Quantum dot material, preparation method therefor, and quantum dot light-emitting device

Abstract

Embodiments of the present disclosure provide a quantum dot material, a preparation method therefor, and a quantum dot light-emitting device. The quantum dot material comprises: a covalent organic framework material, the covalent organic framework material having pores; quantum dot bodies, at least a portion of the quantum dot bodies being located in the pores; and metal complexes located in the pores, each metal complex comprising a metal as well as a first ligand and a second ligand which are coordinated to the metal, the first ligand being coordinately bonded to the covalent organic framework material, and the second ligand being coordinately bonded to a quantum dot body.

Description

Quantum dot material, manufacturing method thereof and quantum dot light emitting device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of quantum dots, and particularly relates to a quantum dot material, a manufacturing method thereof and a quantum dot light emitting device. BACKGROUND

[0002] Quantum dots (QDs), also known as nanocrystals, are a kind of nanometer particles composed of II-VI or III-V elements, and have advantages of high quantum yield, narrow light emission peak, adjustable light emission spectrum and high photochemical stability.

[0003] With the in-depth development of quantum dot preparation technology, the stability and light emission efficiency of quantum dots are continuously improved, and the research on quantum light emitting diodes (QLEDs) is continuously deepened. The QLED has the advantages of self-light emission, low power consumption and high color gamut, and has attracted widespread attention from the academic and industrial circles. The application prospect of the QLED in the display field is increasingly promising.

[0004] SUMMARY

[0005] The present disclosure provides a quantum dot material, a manufacturing method thereof and a quantum dot light emitting device, and the specific solutions are as follows.

[0006] The present disclosure provides a quantum dot material, and the quantum dot material comprises:

[0007] A covalent organic framework material, wherein the covalent organic framework material has a hole;

[0008] A quantum dot body, wherein at least part of the quantum dot body is located in the hole;

[0009] A metal complex, wherein the metal complex is located in the hole, the metal complex comprises a metal and a first ligand and a second ligand coordinated with the metal, the first ligand is connected with the covalent organic framework material in coordination, and the second ligand is connected with the quantum dot body in coordination.

[0010] In a possible implementation, in the above quantum dot material provided by the present disclosure, the first ligand and the second ligand are different in polarity.

[0011] In a possible implementation, in the above quantum dot material provided by the present disclosure, the first ligand is an aqueous ligand, and the second ligand is an oily ligand.

[0012] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the first ligand comprises at least one of the following: a carboxylic acid ligand, an amino acid ligand, a polyol ligand, a phosphoric acid ligand, and a nitrogen-containing heterocyclic ligand.

[0013] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the second ligand comprises at least one of the following: a phosphine ligand, a nitrogen heterocyclic carbene ligand, a sulfide ligand, a thiol ligand, an olefin ligand, an alkyne ligand, an aromatic amine ligand, and a long-chain alkyl ligand.

[0014] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the metal in the metal complex is a main group element of IA, IIA, IIIA, IVA, or a secondary group element of IB and IIB.

[0015] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the metal in the metal complex comprises at least one of the following: Li, Na, K, Ca, Zn, Mg, and Ga.

[0016] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the quantum dot body comprises a first metal element and a non-metal element combined by a chemical bond, the first metal element is a group III element, and the non-metal element is a group V element.

[0017] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the quantum dot body further comprises at least one second metal element different from the first metal element.

[0018] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the first metal element is indium, the non-metal element is phosphorus, and the second metal element comprises at least one of zinc and gallium.

[0019] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, each of the holes comprises 1 to 4 quantum dot bodies, and the average particle size of the quantum dot bodies ranges from 3 nm to 20 nm.

[0020] In a possible implementation, in the quantum dot material provided by the embodiment of the present disclosure, the emission peak of the quantum dot material ranges from 450 nm to 640 nm, the half-peak width of the fluorescence emission spectrum of the quantum dot material ranges from 15 nm to 50 nm, and the luminous efficiency of the quantum dot material ranges from 45% to 100%.

[0021] Correspondingly, the present disclosure also provides a quantum dot light-emitting device, comprising a quantum dot light-emitting layer, wherein the quantum dot light-emitting layer comprises the quantum dot material provided by the present disclosure.

