form a complex with a nanocrystal by coordinating to the surface of the nanocrystal. Preferably, multiple ligands at least partially cover the surface of the nanocrystal. More preferably, multiple ligands cover the surface of the nanocrystal. Nanocrystals generally comprise a crystalline core with a size of about tens of nanometers. Nanocrystals are typically stabilized in colloidal solution by surface-capping ligands, which coordinate to the crystalline core as Lewis acidic (Z-type), Lewis basic (L-type), or anionic (X-type) species.

[0040] 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 An organic compound, where x and y are integers, is used to refer to an organic compound containing at least x and no more than y carbon atoms.

[0041] As used herein, the term "inorganic compound" is used to refer to a compound other than an organic compound.

[0042] As used herein, the terms "median particle size" and "average particle size" refer to the Feret diameter of particles. 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 of the particle. This value can be obtained by standard imaging software or can be determined manually based on micrographs, such as those obtained by TEM.

[0043] A composition comprising an oxide-removing reagent and a group III-V cluster (reagent of step c)) is added to the first mixture at the growth temperature for a total growth time of at least 6 hours to obtain a group III-V nanocrystal composition. The oxide-removing reagent may be added to the first mixture together with or separately from the composition comprising the group III-V cluster. The oxide-removing reagent may be added to the first mixture simultaneously with or sequentially from the composition comprising the group III-V cluster. They may form part of the same solution before addition, or may be separate solutions. Preferably, the reagents of step c) are added simultaneously and separately.

[0044] The reagents of step c) may be added in any suitable manner, for example by injection. The reagents of step c) may be added continuously over the total growth time, in a single injection, or by a combination of these techniques. The reagents of step c) may be added at the growth temperature (a temperature in the range of 200° C. to 350° C.), or at a temperature above or below the reagents of step c). Preferably, the reagents of step c) are added at the growth temperature.

[0045] The first mixture may contain an indium-containing compound and / or a gallium-containing compound. Thus, the first mixture may contain an indium-containing compound but not a gallium-containing compound. Alternatively, the first mixture may contain a gallium-containing compound but not an indium-containing compound. Alternatively, the first mixture may contain an indium-containing compound and may also contain a gallium-containing compound. In a particularly preferred embodiment, the first mixture contains an indium-containing compound.

[0046] Further control over the reaction can be achieved by selecting a preferred indium precursor. The preferred indium-containing compounds and the preferred remarks related to indium-containing compounds apply throughout the present invention to all indium-containing compounds, including the second indium-containing compound discussed below. Preferably, the first mixture contains a first indium-containing compound. Preferably, the first indium-containing compound is selected from the group consisting of indium acetate, indium triformate, indium nitrate, indium nitrate hydrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, indium perchlorate hydrate, and mixtures thereof. More preferably, the first indium-containing compound is indium acetate.

[0047] In some embodiments, the first mixture comprises a first gallium-containing compound. When a gallium-containing compound is used, further control over the shape and reaction can be achieved by selecting a preferred gallium precursor. Preferably, the first 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 gallium perchlorate hydrate. Preferably, the first gallium-containing compound is gallium acetate.

[0048] In some embodiments, the first mixture comprises a first indium-containing compound and a first gallium-containing compound, and the resulting nanocrystals are ternary or quaternary. The preferred indium-containing and gallium-containing compounds described above apply equally to this embodiment.

[0049] The reaction is carried out in a solvent in which the components of the first mixture are soluble. Indium-, gallium-, and pnictogen-containing compounds are generally soluble in both polar and nonpolar solvents. Generally, a nonpolar solvent is used in the initial synthesis because long-chain organic ligands are used. Preferably, the first solvent is therefore a nonpolar solvent. Preferably, the first solvent has a dielectric constant of less than 3, more preferably less than 2.5, at 20°C. As used herein, the term "dielectric constant" refers to the ratio of the dielectric constant of a substance to the dielectric constant of a vacuum, and is a dimensionless number. As defined in "Permittivity (Dielectric Constant) of Liquids" by Christian Wohlfarth, the dielectric constant (often referred to as the dielectric constant) of a substance is the ratio of the electric displacement D to the electric field strength E when an external field is applied to the substance. The dielectric constant is measured using a BI-870 dielectric constant meter available from Brookhaven Instruments, using a sensitivity range of 1 to 200. The instrument may be calibrated with liquids of known dielectric constants: polar solvents generally have higher dielectric constants, while non-polar solvents generally have lower dielectric constants.

[0050] Preferably, the first solvent is a compound of formula C n H 2n+2 Hydrocarbons of formula C n H 2n+1 NH2 is selected from the group consisting of alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary phosphines, and secondary phosphines, and n is in the range of 6 to 20.

[0051] The components in the first mixture may be combined in any suitable amount and in any suitable order, and these suitable amounts will be apparent to those skilled in the art based on common general knowledge. Preferably, the molar ratio of the at least one pnictogen-containing compound to the first indium-containing compound and the first gallium-containing compound is within the range of 0.5:1 to 1:0.5, preferably within the range of 0.5:1 to 1:1, and preferably within the range of 0.6:1 to 1:1. The molar ratio (MR1) of the at least one pnictogen-containing compound to the first indium-containing compound and the first gallium-containing compound is defined as the sum of the total number of moles of all pnictogen-containing compounds in the first mixture to the total number of moles of all indium-containing compounds and all gallium-containing compounds in the first mixture, as illustrated in the following equation:

[0052]

number

[0053] 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 defined above. The ratio of Group V element (pnictogen) to Group III element (MR2) in the first mixture is generally the same as MR1. MR2 is preferably within the range of 0.5:1 to 1:0.5, preferably within the range of 0.5:1 to 1:1, and preferably within the range of 0.6:1 to 1:1. The Group V element may be present in the first mixture as part of a pnictogen-containing compound, and the Group III element may be present in the first mixture as part of a Group III precursor.

[0054] In some embodiments, step b) includes adding one pnictogen-containing compound, where the pnictogen-containing compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds, and antimony-containing compounds. By adding one pnictogen-containing compound, the resulting nanocrystals contain one pnictogen in the crystalline core. Thus, this embodiment can produce InAs nanocrystals, InSb nanocrystals, InP nanocrystals, InGaAs nanocrystals, InGaSb nanocrystals, InGaP nanocrystals, GaAs nanocrystals, GaSb nanocrystals, and GaP nanocrystals.

[0055] In some embodiments, step b) includes adding two pnictogen-containing compounds, where the first pnictogen-containing compound is an arsenic-containing compound and the second pnictogen-containing compound is a phosphorus-containing compound or an antimony-containing compound. By adding two pnictogen-containing compounds, the resulting nanocrystals contain two pnictogens in the crystal core. Thus, this embodiment can produce InAsSb nanocrystals, InAsP nanocrystals, InGaAsSb nanocrystals, and InGaAsP nanocrystals.

[0056] Preferably, the arsenic-containing compound is selected from the group consisting of tris(trialkylsilyl)arsine (wherein the alkyl is methyl, ethyl, propyl, butyl, or substituted), tris(trimethylgermyl)arsine, tris(triphenylsilyl)arsine, triphenylarsine, aminoarsine (RN)As (wherein R is alkyl or aryl), arsenic halides, alkyl or aryl arsenous acids, and mixtures thereof. Preferably, the arsenic-containing compound is selected from the group consisting of tris(trimethylsilyl)arsine, tris(trimethylgermyl)arsine, tris(dimethylamino)arsine, and mixtures thereof. A particularly preferred arsenic-containing compound is tris(trimethylsilyl)arsine.

[0057] Preferably, the antimony-containing compound is selected from the group consisting of tris(trialkylsilyl)antimony (wherein the alkyl is methyl, ethyl, propyl, butyl, or substituted), tris(trimethylgermyl)antimony, and aminoantimony (RN)Sb (wherein R is alkyl or aryl), antimony halides, antimony dialkaylamides, dialkylsilylamides, antimony hydrides, antimony aziridinides, antimony thiolates, antimony carbamates, antimony guanidinates, and mixtures thereof. Preferably, the antimony-containing compound is selected from the group consisting of tris(trimethylsilyl)antimony, tris(trimethylgermyl)antimony, tris(dimethylamino)antimony, and mixtures thereof.

