CN110964507A

CN110964507A - Quantum dot and preparation method thereof

Info

Publication number: CN110964507A
Application number: CN201811157455.9A
Authority: CN
Inventors: 聂志文; 杨一行
Original assignee: TCL Research America Inc
Current assignee: TCL Corp; TCL Research America Inc
Priority date: 2018-09-30
Filing date: 2018-09-30
Publication date: 2020-04-07

Abstract

The invention belongs to the technical field of nano materials, and particularly relates to a quantum dot and a preparation method thereof. The preparation method comprises the following steps: providing a group III cation precursor comprising one or more metal halide precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors and a ligand; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution; and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution. The preparation method has the advantages of stable technology, simple process and low cost, and is beneficial to scale preparation in the later period, and the prepared quantum dots not only improve the luminous efficiency, but also are more beneficial to the growth of a thick shell layer.

Description

Quantum dot and preparation method thereof

Technical Field

The invention belongs to the technical field of nano materials, and particularly relates to a quantum dot and a preparation method thereof.

Background

Quantum dots, also known as semiconductor nanocrystals, have particle radii near or smaller than the exciton bohr radius. Due to the "quantum size" effect, as the size of the quantum dot is further reduced, the continuous energy level structure gradually changes to a discrete, discontinuous energy level structure. After being excited by light with certain wavelength energy, photons in the valence band absorbing certain energy are excited to the conduction band, and electrons in the excited state jump from the conduction band to the valence band, and release energy in the form of light, so that a remarkable fluorescence phenomenon is emitted. Therefore, the size and chemical composition of the quantum dots can be adjusted in a certain way so that the emission spectrum of the quantum dots can cover the whole visible region and even the near infrared region. The preparation of the high-quality quantum dots is usually carried out by a solution method, and on one hand, the quantum dots as a colloidal solution have high dispersibility, so that the physical operation is convenient; on the other hand, quantum dots have the advantages of high color purity, wide color gamut, high stability and the like, and are core materials of a new generation of display technology.

Group II-VI quantum dots have become mature in synthesis and preparation, and the prepared quantum dots are high in quality and excellent in fluorescence performance. Meanwhile, quantum dots used by the high-performance device are constructed by mainly using II-VI compounds, particularly red and green quantum dots, so that the high-performance device has high luminous efficiency and long fluorescence life and can meet the commercial application requirements. However, since the group II-VI quantum dots themselves contain limited heavy metal elements, they are severely limited in practical application and development. In contrast, group III-V quantum dots, typically represented by InP, have many unparalleled properties compared to group II-VI quantum dots. On one hand, the Bohr radius of the InP quantum dots is 13nm, and the quantum dot effect on the InP quantum dots is stronger due to the large Bohr radius; on the other hand, the InP quantum dots do not contain limited heavy metal elements, accord with the green environmental protection concept, have no inherent toxicity, are regarded as the most important core materials for replacing the traditional II-VI group cadmium-based quantum dots with strong toxicity and serious pollution, and are also the key for breaking through the prior display technology.

InP quantum dots have some disadvantages: first, In and P elements In InP quantum dots are covalently bonded, and the stability of the prepared quantum dots is generally poor, compared to conventional type II-VI quantum dots formed by ionic bonding. Secondly, a large number of P dangling bonds exist on the surface of the InP quantum dot, the existence of the dangling bonds as non-radiative recombination transition centers can greatly reduce the luminous efficiency of the InP quantum dot, and the luminous efficiency of an InP core is lower than 1 percent generally. In order to further prepare the quantum dot with high luminous efficiency, one or more layers of shell layer materials with wide band gaps are required to be coated outside the quantum dot, and the core-shell structure can effectively separate carriers confined in a core from a surface state serving as a non-radiative recombination transition center, so that the luminous efficiency of the quantum dot is greatly improved. At present, the commonly used shell layer material is selected to be ZnSe or ZnS, and because InP and ZnSe or ZnS have larger lattice adaptation degree, the ZnSe or ZnS shell layer is difficult to effectively grow on the InP surface, so that the final core-shell structure quantum dot light emitting efficiency is low. Generally, the shell layer of quantum dots with higher synthesis quality has a thickness of no more than 2nm and poor stability. On the one hand, since the thin envelope layer is not favorable for perfect confinement of excitons, it is easy to cause delocalization of electron or hole wavefunction into the envelope layer, which greatly limits its application in new displays. On the other hand, because the P source is limited in selection and too active, a large amount of P monomer is used for nucleation at the moment of high-temperature injection, and not enough P monomer is used for the growth of a subsequent shell layer after nucleation. Therefore, the nucleated particles further undergo ostwald ripening growth, and the final quantum dots have relatively poor size distribution and wide peak width.

At present, the preparation method based on InP quantum dots generally adopts a two-pot method, namely, InP cores are prepared firstly, and then precursors required by transition shells or outer shells are added into a cleaned core solution. The method has the advantages that the control requirement on the heating rate is accurate, long reaction time is required in the nucleation and shell growing processes, spontaneous nucleation is easy to occur in the process of adding the precursor of the shell layer, and the subsequent growth of the shell layer is not facilitated.

Therefore, the prior art is in need of improvement.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a quantum dot and a preparation method thereof, aiming at solving the technical problems of poor stability, low luminous efficiency, long preparation time, high cost and low efficiency of the conventional quantum dot.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a quantum dot, which comprises a III-V group quantum dot core and halide ions and hydroxide ions combined on the surface of the III-V group quantum dot core; wherein the halide and hydroxide ions are bound to group III cations on the surface of the quantum dot core.

And, a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and a halide ion and a hydroxide ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core.

In the quantum dot provided by the invention, halide ions and hydroxide ions are combined with cations on the surface of a III-V group quantum dot core, which is equivalent to that the surface of the quantum dot core is completely coated or not completely coated with a layer of mixed material consisting of metal halide and metal hydroxide; the halide ions are combined with metal cations on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core and effectively inhibit the occurrence of nonradiative transition, so that a large number of defect states on the surface of the III-V group quantum dot formed by covalent bond combination are avoided, and the hydroxide ions are combined with the metal cations on the surface of the III-V group quantum dot core, so that the surface of the III-V group quantum dot core can be passivated, and meanwhile, the hydroxide ions can be used as a buffer outer shell layer, so that the problem of lattice adaptation between the III-V group quantum dot core and the II-VI group semiconductor outer shell layer can be effectively solved, and the growth of a thick outer shell layer is facilitated. Therefore, the halide ions and the hydroxyl ions are combined with the cations on the surface of the III-V family quantum dot core to cooperatively form a layer of mixed material consisting of metal halide and metal hydroxide, so that the luminous efficiency of the quantum dot is greatly improved, the growth of a thick shell layer is facilitated, and the stability of the quantum dot can be greatly improved.

The invention also provides a preparation method of the quantum dot, which comprises the following steps:

providing a group III cation precursor comprising one or more metal halide precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors and a ligand; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

And, another method for preparing quantum dots, comprising the steps of:

providing a cation precursor and a ligand, wherein the cation precursor is a group III cation precursor and a first group II cation precursor, and the cation precursor comprises one or more metal halide precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

The invention provides the preparation method of the quantum dot, before carrying out the nucleation reaction, dissolving the III family cation precursor and the ligand in the solvent, heating under the first temperature condition, thus not only being capable of leading the ligand to be fully coordinated with the III family cation and being beneficial to the full reaction of anion and cation, but also being capable of effectively removing water and oxygen in the reaction embodiment in advance, thereby avoiding the defect that the surface of the generated III-V family quantum dot core is easy to oxidize and improving the luminous effect of the finally prepared quantum dot; meanwhile, the process of carrying out the nucleation reaction from the first temperature to the second temperature is a continuous temperature rise process, so that the nucleation time can be greatly shortened, and the high-temperature nucleation is favorable for improving the crystallinity of the quantum dots and improving the yield of the quantum dots. In addition, at least one metal oxide precursor and/or metal hydroxide precursor and at least one metal halide are introduced into the reaction system in the nucleation process before the nucleation reactionA precursor; thus, in the preparation process, the cation in the metal halide precursor can be used for nucleation reaction, and on the other hand, the halide ion can react with the V-group anion dangling bond on the surface of the nucleated III-V group quantum dot core to generate VX₃The (V is N, P or As, X is halogen) gas is beneficial to the reaction, so that the III group atoms and the V group atoms on the surface of the III-V group quantum dot core are recombined to form the III-V group quantum dot core with more stable atomic ratio, and meanwhile, the halide ions can be combined with the cations on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core; the metal ions in the metal oxide precursor and/or metal hydroxide precursor also participate in the formation of the group III-V quantum dot core, while the anion in the metal oxide precursor, i.e., O^2-First combines with protons in the reaction system solution to form OH^-Final OH^-Can be rapidly combined with cations on the surface of the III-V group quantum dot core, OH^-The metal hydroxide formed after the metal hydroxide is combined with the cations on the surface of the III-V group quantum dot core can also effectively passivate the surface of the III-V group quantum dot core, and meanwhile, the metal hydroxide is equivalent to a buffer outer shell layer, so that the problem of lattice adaptation between the core and the shell layer is effectively solved, and the growth of a thick outer shell layer is facilitated. In the quantum dots finally obtained by the preparation method, the III-V family quantum dot core surface is combined with the halide ions and the hydroxyl ions, so that the III-V family quantum dot core surface can be passivated through the synergistic effect, the luminous efficiency of the quantum dots is greatly improved, the growth of a thick shell layer is facilitated, and the stability of the quantum dots can be greatly improved.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, elements, components, and/or groups thereof. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

In one aspect, an embodiment of the present invention provides a method for preparing a quantum dot, including the following steps:

s001: providing a group III cation precursor and a ligand, dissolving the group III cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

s002: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

According to the preparation method of the quantum dot provided by the embodiment of the invention, before the nucleation reaction is carried out, the III family cation precursor and the ligand are dissolved in the solvent and heated under the condition of the first temperature, so that the ligand and the III family cation can be fully coordinated, the full reaction of anion and cation is facilitated, and water and oxygen in the reaction embodiment can be effectively removed in advance, thereby avoiding the defect that the surface of the generated III-V family quantum dot core is easy to oxidize, and improving the luminous effect of the finally prepared quantum dot; meanwhile, the process of carrying out the nucleation reaction from the first temperature to the second temperature is a continuous temperature rise process, so that the nucleation time can be greatly shortened, and the high-temperature nucleation is favorable for improving the crystallinity of the quantum dots and improving the yield of the quantum dots.

Further, in the step S001: the group III cation precursor is selected from at least one of indium chloride, indium bromide, indium iodide, indium acetate, indium carbonate, indium nitrate, indium perchlorate, indium cyanide, gallium chloride, gallium bromide, gallium iodide, gallium carbonate, gallium nitrate, gallium perchlorate, gallium cyanide, aluminum chloride, aluminum bromide, aluminum iodide, aluminum carbonate, aluminum nitrate, aluminum perchlorate, aluminum cyanide, indium acetylacetonate, gallium acetate, gallium acetylacetonate, aluminum acetate, aluminum acetylacetonate, aluminum isopropoxide, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate, aluminum isopropoxide, aluminum hexafluoroacetylacetonate, indium oxide, indium hydroxide, gallium oxide, gallium hydroxide, aluminum oxide, and aluminum hydroxide; the ligand is selected from at least one of oleic acid, C4-C20 saturated fatty acid (i.e. saturated fatty acid with the carbon number of 4-20), phosphine substituted by C6-C22 alkyl (i.e. organic phosphine with the carbon number of 6-22 of the substituent, such as trioctylphosphine), phosphine oxide substituted by C6-C22 alkyl (organic phosphine oxide with the carbon number of 6-22 of the substituent, such as trioctylphosphine), C6-C22 primary amine (i.e. primary amine with the carbon number of 4-20, such as hexadecylamine), C6-C22 secondary amine (i.e. secondary amine with the carbon number of 6-22 of the substituent, such as dioctylamine) and C6-C40 tertiary amine (i.e. tertiary amine with the carbon number of 6-40 of the substituent, such as trioctylamine). The solvent is a non-ligand solvent selected from at least one of C6-C40 aliphatic hydrocarbons (i.e., aliphatic hydrocarbons having 6-40 carbon atoms such as alkanes, alkenes, or alkynes, specifically hexadecane, octadecane, octadecene, or squalane), C6-C30 aromatic hydrocarbons (i.e., aromatic hydrocarbons having 6-30 carbon atoms such as phenyldodecane, phenyltetradecane, or phenylhexadecane), nitrogen-containing heterocyclic compounds (e.g., pyridine), and C12-C22 aromatic ethers (i.e., aromatic ethers having 12-22 carbon atoms such as phenyl ether or benzyl ether).