[0022] Correspondingly, the present disclosure also provides a method for manufacturing the quantum dot material provided by the present disclosure, comprising:

[0023] forming a metal complex solution, wherein the metal complex comprises a metal, a first ligand and a second ligand coordinated with the metal;

[0024] forming a quantum dot bulk solution;

[0025] adding the metal complex solution and a covalent organic framework material into the quantum dot bulk solution and heating to a preset temperature, so that the first ligand is coordinated with the covalent organic framework material, the second ligand is coordinated with the quantum dot bulk, and the quantum dot bulk and the metal complex are both located in the pores of the covalent organic framework material.

[0026] In a possible implementation, in the method for manufacturing the quantum dot material provided by the present disclosure, the preset temperature is in the range of 270-350°C.

[0027] In a possible implementation, in the method for manufacturing the quantum dot material provided by the present disclosure, the first ligand is coordinated with the covalent organic framework material, specifically comprising: the first ligand replaces the original ligand of the covalent organic framework material, or the first ligand is directly coordinated with the covalent organic framework material.

[0028] The second ligand is coordinated with the quantum dot bulk, specifically comprising: the second ligand replaces the original ligand on the surface of the quantum dot bulk, or the second ligand is directly coordinated with the surface of the quantum dot bulk. BRIEF DESCRIPTION OF DRAWINGS

[0029] FIG. 1 is a structural schematic diagram of a quantum dot material provided by the present disclosure;

[0030] FIG. 2 is an electron microscope photo of the quantum dot material shown in FIG. 1 obtained by transmission electron microscopy test;

[0031] FIG. 3 is a flowchart of a method for manufacturing a quantum dot material provided by the present disclosure;

[0032] FIG. 4 is an ultraviolet-visible light absorption spectrum diagram of the quantum dot material corresponding to Example 1 and Comparative Example 1;

[0033] FIG. 5 is a fluorescence emission spectrum diagram of the quantum dot material corresponding to Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the following will be combined with the drawings of the embodiments of the present disclosure to make a clear and complete description of the technical solutions of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. And the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present disclosure.

[0035] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the ordinary meaning understood by a person of ordinary skill in the art to which the present disclosure belongs. The similar words such as "comprise" or "contain" used in the present disclosure mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and other elements or objects are not excluded. The similar words such as "connect" or "connected" are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "In", "out", "up", "down", and the like are only used to indicate relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] It should be noted that the size and shape of each figure in the drawings do not reflect the true proportion, but only serve to illustrate the present disclosure. And the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout.

[0037] As a new type of light-emitting material, quantum dots have the advantages of high light color purity, high light-emitting quantum efficiency, adjustable light-emitting color, long service life, etc. However, when preparing quantum dots, how to control the particle size and distribution of quantum dots is a key problem, and unstable quantum dots are prone to agglomeration and increase light absorption loss.

[0038] The embodiments of the present disclosure provide a quantum dot material, as shown in FIG. 1, comprising:

[0039] A covalent organic framework material 1, the covalent organic framework material 1 has a hole V;

[0040] A quantum dot body 2, at least part of the quantum dot body 2 is located in the hole V;

[0041] A metal complex 3, the metal complex 3 is located in the hole V, the metal complex 3 comprises a metal M and a first ligand 31 and a second ligand 32 coordinated with the metal M, the first ligand 31 is connected with the covalent organic framework material 1 in coordination, and the second ligand 32 is connected with the quantum dot body 2 in coordination.

[0042] The quantum dot material provided by the embodiments of the present disclosure can improve the particle size and size distribution of the quantum dot body, and improve the monodispersity and stability of the quantum dot body, by embedding the quantum dot body in the pores of the covalent organic framework material using a metal complex, and controlling the addition of the covalent organic framework material during the preparation of the quantum dot material. Meanwhile, using a metal complex as a connecting agent can increase the fault tolerance of the quantum dot body and the covalent organic framework material, make the quantum dot nucleation and growth process smoother, prevent the agglomeration of the quantum dot body, and reduce light absorption loss, thereby further improving the light-emitting efficiency of the quantum dot material.

[0043] It should be noted that the quantum dot body mentioned above is embedded in the pores of the covalent organic framework material, where embedding refers to physical space occupation. For example, the quantum dot body can be entirely embedded in the pores of the covalent organic framework material, or a part of the quantum dot body can be embedded in the pores of the covalent organic framework material.

[0044] It should be noted that the covalent organic framework material (COF) is a two-dimensional or three-dimensional crystalline porous polymer material formed by connecting organic structural units through covalent bonds, and has the characteristics of high thermal stability, large specific surface area, rich pores, adjustable molecular structure, and many active sites. COFs can be composed entirely of light elements such as carbon, hydrogen, nitrogen, and oxygen. The size of the material pore diameter can be controlled by changing the size of the building block and regulating the length of the side chain. The covalent organic framework material and its monomer can be obtained by purchase or prepared by existing preparation methods.