[0058] Preferably, the phosphorus-containing compound is selected from the group consisting of tris(trialkylsilyl)phosphine (wherein the alkyl is methyl, ethyl, propyl, butyl, or substituted), tris(trimethylgermyl)phosphine, tris(triphenylsilyl)phosphine, triphenylphosphine, aminophosphine (RN)P (wherein R is alkyl or aryl), phosphonic acid halides, alkyl or aryl phosphonic acids, and mixtures thereof. Preferably, the phosphorus-containing compound is selected from the group consisting of tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine, and mixtures thereof. A particularly preferred phosphorus-containing compound is tris(trimethylsilyl)phosphine.

[0059] The ligands (e.g., first and second ligands) of the present invention are generally provided as a plurality of ligands. The term "first ligand" is used to refer to the ligand component of the first mixture, and it will be readily understood that the first ligand component will include a plurality of ligands. Similarly, as discussed below, this also applies to the second ligand in the second mixture.

[0060] The first ligand is a C-C ligand containing a functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid. 24 The first ligand is an organic compound. The first ligand can be any such compound that is capable of forming a complex with the nanocrystal by coordinating to the surface of the nanocrystal.

[0061] The molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound may be any suitable ratio, and suitable values ​​will be apparent to those skilled in the art based on common general knowledge. The molar ratio of the first ligand to the first indium-containing compound and / or gallium-containing compound may be sufficient to coordinate the ligand to the crystalline core of the nanocrystal under development and 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, preferably at least 2.5:1.

[0062] Preferably, the first ligand is of formula C n H 2n+1 NH2 alkylamines, formula C n H 2n+1 COOH alkyl carboxylic acid, formula C n H 2n+1and n is selected from the group consisting of alkyl phosphonic acids of PO3H2, aromatic phosphonic acids, alkyl or aryl thiols, alkyl or aryl arsenous acids, and mixtures thereof, and n is in the range of 6 to 20. Preferably, the first ligand is selected from the group consisting of aminobenzoic acid, dicarboxylic acids, aminoalkylcarboxylic acids, mercaptopropionic acid, mercaptobenzoic acid, thioalkanes, dithioalkanes, thiocarboxylic acids, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl)-terminated poly(ethylene 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 the group consisting of mercaptopropionic acid, mercaptobenzoic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl) terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, and bis(diphenylphosphino)methane.

[0063] The growth temperature can be any temperature at which nanocrystals grow. Maintaining the mixture at the growth temperature can include maintaining the temperature of the mixture at a specific suitable temperature. However, it should be understood that the temperature can vary during the total growth time and during the first and second growth times, as discussed below. Thus, maintaining the first mixture at the growth temperature can 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.

[0064] 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.

[0065] The growth temperature can be varied to produce nanocrystals of different sizes. For example, lower growth temperatures (e.g., 200°C to 250°C) can lead to smaller nanocrystals, whereas higher growth temperatures (e.g., above 270°C) can lead to larger nanocrystals. Thus, if smaller nanocrystals are desired, a lower growth temperature may be preferred.

[0066] The growth time is the length of time that the first mixture is at the suitable growth temperature; for example, the growth time may be the length of time that the first mixture is at a temperature in the range of 200°C to 350°C. The total growth time is the total length of time that the first mixture is at the growth temperature during synthesis. The total growth time may be an uninterrupted period, i.e., a period during which the temperature of the first mixture does not exceed or fall below the suitable growth temperature range. Alternatively, the total growth time may be divided into segments, such as a first growth time and a second growth time, during which the temperature of the first mixture may fall below or exceed the suitable growth temperature range. For example, the first mixture may be maintained at the suitable growth temperature for a first growth time of 4 hours, cooled, and then reheated to the suitable growth temperature for a second growth time of 8 hours. In this example, the total growth time would be 12 hours.

[0067] Preferably, the total growth time is in the range of 6 to 30 hours, preferably in the range of 8 to 26 hours, preferably in the range of 8 to 24 hours, preferably in the range of 9 to 23 hours, preferably in the range of 10 to 22 hours.

[0068] Contrary to what has been believed in previous literature, the present inventors have found that slow growth of nanocrystals allows for greater thermodynamic control of the nanocrystal facets, with longer total growth times as required by the method of the first aspect of the present invention. Longer total growth times generally result in cubo-octahedral nanocrystals.

[0069] The total growth time may be varied to tune the bandgap of the resulting nanocrystals. For example, shorter total growth times (e.g., in the range of 6 to 10 hours) may lead to InAs nanocrystals with an absorption peak around 1400 nm, while longer total growth times (e.g., greater than 12 hours) may lead to InAs nanocrystals with an absorption peak around 1600 nm. This tunability is highly advantageous, allowing for the production of a wide variety of nanocrystals for a wide variety of purposes.

[0070] If a smaller bandgap is desired, the total growth time is preferably in the range of 8 to 19 hours, preferably in the range of 9 to 18 hours, preferably in the range of 10 to 17 hours, preferably in the range of 11 to 16 hours.

[0071] If a larger bandgap 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, preferably in the range of 17 to 22 hours.

[0072] Preferably, the nanocrystal composition comprises a III-V nanocrystal, the nanocrystal comprising a crystalline core and a plurality of first ligands coordinated to the surface of the crystalline core. The crystalline core generally comprises indium and / or gallium introduced by an indium-containing compound and / or a gallium-containing compound. The crystalline core generally comprises a pnictogen introduced by a pnictogen-containing compound. Thus, a wide variety of different nanocrystal systems can be produced by the method of the first aspect.

[0073] As the nanocrystals grow, the first ligand coordinates to the surface of the crystalline core of the nanocrystals, thereby stabilizing the nanocrystals and aiding in their growth.

[0074] The oxide remover is used in the method of the first embodiment to at least partially remove any surface oxidation that may occur on the surface of the crystalline core of the nanocrystal as it grows. For example, Chaudret et al. (Journal of American Chemical Society, 2010, 18147-18157, 132 (51)) has hypothesized that the surface of the crystalline core may be oxidized during nanocrystal synthesis. Without wishing to be bound by theory, it is believed that the layer of oxidized material around the nanocrystal resulting from surface oxidation prevents and / or hinders further growth of the nanocrystal. Therefore, surface oxidation is undesirable.

[0075] The oxide removing agent of the present invention may be any suitable compound or composition, and suitable oxide removing agents will be recognized by those skilled in the art based on common general knowledge. Preferably, the oxide removing agent is a compound capable of reacting with oxides on the surface of the crystalline core to remove the oxides from the surface of the crystalline core. Preferably, the oxide removing agent is an organic acid, an organic alkali, or a metal halide. Preferably, the oxide removing agent is selected from the group consisting of 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, and the metal is bismuth, lead, or cadmium. In a particularly preferred embodiment, the oxide removing agent is hydrobromic acid.

[0076] The oxide-removing agent is preferably added in a small amount, for example, 10 ppm. Preferably, the molar ratio of the oxide-removing reagent 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, and more preferably in the range of 1:000 to 1:50,000. Preferably, the amount of the oxide-removing reagent 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 may correspond to a concentration in the first mixture immediately after addition of the oxide-removing reagent in the range of 5 μM to 1,000 μM, preferably in the range of 50 μM to 500 μM.

[0077] Preferably, steps a), b) and c) are carried out under inert conditions, for example, steps a), b) and c) may be carried out under nitrogen, argon, or another inert gas.

[0078] In a preferred embodiment, step a) further comprises degassing the first mixture under vacuum (about 0.1 mbar) for a degassing time in the range of 5 to 180 minutes at a degassing temperature in the range of 50°C to 150°C. Preferably, the degassing time is in the range of 20 to 160 minutes, preferably in the range of 40 to 140 minutes, preferably in the range of 60 to 120 minutes, preferably in the range of 80 to 100 minutes. Preferably, the degassing temperature is in the range of 70°C to 150°C, preferably in the range of 80 to 140°C, preferably in the range of 90 to 130°C, preferably in the range of 100 to 120°C.