Furthermore, the heating treatment is carried out in an inert atmosphere and under the first temperature condition, the inert atmosphere is preferably nitrogen, and the inert atmosphere can isolate air, so that the reaction system is more stable; preferably, the first temperature is 100-; the time for carrying out the heating treatment under the first temperature condition is 1-2 h. In the temperature and time range, the ligand and the III group cation have better coordination effect, and the water and oxygen in the reaction system have the best removal effect. Further, in the embodiment of the present invention, before the heating process under the first temperature condition, a vacuum process step is further included. The vacuum treatment allows for as complete a removal of water oxygen as possible throughout the reaction regime before nucleation occurs. More preferably, the temperature of the vacuum treatment is 80-150 ℃; the vacuum treatment time is 30min-1 h.

Further, a first group II cation precursor, the group III cation precursor, and the ligand are dissolved in a solvent, and heat treatment is performed under a first temperature condition. The group II cation precursor is added into the reaction system before the nucleation reaction, and the group II cation can be effectively combined on the surface of the group III-V quantum dot core at the nucleation moment, so that the group III-V quantum dot core is passivated, and meanwhile, the precursor can also be used as a precursor for the growth of a subsequent group II-VI semiconductor shell layer.

Specifically, the first group II cation precursor is selected from zinc chloride, zinc bromide, zinc iodide, zinc acetate, zinc stearate, zinc undecylenate, zinc acetylacetonate, zinc hexafluoroacetylacetonate, zinc oxide, zinc hydroxide, zinc carbonate, zinc nitrate, zinc perchlorate, zinc cyanide, cadmium chloride, cadmium bromide, cadmium iodide, cadmium acetate, cadmium stearate, cadmium undecylenate, cadmium acetylacetonate, cadmium hexafluoroacetylacetonate, cadmium oxide, cadmium hydroxide, cadmium carbonate, cadmium nitrate, cadmium perchlorate, cadmium cyanide, magnesium chloride, magnesium bromide, magnesium iodide, magnesium acetate, magnesium stearate, magnesium undecylenate, magnesium acetylacetonate, magnesium hexafluoroacetylacetonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium nitrate, magnesium perchlorate, magnesium cyanide, mercury chloride, mercury bromide, mercury iodide, mercury acetate, mercury acetylacetonate, mercury oxide, mercury hydroxide, mercury carbonate, mercury nitrate, At least one of mercury perchlorate and mercury cyanide.

Further, in the step S002: the group V anion precursor is at least one selected from the group consisting of tris (trimethylsilyl) phosphine, tris (germyl) phosphine, tris (dimethylamino) phosphine, tris (diethylamino) phosphine, triethylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, tris (trimethylsilyl) arsenic, tris (dimethylamino) arsenic, tris (diethylamino) arsenic, triethylarsenic, tributylarsenic, trioctylalarsenic, triphenylarsenic, tricyclohexylarsenic, arsenic oxide, arsenic chloride, arsenic bromide, arsenic iodide, arsenic sulfide and ammonia gas. Further, the second temperature is 260-320 ℃; the time of the nucleation reaction is 1-20 min. The second temperature is the generation temperature of the III-V group quantum dot core, and the III-V group quantum dot core can be formed better in the temperature and time range.

Further, immediately after the nucleation reaction is completed, adding a second II group cation precursor and a VI group anion precursor into the III-V group core solution, and performing shell layer growth under a third temperature condition to form a II-VI group semiconductor shell layer on the surface of the III-V group quantum dot core to obtain the core-shell quantum dot solution. Specifically, the second group II cation precursor is selected from at least one of cadmium oleate, cadmium butyrate, cadmium n-decanoate, cadmium hexanoate, cadmium octanoate, cadmium dodecanoate, cadmium myristate, cadmium palmitate, cadmium stearate, mercury oleate, mercury butyrate, mercury n-decanoate, mercury hexanoate, mercury octanoate, mercury dodecanoate, mercury myristate, mercury palmitate, mercury stearate, zinc oleate, zinc butyrate, zinc n-decanoate, zinc hexanoate, zinc octanoate, zinc dodecanoate, zinc palmitate, zinc stearate, magnesium oleate, magnesium butyrate, magnesium n-decanoate, magnesium hexanoate, magnesium octanoate, magnesium dodecanoate, magnesium myristate, magnesium palmitate, and magnesium stearate; the group VI anion precursor is selected from at least one of hexanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, mercaptopropylsilane, trioctylphosphine sulfide, tributylphosphine sulfide, triphenylphosphine sulfide, trioctylamine sulfide, tris (trimethylsilyl) sulfide, ammonium sulfide, sodium sulfide, trioctylphosphine selenide, tributylphosphine selenide, triphenylphosphine selenide, tributylphosphine telluride, trioctylphosphine telluride, and triphenylphosphine telluride.

Further, the third temperature is 260-320 ℃; and the time for performing the shell layer growth under the third temperature condition is 15-90 min. The third temperature is a growth temperature of the group II-VI semiconductor shell layer at which the group II-VI semiconductor shell layer can be better formed.

Furthermore, after the core-shell quantum dot solution is obtained, the method further comprises the steps of carrying out solid-liquid separation on the core-shell quantum dot solution and then carrying out vacuum drying. Specifically, the solid core-shell quantum dot can be obtained by centrifuging and precipitating the core-shell quantum dot solution, and finally drying the core-shell quantum dot solution in vacuum for 12-24 hours.

In the preparation method of the quantum dot in the embodiment of the invention, the quantum dots with different luminescence properties, such as quantum dots with narrow peak width, quantum dots with high luminescence efficiency or quantum dots with high stability, can be prepared by adopting cation precursors with different activities.

In one embodiment of the invention, a quantum dot is provided, which comprises a III-V group quantum dot core and halide ions combined on the surface of the III-V group quantum dot core; wherein the halide ions bind to the group III cations on the surface of the group III-V quantum dot core.

In another embodiment of the present invention, there is provided a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a surface of the group III-V quantum dot core, and a halide ion bound to the group III cation and the group II cation on the surface of the group III-V quantum dot core.

In the quantum dot of the embodiment of the invention, the halide ions are combined with metal cations (such as III group cations, or III group cations and II group cations) on the surface of the III-V group quantum dot core, which is equivalent to completely coating or not completely coating a layer of metal halide on the surface of the quantum dot core, and the metal halide can passivate the surface of the III-V group quantum dot core and can also serve as a transition shell layer, so that the occurrence of the nonradiative transition is more effectively inhibited, and the luminous efficiency of the quantum dot is greatly improved (the luminous efficiency is more than 70%).

Further, the material of the III-V group quantum dot core is at least one selected from GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa. The group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the group II cation is at least one of zinc ion, cadmium ion, mercury ion and magnesium ion; the halide ions are selected from at least one of chloride ions, bromide ions and iodide ions, and in particular, in the case of a group III-V quantum dot core, the halide ions can be combined with group III cations on the surface, which corresponds to a complete coating or a non-complete coating of a layer of metal halide on the surface of the quantum dot core, for example, at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide and aluminum iodide is formed. When group II cations bound to the surface of the III-V quantum dot core exist on the surface of the III-V quantum dot core, the halide ions can be simultaneously bound with the group III cations and the group II cations on the surface of the III-V quantum dot core, which is equivalent to completely coating or not completely coating a layer of metal halide on the surface of the III-V quantum dot core, wherein the metal halide comprises at least one of group III metal halide such as indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide and aluminum iodide, and group II metal halide such as zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercury chloride, mercury bromide and mercury iodide.

Further, the surface of the III-V group quantum dot core is coated with a II-VI group semiconductor outer shell layer, and the II-VI group semiconductor outer shell layer coats the III-V group quantum dot core and halogen ions bonded on the surface of the III-V group quantum dot core. Alternatively, in another further embodiment, the group III-V quantum dot core is surface coated with a group II-VI semiconductor shell layer that coats the group III-V quantum dot core and the group II metal ions and halide ions bound to the surface of the group III-V quantum dot core. A halide ion is located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. Therefore, the metal halide formed by the halide ions and the metal cations on the surface of the III-V group quantum dot core and the II-VI group semiconductor shell layer have synergistic effect, and the formed core-shell quantum dot structure can more effectively separate the current carriers confined in the core from the surface state serving as the non-radiative recombination transition center, thereby greatly improving the luminous efficiency of the quantum dot. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

In an embodiment of the present invention, a method for preparing the quantum dot includes the following steps:

SA 011: providing a group III cation precursor and a ligand, the group III cation precursor comprising one or more metal halide precursors; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SA 012: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 011: providing a group III cation precursor, a first group II cation precursor, and a ligand; wherein the group III cation precursor comprises one or more metal halide precursors, and/or the first group II cation precursor comprises one or more metal halide precursors; dissolving the III group cation precursor, the first II group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SB 012: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Before the nucleation reaction occurs, at least one metal halide precursor is introduced into the precursor, cations in the metal halide precursor can be used for the nucleation reaction, and anions, namely halide ions, can react with the V-group anion dangling bond on the surface of the nucleated III-V-group quantum dot core to generate VX₃The (V is N, P or As, X is halogen) gas is favorable for reaction, so that the III group and V group atoms on the surface of the III-V group quantum dot core are recombined to form the III-V group quantum dot core with more stable atomic ratio, and the halide ions can be combined with cations (such As III group cations) on the surface of the III-V group quantum dot coreOr the III group cation and the II group cation) is combined, namely a layer of metal halide is completely coated or not completely coated on the surface of the III-V group quantum dot core, and the metal halide can passivate the surface of the III-V group quantum dot core and can also serve as a transition shell layer, so that the generation of non-radiative transition is effectively inhibited, the luminous efficiency of the quantum dot is greatly improved, and the prepared quantum dot has higher luminous efficiency (more than 70%).

Specifically, in step SA011 above: the group III cation precursor may include one or more metal halide precursors, that is, the group III cation precursor may only include the metal halide precursor, or may include other precursors besides the metal halide precursor, such as aluminum isopropoxide, indium acetate, indium carbonate, indium nitrate, indium perchlorate, indium cyanide, gallium carbonate, gallium nitrate, gallium perchlorate, gallium cyanide, aluminum carbonate, aluminum nitrate, aluminum perchlorate, aluminum cyanide, and the like. And the metal halide precursor in the group III cation precursor is at least one selected from the group consisting of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide and aluminum iodide.

In the above step SB 011: the group III cation precursor comprises one or more metal halide precursors, and/or the first group II cation precursor comprises one or more metal halide precursors, which may be understood as: the group III cation precursor comprises one or more metal halide precursors, or the first group II cation precursor comprises one or more metal halide precursors, or both the group III cation precursor and the first group II cation precursor comprise one or more metal halide precursors; when the group III cation precursor comprises one or more metal halide precursors, the metal halide precursor is selected from at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide; when the first group II cation precursor comprises one or more metal halide precursors, the metal halide precursor is selected from at least one of zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercuric chloride, mercuric bromide, and mercuric iodide; the first group II cation precursor may include, in addition to the metal halide precursor, at least one precursor selected from zinc acetate, zinc stearate, zinc undecylenate, zinc carbonate, zinc nitrate, zinc perchlorate, zinc cyanide, cadmium acetate, cadmium stearate, cadmium undecylenate, cadmium carbonate, cadmium nitrate, cadmium perchlorate, cadmium cyanide, magnesium acetate, magnesium stearate, magnesium undecylenate, magnesium carbonate, magnesium nitrate, magnesium perchlorate, magnesium cyanide, mercury acetate, mercury carbonate, mercury nitrate, mercury perchlorate, mercury cyanide, and the like.

For step SA011, halide ions combine with group III cations on the surface of the III-V quantum dot core to form a metal halide, which is equivalent to completely or incompletely coating a layer of metal halide on the surface of the III-V quantum dot core, where the metal halide includes at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide;

for step SB011, since the first group II cation precursor was introduced: the group II cations are combined with group V anions (such as P) on the surface of the III-V quantum dot core, so as to leave group III cation vacancies, the halide ions are combined with the group III cation vacancies on the surface of the core, and the halide ions are combined with the group II cations on the surface of the III-V quantum dot core, namely the halide ions are combined with the group III cations and the group II cations on the surface of the III-V quantum dot core simultaneously, which is equivalent to completely or incompletely coating the surface of the quantum dot core with a metal halide material consisting of group III metal halides and group II metal halides, wherein the metal halide material comprises at least one of group III metal halides such as indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide and aluminum iodide, and group II metal halides such as zinc chloride, zinc bromide, zinc iodide, At least one of cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercuric chloride, mercuric bromide, and mercuric iodide. The surface of the III-V group quantum dot core is completely or incompletely coated with a metal halide material consisting of III group metal halide and II group metal halide, so that the whole III-V group quantum dot core can be more effectively coated, excitons can be more effectively bound in the core, and the luminous efficiency is greatly improved.

Further, after the nucleation reaction in step SA012 or SB012 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, shell growth is performed under a third temperature condition, and a group II-VI semiconductor shell is formed on the surface of the group III-V quantum dot core, so as to obtain a core-shell quantum dot solution. Because the surface of the III-V group quantum dot core is combined with halide ions, the metal halide can serve as a transition shell layer, and the growth of the I-VI group semiconductor shell layer is facilitated.