[0045] In some embodiments, the covalent organic framework material used by the embodiments of the present disclosure is a two-dimensional covalent organic framework material. The covalent organic framework material includes but is not limited to COF-5, COF-6, etc. The closer the ring structure of the covalent organic framework material is to a circle, the better the embedding effect. For example, as shown in FIG. 1 of the embodiments of the present disclosure, a two-dimensional covalent organic framework material 1 with a six-membered ring structure is taken as an example. The six-membered ring represents the repeating structural unit of the covalent organic framework material 1, and the pores formed by the six-membered ring are the pores V of the covalent organic framework material 1. The quantum dot body 2 is embedded in the pores V of the covalent organic framework material 1 through the metal complex 3.

[0046] In some embodiments, the pore size of the hole V of the covalent organic framework material 1 can be 20 nm-200 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, etc.

[0047] In some embodiments, in the above quantum dot material provided by the embodiments of the present disclosure, as shown in FIG. 1, the polarities of the first ligand 31 and the second ligand 32 are different, so that a metal complex 3 with different polarities of the first ligand 31 and the second ligand 32 can be selected, so that the metal complex 3 can be simultaneously coordinated with the covalent organic framework material 1 and the quantum dot body 2, and at least part of the quantum dot body 2 is filled in the hole V of the covalent organic framework material 1.

[0048] In some embodiments, in the above quantum dot material provided by the embodiments of the present disclosure, as shown in FIG. 1, the first ligand 31 is an aqueous ligand, and the second ligand 32 is an oily ligand. This is because the quantum dot body 2 is generally synthesized in an oily solvent, and the covalent organic framework material 1 is generally synthesized in an aqueous solvent. Therefore, by using a metal complex 3 with both aqueous ligands and oily ligands, the quantum dot body 2 can be connected to the covalent organic framework material 1, and the quantum dot body 2 is preferentially filled in the hole V of the covalent organic framework material 1.

[0049] In some embodiments, in the above quantum dot material provided by the embodiments of the present disclosure, as shown in FIG. 1, the first ligand 31 can include but is not limited to at least one of the following: a carboxylic acid ligand, an amino acid ligand, a polyol ligand, a phosphoric acid ligand, and a nitrogen-containing heterocyclic ligand.

[0050] Optionally, the carboxylic acid ligand can be acetic acid, propionic acid, etc., the amino acid ligand can be glycine, alanine, etc., the polyol ligand can be ethylene glycol, glycerol, etc., the phosphoric acid ligand can be phosphoric acid, dihydrogen phosphate, etc., and the nitrogen-containing heterocyclic ligand can be pyridine, imidazole, etc.

[0051] In some embodiments, in the above quantum dot material provided by the embodiments of the present disclosure, as shown in FIG. 1, the second ligand 32 can include but is not limited to at least one of the following: a phosphine ligand, a nitrogen heterocyclic carbene (NHC) ligand, a sulfide ligand, a thiol ligand, an olefin ligand, an alkyne ligand, an aromatic amine ligand, and a long-chain alkyl ligand.

[0052] Optionally, the phosphine ligand can be triphenylphosphine, tricyclohexylphosphine, etc., the N-heterocyclic carbene ligand can be IMes (1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), SIMes (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), etc.; the sulfide ligand can be dimethyl sulfide, etc., the thiol ligand can be phenylthiol, etc., the olefin can be ethylene, etc., the alkyne ligand can be acetylene, etc., the aromatic amine ligand can be pyridine, pyrrole, aniline and derivatives thereof, etc., and the long-chain alkyl ligand can be n-octyl, n-dodecyl, etc.

[0053] In some embodiments, the quantum dot body in the present disclosure can include any one of: a Group IIB-VIA quantum dot, a Group IIIA-VA quantum dot, a Group IV-A VIA quantum dot, a core-shell quantum dot, and an ABX3 type perovskite quantum dot. In the ABX3 type perovskite quantum dot, A is one or more of CH3NH3 + (methylamine), NH2CH=NH2(formamidine), and Cs + , B is one or both of Pb 2+ and Sn 2+ , and X is one or more of Cl - , Br - , and I - The ABX3 type perovskite quantum dot includes CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3, and CsPbI3.