[0079] Preferably, step a) further comprises heating the first mixture to a first temperature in the range of from 50° C. to 150° C. Preferably, the first temperature is in the range of from 60° C. to 140° C., preferably in the range of from 70° C. to 130° C., preferably in the range of from 80° C. to 120° C., preferably in the range of from 90° C. to 110° C.

[0080] When the first mixture is degassed and heated to the first temperature, the degassing occurs before heating the first mixture to the first temperature.

[0081] Preferably, step c) comprises: i) adding a first oxide removal reagent and a composition comprising a group III-V cluster to a first mixture at a growth temperature for a first growth time ranging from 2 hours to 8 hours to obtain a plurality of nanocrystals in the first mixture; ii) allowing the first mixture to cool; iii) heating the first mixture to a growth temperature; iv) adding a third oxide removal reagent and a composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time in the range of 6 hours to 20 hours to obtain a III-V nanocrystal composition. Includes:

[0082] When step c) comprises steps i) to iv) as described above, the method of the first aspect further comprises the steps of: forming a first mixture including 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 hydroxyl functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid; 24 an organic compound; adding at least one pnictogen-containing compound to the first mixture and heating the first mixture to a growth temperature in the range of 200° C. to 350° C.; adding a first oxide removal reagent and a composition comprising a group III-V cluster to the first mixture at a growth temperature for a first growth time in the range of 2 hours to 8 hours to obtain a plurality of nanocrystals in the first mixture; allowing the first mixture to cool; heating the first mixture to a growth temperature; adding a third oxide removal reagent and a composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time in the range of 6 to 20 hours to obtain a III-V nanocrystal composition; This essentially involves:

[0083] Preferably, step iii) further comprises adding a second oxide-removing reagent to the first mixture before heating the first mixture to the growth temperature.

[0084] 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., preferably in the range of 90° C. to 110° C. The second oxide-removing reagent is preferably added when the first mixture is at the third temperature.

[0085] The nanocrystals produced by step i) generally exhibit a lower absorption peak. For example, for InAs nanocrystals produced by step i), the absorption peak may be around 1100 nm. This absorption peak then increases over the total growth time.

[0086] 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.

[0087] 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.

[0088] As explained above, the total growth time here will be the sum of the first growth time and the second growth time.

[0089] Preferably, the nanocrystal composition comprises a III-V nanocrystal, the nanocrystal comprising a crystalline core and a plurality of first ligands coordinated to the surface of the crystalline core, and the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are each independently compounds capable of reacting with oxides on the surface of the crystalline core to remove oxides from the surface of the crystalline core.

[0090] The first oxide removal reagent, the second oxide removal reagent and the third oxide removal reagent are each independently selected with the same preferences as described above with respect to the oxide removal agent in step c).

[0091] In some embodiments, the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are the same compound or different compounds. Preferably, the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are the same compound. Preferably, the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are hydrobromic acid.

[0092] Preferably, the first mixture contains a compound selected from the group consisting of secondary amines, zinc carboxylates, and mixtures thereof, and preferably, the compound is dioctylamine. This compound is used to further enhance shape control of the nanocrystals by complexing with the pnictogen-containing compound. In this way, the reactivity of the pnictogen-containing compound can be reduced, leading to better control over the size and size distribution of the nanocrystals. Preferably, this compound is used when the pnictogen-containing compound is tris(trimethylsilyl)arsine or tris(trimethylsilyl)antimony, because these compounds are particularly reactive.

[0093] The method of the first aspect involves adding III-V clusters to the first mixture. III-V clusters, as defined herein, are amorphous particles containing group III and group V elements, with diameters of less than 2 nm as measured by TEM. These particles are sometimes referred to as magic-size particles (MSCs). The composition containing III-V clusters used in the method of the first aspect of the invention may be prepared in advance or may be prepared as part of the method of the first aspect of the invention.

[0094] In some embodiments, the method further comprises preparing a composition comprising a group III-V cluster; 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 aryl group containing a functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid. 24 an organic compound; B) adding at least one pnictogen-containing compound to the second mixture under constant stirring to obtain III-V clusters; Includes:

[0095] Preferably, the III-V cluster contains phosphorus, arsenic, antimony, or a mixture 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 a characteristic absorption peak around 330 to 400 nm. InAs clusters exhibit this absorption peak around 370 to 570 nm. InSb clusters exhibit a characteristic absorption peak around 380 to 650 nm. InGaAs clusters exhibit a characteristic absorption peak around 300 to 400 nm.

[0096] The second mixture generally corresponds to the first mixture. For example, if the first mixture contains a first indium-containing compound, the second mixture generally should contain a second indium-containing compound. Furthermore, the preference of the first indium-containing compound and the second indium-containing compound is the same, that is, the second indium-containing compound is preferably any of the indium-containing compounds specified above in relation to the first indium-containing compound, particularly 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.

[0097] Preferably, the second mixture includes a second indium-containing compound.

[0098] In some embodiments, the second mixture comprises a second gallium-containing compound.Furthermore, the preference of the first gallium-containing compound and the second gallium-containing compound is the same, that is, the second gallium-containing compound is preferably any of the gallium-containing compounds specified above in relation to the first gallium-containing compound, particularly gallium acetate.The first gallium-containing compound and the second gallium-containing compound can be the same or different.Preferably, the first gallium-containing compound and the second gallium-containing compound are the same.

[0099] In some embodiments, the second mixture includes a second indium-containing compound and a second gallium-containing compound.

[0100] The first and second solvents have the same preference, i.e., the second solvent is preferably any of the solvents specified above in relation to the first solvent. The first and second solvents may be the same or different. Preferably, the first and second solvents are the same. Preferably, the second solvent is a non-polar solvent. Preferably, the second solvent has a dielectric constant at 20°C of less than 3, more preferably less than 2.5. Preferably, the second solvent is a solvent represented by the formula C n H 2n+2 Hydrocarbons of formula C n H 2n+1 The second solvent is selected from the group consisting of alkylamines of NH, 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.

[0101] The molar ratios as specified above in relation to the first indium-containing compound and / or the first gallium-containing compound apply equally to the preferred ratios in the method of producing III-V clusters.

[0102] The components in the second mixture may be combined in any suitable amount and in any suitable order, and these suitable amounts will be apparent to those skilled in the art based on common general knowledge. Preferably, the molar ratio of the at least one pnictogen-containing compound to the second indium-containing compound and the second gallium-containing compound is within the range of 0.5:1 to 1:0.5, preferably within the range of 0.5:1 to 1:1, and preferably within the range of 0.6:1 to 1:1. The molar ratio (MR3) of the at least one pnictogen-containing compound to the second indium-containing compound and the second gallium-containing compound is defined as the sum of the total number of moles of all pnictogen-containing compounds in the second mixture to the total number of moles of all indium-containing compounds and all gallium-containing compounds in the first mixture, as illustrated in the following equation:

[0103]

number

[0104] The second indium-containing compound and the second gallium-containing compound are each a Group III precursor. The ratio of Group V element (pnictogen) to Group III element (MR4) in the second mixture is generally the same as MR3. MR4 is preferably 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. The Group V element may be present in the second mixture as part of a pnictogen-containing compound, and the Group III element may be present in the second mixture as part of a Group III precursor.

[0105] Preferably, the molar ratio of the at least one pnictogen-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.

[0106] In certain embodiments, step B) comprises adding one pnictogen-containing compound, wherein the pnictogen-containing compound is selected from the group consisting of a phosphorus-containing compound, an arsenic-containing compound, and an antimony-containing compound.

[0107] In certain embodiments, step B) includes adding two pnictogen-containing compounds, wherein a first pnictogen-containing compound is an arsenic-containing compound and a second pnictogen-containing compound is a phosphorus-containing compound or an antimony-containing compound.

[0108] The first phosphorus-containing compound and the second phosphorus-containing compound have the same preference, i.e., the second phosphorus-containing compound is preferably any of the phosphorus-containing compounds specified above in relation to 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.