Namely, a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and halide ions bonded on the surface of the III-V quantum dot core. Or a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and the II group metal ions and the halogen ions combined on the surface of the III-V quantum dot core. A halide ion is located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. Therefore, the metal halide formed by the halide ions and the metal cations on the surface of the III-V group quantum dot core and the II-VI group semiconductor shell layer have synergistic effect, and the formed core-shell quantum dot structure can more effectively separate the current carriers confined in the core from the surface state serving as the non-radiative recombination transition center, thereby greatly improving the luminous efficiency of the quantum dot. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

Preferred examples of the above-described method for producing quantum dots are shown in examples 1-1 to 1-6.

In one embodiment of the invention, the quantum dot comprises a III-V group quantum dot core and acetylacetone radical ions combined on the surface of the III-V group quantum dot core; wherein the acetylacetonate ions are bound to group III cations on the surface of the III-V quantum dot core.

In another embodiment of the present invention, there is provided a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a surface of the group III-V quantum dot core, and an acetylacetonate ion bound to the group III cation and the group II cation on the surface of the group III-V quantum dot core.

The acetylacetone radical ions have smaller radial dimension and bidentate coordination points and can exchange with introduced ligands such as carboxylic acid, and the acetylacetone radical ions are combined with metal cations (such as III group cations or III group cations and II group cations) on the surface of the III-V group quantum dot core, namely, a layer of acetylacetone metal compound is completely or incompletely coated on the surface of the quantum dot core, so that the original ligands on the surface of the III-V group quantum dot core can be reduced, the separation of nucleation and growth can be realized, the size dispersibility of the quantum dots can be effectively improved, the peak width of the quantum dots is remarkably narrowed, and the peak width range is less than 45 nm.

Further, the material of the III-V group quantum dot core is at least one selected from GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa. The group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the group II cation is at least one selected from zinc ion, cadmium ion, mercury ion and magnesium ion. The acetylacetonato ion is at least one selected from the group consisting of a hexahydroacetylacetonato ion and a hexafluoroacetylacetonato ion.

Specifically, for the III-V quantum dot core, the hexahydroacetylacetonate ion and hexafluoroacetylacetonate ion form at least one of hexahydroacetylacetone indium, hexahydroacetylacetone gallium, hexahydroacetylacetone aluminum, hexafluoroacetylacetone indium, hexafluoroacetylacetone gallium, and hexafluoroacetylacetone aluminum with the group III cation of the surface.

In particular, when group II cations bound to the surface of the core are present on the surface of the III-V quantum dot core, the acetylacetone radical ions can be combined with the group III cations and the group II cations on the surface of the III-V quantum dot core at the same time, which is equivalent to completely coating or not completely coating a layer of acetylacetone metal compound on the surface of the quantum dot core to form a layer containing at least one of group III acetylacetone metal compounds such as indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate and aluminum hexafluoroacetylacetonate, and a group II metal acetylacetone compound such as at least one of zinc hexahydroacetylacetonate, cadmium hexahydroacetylacetonate, magnesium hexahydroacetylacetonate, mercury hexahydroacetylacetonate, zinc hexafluoroacetylacetonate, cadmium hexafluoroacetylacetonate, magnesium hexafluoroacetylacetonate, and mercury hexafluoroacetylacetonate.

Further, the surface of the III-V group quantum dot core is coated with a II-VI group semiconductor outer shell layer, and the outer shell layer coats the III-V group quantum dot core and the acetylacetonato ions bonded on the surface of the III-V group quantum dot core. Alternatively, in another further embodiment, the group III-V quantum dot core is surface coated with a group II-VI semiconductor outer shell layer that coats the group III-V quantum dot core and the group II metal ions and the acetylacetonate ions bound to the surface of the group III-V quantum dot core. The acylacetonate ion is located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. Thus, the acetylacetone metal compound formed by the acetylacetone ions and the metal cations on the surface of the III-V group quantum dot core and the II-VI group semiconductor shell layer have synergistic effect, and the formed core-shell quantum dot structure can more effectively separate the current carriers confined in the core from the surface state serving as the non-radiative composite transition center, thereby greatly improving the luminous efficiency of the quantum dot. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

SA 021: providing a group III cation precursor and a ligand; the group III cation precursor comprises one or more acetylacetone metal salt precursors; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SA 022: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 021: providing a group III cation precursor, a first group II cation precursor, and a ligand; wherein the group III cation precursor comprises one or more acetylacetone metal salt precursors, and/or the first group II cation precursor comprises one or more acetylacetone metal salt precursors; dissolving the III group cation precursor, the second II group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SB 022: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Traditional III-V group quantum dots are generally prepared by combining a non-ligand solvent and a fatty acid ligand, and although the reaction speed of a system is improved by introducing the fatty acid ligand, the nucleation process of the III-V group semiconductor quantum dots is accelerated, and the particle size of generated crystal nuclei is relatively uniform, the fatty acid ligand is combined with III group cations through oxygen In carboxylate radicals, the combination energy of the III group cations and the oxygen is larger than that of II group cations In the same period, for example, the combination energy between In-O bonds is a multiple magnitude of that between Cd-O bonds: on one hand, carboxylic acid ligands can be tightly combined with In on the surface of the InP quantum dots at high temperature, so that the distribution of the carboxylic acid ligands on the surface of the InP quantum dots is much higher than that of the II-VI group quantum dots; on the other hand, the tight binding of the carboxylic acid ligand to the surface of the InP quantum dot is very unfavorable for the separation of the subsequent growth in the nucleation stage, and thus, the removal of the dense carboxylic acid ligand on the surface of the group III-V quantum dot is very necessary to achieve the separation of nucleation and growth. In the above preparation method according to the embodiment of the present invention, before the nucleation reaction, at least one acetylacetone metal salt precursor is introduced into the precursor, and cations in the acetylacetone metal salt precursor can be used for the nucleation reaction, and on the other hand, at the nucleation instant, due to acetylacetone radical ions having smaller radial dimensions and more (2) coordination dots, the acetylacetone metal salt precursor exchanges with carboxylic acid ligands and is combined with metal cations (such as group III cations, or group III cations and group II cations) on the surface of the group III-V quantum dot core, which is equivalent to completely coating or not completely coating a layer of acetylacetone metal compound on the surface of the quantum dot core, so that the original ligands on the surface of the group III-V quantum dot core can be reduced, and further, the nucleation and growth separation can be achieved. The finally prepared quantum dots have good size dispersibility, and can obviously narrow the peak width, so that the peak width range is less than 45 nm.

Specifically, in step SA021 above: the group III cation precursor comprises one or more acetylacetone metal salt precursors, namely the group III cation precursor can only comprise the acetylacetone metal salt precursor, and can also comprise other precursors besides one or more acetylacetone metal salt precursors. And the acetylacetone metal salt precursor in the group III cation precursor is selected from at least one of acetylacetone indium, hexafluoroacetylacetone indium, acetylacetone gallium, hexafluoroacetylacetone gallium, acetylacetone aluminum, and hexafluoroacetylacetone aluminum.

In the step SB 021: the group III cation precursor comprises one or more acetylacetone metal salt precursors, and/or the first group II cation precursor comprises one or more acetylacetone metal salt precursors, with the understanding that the group III cation precursor comprises one or more acetylacetone metal salt precursors, or the first group II cation precursor comprises one or more acetylacetone metal salt precursors, or both the group III cation precursor and the first group II cation precursor comprise one or more acetylacetone metal salt precursors; when the group III cation precursor comprises one or more acetylacetone metal salt precursors, the acetylacetone metal salt precursor is selected from at least one of indium acetylacetonate, indium hexafluoroacetylacetonate, gallium acetylacetonate, gallium hexafluoroacetylacetonate, aluminum acetylacetonate, and aluminum hexafluoroacetylacetonate; when the first group II cation precursor comprises one or more acetylacetone metal salt precursors, the acetylacetone metal salt precursors are selected from the group consisting of zinc acetylacetonate, zinc hexafluoroacetylacetonate, cadmium acetylacetonate, cadmium hexafluoroacetylacetonate, magnesium acetylacetonate, cadmium hexafluoroacetylacetonate, and mercury acetylacetonate. While the group II cation precursor may also contain other precursors.

For step SA021, the acetylacetonate ions combine with the group III cations on the surface of the group III-V quantum dot core to form at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate, and aluminum hexafluoroacetylacetonate.

In step SB021, after the group II cation precursor is added, the group II cation will combine with the group V anion (e.g. P) on the surface of the group III-V quantum dot core, so as to leave a group III cation vacancy, and the small molecule acetylacetonato ion ligand can exchange with the carboxylic acid on the surface of the group III cation, so that the acetylacetonato ion also combines with the group III cation on the surface of the core, and at the same time, the acetylacetonato ion can also combine with the group II cation on the surface of the group III-V quantum dot core, that is, the acetylacetonato ion combines with the group III cation and the group II cation on the surface of the group III-V quantum dot core, which is equivalent to completely coating or not completely coating a layer of acetylacetonato metal compound composed of the group III acetylacetonato metal compound and the group II acetylacetonato metal compound on the surface of the quantum dot core. The forming includes forming a group III acetylacetone metal compound including at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate, and aluminum hexafluoroacetylacetonate, and forming a group II acetylacetone metal compound including at least one of zinc hexahydroacetylacetonate, cadmium hexahydroacetylacetonate, magnesium hexahydroacetylacetonate, mercury hexahydroacetylacetonate, zinc hexafluoroacetylacetonate, cadmium hexafluoroacetylacetonate, magnesium hexafluoroacetylacetonate, and mercury hexafluoroacetylacetonate.

Further, immediately after the nucleation reaction in step SA022 or SB022 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, shell growth is performed under a third temperature condition, and a group II-VI semiconductor shell layer is formed on the surface of the group III-V quantum dot core, so as to obtain a core-shell quantum dot solution.

Namely, a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and acetylacetonato ions bonded on the surface of the III-V quantum dot core. Or a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the II-VI semiconductor shell layer coats the III-V quantum dot core and the II group metal ions and the acetylacetone radical ions combined on the surface of the III-V quantum dot core. The acetylacetonate ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. Thus, the acetylacetone metal compound formed by acetylacetone radical ions and metal cations on the surface of the III-V group quantum dot core and the II-VI group semiconductor shell layer have synergistic effect, and the formed core-shell quantum dot structure can more effectively separate current carriers limited in the core from a surface state serving as a non-radiative composite transition center, thereby greatly improving the luminous efficiency of the quantum dot. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

Preferred examples of the above-described method for producing quantum dots are shown in examples 2-1 to 2-6.

In one embodiment of the invention, the quantum dot comprises a III-V group quantum dot core and halide ions and acetylacetone radical ions which are combined on the surface of the III-V group quantum dot core; wherein the halide and acetylacetonate ions are bound to group III cations on the surface of the group III-V quantum dot core. In another embodiment of the present invention, there is provided a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and a halide ion and an acetylacetonate ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core. In the quantum dot of this embodiment, the surface of the III-V group quantum dot core is simultaneously bound with halide ions and acetylacetonato ions, which is equivalent to completely coating or not completely coating a layer of a mixed material composed of metal halides and acetylacetonato metal compounds on the surface of the III-V group quantum dot core. The halide ions are combined with metal cations on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core and effectively inhibit the occurrence of nonradiative transition, so that a large number of defect states on the surface of the III-V group quantum dot formed by covalent bond combination are avoided, and acetylacetone radical ions with smaller radial dimensions and bidentate coordination points can exchange with introduced carboxylic acid ligands, so that original ligands on the surface of the III-V group quantum dot core can be reduced, and the separation of nucleation and growth is realized. Therefore, the halide ions and the acetylacetone radical ions can be combined with cations on the surface of the III-V family quantum dot core to cooperatively form a layer of mixed material consisting of metal halide and acetylacetone metal compounds, so that the III-V family quantum dot core surface can be passivated, the luminous efficiency of the quantum dot is greatly improved, and the size dispersibility of the quantum dot can be improved, thereby obviously narrowing the peak width; the luminous efficiency of the final quantum dots is more than 70%, and the peak width range is less than 45 nm.

Further, the material of the III-V group quantum dot core is selected from at least one of GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa; the group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the halide ion is at least one selected from chloride ion, bromide ion and iodide ion. The acetylacetonato ion is at least one selected from the group consisting of a hexahydroacetylacetonato ion and a hexafluoroacetylacetonato ion.