[0054] For example, the Group IIB-VIA quantum dot is selected from one or more of: binary compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, and MgS; ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or a mixture thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or a mixture thereof, but not limited thereto.

[0055] IIIA-VA group quantum dots are selected from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but are not limited thereto.

[0056] IVA-VIA group quantum dots are selected from: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but are not limited thereto. IVA-VIA group quantum dots are, for example, selected from: elemental (uninary) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto.

[0057] Core-shell quantum dots refer to quantum dots in which one material is the core material and another material is the shell material. For example, quantum dots of CdS / ZnS refer to quantum dots in which the core material is CdS and the shell material is ZnS.

[0058] In other embodiments, the quantum dot body can be other nanoscale materials such as nanorods, nanosheets, etc. The composition of the other nanoscale materials can include at least one of CdS, CdSe, CdTe, ZnSe, InP, PbS, CuInS2, ZnO, CsPbCl3, CsPbBr3, CsPhI3, CdS / ZnS, CdSe / ZnS, ZnSe, InP / ZnS, PbS / ZnS, InAs, InGaAs, InGaN, GaNk, ZnTe, Si, Ge, and C, etc.

[0059] For example, the quantum dot body can include cadmium (Cd)-free quantum dots. Cd-free quantum dots are quantum dots that do not include cadmium (Cd).

[0060] In some embodiments, in the quantum dot material provided by the embodiments of the present disclosure, the quantum dot body comprises a first metal element and a non-metal element combined by a chemical bond, the first metal element can be a group III element, and the non-metal element can be a group V element. In this way, the quantum dot body provided by the embodiments of the present disclosure has a non-toxic and environmentally friendly structure. Specifically, the first metal element can be indium (In), and the non-metal element can be phosphorus (P).

[0061] In some embodiments, in the quantum dot material provided by the embodiments of the present disclosure, the quantum dot body can further comprise at least one second metal element different from the first metal element, and the second metal element can include at least one of, but is not limited to, zinc and gallium. In this way, when preparing the quantum dot body, a precursor of the second metal element can be mixed with an indium precursor to form a three-element quantum dot body (for example, InZnP), so that the optical band gap of the quantum dot body tends to increase, and by controlling the content of the precursor of the second metal element, the emission wavelength can be adjusted. For example, a red quantum dot does not need to add a precursor of the second metal element, while a blue and green quantum dot needs to mix a precursor of the second metal element with an indium precursor.

[0062] In some embodiments, the shape of the quantum dot material includes, but is not limited to, any geometric shape of quantum dot material such as spherical, spherical, ellipsoidal, polyhedral, rod-shaped, cross-shaped, ring-shaped, etc.

[0063] In some embodiments, in the quantum dot material provided by the embodiments of the present disclosure, as shown in FIG. 1, the metal M in the metal complex 3 and the first metal element in the quantum dot body 2 are required to be elements with similar group numbers and similar ionic radii, so that the first metal element in the quantum dot body 2 can match the metal M in the metal complex 3, and the metal complex 3 can connect the quantum dot body 2 in the hole V of the covalent organic framework material 1. Therefore, the metal M in the metal complex 3 can be a main group element of IA, IIA, IIIA, IVA, or a secondary group element of IB and IIB. Alternatively, the metal M in the metal complex 3 can include, but is not limited to, at least one of Li, Na, K, Ca, Zn, Mg, and Ga.

[0064] In some embodiments, in the quantum dot material provided in the embodiments of the present disclosure, as shown in FIG. 1 and FIG. 2, FIG. 2 is an electron microscope photo of the quantum dot material shown in FIG. 1 obtained by transmission electron microscopy test, wherein the black dots are quantum dot bodies 2 (InP), the gray part surrounding the black dots is covalent organic framework material 1, 1-4 quantum dot bodies 2 can be included in each hole V, the average particle size of the quantum dot body 2 ranges from 3 nm to 20 nm, for example, the average particle size of the quantum dot body 2 is 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc.

[0065] In some embodiments, in the quantum dot material provided in the embodiments of the present disclosure, the emission peak of the quantum dot material ranges from 450 nm to 640 nm, for example, the emission peak can be 487 nm, 505 nm, 620 nm; the half-peak width of the fluorescence emission spectrum of the quantum dot material ranges from 15 nm to 50 nm, the half-peak width is relatively narrow, and the size uniformity of the quantum dot structure is good; the luminous efficiency of the quantum dot material ranges from 45% to 100%, and the fluorescence quantum yield is relatively high.