[0109] The preference of the first arsenic-containing compound and the second arsenic-containing compound is the same, that is, the second arsenic-containing compound is preferably any of the arsenic-containing compounds specified above in relation to 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.

[0110] The first antimony-containing compound and the second antimony-containing compound have the same preference, i.e., the second antimony-containing compound is preferably any of the antimony-containing compounds specified above in relation to 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.

[0111] As noted 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.

[0112] The first and second ligands have the same preference, i.e., the second ligand is preferably any of the ligands specified above in relation to the first ligand. The first and second ligands may be the same or different. Preferably, the first and second ligands are the same.

[0113] III-V nanocrystal compositions obtainable by the method of the first aspect of the present invention. III-V nanocrystal compositions obtainable by the method of the first aspect of the present invention may be readily distinguished from nanocrystal compositions prepared by prior art methods because the nanocrystals produced by the method of the present invention are cuboctahedral.

[0114] product According to a second aspect, the present invention provides a substantially cuboctahedral III-V nanocrystal. Preferably, the nanocrystal is cuboctahedral. To the best of the inventors' knowledge, there have been no disclosures of cuboctahedral III-V nanocrystals, the shape of which leads to improved optoelectronic properties, as discussed above.

[0115] As used herein, the term "cuboctahedral" refers to the supramolecular structure of a crystalline material in which the 3D shape of the material resembles a cuboctahedron. A cuboctahedron is a polyhedron with eight triangular faces and six square faces. A cuboctahedron has 12 identical vertices, where two triangles and two squares meet, and 24 identical edges, separating each triangle from a square. Shape and structure are well understood by those skilled in the art and can be analyzed via TEM. Typically, nanocrystal shape is determined from TEM and HR TEM images, either by human eye or via image analysis software (e.g., Image J) that requires user input.

[0116] High-resolution TEM (HRTEM) may be used to image nanocrystals and determine their shape. Fast Fourier transform (FFT) analysis may be performed on HRTEM micrographs. If the nanocrystals are cuboctahedral, they will often appear in TEM images looking along the 0110 zone axis with six boundary facets (four {111} and two {002}). These features correspond to single-crystalline fcc nanoparticles with a cuboctahedral shape. HR TEM images of single particles provide additional detail in accurately determining shape.

[0117] In cuboctahedral III-V nanocrystals, the atoms forming the cuboctahedron are generally Group III and Group V elements. Preferably, the nanocrystals comprise a crystalline core comprising indium and / or gallium and a pnictogen. Preferably, the pnictogen is phosphorus, arsenic, antimony, or a mixture thereof. Preferably, the pnictogen is arsenic, antimony, or a mixture thereof.

[0118] In some embodiments, multiple ligands are coordinated to the surface of the crystalline core of the nanocrystal.Preferably, the ligands are organic compounds, inorganic compounds, or mixtures thereof.The preference of the ligands of the second aspect and the first aspect is the same, that is, the ligands of the second aspect are preferably any of the ligands specified above in relation to the first aspect.

[0119] The absorption peaks exhibited by nanocrystals vary significantly depending on the composition of the nanocrystal's crystalline core. Generally, nanocrystal compositions exhibit an absorption peak within the range of 500 nm to 3000 nm. The absorption peak can be tailored anywhere within the known confinement range for each nanocrystal system according to the desired function of the nanocrystal. For example, the absorption peak position of InAs can be within the range of 500 nm to 1700 nm. For InAs / Sb nanocrystals, the absorption peak can be within the range of 700 nm to 2200 nm and can be varied by, for example, varying the antimony composition, reaction conditions, temperature, and growth time. For InSb, the absorption peak can be within the range of 700 nm to 3000 nm.

[0120] When the crystalline core is composed of indium and arsenic, the absorption peak is 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. Preferably, the InAs 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.

[0121] The aim in the industry is to grow the size of InAs QDs in order to push their absorption further into the SWIR region. Absorption peaks above the "eye safety threshold" of 1350 nm are of particular interest for optical sensing applications. However, despite advances in the synthesis of colloidal InPn QDs, previous attempts in the prior art to push the lowest energy electronic transition (LEET) beyond 1400 nm resulted in losses in synthesis control and severe peak broadening.

[0122] Extending the first exciton transition energy beyond 1400 nm while maintaining a homogeneous size distribution remains a significant challenge. Key optical metrics such as the peak-to-valley (P / V) ratio and emission full width at half maximum (FWHM) tend to decrease and broaden, respectively, as QDs grow beyond approximately 7 nm. This may be explained in part by the morphology-dependent absorbance of InPn QDs, which changes as the QDs grow, but generally, the loss of synthetic control leads to nonspecific absorbance profiles.

[0123] The present invention provides the ability to push the lowest energy electronic transition (LEET) beyond 1400 nm up to greater than 1600 nm, as shown in the examples below, which is an additional advantage of the present invention.

[0124] In other systems, such as InAs / Sb and InSb, the absorption peak can be pushed higher than in the case of InAs nanocrystals. In the InAs / Sb system, the absorption peak is preferably in the range of 700 nm to 2200 nm, preferably in the range of 1000 nm to 2000 nm, preferably in the range of 1200 nm to 1800 nm. In the InSb system, the absorption peak is preferably in the range of 700 nm to 3000 nm, preferably in the range of 1000 nm to 2500 nm, preferably in the range of 1300 nm to 2200 nm.

[0125] According to a third aspect, the present invention provides a III-V nanocrystal composition comprising a plurality of nanocrystals according to the second aspect.

[0126] The nanocrystals present in the nanocrystal composition of the third embodiment may additionally include nanocrystals that are not cuboctahedral. Preferably, at least 50%, preferably at least 60%, preferably at least 70%, preferably at least 80%, preferably 90% of the nanocrystals present in the nanocrystal composition are cuboctahedral. This can be determined by TEM.

[0127] Preferably, 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, as measured by TEM.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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%.

[0132] Relative size distribution is a measure of the variation in nanocrystal size. It is determined by measuring the size of a particular batch of nanoparticles and determining the difference from the average size. This can be expressed as a range of particle sizes plus or minus a particular average size x. Relative size distribution is measured by TEM.

[0133] According to a fourth aspect, the present invention provides an ink comprising the III-V nanocrystal composition of the third aspect. Formation of the ink generally involves a ligand exchange step, whereby long-chain organic ligands are replaced with conductive ligands, such as inorganic ligands or short-chain organic ligands. The nanocrystals, optionally after washing with acetone, are dissolved in a polar solvent. The polar solvent may be selected from the group consisting of 2,6-difluoropyridine, propylene carbonate, dimethylformamide, and combinations thereof.

[0134] According to a fifth aspect, the present invention provides a thin film comprising the III-V nanocrystal composition of the third aspect.

[0135] According to a sixth aspect, the present invention provides a device selected from the group consisting of an IR 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 metamaterial, a fiber amplifier, an optical gain medium, an optical fiber, an infrared LED, a laser, and an electroluminescent device, comprising the nanocrystal composition of the present invention. Preferably, the IR sensor or photodetector is modified for applications as a 3D camera and a 3D time-of-flight camera in a mobile device, as well as consumer, automotive, medical, industrial, defense, or aerospace applications. Preferably, the bioimaging or biosensing composition is modified for use as a biolabel or biotag in in vitro or ex vivo applications. Preferably, the infrared LED and electroluminescent device are modified for use in communications devices, night vision devices, solar energy conversion, surveillance devices, thermoelectric or energy generation applications. [Example]

[0136] Below are described examples illustrating methods according to the present disclosure.

[0137] While particular examples of the present invention are described below for purposes of illustration, it will be apparent to those skilled in the art that many changes in the details of the invention can be made without departing from the invention as defined in the appended claims.

[0138] Unless otherwise indicated, in the following examples and throughout the specification, all parts and percentages are by weight, respectively.

[0139] The absorption spectra of the colloidal quantum dots or quantum dot thin films were acquired on a JASCO V-770 UV-visible / NIR spectrometer, which can provide measurements at wavelengths from 400 to 3200 nm.