Specifically, for the group III-V quantum dot core, the hexahydroacetylacetonate ion and hexafluoroacetylacetonate ion form at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate and aluminum hexafluoroacetylacetonate with the group III cation on the surface of the group III-V quantum dot core. The halide ions form with the group III cations on the surface of the group III-V quantum dot core, such as at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide. Furthermore, the quantum dot also comprises an outer shell layer, the material of the outer shell layer is II-VI semiconductor material, and the outer shell layer coats the III-V quantum dot core and the halide ions and acetylacetonato ions bonded on the surface of the quantum dot core. Halide ions and acetylacetonate ions are located between the group III-V quantum dot core and the shell layer of group II-VI semiconductor material. Thus, the core-shell quantum dot structure formed by the synergistic effect of the halide ions, the acetylacetone ions and the II-VI semiconductor shell layer has higher luminous efficiency. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

Specifically, when there is a group II cation bound on the surface of the III-V quantum dot core, the acetylacetonato ion can be bound with the group III cation and the group II cation on the surface of the III-V quantum dot core simultaneously, which is equivalent to completely or incompletely coating a layer of a mixed material composed of a metal acetylacetonate compound and a metal halide on the surface of the III-V quantum dot core to form a mixed material including at least one of a group III acetylacetonato metal compound such as indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate and aluminum hexafluoroacetylacetonate, and a group II metal acetylacetone compound such as zinc hexahydroacetylacetonate, cadmium hexahydroacetylacetonate, magnesium hexahydroacetylacetonate, mercury hexahydroacetylacetonate, zinc hexafluoroacetylacetonate, cadmium hexafluoroacetylacetonate, magnesium hexafluoroacetylacetonate, At least one of mercury hexafluoroacetylacetonate. The metal halide is selected from at least one of group III metal halides such as indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide, and at least one of group II metal halides such as zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercury chloride, mercury bromide, and mercury iodide.

Furthermore, the quantum dot also comprises an outer shell layer, the material of the outer shell layer is II-VI semiconductor material, and the outer shell layer coats the III-V quantum dot core and II cations, halide ions and acetylacetonato ions which are combined on the surface of the III-V quantum dot core. Halide ions and acetylacetonate ions are located between the group III-V quantum dot core and the shell layer of group II-VI semiconductor material. Thus, the core-shell quantum dot structure formed by the synergistic effect of the halide ions, the acetylacetone ions and the II-VI semiconductor shell layer has higher luminous efficiency. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

SA 031: providing a group III cation precursor and a ligand; the group III cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal halide precursors; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SA 032: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 031: providing a cation precursor and a ligand, wherein the cation precursor is a group III cation precursor and a first group II cation precursor, and the cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal halide precursors; dissolving the cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SB 033: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

In the preparation method of the embodiment of the invention, at least one acetylacetone metal salt precursor and at least one metal halide precursor are introduced into the precursor before the nucleation reaction, so that metal cations in the acetylacetone metal salt precursor can be used for the nucleation reaction in the preparation process, and on the other hand, the acetylacetone radical ions have smaller radial dimension and more (2) coordination sites and can exchange with carboxylic acid ligands at the nucleation moment, so that the original ligands on the surface of the III-V group quantum dot nuclei can be reduced, and the separation of nucleation and growth is further realized; and the cation in the metal halide precursor can also be used for nucleation reaction, and on the other hand, the halide ion can react with the V-group anion dangling bond on the surface of the nucleated III-V-group quantum dot core to generate VX₃The (V is N, P or As, X is halogen) gas is beneficial to the reaction, so that the III group atoms and the V group atoms on the surface of the III-V group quantum dot core are recombined to form the III-V group quantum dot core with more stable atomic ratio, and meanwhile, the halide ions can be combined with the cations on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core; finally, halide ions and acetylacetone radical ions can be simultaneously combined with cations on the surface of the nucleated III-V group quantum dot core, which is equivalent to that the surface of the III-V group quantum dot core is completely or incompletely coated with a layer of mixed material consisting of acetylacetone metal compound and metal halide, so that the surface of the III-V group quantum dot core can be passivated, the luminous efficiency of the quantum dot is greatly improved, and the size dispersibility of the quantum dot can be improved, thereby obviously narrowing the peak width; the luminous efficiency of the final quantum dots is more than 70%, and the peak width range is less than 45 nm.

Specifically, in step SA 031: the group III cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal halide precursors, namely the group III cation precursor can only contain the acetylacetone metal salt precursor and the metal halide precursor, and can also contain other precursors besides the acetylacetone metal salt precursor and the metal halide precursor; and the acetylacetone metal salt precursor in the III-group cation precursor is selected from at least one of acetylacetone indium, hexafluoroacetylacetone indium, acetylacetone gallium, hexafluoroacetylacetone gallium, acetylacetone aluminum and hexafluoroacetylacetone aluminum, and at least one of metal halide precursors of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide and aluminum iodide.

In step SB031 above: the inclusion of one or more acetylacetonato metal salt precursors and one or more metal halide precursors in the cation precursors (group III cation precursor and first group II cation precursor) can be understood to be a variety of cases as follows: (1) the group III cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal halide precursors; (2) the first group II cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal halide precursors; (3) the group III cation precursor comprises one or more acetylacetonato metal salt precursors (the group III cation precursor may further comprise one or more metal halide precursors), and the first group II cation precursor comprises one or more metal halide precursors (the first group II cation precursor may further comprise one or more acetylacetonato metal salt precursors); (4) the group III cation precursor may include one or more metal halide precursors (the group III cation precursor may further include one or more metal acetylacetonate precursors), and the first group II cation precursor may include one or more metal acetylacetonate precursors (the first group II cation precursor may further include one or more metal halide precursors), and the like; as long as the cation precursor composed of the group III cation precursor and the first group II cation precursor contains both a halogen ion and an acetylacetonate ion.

In step SA031, halide ions and acetylacetonato ions are simultaneously bound to group III cations on the surface of the group III-V quantum dot core; the method is equivalent to completely coating or not coating a layer of mixed material consisting of III acetylacetone metal compound and III metal halide on the surface of the III-V group quantum dot core.

In step SB031, after the group II cation precursor is added, the group II cation will combine with the group V anion (e.g. P) on the surface of the III-V quantum dot core, thereby leaving a group III cation vacancy, and both the small molecule halide ion and the acetylacetonate ion ligand can combine with the group III cation on the surface of the core, and the halide acetylacetonate ion can also combine with the group II cation on the surface of the III-V quantum dot core, that is, the halide ion and the acetylacetonate ion can combine with the group III cation and the group II cation on the surface of the III-V quantum dot core. The quantum dot core is coated with a layer of mixed material consisting of II-group acetylacetone metal compound, III-group acetylacetone metal compound, II-group metal halide and III-group metal halide completely or incompletely.

Further, after the nucleation reaction in step SA032 or SB032 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, and shell layer growth is performed under a third temperature condition, so that a group II-VI semiconductor shell layer is formed on the surface of the group III-V quantum dot core, and a core-shell quantum dot solution is obtained.

Namely, a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and acetylacetone radical ions and halide ions combined on the surface of the III-V quantum dot core. Or a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and II group metal ions, acetylacetone ions and halide ions which are combined on the surface of the III-V quantum dot core. Halide ions, acetylacetonate ions are located between said group III-V quantum dot core and said group II-VI semiconductor shell layer. Thus, the halide ions and the acetylacetone radical ions respectively cooperate with the metal halide formed by the metal cations on the surface of the III-V group quantum dot core, the acetylacetone metal compound and the II-VI group semiconductor shell layer to form the core-shell quantum dot structure, so that the current carriers confined in the core can be effectively separated from the surface state serving as the non-radiative composite transition center, and the luminous efficiency of the quantum dot is greatly improved. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

Preferred examples of the above-described method for producing quantum dots are shown in examples 3-1 to 3-6.

In one embodiment of the invention, a quantum dot is provided, which comprises a III-V group quantum dot core and hydroxide ions combined on the surface of the III-V group quantum dot core; wherein the hydroxide ions are bound to group III cations on the surface of the quantum dot core.

In another embodiment of the present invention, there is provided a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and a hydroxide ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core.

According to the quantum dot of the embodiment, the hydroxyl ions are combined with the III metal cations on the surface of the III-V group quantum dot core, namely a layer of metal hydroxide which is completely coated or not completely coated on the surface of the III-V group quantum dot core is formed, so that the surface of the III-V group quantum dot core can be passivated, and the III-V group quantum dot core can be used as a buffer outer shell layer, the problem of lattice adaptation between the III-V group quantum dot core and the II-VI group semiconductor outer shell layer can be effectively solved, the growth of a thick outer shell layer is facilitated, and therefore the stability of the quantum dot can be greatly improved by combining the hydroxyl ions on the surface of the III-V group quantum dot core. The group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the group II cation is at least one selected from zinc ion, cadmium ion, mercury ion and magnesium ion. Further, the material of the III-V group quantum dot core is at least one selected from GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa.

Specifically, for the III-V quantum dot core, the hydroxide ions form a structure of a comparable metal hydroxide layer with the surface group III cations, for example, at least one of indium hydroxide, gallium hydroxide, and aluminum hydroxide. Furthermore, the quantum dot also comprises an outer shell layer, the material of the outer shell layer is II-VI semiconductor material, and the outer shell layer coats the III-V quantum dot core and hydroxyl ions combined with the surface of the III-V quantum dot core. Preferably, the group II-VI semiconductor material is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSe and MgZnS.

Specifically, when there is a group II cation bound on the surface of the III-V quantum dot core, the hydroxide ions can combine with the group III cation and the group II cation on the surface of the III-V quantum dot core to form a layer of metal hydroxide completely or incompletely coated on the surface of the III-V quantum dot core, where the metal hydroxide includes at least one of group III metal hydroxide such as indium hydroxide, gallium hydroxide, and aluminum hydroxide, and at least one of group II metal hydroxide such as zinc hydroxide, cadmium hydroxide, magnesium hydroxide, and mercury hydroxide. Still further preferably, the quantum dot further comprises an outer shell layer, the material of the outer shell layer is II-VI semiconductor material, and the outer shell layer covers the III-V quantum dot core and the II cations and hydroxide ions combined on the surface of the III-V quantum dot core. The hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer.

Therefore, the structure equivalent to the metal hydroxide layer is formed by the hydroxide ions and the metal cations on the surface of the III-V group quantum dot core and the synergistic effect of the II-VI group semiconductor shell layer, and the formed core-shell quantum dot structure has higher luminous efficiency. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

Furthermore, the thickness of the shell layer made of the II-VI group semiconductor material is 3-5nm, and the existence of the equivalent metal hydroxide layer increases the thickness of the II-VI group semiconductor shell layer, so that the luminous efficiency of the core-shell quantum dot is improved.

SA 041: providing a group III cation precursor and a ligand; the group III cation precursor comprises one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the III group cation precursor and the ligand in a solvent, and carrying out first heating treatment to obtain a mixed solution; adding a V-group anion precursor into the mixed solution, and heating under a first temperature condition to obtain a mixed solution;

SA 042: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 041: providing a cation precursor and a ligand, wherein the cation precursor is a group III cation precursor and a first group II cation precursor, and the cation precursor comprises one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SB 042: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

In the above preparation method according to an embodiment of the present invention, at least one metal oxide precursor and/or metal hydroxide precursor is introduced into the precursor before the nucleation reaction, so that during the preparation process, metal ions in the metal oxide precursor and/or metal hydroxide precursor participate in the formation of the III-V quantum dot nuclei, and anions in the metal oxide precursor, i.e., O^2-First combines with protons in the reaction system solution to form OH^-，OH^-Can be rapidly combined with III-V groupCations (such as III group cations or III group cations and II group cations) on the surface of the quantum dot core are combined to form a metal oxide layer which completely covers or does not completely cover the surface of the III-V group quantum dot, so that the surface of the III-V group quantum dot core can be effectively passivated, and the metal oxide layer can be used as a buffer outer shell layer to effectively reduce the problem of lattice adaptation between the core and the outer shell layer, and is favorable for the growth of a thick outer shell layer.

In step SA041 above: the group III cation precursor includes one or more metal oxide precursors and/or one or more metal hydroxide precursors, i.e., the group III cation precursor may contain only one or more metal oxide precursors, or the group III cation precursor may contain only one or more metal hydroxide precursors, or the group III cation precursor may have both one or more metal oxide precursors and one or more metal hydroxide precursors. In addition, the group III cation precursor may contain other precursors in addition to one or more metal oxide precursors and/or metal hydroxide precursors. And when the group III cation precursor comprises one or more metal oxide precursors, the metal oxide precursor is at least one selected from indium oxide, gallium oxide and aluminum oxide; and/or, when the group III cation precursor includes one or more metal hydroxide precursors, the group III metal hydroxide precursor is selected from at least one of indium hydroxide, gallium hydroxide, and aluminum hydroxide.