[0066] Based on the same inventive concept, the embodiments of the present disclosure also provide a manufacturing method of a quantum dot material, which is used to manufacture the above-mentioned quantum dot material provided in the embodiments of the present disclosure. Since the problem-solving principle of the manufacturing method is similar to that of the above-mentioned quantum dot structure, the implementation of the manufacturing method can be referred to the implementation of the above-mentioned quantum dot structure, and the repeated parts will not be described herein.

[0067] The manufacturing method of the above-mentioned quantum dot material provided in the embodiments of the present disclosure, as shown in FIG. 3, comprises the following steps:

[0068] S301, forming a metal complex solution; the metal complex comprises a metal and a first ligand and a second ligand which are coordinated with the metal;

[0069] S302, forming a quantum dot body solution;

[0070] S303, adding the metal complex solution and the covalent organic framework material into the quantum dot body solution and heating to a preset temperature, so that the first ligand is coordinated with the covalent organic framework material, the second ligand is coordinated with the quantum dot body, and the quantum dot body and the metal complex are both located in the hole of the covalent organic framework material.

[0071] The manufacturing method provided by the embodiments of the present disclosure can connect the quantum dot body to the pores of the covalent organic framework material through the metal complex, so that the formed quantum dot material does not agglomerate, and the monodispersity and stability of the quantum dot are improved. The manufacturing method provided by the embodiments of the present disclosure has the ability of mass production, and provides a new solution for the application of cadmium-free quantum dots in the optoelectronic field.

[0072] In some embodiments, in the manufacturing method provided by the embodiments of the present disclosure, the step S301 can first form a metal complex with a first ligand, and then add a second ligand solution to the metal complex with the first ligand to form a metal complex with both the first ligand and the second ligand. Alternatively, a metal complex with a second ligand can be first formed, and then a first ligand solution is added to the metal complex with the second ligand to form a metal complex with both the first ligand and the second ligand.

[0073] In some embodiments, in the manufacturing method provided by the embodiments of the present disclosure, the step S302 of forming the quantum dot body solution can specifically include: adding a first metal element precursor, a second metal element precursor, a fatty acid ligand, and a non-coordination solvent into a reaction container; introducing an inert gas into the reaction container and heating to a first temperature, and then vacuumizing for a preset time length; then, heating the mixed solution to a second temperature, and adding a phosphorus source and a phosphorus coordination solvent, and keeping warm for a certain time length to complete the preparation of the quantum dot body.

[0074] Specifically, the first temperature is in the range of 100-180°C. Setting the first temperature in the range of 100-180°C can ensure that the first metal element precursor, the second metal element precursor containing a surface activator, and the fatty acid ligand can be dissolved in the non-coordination solvent, and water vapor and oxygen can be removed. The second temperature is in the range of 180-310°C. Heating the mixed solution to the second temperature is conducive to the combination of the second metal element with the non-metal element to be added. Setting the second temperature in the range of 180-300°C can ensure that the second metal element can be combined with the non-metal element (phosphorus source) smoothly.

[0075] In some embodiments, the corresponding second metal element precursor needs to be added to the reaction container according to the amount of the second metal element to be contained in the quantum dot body to be formed. For example, if the quantum dot body to be formed contains only Zn as the second metal element, zinc carboxylate (such as zinc stearate) can be added to the reaction container. If the quantum dot structure to be formed contains both Zn and Ga as the second metal elements, zinc stearate and gallium acetylacetone can be added to the reaction container at the same time.

[0076] In some embodiments, the fatty acid ligand is a surface ligand that can coordinate with the precursor of the first metal element, and the fatty acid after coordination can be removed at a high temperature to combine the first metal element with the non-metal element, and the fatty acid is not easy to be removed at a low temperature to play a stabilizing role at the low temperature.

[0077] In some embodiments, the fatty acid ligand can be one or a combination of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, and eicosanoic acid, or other materials can also be used, which are not limited herein.

[0078] In some embodiments, the non-coordinating solvent can be selected from non-toxic and environmentally friendly solvents, for example, octadecene can be selected.

[0079] In specific implementation, the inert gas is introduced into the reaction container and heated to the first temperature, so that the precursor of the first metal element, the precursor of the second metal element containing the surface activator, and the fatty acid ligand are dissolved in the non-coordinating solvent, and the water vapor and oxygen in the reaction container are discharged, so that the reactants are kept in an inert gas environment to avoid oxidation. Specifically, the reaction container can be a three-necked flask, or other containers, which are not limited herein. The inert gas can be nitrogen, or other inert gases, which are not limited herein.