[0140] XRD data were collected on a Panalytical X'Pert PRO MPD diffractometer using Cu Ka1 X-ray radiation (l = 1.5406 Å) over a range of 10 < 2q < 90° at room temperature. 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 Corporation's Smart Lab Studio II software, and searched and matched using the Crystallography Open Database.

[0141] TEM and high-resolution transmission electron microscopy (HRTEM) images were acquired on an 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 an FEI CETA 4k x 4k CMOS camera. In each case, a few drops of QDs dispersed in solvent were placed on a carbon-coated copper grid and allowed to evaporate. Samples were either used as is or treated with acetone and then methanol to remove unwanted organic material before imaging.

[0142] [Example 1] Preparation of amorphous InAs clusters A 250 mL three-neck flask was charged with 3.0 mmol of In(OAc), 9.2 mmol of oleic acid, and 15 mL of heptadecane and evacuated under vacuum (approximately 0.1 mbar) at 110 °C for 90 min. During this step, indium oleate was formed and 9 mmol of acetic acid was collected in a cold trap. In(OAc)3 + R-COOH (R = C 17 H 33 ) → In-COOR+CH3COOH

[0143] The flask was switched to a nitrogen atmosphere and slowly cooled to room temperature. The flask was then transferred to a glovebox. In the glovebox, 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 thoroughly vortexed. With constant stirring, the indium oleate solution was mixed with the TMSi-As solution to obtain a composition containing InAs clusters.

[0144] The composition containing InAs clusters produced according to Example 1 was used in Example 2 as the composition containing III-V clusters.

[0145] [Example 2] Preparation of cuboctahedral InAs nanocrystals with an absorption peak around 1400 nm In this example, the preparation of InAs nanocrystals is divided into two periods of crystal growth. First, InAs nanocrystals are formed that exhibit an absorption peak around 1100 nm (first growth period of 4.5 hours). The UV-visible spectra of these nanocrystals are shown in Figure 2. Second, these nanocrystals are used to prepare nanocrystals that exhibit an absorption peak around 1400 nm (second growth period of 8 hours). The UV-visible spectra of these nanocrystals are shown in Figure 1. The total growth time is 12.5 hours.

[0146] 1100nm QDs A 250 mL three-neck flask was charged with 0.4 mmol of In(OAc), 1.2 mmol of oleic acid, and 6 mL of heptadecane and degassed under vacuum (approximately 0.1 mbar) at 110 °C for 90 min. During this step, indium oleate was formed and 1.2 mmol of acetic acid was collected in a cold trap. In(OAc)3 + R-COOH (R = C 17 H 33 ) → In-COOR+CH3COOH

[0147] The flask was switched to a nitrogen atmosphere and the temperature was maintained at 100°C. Inside the glove box, 0.32 mmol of (TMSi)3As, 0.56 mmol of dioctylamine, and 1 mL of degassed heptadecane were loaded into a syringe. This solution was added to the indium oleate solution at 100°C. There was an immediate color change after the injection of the arsenic precursor solution. The solution was simply heated to 287°C(*), and once the temperature reached 287°C(*), growth was allowed to continue for 15 minutes. 10 mL of the amorphous cluster solution from Example 1 was loaded into a syringe (20 mm diameter) and added at an injection rate of 2.230 mL / hour over nearly 4 hours and 30 minutes. After all of the amorphous cluster solution was injected, the solution was maintained at 287°C(*) for another 10 minutes. While the cluster addition was taking place, 270 μL of a dilute HBr solution in acetone (prepared by diluting 40 μL of HBr in 2 mL of acetone solution) was added over a period of 4 h 30 min. The heating was turned off and the solution was allowed to cool naturally. The CQDs were transferred to a glove box for further use. CQD growth was monitored by taking aliquots and measuring their absorption spectra.

[0148] The nanocrystals, which have an absorption maximum at approximately 1100 nm, have an average size of 5.9±0.1 nm with a standard deviation of 0.76 nm, as determined by TEM image analysis.

[0149] 1400nm QDs To a 250 mL three-neck flask connected under vacuum, 6 mL of InAs CQDs (50 mg / mL) (with an absorption maximum around 1100 nm) and 4 mL of degassed heptadecane were added. The contents of the flask were evacuated under vacuum (approximately 0.1 mbar) at 100 °C for 30 min. The flask was switched to nitrogen. 200 μL of dilute HBr solution was added to the flask and maintained at 100 °C for 10 min. The temperature was then increased to 285 °C. Once the temperature reached approximately 285 °C, amorphous InAs clusters were loaded into a syringe and added at a rate of 1.16 mL / h using a syringe pump over approximately 8 h. During the cluster addition, 120 μL of dilute HBr was added over 8 h. The heat was turned off, and the solution was allowed to cool naturally. The CQDs were transferred to a glove box for further use. CQD growth was monitored by taking aliquots and measuring their absorption spectra. The nanocrystals are cuboctahedral after this step.

[0150] purification The contents of the flask were transferred to a glove box. 5 mL of hexane, followed by 40 mL of acetone, was added to the QDs. The solution was divided into centrifuge tubes and centrifuged at 6000 RPM for 10 minutes. The clear supernatant was discarded, and the CQD pellet was redispersed in hexane. Acetone and IPA were added in a 2:1 volume ratio, and the mixture was centrifuged again at 6000 RPM for 10 minutes. The supernatant was discarded, and the CQD pellet was redispersed in n-octane. The CQDs in octane were centrifuged at 6000 RPM for 10 minutes to remove any solid impurities. The sediment was discarded, and the clear QD solution was filtered through 0.1 μm PTFE to obtain the product.

[0151] The resulting nanocrystals exhibit an absorption peak at approximately 1400 nm, as shown in Figure 1, and are cuboctahedral, as shown by the TEM images in Figures 3 and 4. After inorganic ligand exchange, the dots are assembled and compressed into a dense solid thin film, which plays a key role in improving device performance.

[0152] Without wishing to be bound by theory, improved facet alignment in cuboctahedral nanocrystals leads to improved charge transport.

[0153] The nanocrystals, which have an absorption maximum at approximately 1400 nm, have an average size of 9.0±0.1 nm with a standard deviation of 2.22 nm, as determined by TEM image analysis.

[0154] [Example 3] Preparation of cuboctahedral InAs nanocrystals with an absorption peak around 1600 nm The method was the same as in Example 2, except that it called for a second growth time of 14 hours and the addition of the amorphous cluster solution at a rate of 1.1.6 mL / hour.

[0155] The nanocrystals appeared to be cuboctahedral in the TEM images.

[0156] [Example 4] Further preparation of cuboctahedral InAs nanocrystals with an absorption peak around 1400 nm using 240 °C and ZnBr2 additive The method was the same as in Example 2, using the same process for producing amorphous clusters as described in Example 1, with the following differences. i) ZnBr was included in the preparation of the cluster, and therefore the first paragraph of the method in Example 1 was modified as follows: 0.4 mmol In(OAc) , 0.2 mmol ZnBr, 1.2 mmol oleic acid, and 6 mL heptadecane were placed in a 250 mL three-neck flask and degassed under vacuum (approximately 0.1 mbar) at 110 °C for 90 min. During this step, indium oleate was formed and 1.2 mmol acetic acid was collected in a cold trap. ii) Nanocrystals were grown using a temperature of 240° C. instead of the growth temperatures marked with an asterisk (*) above.

[0157] The nanocrystals with an absorption maximum at approximately 1100 nm have an average size of 5.85±0.4 nm as measured by TEM image analysis. The nanocrystals with an absorption maximum at approximately 1400 nm have an average size of 8.9±0.6 nm as measured by TEM image analysis.

[0158] The absorption spectra of these nanocrystals are shown in FIG.

[0159] The nanocrystals appeared to be cuboctahedral in the TEM image of FIG.

[0160] Embodiment 1. A method for producing a III-V nanocrystal composition, 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 hydroxyl functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid; 24 an organic compound; b) adding at least one pnictogen-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 removal reagent 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 obtain a III-V nanocrystal composition; A method comprising:

[0161] 2. The method of embodiment 1, wherein the first mixture comprises a first indium-containing compound.