In step SB041 above: the inclusion of one or more metal oxide precursors and/or one or more metal hydroxide precursors in the cation precursors (group III cation precursor and first group II cation precursor) can be understood to be a number of situations as follows: (1) the group III cation precursor includes one or more metal oxide precursors and/or metal hydroxide precursors, in which case the group III cation precursor can contain only one or more metal oxide precursors, or the group III cation precursor can contain only one or more metal hydroxide precursors, or the group III cation precursor can contain both one or more metal oxide precursors and one or more metal oxide precursorsOne or more metal hydroxide precursors. (2) The first group II cation precursor comprises one or more metal oxide precursors and/or metal hydroxide precursors, in which case the first group II cation precursor may contain only one or more metal oxide precursors, or the first group II cation precursor may contain only one or more metal hydroxide precursors, or the first group II cation precursor may contain both one or more metal oxide precursors and one or more metal hydroxide precursors. (3) The group III cation precursor comprises one or more metal oxide precursors, and the first group II cation precursor comprises one or more metal oxide precursors and/or metal hydroxide precursors; (4) the group III cation precursor includes one or more metal hydroxide precursors, and the first group II cation precursor includes one or more metal oxide precursors and/or metal hydroxide precursors. (5) The group III cation precursor includes one or more metal oxide precursors and one or more metal hydroxide precursors, and the first group II cation precursor includes one or more metal oxide precursors and/or metal hydroxide precursors, and the like, as long as O is present in the mixture of the group III cation precursor and the first group II cation precursor^2-And/or OH^-And (4) finishing. For one or more metal oxides and/or metal hydroxides in the first group II cation precursor, the metal oxide is selected from at least one of indium oxide, gallium oxide, and aluminum oxide, and the metal hydroxide is selected from at least one of indium hydroxide, gallium hydroxide, and aluminum hydroxide. For the metal oxide precursor and/or the metal hydroxide precursor in the first group II cation precursor, the group II metal oxide is selected from at least one of zinc oxide, cadmium oxide, magnesium hydroxide, and mercury oxide, and the group II metal hydroxide is selected from at least one of zinc hydroxide, cadmium hydroxide, magnesium hydroxide, and mercury hydroxide. While the first group II cation precursor may also contain other precursors in addition to the metal oxide and/or metal hydroxide.

For step SA041, the group III cation precursor comprisesOne or more metal oxides and/or metal hydroxides, the anion of the metal oxide being O^2-First combines with protons in the reaction system solution to form OH^-，OH^-The metal hydroxide is combined with III group cations on the surface of the III-V group quantum dot core, namely a layer of metal hydroxide coated on the quantum dot core is formed on the surface of the quantum dot core, and the metal hydroxide is at least one of indium hydroxide, gallium hydroxide and aluminum hydroxide;

for step SB041, since the first group II cation precursor was introduced: the group II cations will combine with group V anions (e.g., P) on the surface of the III-V quantum dot core, leaving a group III cation vacancy, OH^-Combined with group III cations on the surface of the core, with OH^-And the compound can be combined with group II cations combined on the surface of the III-V quantum dot core, namely forming a layer of mixed material consisting of group II metal hydroxide and group III metal hydroxide coated on the surface of the quantum dot core, wherein the group III metal hydroxide is at least one of indium hydroxide, gallium hydroxide and aluminum hydroxide, and the group II metal hydroxide is at least one of zinc hydroxide, cadmium hydroxide, magnesium hydroxide and mercury hydroxide.

Further, after the nucleation reaction in step SA042 or SB042 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, shell growth is performed under a third temperature condition, and a group II-VI semiconductor shell is formed on the surface of the group III-V quantum dot core, so as to obtain a core-shell quantum dot solution.

Namely, a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and combines hydroxyl ions on the surface of the III-V quantum dot core. Or a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and the II cations and hydroxyl ions combined on the surface of the III-V quantum dot core. The hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. Therefore, the structure equivalent to the metal hydroxide layer is formed by the hydroxide ions and the metal cations on the surface of the III-V group quantum dot core and the synergistic effect of the II-VI group semiconductor shell layer, and the formed core-shell quantum dot structure has higher luminous efficiency. Preferably, the material of the group II-VI semiconductor shell layer is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgTe, MgZnSe, and MgZnS.

Preferred examples of the above-described method for producing quantum dots are shown in examples 4-1 to 4-6.

In one embodiment of the invention, a quantum dot is provided, which comprises a III-V group quantum dot core and halide ions and hydroxide ions combined on the surface of the III-V group quantum dot core; wherein the halide and hydroxide ions are bound to group III cations on the surface of the quantum dot core.

In another embodiment of the present invention, there is provided a quantum dot, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and a halide ion and a hydroxide ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core.

In the quantum dot of this embodiment, the combination of the halide ion and the hydroxyl ion with the cation on the surface of the III-V group quantum dot core is equivalent to the complete coating or the incomplete coating of the mixed material layer composed of the metal halide and the metal hydroxide on the surface of the quantum dot core, and the halide ion is combined with the metal cation on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core and effectively suppress the occurrence of nonradiative transition, thereby avoiding a large number of defect states on the surface of the III-V group quantum dot formed by covalent bonding, while the combination of the hydroxyl ion with the metal cation on the surface of the III-V group quantum dot core can not only passivate the surface of the III-V group quantum dot core, but also can be used as a buffer shell layer, thereby effectively reducing the problem of lattice adaptation between the III-V group quantum dot core and the II-VI group semiconductor shell layer, the growth of a thick shell layer is facilitated, the luminous efficiency (more than 70%) of the quantum dot is improved, and the stability of the quantum dot is improved.

Further, the material of the III-V group quantum dot core is selected from at least one of GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa; the group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the group II cation is at least one of zinc ion, cadmium ion, mercury ion and magnesium ion; the halide ion is at least one selected from chloride ion, bromide ion and iodide ion. A hydroxide ion-forming group III metal hydroxide such as at least one of indium hydroxide, gallium hydroxide, and aluminum hydroxide, and a hydroxide ion-forming group II metal hydroxide such as at least one of zinc hydroxide, cadmium hydroxide, magnesium hydroxide, and mercury hydroxide. The halide ions form at least one of a group III metal halide such as indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide, and the halide ions form at least one of a group II metal halide such as zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercury chloride, mercury bromide, and mercury iodide.

Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, and the shell layer coats the group III-V quantum dot core and the halide ions and hydroxide ions bound on the surface of the group III-V quantum dot core. Halide and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer.

Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, which coats the group III-V quantum dot core and group II cations, halide ions and hydroxide ions bound to the surface of the group III-V quantum dot core. Halide and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer.

Thus, the halogen ions passivate the surface of the III-V group quantum dot core and effectively inhibit the generation of non-radiative transition, the hydroxyl ions can enable the crystal lattices between the III-V group quantum dot core and the II-VI group semiconductor shell layer to be matched, and the II-VI group semiconductor shell layer more effectively separates carriers confined in the core from surface states serving as non-radiative recombination transition centers; the core-shell quantum dot structure formed by the synergistic effect of the halide ions, the hydroxide ions and the II-VI group semiconductor shell layer has higher luminous efficiency. The II-VI group semiconductor shell layer is made of at least one material selected from CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSZnSe and MgZnS; still further, the II-VI semiconductor shell layer has a thickness of 3-5 nm.

SA 051: providing a group III cation precursor and a ligand; the group III cation precursor comprises one or more metal halide precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SA 052: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 051: providing a cation precursor and a ligand, wherein the cation precursor is a group III cation precursor and a first group II cation precursor, and the cation precursor comprises one or more metal halide precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution; (ii) a

SB 052: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Examples of the inventionThe above preparation method of (1) is characterized by introducing at least one metal oxide precursor and/or metal hydroxide precursor, and at least one metal halide precursor into the reaction system during the nucleation process before the nucleation reaction; thus, in the preparation process, on one hand, cations in the metal halide precursor can be used for nucleation reaction, and on the other hand, halide ions can react with the group V anion dangling bond on the surface of the nucleated III-V group quantum dot core to generate VX₃The (V is N, P or As, X is halogen) gas is beneficial to the reaction, so that the III group atoms and the V group atoms on the surface of the III-V group quantum dot core are recombined to form the III-V group quantum dot core with more stable atomic ratio, and meanwhile, the halide ions can be combined with the cations on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core; the metal ions in the metal oxide and/or metal hydroxide also participate in the formation of the III-V group quantum dot core, and the anion in the metal oxide, i.e., O^2-First combines with protons in the reaction system solution to form OH^-Final OH^-Can be rapidly combined with cations on the surface of the III-V group quantum dot core, OH^-The metal hydroxide is formed after the metal hydroxide is combined with the metal on the surface of the III-V group quantum dot core, so that the surface of the III-V group quantum dot core can be effectively passivated, the problem of lattice adaptation between the core and the shell layer is effectively reduced, and the growth of a thick shell layer is facilitated. In the quantum dots finally obtained by the preparation method, the III-V family quantum dot core surface is combined with halide ions and hydroxyl ions, so that the III-V family quantum dot core surface can be passivated through the synergistic effect, the luminous efficiency of the quantum dots is greatly improved, the luminous efficiency of the quantum dots is finally higher than 70%, the growth of a thick outer shell layer is facilitated, and the stability of the quantum dots can be greatly improved.

In the above step SA 051: the group III cation precursor includes one or more metal halide precursors, and includes one or more metal oxide precursors and/or metal hydroxide precursors, understood to be: (1) the group III cation precursor has both one or more metal halide precursors and one or more metal oxide precursors, (2) the group III cation precursor has both one or more metal halide precursors and one or more metal hydroxide precursors, and (3) the group III cation precursor has both one or more metal halide precursors, one or more metal oxide precursors, and one or more metal hydroxide precursors. In addition, the group III cation precursor contains other precursors in addition to one or more metal halide precursors, one or more metal oxide precursors, and/or metal hydroxide precursors.

In step SB051 above: the cation precursors (group III cation precursor and first group II cation precursor) include one or more metal halide precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors, which can be understood as follows: (1) the group III cation precursor comprises one or more metal halide precursors, and comprises one or more metal oxide precursors and/or metal hydroxide precursors; (2) the first group II cation precursor comprises one or more metal halide precursors and comprises one or more metal oxide and/or metal hydroxide precursors, (3) the group III cation precursor comprises one or more metal halide precursors (the group III cation precursor may further comprise one or more metal oxide precursors and/or metal hydroxide precursors), and the first group II cation precursor comprises one or more metal oxide and/or metal hydroxide precursors (the first group II cation precursor may further comprise one or more metal halide precursors); (4) the group III cation precursor comprises one or more metal oxide precursors and/or metal hydroxide precursors (the group III cation precursor may further comprise one or more metal halide precursors), while the first group II cation precursor comprises one or more metal halide precursors (the first group II cation precursor may further comprise one or more metal oxide precursors and/or metal hydroxide precursors); and the like; provided that the cation precursor composed of the group III cation precursor and the first group II cation precursor is the same as that of the group III cation precursorIn the presence of a halide ion, and O^2-And/or OH^-And (4) finishing.

For step SA051, halide ions and hydroxide ions are simultaneously combined with group III cations on the surface of the III-V quantum dot core; the method is equivalent to completely coating or not coating a mixed material layer consisting of III group metal halide and III group metal hydroxide on the surface of the quantum dot core. The group III metal hydroxide is at least one of indium hydroxide, gallium hydroxide and aluminum hydroxide. The metal halide is selected from at least one of group III metal halides such as indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide.

For step SB051, after adding the group II cation precursor, the group II cation will combine with the group V anion (such as P) on the surface of the III-V quantum dot core, thereby leaving a group III cation vacancy, the small molecule halide ion and hydroxide ion ligand can combine with the group III cation on the surface of the core, and simultaneously the halide ion and hydroxide ion can combine with the group II cation on the surface of the III-V quantum dot core, namely the halide ion and hydroxide ion can combine with the group III cation and the group II cation on the surface of the III-V quantum dot core simultaneously. The quantum dot core is coated with a mixed material layer consisting of II group metal halide, III group metal halide, II group metal hydroxide and III group metal hydroxide completely or not.

Further, after the nucleation reaction in step SA052 or SB052 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, and shell layer growth is performed under a third temperature condition to form a group II-VI semiconductor shell layer on the surface of the group III-V quantum dot core, thereby obtaining a core-shell quantum dot solution.

Namely, a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and halogen ions and hydroxyl ions combined on the surface of the III-V quantum dot core. Halide and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer.

Or a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, and the shell layer coats the III-V quantum dot core and II cations, halogen ions and hydroxyl ions combined on the surface of the III-V quantum dot core. Halide and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer.

Preferred examples of the above-described method for producing quantum dots are shown in examples 5-1 to 5-6.

In one embodiment of the invention, the quantum dot comprises a III-V group quantum dot core and acetylacetone ions and hydroxide ions combined on the surface of the III-V group quantum dot core; wherein the acetylacetonate ions and hydroxide ions are bound to group III cations on the surface of the group III-V quantum dot core.

In another embodiment of the present invention, there is provided a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and an acetylacetonate ion and a hydroxide ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core.