[0080] In some embodiments, in the manufacturing method provided in the embodiments of the present disclosure, the first metal element can be indium, and the precursor of the first metal element can be one or a combination of indium methanesulfonate, indium acetate, indium dodecanoate, indium tetradecanoate, indium hexadecanoate, indium octadecanoate, and indium eicosanoate. In specific implementation, the first metal element can also be other elements in the group III elements, and correspondingly, the precursor of the first metal element can also be other materials, which are not limited herein.

[0081] In some embodiments, the phosphorus source can be tris(trimethylsilyl) phosphine or other materials, and the phosphorus coordination solvent can be trioctylphosphine, which plays a role of coordination and slowing down the reactivity of tris(trimethylsilyl) phosphine. The phosphorus coordination solvent can be wrapped on the surface of the phosphorus source to prevent the phosphorus source from being eroded by water vapor and oxygen, so that the phosphorus source is more stable.

[0082] Specifically, in the manufacturing method provided in the embodiments of the present disclosure, the metal complex solution and the covalent organic framework material are added into the quantum dot body solution and heated to a preset temperature, and the preset temperature can be in the range of 270°C to 350°C. The preset temperature is set in the range of 270°C to 350°C, so that the first ligand of the metal complex is coordinated and connected with the covalent organic framework material, the second ligand is coordinated and connected with the quantum dot body, and the quantum dot body and the metal complex are located in the pores of the covalent organic framework material.

[0083] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, the step S303 that the first ligand is coordinated and connected with the covalent organic framework material can specifically include: the first ligand replaces the original ligand of the covalent organic framework material, or the first ligand is directly coordinated and connected with the covalent organic framework material.

[0084] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, the step S303 that the second ligand is coordinated and connected with the quantum dot body can specifically include: the second ligand replaces the original ligand on the surface of the quantum dot body, or the second ligand is directly coordinated and connected with the surface of the quantum dot body.

[0085] In order to more clearly illustrate the above manufacturing method provided by the embodiments of the present disclosure, the following takes the preparation of InZnP-Ga-COF quantum dot material with a fluorescence emission peak of 505 nm (Embodiment 1) as an example to illustrate the above manufacturing method in detail, and Embodiment 1 specifically includes the following steps:

[0086] (1) Preparation of metal (Ga) complex solution: polar and non-polar solvents (1:1) are added to a reaction kettle, and a metal precursor (for example, Ga(NO3)3·9H2O) and an aqueous ligand (for example, acetic acid) are injected into the reaction kettle and stirred at a low speed for 1 hour, and then an oily ligand (for example, triphenylphosphine) is added and stirred at a low speed for 1 hour to obtain a metal complex solution, and the metal complex includes metal (Ga) and acetic acid and triphenylphosphine coordinated and connected with the metal (Ga).

[0087] (2) 0.15 mmol of indium acetate (indium precursor), 0.1 mmol of zinc stearate, 0.45 mmol of hexadecanoic acid (fatty acid ligand), and octadecene (non-coordination solvent) are added to a three-necked flask, and nitrogen is introduced into the three-necked flask, and the temperature is raised to 120°C and vacuumized for 30 minutes; then the mixed solution is heated to 260°C, and 0.1 mmol of tris(trimethylsilyl)phosphine (phosphorus source) and 1 mL of trioctylphosphine solution (coordination solvent of the phosphorus source) are quickly injected into the reaction, and the temperature is kept for 3 minutes to complete the preparation of the InZnP quantum dot body.

[0088] (3) The InZnP quantum dot body solution is heated to 310°C, and 0.2 mL of a mixed solution of metal (Ga) complex and covalent organic framework material is quickly injected into the reaction, and the temperature is kept for 3 minutes to complete the preparation of the InZnP-Ga-COF quantum dot material.

[0089] Example 2: The preparation method is basically carried out according to the above steps (1)-(3), except that in step (2), 0.2 mL of the mixed solution of metal complex and covalent organic framework material is replaced by 0.4 mL of the mixed solution of metal complex and covalent organic framework material.

[0090] Example 3: The preparation method is basically carried out according to the above steps (1)-(3), except that in step (2), 0.2 mL of the mixed solution of metal complex and covalent organic framework material is replaced by 0.6 mL of the mixed solution of metal complex and covalent organic framework material.

[0091] Example 4: The preparation method is basically carried out according to the above steps (1)-(3), except that in step (1), Ga(NO3)3·9H2O is replaced by Zn(NO3)2·6H2O.