[0162] 3. The method of embodiment 2, wherein the first indium-containing compound is selected from the group consisting of indium acetate, indium triformate, indium nitrate, indium nitrate hydrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, indium perchlorate hydrate, and mixtures thereof.

[0163] 4. The method of embodiment 3, wherein the first indium-containing compound is indium acetate.

[0164] 5. The method of any one of embodiments 1 to 4, wherein the first mixture comprises a first gallium-containing compound.

[0165] 6. The method of embodiment 5, wherein the first 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 gallium perchlorate hydrate.

[0166] 7. The method of embodiment 6, wherein the first gallium-containing compound is gallium acetate.

[0167] 8. The method of any one of embodiments 1 to 7, wherein the first mixture comprises a first indium-containing compound and a first gallium-containing compound.

[0168] 9. The method of any one of embodiments 1 to 8, wherein the first solvent is a non-polar solvent.

[0169] 10. The method of any one of embodiments 1 to 9, wherein the first solvent has a dielectric constant at 20° C. of less than 3, more preferably less than 2.5.

[0170] 11. A first solvent is a compound of formula C n H2n+2 Hydrocarbons of formula C n H 2n+1 11. The method of any one of embodiments 1 to 10, wherein n is selected from the group consisting of NH, alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary phosphines, and secondary phosphines, and n is in the range of 6 to 20.

[0171] 12. The method of any one of embodiments 1 to 11, wherein the molar ratio of the at least one pnictogen-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, preferably in the range of 0.6:1 to 1:1.

[0172] 13. The method of any one of embodiments 1 to 12, wherein step b) comprises adding one pnictogen-containing compound, wherein the pnictogen-containing compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds, and antimony-containing compounds.

[0173] 14. The method of any one of embodiments 1 to 12, wherein step b) comprises adding two pnictogen-containing compounds, wherein the first pnictogen-containing compound is an arsenic-containing compound and the second pnictogen-containing compound is a phosphorus-containing compound or an antimony-containing compound.

[0174] 15. The method of embodiment 13 or embodiment 14, wherein the arsenic-containing compound is selected from the group consisting of tris(trialkylsilyl)arsine (wherein the alkyl is methyl, ethyl, propyl, butyl, or is substituted), tris(trimethylgermyl)arsine, tris(triphenylsilyl)arsine, triphenylarsine, aminoarsine (RN)As (wherein R is alkyl or aryl), arsenic halides, alkyl or aryl arsenous acids, and mixtures thereof.

[0175] 16. The method of embodiment 15, wherein the arsenic-containing compound is selected from the group consisting of tris(trimethylsilyl)arsine, tris(trimethylgermyl)arsine, tris(dimethylamino)arsine, and mixtures thereof.

[0176] 17. The method of any one of embodiments 13 to 16, wherein the antimony-containing compound is selected from the group consisting of tris(trialkylsilyl)antimony (wherein the alkyl is methyl, ethyl, propyl, butyl, or substituted), tris(trimethylgermyl)antimony, and aminoantimony (RN)Sb (wherein R is alkyl or aryl), antimony halides, antimony dialkaylamides, dialkylsilylamides, antimony hydrides, antimony aziridinides, antimony thiolates, antimony carbamates, antimony guanidinates, and mixtures thereof.

[0177] 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.

[0178] 19. The method of embodiment 18, wherein the phosphorus-containing compound is selected from the group consisting of tris(trialkylsilyl)phosphine (wherein the alkyl is methyl, ethyl, propyl, butyl, or substituted), tris(trimethylgermyl)phosphine, tris(triphenylsilyl)phosphine, triphenylphosphine, aminophosphine (RN)P (wherein R is alkyl or aryl), phosphonic acid halides, alkyl or aryl phosphonic acids, and mixtures thereof; preferably, the phosphorus-containing compound is selected from the group consisting of tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine, and mixtures thereof; preferably, the phosphorus-containing compound is tris(trimethylsilyl)phosphine.

[0179] 20. The method of any one of embodiments 1 to 19, 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.

[0180] 21. The first ligand is a compound of formula C n H 2n+1 NH2 alkylamines, formula C n H 2n+1 COOH alkyl carboxylic acid, formula C n H 2n+1 21. The method of any one of embodiments 1 to 20, wherein n is selected from the group consisting of alkyl phosphonic acids of PO3H2, aromatic phosphonic acids, alkyl or aryl thiols, alkyl or aryl arsenous acids, and mixtures thereof; and n is in the range of 6 to 20.

[0181] 22. The method of embodiment 21, wherein the first ligand is selected from the group consisting of aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkane, dithioalkane, thiocarboxylic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl)-terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, and alkylamines.

[0182] 23. The method of embodiment 22, wherein the first ligand is selected from the group consisting of mercaptopropionic acid, mercaptobenzoic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl)-terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, preferably oleic acid, oleylamine, mercaptopropionic acid, or a mixture thereof.

[0183] 24. The method of any one of embodiments 1 to 23, 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.

[0184] 25. The method of any one of embodiments 1 to 24, 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.

[0185] 26. The method of embodiment 25, 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.

[0186] 27. The method of embodiment 25, 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.

[0187] 28. The method of any one of embodiments 1 to 27, wherein the nanocrystal composition comprises a III-V nanocrystal, the nanocrystal comprising a crystalline core and a plurality of first ligands coordinated to the surface of the crystalline core.

[0188] 29. The method of embodiment 28, wherein the oxide-removing reagent is a compound capable of reacting with oxides on the surface of the crystalline core to remove the oxides from the surface of the crystalline core.

[0189] 30. The method of any one of embodiments 1 to 29, wherein the oxide removal reagent is selected from the group consisting of hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halides, indium halides, and metal halides, and the metal is bismuth, lead, or cadmium.

[0190] 31. The method of embodiment 30, wherein the oxide removal reagent is hydrobromic acid.

[0191] 32. The method of any one of embodiments 1 to 31, wherein the molar ratio of the oxide removal reagent 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 1:1000 to 1:100,000, and more preferably in the range of 1:000 to 1:50,000.

[0192] 33. The method of any one of embodiments 1 to 32, wherein the concentration of the oxide-removing reagent in the first mixture is in the range of 5 μM to 1000 μM, preferably in the range of 50 μM to 500 μM.

[0193] 34. The method of any one of embodiments 1 to 33, wherein steps a), b) and c) are carried out under inert conditions.

[0194] 35. The method of any one of embodiments 1 to 34, wherein step a) further comprises heating the first mixture to a first temperature in the range of 50°C to 150°C.

[0195] 36. The method of 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.

[0196] 37. Step c) i) adding a first oxide removal reagent and a composition comprising a group III-V cluster to a first mixture at a growth temperature for a first growth time ranging from 2 hours to 8 hours to obtain a plurality of nanocrystals in the first mixture; ii) allowing the first mixture to cool; iii) adding a second oxide removal reagent to the first mixture and heating the first mixture to a growth temperature; iv) adding a third oxide removal reagent and a composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time in the range of 6 hours to 20 hours to obtain a III-V nanocrystal composition. 37. The method of any one of embodiments 1 to 36, comprising:

[0197] 38. The method of embodiment 37, wherein step iii) further comprises adding a second oxide-removing reagent to the first mixture before heating the first mixture to the growth temperature.

[0198] 39. The method of 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, preferably in the range of 90°C to 110°C.

[0199] 40. The method of 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.

[0200] 41. The method of 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.

[0201] 42. The method of any one of embodiments 37 to 41, wherein the nanocrystal composition comprises a III-V nanocrystal, the nanocrystal comprising a crystalline core and a plurality of first ligands coordinated to the surface of the crystalline core, and the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are each independently compounds capable of reacting with oxides on the surface of the crystalline core to remove oxides from the surface of the crystalline core.

[0202] 43. The method of any one of embodiments 37 to 42, wherein the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are each independently a compound selected from the group consisting of hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halides, indium halides, and metal halides, and the metal is bismuth, lead, or cadmium.

[0203] 44. The method of any one of embodiments 37 to 43, wherein the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are the same compound.