In the quantum dot of the embodiment, acetylacetone radical ions have smaller radial dimensions and bidentate coordination points and can exchange with introduced carboxylic acid ligands, so that original ligands on the surface of a III-V group quantum dot core can be reduced, the separation of nucleation and growth is realized, hydroxyl ions and cations on the surface of the III-V group quantum dot core can be combined, not only can the surface of the III-V group quantum dot core be passivated, but also the hydroxyl ions can be used as a buffer outer shell layer, the problem of lattice adaptation between the III-V group quantum dot core and a II-VI group semiconductor outer shell layer can be effectively reduced, and the growth of a thick outer shell layer is facilitated. Therefore, the combination of acetylacetone ions and hydroxide ions with cations on the surface of the III-V group quantum dot core is equivalent to the complete coating or the incomplete coating of a mixed material layer consisting of acetylacetone metal compounds and metal hydroxides on the surface of the III-V group quantum dot core. In one embodiment, the acetylacetonate ions and hydroxide ions combine with group III cations on the surface of the group III-V quantum dot core to form a group III acetylacetonate metal compound and a group III metal hydroxide. In one embodiment, the acetylacetonate ions and hydroxide ions combine with group III cations and group II cations on the surface of the group III-V quantum dot core to form a group III acetylacetonate metal compound, a group II metal hydroxide, and a group III metal hydroxide. The mixed material not only improves the size dispersibility of the quantum dots, thereby obviously narrowing the peak width, but also is beneficial to the growth of a thick shell layer, and can greatly improve the stability of the quantum dots.

Further, the material of the III-V group quantum dot core is selected from at least one of GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa; the group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the group II cation is at least one selected from zinc ion, cadmium ion, mercury ion and magnesium ion. The acetylacetonato ion is at least one selected from the group consisting of a hexahydroacetylacetonato ion and a hexafluoroacetylacetonato ion.

The group III acetylacetone metal compound is at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate, and aluminum hexafluoroacetylacetonate. The II group metal acetylacetone compound is at least one of zinc hexahydroacetylacetonate, cadmium hexahydroacetylacetonate, magnesium hexahydroacetylacetonate, mercury hexahydroacetylacetonate, zinc hexafluoroacetylacetonate, cadmium hexafluoroacetylacetonate, magnesium hexafluoroacetylacetonate, and mercury hexafluoroacetylacetonate. Hydroxide ion-forming group III metal hydroxide such as at least one of indium hydroxide, gallium hydroxide and aluminum hydroxide, and hydroxide ion-forming group II metal hydroxide such as at least one of zinc hydroxide, cadmium hydroxide, magnesium hydroxide and mercury hydroxide

Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, which coats the group III-V quantum dot core and acetylacetonato ions and hydroxide ions bound to the surface of the group III-V quantum dot core. Acetylacetonato and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer.

Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, which coats the group III-V quantum dot core and the group II cations, acetylacetonato ions and hydroxide ions bound to the surface of the group III-V quantum dot core. Acetylacetonato and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. The core-shell quantum dot structure formed by the synergistic effect of the acetylacetone ions, the hydroxyl ions and the II-VI group semiconductor shell layer has higher luminous efficiency. The II-VI group semiconductor shell layer is made of at least one material selected from CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSZnSe and MgZnS; still further, the II-VI semiconductor shell layer has a thickness of 3-5 nm.

SA 061: providing a group III cation precursor and a ligand; the group III cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SA 062: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 061: providing a cation precursor and a ligand, wherein the cation precursor is a group III cation precursor and a first group II cation precursor, and the cation precursor comprises one or more acetylacetone metal salt precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SB 062: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

In the quantum dot preparation method of the embodiment, before a nucleation reaction, at least one metal oxide precursor and/or metal hydroxide precursor and at least one acetylacetone metal salt precursor are introduced into a reaction system in a nucleation process; in the preparation process, cations in the acetylacetone metal salt precursor can be used for nucleation reaction, and on the other hand, acetylacetone radical ions have smaller radial dimensions and more (2) coordination sites and can exchange with carboxylic acid ligands at the nucleation moment, so that the original ligands on the surface of the III-V group quantum dot nuclei can be reduced, and further the separation of nucleation and growth is realized; the metal ions in the metal oxide precursor and/or metal hydroxide precursor also participate in the formation of the group III-V quantum dot core, while the anion in the metal oxide precursor, i.e., O^2-First combines with protons in the reaction system solution to form OH^-Final OH^-The surface of the III-V group quantum dot core can be quickly combined with cations on the surface of the III-V group quantum dot core to effectively passivate the surface of the III-V group quantum dot core, and meanwhile, the buffer shell layer is used as a layer of buffer shell layer to effectively reduce the problem of lattice adaptation between the core and the shell layer, thereby being beneficial to the growth of a thick shell layer. According to the quantum dot finally obtained by the preparation method, the acetylacetone ions and the hydroxyl ions are combined with the cations on the surface of the III-V family quantum dot core, namely, the surface of the III-V family quantum dot core is completely coated or not completely coated with a mixed material layer consisting of acetylacetone metal compounds and metal hydroxides, and the mixed material not only improves the size dispersibility of the quantum dot, so that the peak width is remarkably narrowed (the range of the peak width is less than 45nm), but also is beneficial to the growth of a thick outer shell layer, and the stability of the quantum dot can be greatly improved.

In step SA061, acetylacetonato ions and hydroxide ions are simultaneously combined with group III cations on the surface of the III-V quantum dot core; in one embodiment, the acetylacetonato and hydroxide ions combine with the group III cations on the surface of the group III-V quantum dot core to form a group III acetylacetonato metal compound and a group III metal hydroxide, which corresponds to a complete or incomplete coating of the surface of the group III-V quantum dot core with a mixed material layer composed of the group III acetylacetonato metal compound and the group III metal hydroxide.

In step SB061, after the group II cation precursor is added, the group II cation will combine with the group V anion (e.g. P) on the surface of the III-V quantum dot core, thereby leaving a group III cation vacancy, and both the small molecule acetylacetonate ion and hydroxide ion ligand can combine with the group III cation on the surface of the core, and simultaneously the acetylacetonate ion and hydroxide ion can also combine with the group II cation on the surface of the III-V quantum dot core, i.e. both the acetylacetonate ion and hydroxide ion combine with the group III cation and group II cation on the surface of the III-V quantum dot core. The method is equivalent to completely coating or not coating a mixed material layer consisting of a group III acetylacetone metal compound, a group II metal hydroxide and a group III metal hydroxide on the surface of the group III-V quantum dot core.

In one embodiment, the acetylacetonate ions and hydroxide ions combine with group III cations on the surface of the group III-V quantum dot core to form a group III acetylacetonate metal compound and a group III metal hydroxide. In one embodiment, the acetylacetonate ions and hydroxide ions combine with group III cations and group II cations on the surface of the group III-V quantum dot core to form a group III acetylacetonate metal compound, a group II metal hydroxide, and a group III metal hydroxide.

In the above step SA 061: the group III cation precursor comprises one or more acetylacetone metal salt precursors, and comprises one or more metal oxide precursors and/or metal hydroxide precursors, which can be understood as: (1) the group III cation precursor has one or more acetylacetone metal salt precursors and one or more metal oxide precursors at the same time, (2) the group III cation precursor has one or more acetylacetone metal salt precursors and one or more metal hydroxide precursors at the same time, (3) the group III cation precursor has one or more acetylacetone metal salt precursors, one or more metal oxide precursors and one or more metal hydroxide precursors at the same time. In addition, the group III cation precursor may contain other precursors in addition to one or more acetylacetonates metal salt precursors, one or more metal oxide precursors, and/or metal hydroxide precursors.

In the above step SB 061: the cation precursors (group III cation precursor and first group II cation precursor) include one or more acetylacetone metal salt precursors and one or more metal oxide precursors and/or one or more metal hydroxide precursors, which can be understood as follows: (1) the group III cation precursor comprises one or more acetylacetone metal salt precursors, and comprises one or more metal oxide precursors and/or metal hydroxide precursors; (2) the first group II cation precursor comprises one or more acetylacetone metal salt precursors, one or more metal oxide precursors and/or metal hydroxidesA precursor, (3) the group III cation precursor comprises one or more acetylacetone metal salt precursors (the group III cation precursor may further comprise one or more metal oxide precursors and/or metal hydroxide precursors), and, at the same time, the first group II cation precursor comprises one or more metal oxide precursors and/or metal hydroxide precursors (the first group II cation precursor may further comprise one or more acetylacetone metal salt precursors); (4) the group III cation precursor may include one or more metal oxide precursors and/or metal hydroxide precursors (the group III cation precursor may further include one or more acetylacetone metal salt precursors), and the first group II cation precursor may include one or more acetylacetone metal salt precursors (the first group II cation precursor may further include one or more metal oxide precursors and/or metal hydroxide precursors); provided that the mixture of the group III cation precursor and the first group II cation precursor contains both acetylacetonate ions and O^2-And/or OH^-And (4) finishing.

Further, after the nucleation reaction in step SA062 or SB062 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, shell growth is performed under a third temperature condition, and a group II-VI semiconductor shell layer is formed on the surface of the group III-V quantum dot core, resulting in a core-shell quantum dot solution. Namely, a II-VI semiconductor shell layer is coated on the surface of the III-V quantum dot core, the shell layer coats the III-V quantum dot core and acetylacetone ions and hydroxide ions combined on the surface of the III-V quantum dot core, and halogen ions and hydroxide ions are positioned between the III-V quantum dot core and the II-VI semiconductor shell layer. Or coating a II-VI semiconductor shell layer on the surface of the III-V quantum dot core, wherein the shell layer coats the III-V quantum dot core and II cations, acetylacetone ions and hydroxide ions combined on the surface of the III-V quantum dot core, and the acetylacetone ions and the hydroxide ions are positioned between the III-V quantum dot core and the II-VI semiconductor shell layer. The core-shell quantum dot structure formed by the synergistic effect of the acetylacetone ions, the hydroxyl ions and the II-VI group semiconductor shell layer has higher luminous efficiency. The II-VI group semiconductor shell layer is made of at least one material selected from CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSZnSe and MgZnS; still further, the II-VI semiconductor shell layer has a thickness of 3-5 nm.

Preferred examples of the above-described method for producing quantum dots are shown in examples 6-1 to 6-6.

In one embodiment of the invention, the quantum dot comprises a III-V group quantum dot core and halide ions, acetylacetone ions and hydroxide ions which are combined on the surface of the III-V group quantum dot core; wherein the halide, acetylacetonate, and hydroxide ions bind to group III cations on the surface of the group III-V quantum dot core.

In another embodiment of the present invention, there is provided a quantum dot comprising a group III-V quantum dot core, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and a halide ion, an acetylacetonate ion, and a hydroxide ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core.

In the quantum dot of the embodiment, halide ions are combined with metal cations on the surface of a III-V group quantum dot core to passivate the surface of the III-V group quantum dot core, so that the occurrence of nonradiative transition is effectively inhibited, and a large number of defect states on the surface of the III-V group quantum dot formed by covalent bonding are avoided, acetylacetone radical ions having smaller radial dimensions and bidentate coordination points can exchange with introduced carboxylic acid ligands, so that original ligands on the surface of the III-V group quantum dot core can be reduced, the separation of nucleation and growth is realized, hydroxide radical ions are combined with the metal cations on the surface of the III-V group quantum dot core, so that not only can the surface of the III-V group quantum dot core be passivated, but also can be used as a buffer outer shell layer, so that the problem of lattice adaptation between the III-V group quantum dot core and the II-VI group semiconductor outer shell layer can be effectively reduced, facilitating the growth of thick crust layers. Therefore, the combination of the halide ions, the acetylacetone ions and the hydroxide ions with the cations on the surface of the III-V group quantum dot core is equivalent to the complete coating or the incomplete coating of the surface of the III-V group quantum dot core by a mixed material layer consisting of acetylacetone metal compounds and metal hydroxides. In one embodiment, the acetylacetonate and hydroxide ions combine with the group III cations on the surface of the group III-V quantum dot core to form a group III acetylacetonate metal compound, a group III metal hydroxide, and a group III metal halide. In one embodiment, the acetylacetonate and hydroxide ions combine with the group III and II cations on the surface of the group III-V quantum dot core to form a group III acetylacetonate metal compound, a group II metal hydroxide, a group III metal hydroxide, a group II metal halide, and a group III metal halide. The halide ions, the acetylacetone ions and the hydroxyl ions are combined with the cations on the surface of the III-V family quantum dot core to cooperatively form a mixed material layer, so that the luminous efficiency (greater than 70%) of the quantum dot is greatly improved, the size dispersibility of the quantum dot is improved, the peak width (the peak width range is less than 45nm) is obviously narrowed, the growth of a thick shell layer is facilitated, and the stability of the quantum dot can be greatly improved.

Further, the material of the III-V group quantum dot core is selected from at least one of GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaSb, AlNP, AlNAs, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and InPGa; the group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; the group II cation is at least one of zinc ion, cadmium ion, mercury ion and magnesium ion; the halide ion is at least one selected from chloride ion, bromide ion and iodide ion. The acetylacetonato ion is at least one selected from the group consisting of a hexahydroacetylacetonato ion and a hexafluoroacetylacetonato ion.