[0092] Example 5: The preparation method is basically carried out according to the above steps (1)-(3), except that in step (1), Ga(NO3)3·9H2O is replaced by Mg(NO3)2·6H2O.

[0093] Example 6: InZnP-Ga-COF quantum dot material with a fluorescence emission peak of 620 nm is prepared, and the preparation is basically carried out according to steps (1)-(3) of Example 1, except that in step (2), no zinc stearate precursor is added to realize a quantum dot sample with a red light emitting wavelength.

[0094] Example 7:

[0095] InZnP-Ga-COF quantum dot material with a fluorescence emission peak of 487 nm is prepared, and the preparation is basically carried out according to steps (1)-(3) of Example 1, except that in step (2), 0.3 mmol of zinc stearate precursor is added to realize a quantum dot sample with a blue light emitting wavelength.

[0096] Comparative Example 1: The preparation method is carried out according to steps (1) and (2) of the above Example 1.

[0097] Comparative Example 2: The preparation method is basically carried out according to steps (1)-(3) of Example 1, except that in step (2), 120°C is replaced by 90°C.

[0098] Comparative Example 3: The preparation method is basically carried out according to steps (1)-(3) of Example 1, except that in step (2), 120°C is replaced by 190°C.

[0099] Comparative Example 4: The preparation method is basically carried out according to steps (1)-(3) of Example 1, except that in step (2), 260°C is replaced by 170°C.

[0100] Comparative Example 5: The preparation method was basically performed according to steps (1)-(3) of Example 1, except that 260°C was replaced by 320°C in step (2).

[0101] Comparative Example 6: The preparation method was basically performed according to steps (1)-(3) of Example 1, except that 310°C was replaced by 260°C in step (3).

[0102] Comparative Example 7: The preparation method was basically performed according to steps (1)-(3) of Example 1, except that 310°C was replaced by 360°C in step (3).

[0103] Comparative Example 8: The preparation method was basically performed according to steps (1) and (2) of Example 6.

[0104] Comparative Example 9: The preparation method was basically performed according to steps (1) and (2) of Example 7.

[0105] FIGS. 4 and 5 are respectively the ultraviolet-visible light absorption spectrum and the fluorescence emission spectrum of the quantum dot material corresponding to Example 1 and Comparative Example 1, which can be measured by a fluorescence spectrometer. In FIG. 4, the abscissa is wavelength, and the ordinate is absorbance. In FIG. 5, the abscissa is wavelength, and the ordinate is photoluminescence intensity. As can be seen from FIG. 4, the quantum dot material prepared in Example 1 has high absorbance, and the size distribution of the quantum dot material is more uniform, which is conducive to high luminescent efficiency. As can be seen from FIG. 5, the emission peak of the quantum dot material prepared in Example 1 is at 503 nm, and the half-peak width is relatively narrow, about 45 nm. The size uniformity of the quantum dot material is good, and the fluorescence quantum yield is high.

[0106] Table 1 below is a comparison table of the luminescent efficiency of each quantum dot material corresponding to Examples 1-7 and Comparative Examples 1-9.

[0107] Table 1

[0108] As can be seen from Table 1, the half-peak width of the quantum dot material provided in the embodiments of the present disclosure is relatively narrow (15 nm-50 nm), and the fluorescence yield is relatively high (45%-100%).

[0109] Based on the same inventive concept, the embodiments of the present disclosure also provide a quantum dot light-emitting device, which comprises a quantum dot light-emitting layer, and the quantum dot light-emitting layer comprises the above-mentioned quantum dot material provided in the embodiments of the present disclosure. The principle of solving problems of the quantum dot light-emitting device is similar to that of the aforementioned quantum dot material, and therefore the implementation of the quantum dot light-emitting device can be referred to the implementation of the aforementioned quantum dot material, and the repeated parts will not be described here.

[0110] Optionally, the quantum dot light-emitting device provided by the embodiments of the present disclosure can be a quantum dot light-emitting diode, a white OLED+ quantum dot color film device, a photodetector, a photovoltaic solar cell, and the like, but is not limited thereto.