[0204] 45. The method of any one of embodiments 37 to 44, wherein the first oxide removal reagent, the second oxide removal reagent, and the third oxide removal reagent are hydrobromic acid.

[0205] 46. ​​The method of any one of embodiments 1 to 45, 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.

[0206] 47. The method of any one of embodiments 1 to 46, wherein the III-V clusters are amorphous particles comprising a group III element and a group V element, and the particles have a diameter of less than 2 nm.

[0207] 48. The method of embodiment 48, wherein the III-V cluster comprises phosphorus, arsenic, antimony, or a mixture thereof.

[0208] 49. The method of embodiment 48 or embodiment 49, wherein the III-V clusters are amorphous clusters exhibiting an absorption peak in the range of 900 nm to 1200 nm, preferably in the range of 1000 nm to 1200 nm.

[0209] 50. The method further comprises preparing a composition comprising a group III-V cluster; 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 aryl group containing a functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid. 24 an organic compound; B) adding at least one pnictogen-containing compound to the second mixture under constant stirring to obtain III-V clusters; 50. The method of any one of embodiments 1 to 49, comprising:

[0210] 51. The method of embodiment 50, wherein the second mixture comprises a second indium-containing compound.

[0211] 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, indium nitrate hydrate, indium sulfate, indium hydroxide, indium trifluoromethanesulfonate, indium trifluoroacetylacetonate, indium hexafluoroacetylacetonate, indium acetylacetonate, indium trifluoroacetate, indium phosphate, indium perchlorate hydrate, and mixtures thereof.

[0212] 53. The method of embodiment 52, wherein the second indium-containing compound is indium acetate.

[0213] 54. The method of any one of embodiments 50 to 53, wherein the second mixture comprises a second gallium-containing compound.

[0214] 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 gallium perchlorate hydrate.

[0215] 56. The method of embodiment 55, wherein the second gallium-containing compound is gallium acetate.

[0216] 57. The method of any one of embodiments 50 to 56, wherein the second mixture comprises a second indium-containing compound and a second gallium-containing compound.

[0217] 58. The method of any one of embodiments 50 to 57, wherein the second solvent is a non-polar solvent.

[0218] 59. The method of any one of embodiments 50 to 58, wherein the second solvent has a dielectric constant at 20°C of less than 3, more preferably less than 2.5.

[0219] 60. The second solvent is a compound of formula C n H 2n+2 Hydrocarbons of formula C n H 2n+1 60. The method of any one of embodiments 50 to 59, wherein n is selected from the group consisting of NH, alkylamines, octadecene, oleylamine, octylamine, butylamine, dioctylamine, trioctylamine, heptadecane, hexadecane, oleic acid, tertiary phosphines, and secondary phosphines, and n is in the range of 6 to 20.

[0220] 61. The method of any one of embodiments 50 to 60, wherein the second solvent is the same as the first solvent.

[0221] 62. The method of any one of embodiments 50 to 61, wherein the molar ratio of the at least one pnictogen-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.

[0222] 63. The method of any one of embodiments 50 to 62, wherein step B) comprises adding one pnictogen-containing compound, and the pnictogen-containing compound is selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds, and antimony-containing compounds.

[0223] 64. The method of any one of embodiments 50 to 62, wherein step B) comprises adding two pnictogen-containing compounds, wherein the first pnictogen-containing compound is an arsenic-containing compound and the second pnictogen-containing compound is a phosphorus-containing compound or an antimony-containing compound.

[0224] 65. The method of embodiment 63 or embodiment 64, wherein the arsenic-containing compound is selected from the group consisting of tris(trialkylsilyl)arsine (wherein the alkyl is methyl, ethyl, propyl, butyl, or is substituted), tris(trimethylgermyl)arsine, tris(triphenylsilyl)arsine, triphenylarsine, aminoarsine (RN)As (wherein R is alkyl or aryl), arsenic halides, alkyl or aryl arsenous acids, and mixtures thereof.

[0225] 66. The method of embodiment 65, wherein the arsenic-containing compound is tris(trimethylsilyl)arsine.

[0226] 67. The method of any one of embodiments 63 to 66, wherein the antimony-containing compound is selected from the group consisting of tris(trialkylsilyl)antimony (wherein the alkyl is methyl, ethyl, propyl, butyl, or substituted), tris(trimethylgermyl)antimony, and aminoantimony (RN)Sb (wherein R is alkyl or aryl), antimony halides, antimony dialkaylamides, dialkylsilylamides, antimony hydride, antimony aziridinide, antimony thiolate, antimony carbamate, and antimony guanidinate.

[0227] 68. The method of embodiment 67, wherein the antimony-containing compound is tris(trimethylsilyl)antimony.

[0228] 69. The method of any one of embodiments 63 to 68, wherein the phosphorus-containing compound is selected from the group consisting of:

[0229] 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.

[0230] 71. The second ligand is a compound of formula C n H 2n+1 NH2 alkylamines, formula C n H 2n+1 COOH alkyl carboxylic acid, formula C n H 2n+1 71. The method of any one of embodiments 50 to 70, wherein n is selected from the group consisting of alkyl phosphonic acids of PO3H2, aromatic phosphonic acids, alkyl or aryl thiols, alkyl or aryl arsenous acids, and mixtures thereof; and n is in the range of 6 to 20.

[0231] 72. The method of embodiment 71, wherein the second ligand is selected from the group consisting of aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkane, dithioalkane, thiocarboxylic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl)-terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, and alkylamines.

[0232] 73. The method of embodiment 72, wherein the second ligand is selected from the group consisting of mercaptopropionic acid, mercaptobenzoic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl)-terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, and bis(diphenylphosphino)methane.

[0233] 74. The method of any one of embodiments 50 to 73, wherein the second ligand is the same as the first ligand.

[0234] 75. A III-V nanocrystal composition obtainable by any one of embodiments 1 to 74.

[0235] 76. Substantially cuboctahedral III-V nanocrystals.

[0236] 77. The nanocrystal of embodiment 76, which is a cuboctahedron.

[0237] 78. The nanocrystal of embodiment 76 or embodiment 77, comprising a crystalline core comprising indium and / or gallium and a pnictogen.

[0238] 79. The nanocrystal of embodiment 78, wherein the pnictogen is phosphorus, arsenic, antimony, or a mixture thereof.

[0239] 80. The nanocrystal of embodiment 79, wherein the pnictogen is arsenic, antimony, or a mixture thereof.

[0240] 81. The nanocrystal of any one of embodiments 78 to 80, wherein a plurality of ligands are coordinated to the surface of the crystalline core.

[0241] 82. The nanocrystal of embodiment 81, wherein the ligand is an organic compound, an inorganic compound, or a mixture thereof.

[0242] 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.

[0243] 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.

[0244] 85. A III-V nanocrystal composition comprising a plurality of nanocrystals according to any one of embodiments 76 to 84.

[0245] 86. The nanocrystal 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.

[0246] 87. The nanocrystal composition of embodiment 85 or embodiment 86, exhibiting 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.

[0247] 88. The nanocrystal composition of any one of embodiments 85 to 87, exhibiting 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.

[0248] 89. The nanocrystalline composition of any one of embodiments 85 to 88, exhibiting 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.

[0249] 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% to 20%, preferably in the range of 2% to 15%, preferably in the range of 3% to 10%.

[0250] 91. An ink comprising the III-V nanocrystal composition of any one of embodiments 85 to 90.

[0251] 92. A thin film comprising the III-V nanocrystal composition of any one of embodiments 85 to 90.

[0252] References

[0253] [Table 1]

Claims

1. 1. A method for producing a III-V nanocrystal composition, 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 comprises a functional group selected from the group consisting of amino, thiol, hydroxyl, and carboxylic acid; ６ ~C ２４ an organic compound; b) adding at least one pnictogen-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 removal reagent and a composition comprising a group III-V cluster to the first mixture at the growth temperature for a total growth time in a range of at least 6 hours to obtain the group III-V nanocrystal composition; A method comprising:

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

3. the first mixture comprises the first gallium-containing compound; Preferably, the first 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 gallium perchlorate hydrate; Preferably, the first gallium-containing compound is gallium acetate. The method according to claim 1 or claim 2.