The group III acetylacetone metal compound is at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate, and aluminum hexafluoroacetylacetonate. The II group metal acetylacetone compound is at least one of zinc hexahydroacetylacetonate, cadmium hexahydroacetylacetonate, magnesium hexahydroacetylacetonate, mercury hexahydroacetylacetonate, zinc hexafluoroacetylacetonate, cadmium hexafluoroacetylacetonate, magnesium hexafluoroacetylacetonate, and mercury hexafluoroacetylacetonate. The group III metal halide is at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide. The group II metal halide is at least one of zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercuric chloride, mercuric bromide, and mercuric iodide.

Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, which coats the group III-V quantum dot core and the halide ion, acetylacetonate ion and hydroxide ion bound to the surface of the group III-V quantum dot core. Halide, acetylacetonate, and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer

Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, which coats the group III-V quantum dot core and group II cations, halides, acetylacetonates, and hydroxides bound to the surface of the group III-V quantum dot core. Halide, acetylacetonate, and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer. The halide ions passivate the surface of the III-V group quantum dot core, so that the occurrence of non-radiative transition is effectively inhibited, acetylacetone radical ions realize the separation of nucleation and growth, hydroxyl ions can enable the crystal lattices between the III-V group quantum dot core and the II-VI group semiconductor shell layer to be matched, and the II-VI group semiconductor shell layer more effectively separates carriers confined in the core from surface states serving as non-radiative composite transition centers; therefore, the core-shell quantum dot structure formed by the synergistic effect of the halide ions, the acetylacetone ions, the hydroxyl ions and the II-VI semiconductor shell layer has higher luminous efficiency. The II-VI group semiconductor shell layer is made of at least one material selected from CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSZnSe and MgZnS; still further, the II-VI semiconductor shell layer has a thickness of 3-5 nm.

SA 071: providing a group III cation precursor and a ligand; the group III cation precursor comprises one or more metal halide precursors, one or more acetylacetone metal salt precursors, and one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the III-group cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SA 072: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

Alternatively, another preparation method comprises the following steps:

SB 071: providing a cation precursor and a ligand, wherein the cation precursor is a group III cation precursor and a first group II cation precursor, and the cation precursor comprises one or more acetylacetone metal salt precursors, one or more metal halide precursors, one or more metal oxide precursors and/or one or more metal hydroxide precursors; dissolving the cation precursor and the ligand in a solvent, and heating under a first temperature condition to obtain a mixed solution;

SB 072: and continuously heating the mixed solution to a second temperature, adding a V-group anion precursor into the mixed solution, and carrying out a nucleation reaction to obtain a III-V-group quantum dot nucleation solution.

In the above preparation method of the embodiment of the present invention, at least one metal oxide and/or metal hydroxide, at least one acetylacetone metal salt precursor, and at least one metal salt precursor are introduced into the reaction system during the nucleation process before the nucleation reactionAt least one metal halide precursor; in the preparation process, cations in the acetylacetone metal salt precursor can be used for nucleation reaction, and on the other hand, acetylacetone radical ions have smaller radial dimensions and more (2) coordination sites and can exchange with carboxylic acid ligands at the nucleation moment, so that the original ligands on the surface of the III-V group quantum dot nuclei can be reduced, and further the separation of nucleation and growth is realized; cations in the metal halide precursor can be used for nucleation, and on the other hand, halide ions can react with the group V anion dangling bond on the surface of the nucleated III-V group quantum dot core to generate VX₃The (V is N, P or As, X is halogen) gas is beneficial to the reaction, so that the III group atoms and the V group atoms on the surface of the III-V group quantum dot core are recombined to form the III-V group quantum dot core with more stable atomic ratio, and meanwhile, the halide ions can be combined with the cations on the surface of the III-V group quantum dot core to passivate the surface of the III-V group quantum dot core; the metal ions in the metal oxide precursor and/or metal hydroxide precursor also participate in the formation of the group III-V quantum dot core, while the anion in the metal oxide precursor, i.e., O^2-First combines with protons in the reaction system solution to form OH^-So that the anions generated by the metal oxide precursor and/or the metal hydroxide precursor introduced in the precursor are present only in OH^-Final OH^-The buffer shell can be rapidly combined with cations on the surface of the III-V group quantum dot core, so that the surface of the III-V group quantum dot core is effectively passivated, and the buffer shell is used as a buffer shell layer to effectively reduce the problem of lattice adaptation between the core and the shell layer, and is favorable for the growth of a thick shell layer. In the quantum dot finally obtained by the preparation method, acetylacetone ions, halide ions and hydroxyl ions are simultaneously combined on the surface of the III-V family quantum dot core, so that the luminous efficiency (more than 70%) of the quantum dot is greatly improved, the size dispersibility of the quantum dot is improved, the peak width (the peak width range is less than 45nm) is obviously narrowed, the growth of a thick outer shell layer is facilitated, and the stability of the quantum dot can be greatly improved.

In the above step SA 071: the group III cation precursors include one or more metal halide precursors, one or more acetylacetone metal salt precursors, and one or more metal oxide precursors and/or one or more metal hydroxide precursors, which may be understood as: (1) the group III cation precursor has one or more metal halide precursors, one or more metal acetylacetonate precursors, and one or more metal oxide precursors at the same time, (2) the group III cation precursor has one or more metal halide precursors, one or more metal acetylacetonate precursors, and one or more metal hydroxide precursors at the same time, and (3) the group III cation precursor has one or more metal halide precursors, one or more metal acetylacetonate precursors, one or more metal oxide precursors, and one or more metal hydroxide precursors at the same time. In addition, the group III cation precursor may contain other precursors in addition to one or more metal halides, one or more acetylacetonates, one or more metal oxide precursors, and/or metal hydroxide precursors.

In step SB071 above: the cationic precursors (group III cationic precursor and first group II cationic precursor) include one or more acetylacetonates metal salt precursors, one or more metal halides, and one or more metal oxide precursors and/or one or more metal hydroxide precursors, which can be understood as follows: (1) the group III cation precursor comprises one or more metal halide precursors and one or more acetylacetone metal salt precursors, and comprises one or more metal oxide precursors and/or metal hydroxide precursors; (2) the first group II cation precursor comprises one or more metal halide precursors and one or more acetylacetone metal salt precursors, and comprises one or more metal oxide precursors and/or metal hydroxide precursors, (3) the group III cation precursor comprises one or more acetylacetone metal salt precursors (the group III cation precursor can further comprise one or more metal oxide precursors and/or metal hydroxide precursors, one or more metal halides), and at the same time, the first group II cation precursor comprises one or more acetylacetone metal salt precursorsA metal halide and one or more metal oxide precursors and/or metal hydroxide precursors (the first group II cation precursor may further comprise one or more acetylacetone metal salt precursors); (4) the group III cation precursor comprises one or more metal oxide precursors and/or metal hydroxide precursors (the group III cation precursor may further comprise one or more acetylacetone metal salt precursors, one or more metal halide precursors), while the first group II cation precursor comprises one or more metal halides and one or more acetylacetone metal salt precursors (the first group II cation precursor may further comprise one or more metal oxide precursors and/or metal hydroxide precursors); (5) the group III cation precursor may further include one or more metal halides (the group III cation precursor may further include one or more metal oxide precursors and/or metal hydroxide precursors, and one or more metal acetylacetonate precursors), and the first group II cation precursor may include one or more metal acetylacetonate precursors and one or more metal oxide precursors and/or metal hydroxide precursors (the first group II cation precursor may further include one or more metal halides); provided that the cation precursor mixture composed of the group III cation precursor and the first group II cation precursor contains halogen ions, acetylacetonato ions, and O^2-And/or OH^-And (4) finishing.

In step SA071, acetylacetonato ions, halide ions and hydroxide ions are simultaneously combined with group III cations on the surface of the III-V quantum dot core; the quantum dot core is coated with a mixed material layer consisting of III group metal halide, III group metal hydroxide and III group metal acetylacetone compound completely or not. The group III metal hydroxide is at least one of indium hydroxide, gallium hydroxide and aluminum hydroxide. The group III metal acetylacetone compound includes at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate, and aluminum hexafluoroacetylacetonate. The group III metal halide includes at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide,

in step SB071, after adding the group II cation precursor, the group II cation will combine with the group V anion (such as P) on the surface of the III-V quantum dot core, thereby leaving a group III cation vacancy, and all of the acetylacetonato ion, the halide ion and the hydroxide ion ligand can combine with the group III cation on the core surface, and at the same time, the acetylacetonato ion, the halide ion and the hydroxide ion can also combine with the group II cation on the surface of the III-V quantum dot core, that is, the acetylacetonato ion, the halide ion and the hydroxide ion can combine with the group III cation and the group II cation on the surface of the III-V quantum dot core simultaneously. The quantum dot core is coated with a mixed material layer consisting of II group metal halide, III group metal halide, II group metal hydroxide, III group metal hydroxide, II group metal acetylacetone compound and III group metal acetylacetone compound. The group III acetylacetone metal compound comprises at least one of indium hexahydroacetylacetonate, gallium hexahydroacetylacetonate, aluminum hexahydroacetylacetonate, indium hexafluoroacetylacetonate, gallium hexafluoroacetylacetonate and aluminum hexafluoroacetylacetonate, and the group II metal acetylacetone compound comprises at least one of zinc hexahydroacetylacetonate, cadmium hexahydroacetylacetonate, magnesium hexahydroacetylacetonate, mercury hexahydroacetylacetonate, zinc hexafluoroacetylacetonate, cadmium hexafluoroacetylacetonate, magnesium hexafluoroacetylacetonate and mercury hexafluoroacetylacetonate. The group III metal halide includes at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide, and the group II metal halide includes at least one of zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercuric chloride, mercuric bromide, and mercuric iodide. The group III metal hydroxide includes at least one of indium hydroxide, gallium hydroxide, and aluminum hydroxide, and the group II metal hydroxide includes at least one of zinc hydroxide, cadmium hydroxide, magnesium hydroxide, and mercury hydroxide.

Further, after the nucleation reaction in step SA072 or SB072 is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V core solution, shell layer growth is performed under a third temperature condition, a group II-VI semiconductor shell layer is formed on the surface of the group III-V quantum dot core, and a core-shell quantum dot solution is obtained. Still further preferably, the surface of the group III-V quantum dot core is coated with a group II-VI semiconductor shell layer, which coats the group III-V quantum dot core and the halide ion, acetylacetonate ion and hydroxide ion bound to the surface of the group III-V quantum dot core. Halide, acetylacetonate, and hydroxide ions are located between the group III-V quantum dot core and the group II-VI semiconductor shell layer

Preferred examples of the above-described method for producing quantum dots are shown in examples 7-1 to 7-6.

The invention is described in further detail with reference to a part of the test results, which are described in detail below with reference to specific examples.

Examples 1 to 1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium chloride and 1mmol of zinc acetate were added to a 50ml three-necked flask at room temperature, followed by 1ml of oleic acid and 10ml of octadecene. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

To the InP: Zn quantum dot core solution was added 0.3ml of octyl mercaptan and 2mmol of zinc oleate at 300 ℃. And reacting for 60mins to obtain the InP/ZnS core-shell quantum dot.

Examples 1 to 2

(1) Preparation of Quantum dot core InP: Zn solution

(2) Synthesizing quantum dot shell ZnSe/ZnS for coating quantum dot core InP and Zn

And adding 0.2mmol of tributyl phosphine selenide into the InP/Zn quantum dot core solution at 300 ℃. After 20mins of reaction, 0.2ml of octyl mercaptan and 2mmol of zinc oleate were added. And reacting for 40mins to obtain the InP/ZnSe/ZnS core-shell quantum dot.

Examples 1 to 3

(1) Preparation of Quantum dot core InP: Zn solution

(2) Synthesizing quantum dot shell ZnSeS coating the quantum dot core InP and Zn

To the InP: Zn quantum dot core solution was added 0.2mmol tributyl phosphine selenide, 0.2ml octyl mercaptan and 2mmol zinc oleate at 300 deg.C. And reacting for 60mins to obtain the InP/ZnSeS core-shell quantum dot.

Examples 1 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol indium chloride, 0.17mmol gallium chloride, 1.5mmol zinc acetate were added to a 50ml three-necked flask at room temperature, followed by 1ml oleic acid, 10ml octadecene. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

0.5ml of octyl mercaptan and 3mmol of zinc oleate were added to the InP/GaP: Zn quantum dot core solution at 300 ℃. And reacting for 30mins to obtain the InP/GaP/ZnS core-shell quantum dot.

Examples 1 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

(2) Synthesizing quantum dot shell ZnSe/ZnS coating the quantum dot core InP/GaP: Zn

0.2mmol tributyl phosphine selenide is added to the InP/GaP: Zn quantum dot core solution at 300 ℃. After 20mins of reaction, 0.2ml of octyl mercaptan and 2mmol of zinc oleate were added. And reacting for 40mins to obtain the InP/ZnSe/ZnS core-shell quantum dot.