[0111] The embodiments of the present disclosure provide a quantum dot material, a manufacturing method thereof, and a quantum dot light-emitting device. By embedding a quantum dot body in a pore of a covalent organic framework material using a metal complex, and controlling the addition of the covalent organic framework material in the process of preparing the quantum dot material, the quantum dot body can be precisely controlled by the covalent organic framework material, so that the particle size and size distribution of the quantum dot body can be improved, and the monodispersity and stability of the quantum dot body are improved. At the same time, using a metal complex as a connecting agent can increase the fault tolerance of the quantum dot body and the covalent organic framework material, make the nucleation and growth process of the quantum dot more smooth, prevent the agglomeration of the quantum dot body, and reduce the light absorption loss, thereby further improving the light-emitting efficiency of the quantum dot material.

[0112] Although the preferred embodiments of the present disclosure have been described, those skilled in the art who are aware of the basic inventive concept can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0113] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Thus, if these modifications and variations of the embodiments of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure also intends to include these modifications and variations.

Claims

1. A quantum dot material, wherein, The quantum dot material comprises: a covalent organic framework material having pores; a quantum dot body, at least part of the quantum dot body being located in the pores; a metal complex, the metal complex being located in the pores, the metal complex comprising a metal and a first ligand and a second ligand coordinated to the metal, the first ligand being coordinated to the covalent organic framework material, and the second ligand being coordinated to the quantum dot body.

2. The quantum dot material of claim 1, wherein, The first ligand and the second ligand are different in polarity.

3. The quantum dot material of claim 2, wherein, The first ligand is an aqueous ligand, and the second ligand is an oily ligand.

4. The quantum dot material of claim 3, wherein, The first ligand comprises at least one of a carboxylic acid ligand, an amino acid ligand, a polyol ligand, a phosphoric acid ligand, and a nitrogen-containing heterocyclic ligand.

5. The quantum dot material of claim 3, wherein, The second ligand comprises at least one of a phosphine ligand, a nitrogen heterocyclic carbene ligand, a sulfide ligand, a thiol ligand, an olefin ligand, an alkyne ligand, an aromatic amine ligand, and a long-chain alkyl ligand.

6. The quantum dot material of claim 1, wherein, The metal in the metal complex is a main group element of IA, IIA, IIIA, IVA, or a secondary group element of IB or IIB.

7. The quantum dot material of claim 6, wherein, The metal in the metal complex comprises at least one of Li, Na, K, Ca, Zn, Mg, and Ga.

8. The quantum dot material of any one of claims 1-7, wherein, The quantum dot body comprises a first metal element and a non-metal element, the first metal element being a group III element, and the non-metal element being a group V element.

9. The quantum dot material of claim 8, wherein, The quantum dot body further comprises at least one second metal element different from the first metal element.

10. The quantum dot material of claim 9, wherein, The first metal element is indium, the non-metal element is phosphorus, and the second metal element comprises at least one of zinc and gallium.

11. The quantum dot material of any of claims 1-10, wherein, Each of the pores comprises 1-4 quantum dot bodies, and the average particle size of the quantum dot bodies ranges from 3 nm to 20 nm.

12. The quantum dot material of any of claims 1-11, wherein, The quantum dot material has an emission peak ranging from 450 nm to 640 nm, a half-peak width of a fluorescence emission spectrum of the quantum dot material ranging from 15 nm to 50 nm, and a luminous efficiency of the quantum dot material ranging from 45% to 100%.

13. A quantum dot light emitting device, wherein, The quantum dot light-emitting layer comprises the quantum dot material according to any one of claims 1-12.

14. A method of producing a quantum dot material for producing a quantum dot material according to any one of claims 1 to 12, wherein, The manufacturing method comprises: forming a metal complex solution, the metal complex comprising a metal and a first ligand and a second ligand coordinated to the metal; forming a quantum dot body solution; adding the metal complex solution and a covalent organic framework material to the quantum dot body solution and heating to a preset temperature, so that the first ligand is coordinated to the covalent organic framework material, the second ligand is coordinated to the quantum dot body, and the quantum dot body and the metal complex are both located in the pores of the covalent organic framework material.

15. The production method according to claim 14, wherein The preset temperature ranges from 270°C to 350°C.

16. The production method according to claim 14, wherein The first ligand is coordinated to the covalent organic framework material, specifically including that the first ligand replaces original ligands of the covalent organic framework material, or the first ligand is directly coordinated to the covalent organic framework material. The second ligand is coordinated to the quantum dot body, specifically including: the second ligand replaces the original ligand on the surface of the quantum dot body, or the second ligand is directly coordinated to the surface of the quantum dot body. The second ligand is coordinated to the quantum dot body, specifically including: the second ligand replaces the original ligand on the surface of the quantum dot body, or the second ligand is directly coordinated to the surface of the quantum dot body.

Images