4. the first solvent is a non-polar solvent; Preferably, the first solvent has a dielectric constant at 20°C of less than 3, more preferably less than 2.5; Preferably, the first solvent is a compound of formula C ｎ H ２ｎ＋２ hydrocarbons of formula C ｎ H ２ｎ＋１ NH ２ 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; 4. The method according to any one of claims 1 to 3.

5. 5. The method of claim 1, wherein a molar ratio of the at least one pnictogen-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, preferably in the range of 0.6:1 to 1:

1.

6. step b) comprises adding one pnictogen-containing compound, said pnictogen-containing compound being selected from the group consisting of phosphorus-containing compounds, arsenic-containing compounds and antimony-containing compounds; or step b) comprises adding two pnictogen-containing compounds, wherein a first pnictogen-containing compound is an arsenic-containing compound and a second pnictogen-containing compound is a phosphorus-containing compound or an antimony-containing compound; 6. The method according to any one of claims 1 to 5.

7. The arsenic-containing compound may be selected from the group consisting of tris(trialkylsilyl)arsine (wherein the alkyl is methyl, ethyl, propyl, butyl, or is substituted), tris(trimethylgermyl)arsine, tris(triphenylsilyl)arsine, triphenylarsine, aminoarsine (R ２ N) ３ As (wherein R is alkyl or aryl), arsenic halides, alkyl or aryl arsenous acids, and mixtures thereof; Preferably, the arsenic-containing compound is selected from the group consisting of tris(trimethylsilyl)arsine, tris(trimethylgermyl)arsine, tris(dimethylamino)arsine, and mixtures thereof. The method of claim 6.

8. The antimony-containing compounds include tris(trialkylsilyl)antimony (wherein the alkyl is methyl, ethyl, propyl, butyl, or is substituted), tris(trimethylgermyl)antimony, and aminoantimony (R ２ N) ３ Sb (wherein R is alkyl or aryl), antimony halides, antimony dialkaylamides, dialkylsilylamides, antimony hydrides, antimony aziridinides, antimony thiolates, antimony carbamates, antimony guanidinates, and mixtures thereof; Preferably, the antimony-containing compound is selected from the group consisting of tris(trimethylsilyl)antimony, tris(trimethylgermyl)antimony, tris(dimethylamino)antimony, and mixtures thereof. The method according to claim 6 or claim 7.

9. The phosphorus-containing compound may be tris(trialkylsilyl)phosphine (wherein the alkyl is methyl, ethyl, propyl, butyl, or is substituted), tris(trimethylgermyl)phosphine, tris(triphenylsilyl)phosphine, triphenylphosphine, aminophosphine (R ２ N) ３ 9. The method of any one of claims 6 to 8, wherein the phosphorus-containing compound is selected from the group consisting of tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine, and mixtures thereof, preferably the phosphorus-containing compound is selected from the group consisting of tris(trimethylsilyl)phosphine, tris(trimethylgermyl)phosphine, tris(dimethylamino)phosphine, and mixtures thereof, preferably the phosphorus-containing compound is tris(trimethylsilyl)phosphine.

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

1.

11. The first ligand is represented by formula C ｎ H ２ｎ＋１ NH ２ alkylamines of formula C ｎ H ２ｎ＋１ COOH alkyl carboxylic acids, formula C ｎ H ２ｎ＋１ P.O. ３ H ２ wherein n is selected from the group consisting of alkyl phosphonic acids, aromatic phosphonic acids, alkyl or aryl thiols, alkyl or aryl arsenous acids, and mixtures thereof; and n is in the range of 6 to 20; Preferably, the first ligand is selected from the group consisting of aminobenzoic acid, dicarboxylic acid, aminoalkylcarboxylic acid, mercaptopropionic acid, mercaptobenzoic acid, thioalkane, dithioalkane, thiocarboxylic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl) terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane and alkylamines; Preferably, said first ligand is selected from the group consisting of mercaptopropionic acid, mercaptobenzoic acid, thioglycolic acid, poly(ethylene glycol), bis(3-aminopropyl) terminated poly(ethylene glycol), didodecyldimethylammonium bromide, n-dodecylammonium bromide, dodecyltrimethylammonium bromide, dimercaptosuccinic acid, oleic acid, oleylamine, bis(diphenylphosphino)methane, preferably oleic acid, oleylamine, mercaptopropionic acid or mixtures thereof; 11. The method according to any one of claims 1 to 10.

12. 12. The method according to any one of claims 1 to 11, 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 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, 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, 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.

13. The method according to any one of claims 1 to 12.

14. the nanocrystal composition comprises a III-V nanocrystal, the nanocrystal comprising a crystalline core and a plurality of first ligands coordinated to a surface of the crystalline core; Preferably, the oxide removal reagent is a compound capable of reacting with oxides on the surface of the crystalline core to remove the oxides from the surface of the crystalline core; Preferably, the oxide removal reagent is selected from the group consisting of hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hypophosphorous acid, phosphoric acid, ammonium hydroxide, potassium hydroxide, sodium hydroxide, zinc halides, indium halides and metal halides, wherein the metal is bismuth, lead or cadmium; Preferably, the oxide removal reagent is hydrobromic acid.

14. The method of any one of claims 1 to 13.

15. the molar ratio of the oxide removal reagent 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 1:1000 to 1:100,000, more preferably in the range of 1:000 to 1:50,000; and / or The concentration of the oxide removing reagent in the first mixture is in the range of 5 μM to 1000 μM, preferably in the range of 50 μM to 500 μM; 15. The method of any one of claims 1 to 14.

16. 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.

16. The method of any one of claims 1 to 15.

17. Step c) i) adding a composition comprising a first oxide removal reagent and a group III-V cluster to the first mixture at the growth temperature for a first growth time ranging from 2 hours to 8 hours to obtain a plurality of nanocrystals in the first mixture; ii) allowing the first mixture to cool; iii) heating the first mixture to the growth temperature; iv) adding a third oxide removal reagent and the composition comprising III-V clusters to the first mixture at the growth temperature for a second growth time in the range of 6 hours to 20 hours to obtain the III-V nanocrystal composition. Including, Preferably, step iii) further comprises adding a second oxide-removing reagent 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 from 50°C to 150°C, preferably in the range of from 60°C to 140°C, preferably in the range of from 70°C to 130°C, preferably in the range of from 80°C to 120°C, preferably in the range of from 90°C to 110°C; 17. The method of any one of claims 1 to 16.

18. 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, preferably in the range of 7 hours to 15 hours; 18. The method of claim 17.

19. the first oxide-removing reagent, the second oxide-removing reagent, and the third oxide-removing reagent are the same compound; Preferably, the first oxide removal reagent, the second oxide removal reagent and the third oxide removal reagent are hydrobromic acid.

19. The method of claim 17 or claim 18.

20. the III-V clusters are amorphous particles comprising a group III element and a group V element, the particles having a diameter of less than 2 nm; Preferably, the III-V cluster comprises phosphorus, arsenic, antimony or a mixture thereof.

20. The method of any one of claims 1 to 19.

21. A III-V nanocrystal composition obtainable by any one of claims 1 to 20.

22. Substantially cuboctahedral III-V nanocrystals.

23. the nanocrystals comprise a crystalline core comprising indium and / or gallium and a pnictogen; Preferably, the pnictogen is phosphorus, arsenic, antimony, or a mixture thereof; Preferably, the pnictogen is arsenic, antimony, or a mixture thereof.

23. The nanocrystal of claim 22.

24. a plurality of ligands are coordinated to the surface of the crystalline core; Preferably, the ligand is an organic compound, an inorganic compound, or a mixture thereof.

24. The nanocrystal of claim 22 or claim 23.

25. the nanocrystalline 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 the nanocrystalline 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; 25. The nanocrystal of any one of claims 22 to 24.

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

27. exhibiting 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 exhibiting 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; 27. The nanocrystalline composition of claim 26.

28. 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 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%; 28. The nanocrystalline composition of claim 26 or claim 27.

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

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