Examples 1 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

(2) Synthesizing quantum dot shell ZnSeS coating the quantum dot core InP/GaP: Zn

To the InP/GaP: Zn quantum dot core solution was added 0.2mmol tributylphosphine selenide, 0.2ml octylmercaptan and 2mmol zinc oleate at 300 ℃. And reacting for 60mins to obtain the InP/ZnSeS core-shell quantum dot.

Example 2-1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium acetylacetonate and 1mmol of zinc acetylacetonate were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

Examples 2 to 2

(1) Preparation of Quantum dot core InP: Zn solution

Examples 2 to 3

(1) Preparation of Quantum dot core InP: Zn solution

Examples 2 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol of indium acetylacetonate, 0.17mmol of gallium acetylacetonate and 1.5mmol of zinc acetylacetonate were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

Examples 2 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

Examples 2 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

Example 3-1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium acetylacetonate and 1mmol of zinc chloride were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

Examples 3 to 2

(1) Preparation of Quantum dot core InP: Zn solution

Examples 3 to 3

(1) Preparation of Quantum dot core InP: Zn solution

Examples 3 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol of indium acetylacetonate, 0.17mmol of gallium chloride and 1.5mmol of zinc acetylacetonate were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

Examples 3 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

Examples 3 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

Example 4-1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium oxide and 1mmol of zinc oxide were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

Example 4 to 2

(1) Preparation of Quantum dot core InP: Zn solution

Examples 4 to 3

(1) Preparation of Quantum dot core InP: Zn solution

Examples 4 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol of indium oxide, 0.17mmol of gallium oxide and 1.5mmol of zinc oxide were added to a 50ml three-necked flask at room temperature, followed by 1ml of oleic acid and 10ml of octadecene. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

Examples 4 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

Examples 4 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

Example 5-1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium chloride and 1mmol of zinc oxide were placed in a 50ml three-necked flask at room temperature, followed by 1ml of oleic acid and 10ml of octadecene. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

Examples 5 and 2

(1) Preparation of Quantum dot core InP: Zn solution

Examples 5 to 3

(1) Preparation of Quantum dot core InP: Zn solution

Examples 5 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol indium chloride, 0.17mmol gallium oxide, 1.5mmol zinc oxide were added to a 50ml three-necked flask at room temperature, followed by 1ml oleic acid, 10ml octadecene. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

Examples 5 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

Examples 5 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

Example 6-1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium acetylacetonate and 1mmol of zinc oxide were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

Example 6 to 2

(1) Preparation of Quantum dot core InP: Zn solution

Examples 6 to 3

(1) Preparation of Quantum dot core InP: Zn solution

Examples 6 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol of indium acetylacetonate, 0.17mmol of gallium acetylacetonate and 1.5mmol of zinc oxide were charged into a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

Examples 6 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

Examples 6 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

Example 7-1

(1) Preparation of Quantum dot core InP: Zn solution

0.2mmol of indium acetylacetonate, 0.5mmol of zinc oxide and 0.5mmol of zinc chloride were placed in a 50ml three-necked flask at room temperature, and then 1ml of oleic acid and 10ml of octadecene were added. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. And heating to 280 ℃, adding 0.15mmol of tris (trimethylsilyl) phosphine, and reacting for 2mins to obtain the InP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP: Zn

Example 7-2

(1) Preparation of Quantum dot core InP: Zn solution

Examples 7 to 3

(1) Preparation of Quantum dot core InP: Zn solution

Examples 7 to 4

(1) Preparation of quantum dot core InP/GaP Zn solution

0.2mmol of indium acetylacetonate, 0.17mmol of gallium chloride and 1.5mmol of zinc oxide were placed in a 50ml three-necked flask at room temperature, followed by 1ml of oleic acid and 10ml of octadecene. Vacuumizing for 60mins at 80 ℃ under the protection of vacuum, and then exhausting nitrogen for 60mins at 140 ℃ under the protection of nitrogen atmosphere. Heating to 280 ℃, adding 0.3mmol of tri (trimethylsilyl) phosphine, and reacting for 2mins to obtain InP/GaP/Zn quantum dot core solution.

(2) Synthesizing quantum dot shell ZnS coating the quantum dot core InP/GaP: Zn

Examples 7 to 5

(1) Preparation of quantum dot core InP/GaP Zn solution

Examples 7 to 6

(1) Preparation of quantum dot core InP/GaP Zn solution

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A quantum dot comprising a group III-V quantum dot core and halide ions and hydroxide ions bound to the surface of the group III-V quantum dot core; wherein the halide and hydroxide ions bind to group III cations on the surface of the III-V quantum dot core.

2. The quantum dot of claim 1, wherein the group III-V quantum dot core is made of a material selected from at least one of GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPSb, AlNP, alinas, AlPAs, AlPSb, InNP, InNAs, InP, and InP ga; and/or

The group III cation is selected from at least one of indium ion, gallium ion and aluminum ion; and/or

The halide ion is selected from at least one of chloride ion, bromide ion and iodide ion.

3. The quantum dot of claim 1 or 2, further comprising an outer shell layer, wherein the material of the outer shell layer is a II-VI semiconductor material, and the outer shell layer covers the III-V quantum dot core and the halide ions and hydroxide ions bound to the surface of the III-V quantum dot core.

4. A quantum dot according to claim 3, wherein the group II-VI semiconductor material is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSe and MgZnS; and/or

The thickness of the outer shell layer is 3-5 nm.

5. A preparation method of quantum dots is characterized by comprising the following steps:

6. The preparation method according to claim 5, wherein immediately after the nucleation reaction is completed, a second group II cation precursor and a group VI anion precursor are added into the group III-V quantum dot core solution, and shell layer growth is performed under a third temperature condition to form a group II-VI semiconductor shell layer on the surface of the group III-V quantum dot core, so as to obtain the core-shell quantum dot solution.

7. The method of claim 5, wherein the metal halide precursor is at least one selected from the group consisting of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide; and/or

The metal oxide precursor is selected from at least one of indium oxide, aluminum oxide and gallium oxide; and/or

The metal hydroxide precursor is selected from at least one of gallium hydroxide, indium hydroxide and aluminum hydroxide; and/or

The group V anion precursor is selected from at least one of tris (trimethylsilyl) phosphine, tris (germyl) phosphine, tris (dimethylamino) phosphine, tris (diethylamino) phosphine, triethylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, tris (trimethylsilyl) arsenic, tris (dimethylamino) arsenic, tris (diethylamino) arsenic, triethylarsenic, tributylarsenic, trioctylalarsenic, triphenylarsenic, tricyclohexylarsenic, arsenic oxide, arsenic chloride, arsenic bromide, arsenic iodide, arsenic sulfide and ammonia gas; and/or

The ligand is selected from at least one of oleic acid, C4-C20 saturated fatty acid, phosphine substituted by C6-C22 alkyl, phosphine oxide substituted by C6-C22 alkyl, C6-C22 primary amine, C6-C22 secondary amine and C6-C40 tertiary amine; and/or

The solvent is at least one selected from C6-C40 aliphatic hydrocarbon, C6-C30 aromatic hydrocarbon, nitrogen-containing heterocyclic compound and C12-C22 aromatic ether.

8. The method of claim 6, wherein the second group II cation precursor is selected from at least one of cadmium oleate, cadmium butyrate, cadmium n-decanoate, cadmium caproate, cadmium caprylate, cadmium dodecanoate, cadmium myristate, cadmium palmitate, cadmium stearate, mercury oleate, mercury butyrate, mercury n-decanoate, mercury caproate, mercury caprylate, mercury dodecanoate, mercury myristate, mercury palmitate, mercury stearate, zinc butyrate, zinc n-decanoate, zinc caproate, zinc caprylate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, magnesium oleate, magnesium butyrate, magnesium n-decanoate, magnesium caproate, magnesium caprylate, magnesium laurate, magnesium myristate, magnesium palmitate, and magnesium stearate; and/or

The group VI anion precursor is selected from at least one of hexanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, mercaptopropylsilane, trioctylphosphine sulfide, tributylphosphine sulfide, triphenylphosphine sulfide, trioctylamine sulfide, tris (trimethylsilyl) sulfide, ammonium sulfide, sodium sulfide, trioctylphosphine selenide, tributylphosphine selenide, triphenylphosphine selenide, tributylphosphine telluride, trioctylphosphine telluride, and triphenylphosphine telluride.

9. The method according to any one of claims 5 to 8, wherein the first temperature is 100 ℃ to 200 ℃; and/or

The time for carrying out the heating treatment under the first temperature condition is 1-2 h; and/or

The second temperature is 260-320 ℃; and/or

The time of the nucleation reaction is 1-20 min.

10. The method according to any one of claims 6 to 8, wherein the third temperature is 260 ℃ to 320 ℃; and/or

And the time for performing the shell layer growth under the third temperature condition is 15-90 min.

11. A quantum dot comprising a group III-V quantum dot core, a group II cation bound to a group V anion on the surface of the group III-V quantum dot core, and a halide and hydroxide ion bound to a group III cation and a group II cation on the surface of the group III-V quantum dot core.

12. The quantum dot of claim 11, wherein the group III-V quantum dot core is made of a material selected from at least one of GaP, GaN, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPSb, AlNP, alinas, AlPAs, AlPSb, InNP, InNAs, InP, and InP ga; and/or

The halide ions are selected from at least one of chloride ions, bromide ions and iodide ions; and/or

The group II cation is at least one selected from zinc ion, cadmium ion, mercury ion and magnesium ion.

13. The quantum dot of claim 11 or 12, further comprising an outer shell layer made of a II-VI semiconductor material, the outer shell layer encapsulating the III-V quantum dot core and group II cations, halides, and hydroxide ions bound to the surface of the III-V quantum dot core.

14. The quantum dot of claim 13, wherein the II-VI semiconductor material is selected from at least one of CdS, CdSe, CdO, CdTe, HgO, HgS, HgTe, HgSe, ZnSe, ZnS, ZnTe, ZnO, MgSe, MgS, MgTe, ZnSeS, ZnSeTe, ZnSTe, MgZnSe, and MgZnS; and/or

The thickness of the outer shell layer is 3-5 nm.

15. A preparation method of quantum dots is characterized by comprising the following steps:

16. The method according to claim 15, wherein immediately after the nucleation reaction is completed, a second group II cation precursor and a group VI anion precursor are added to the group III-V quantum dot core solution, and shell growth is performed under a third temperature condition to form a group II-VI semiconductor shell on the surface of the group III-V quantum dot core, thereby obtaining a core-shell quantum dot solution.

17. The method of claim 15, wherein when the group III cation precursor includes a metal oxide precursor and/or a metal hydroxide precursor, the metal oxide precursor in the group III cation precursor is selected from at least one of indium oxide, aluminum oxide, and gallium oxide, and the metal hydroxide precursor in the group III cation precursor is selected from at least one of gallium hydroxide, indium hydroxide, and aluminum hydroxide; and/or

When the group III cation precursor comprises a metal halide precursor, the metal halide precursor in the group III cation precursor is selected from at least one of indium chloride, indium bromide, indium iodide, gallium chloride, gallium bromide, gallium iodide, aluminum chloride, aluminum bromide, and aluminum iodide;

when the first group II cation precursor comprises a metal oxide precursor and/or a metal hydroxide precursor, the metal oxide precursor in the first group II cation precursor is selected from at least one of zinc oxide, cadmium oxide, magnesium oxide, and mercury oxide, and the metal hydroxide precursor in the first group II cation precursor is selected from at least one of zinc hydroxide, cadmium hydroxide, magnesium hydroxide, and mercury hydroxide; and/or

When the first group II cation precursor comprises a metal halide precursor, the metal halide precursor in the first group II cation precursor is selected from at least one of zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, magnesium chloride, magnesium bromide, magnesium iodide, mercuric chloride, mercuric bromide, and mercuric iodide; and/or

18. The method of claim 16, wherein the second group II cation precursor is selected from at least one of cadmium oleate, cadmium butyrate, cadmium n-decanoate, cadmium caproate, cadmium caprylate, cadmium dodecanoate, cadmium myristate, cadmium palmitate, cadmium stearate, mercury oleate, mercury butyrate, mercury n-decanoate, mercury caproate, mercury caprylate, mercury dodecanoate, mercury myristate, mercury palmitate, mercury stearate, zinc butyrate, zinc n-decanoate, zinc caproate, zinc caprylate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, magnesium oleate, magnesium butyrate, magnesium n-decanoate, magnesium caproate, magnesium caprylate, magnesium laurate, magnesium myristate, magnesium palmitate, and magnesium stearate; and/or

19. The method according to any one of claims 15-18, wherein the first temperature is 100 ℃ and 200 ℃; and/or

The second temperature is 260-320 ℃; and/or

The time of the nucleation reaction is 1-20 min.

20. The method according to claims 16-18, wherein the third temperature is 260 ℃ to 320 ℃; and/or