Composite material, light-emitting device, preparation method of light-emitting device and display device

Abstract

The invention discloses a composite material, a light-emitting device, a preparation method of the light-emitting device and a display device. The light-emitting device comprises quantum dots and amino acid functionalized MXene. According to the composite material, the stability of the composite material can be improved, so that the service life of the quantum dots is prolonged, and the stable electroluminescent performance of the quantum dots is kept.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to a composite material, a light-emitting device, a preparation method thereof, and a display device. Background Art

[0002] Currently, the widely used light-emitting devices are organic light-emitting devices (OLEDs) and quantum dot light-emitting devices (QLEDs). Due to their excellent display performances such as self-luminescence, simple structure, ultra-thinness, fast response speed, wide viewing angle, low power consumption, and flexible display, OLEDs have become the mainstream technology in the field of display technologies. QLEDs have the advantages of saturated emission light color, adjustable wavelength, low turn-on voltage, good solution processability, easy fine control of quantum dots, etc., and have high photoluminescence and electroluminescence quantum yields, and have become a strong competitor to OLEDs in recent years.

[0003] The structures of traditional OLED and QLED devices generally include an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode. Under the action of an electric field, the holes generated by the anode and the electrons generated by the cathode of the light-emitting device move, are respectively injected into the hole transport layer and the electron transport layer, and finally migrate to the light-emitting layer. When the two meet in the light-emitting layer, energy excitons are generated, thereby exciting the light-emitting molecules to finally generate visible light.

[0004] However, the material lifetime of the light-emitting layer in existing devices needs to be further improved. Summary of the Invention

[0005] In view of this, the present application provides a light-emitting device.

[0006] An embodiment of the present application is implemented as follows. A composite material includes quantum dots and amino acid-functionalized MXene.

[0007] Optionally, in some embodiments of the present application, the surface of the quantum dots in the composite material is connected to the amino acid-functionalized MXene through at least one of electrostatic attraction, covalent bond, and hydrogen bond; and / or

[0008] The mass ratio of the quantum dots to the amino acid-functionalized MXene is 1:(1 - 5); and / or

[0009] The molar ratio of the amino acid to MXene in the amino acid-functionalized MXene is (1 - 5):1; and / or

[0010] The average particle size of the quantum dots is 5 - 20 nm.

[0011] Optionally, in some embodiments of the present application, the amino acid in the amino acid-functionalized MXene includes hydrophobic amino acids; and / or

[0012] The chemical general formula of MXene in the amino acid-functionalized MXene is M n+1 X n T x , where M is selected from transition metal elements, and the transition metal elements are selected from one or more of Ti, Nb, V, Mo, Zr, Hf, Ta, Cr, Sc; X is selected from one or more of C and N; T x is a surface active functional group, and the surface active functional group includes one or more of -OH, -O, -F, -Cl, -Br, where 0 < x ≤ 2; n is any integer among 1, 2, and 3; and / or

[0013] The material of the quantum dots is selected from one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials; the materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are respectively selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds; the shell layer of the core-shell structure quantum dots is one or more layers; the II-VI group compounds are selected from one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds are selected from one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V group compounds are selected from one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the I-III-VI group compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2;The quantum dots of the core-shell structure are selected from one or more of CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS, and InP / ZnSe / ZnS; the perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs + ion, M is a divalent metal cation selected from 2+ Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ Ge 2+ Yb 2+ Eu - Cl - Br - I n-2 NH 3+ or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation selected from 2+ Pb 2+ Sn 2 + Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ Ge 2+ Yb 2+ Eu 2+ and X is a halogen anion selected from - Cl - Br - I

[0014] Optionally, in some embodiments of the present application, the hydrophobic amino acids include one or more of tryptophan, phenylalanine, valine, leucine, isoleucine, proline, alanine, and methionine; and / or

[0015] The Mxene includes Ti3C2T x 、Ti2CT x 、TiNbCT x 、Ti3CNT x 、Ta4C3T x 、Nb2CT x 、Nb4C3T x 、V2CT x 、Mo2CT x 、Ti4N3T x and Cr2CT x one or more of them, where 0 < x ≤ 2.

[0016] Correspondingly, the present application also provides a method for preparing a composite material, including the following steps:

[0017] Provide a first hybrid material including amino acid-functionalized MXene, quantum dots, and a first solvent, and obtain a luminescent film after reaction.

[0018] Optionally, in some embodiments of the present application, the mass ratio of the quantum dots to the amino acid-functionalized MXene is 1:(1 - 5); and / or

[0019] The molar ratio of the amino acid to the MXene in the amino acid-functionalized MXene is (1 - 5):1; and / or

[0020] The average particle size of the quantum dots is 5 - 20 nm; and / or

[0021] The first solvent includes one or more of n-octane, dimethylformamide, ethanol, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol; and / or

[0022] The mass concentration of the first hybrid material is 20 - 40 mg / ml.

[0023] Optionally, in some embodiments of the present application, the reaction temperature of the first hybrid material is 180 - 200 °C, and the reaction time of the first hybrid material is 0.5 - 1 h; and / or

[0024] The reaction process of the first hybrid material is carried out under an inert protective atmosphere.

[0025] Optionally, in some embodiments of the present application, the preparation method of the amino acid-functionalized MXene includes:

[0026] Providing a second mixed material including MXene, an amino acid, and a polar solvent, and obtaining the amino acid-functionalized MXene after the reaction.

[0027] Optionally, in some embodiments of the present application, the reaction of the second mixed material includes heating, the temperature of the heating is 40 to 60 °C, and the time is 48 to 60 h; and / or

[0028] After the reaction of the second mixed material and before obtaining the amino acid-functionalized MXene, separation and drying are further included; the temperature of the drying is 60 to 100 °C, and the time of the drying is 12 to 24 h; and / or

[0029] The polar solvent includes one or more of ethanol, isopropanol, and methanol; and / or

[0030] The mass concentration of the second mixed material is 0.3 to 0.8 mg / ml.

[0031] Correspondingly, the present application further provides a light-emitting device, including a first electrode, a light-emitting layer, and a second electrode which are stacked, and the material of the light-emitting layer includes the above composite material.

[0032] Optionally, in some embodiments of the present application, the light-emitting device further includes a first charge carrier functional layer and / or a second charge carrier functional layer, the first charge carrier functional layer is disposed between the first electrode and the light-emitting layer, and the second charge carrier functional layer is disposed between the light-emitting layer and the second electrode.

[0033] Optionally, in some embodiments of the present application, the materials of the first electrode and the second electrode independently include one or more of metals, carbon materials, and metal oxides; the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include metal oxide electrodes or composite electrodes with a metal sandwiched between doped or undoped transparent metal oxides. The materials of the metal oxide electrodes include one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, and the composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or

[0034] The first carrier functional layer includes a hole functional layer, and the materials of the hole functional layer include 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent material, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-phenylene vinylene), poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro-NPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinodimethane, doped graphene, undoped graphene, transition metal oxide, transition metal sulfide, transition metal stannide, doped or undoped zinc oxide, barium oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc selenide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, quinoxaline compound, imidazole compound, triazine compound, fluorene-containing compound, hydroxyquinoline compound, or one or more of them; and / or

[0035] The second carrier functional layer includes an electron functional layer. The material of the electron functional layer includes one or more of inorganic electron functional materials and organic electron functional materials. The inorganic electron functional materials include one or more of metal oxides, doped metal oxides, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The metal oxides include one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxides in the doped metal oxides include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The dopants in the doped metal oxides include one or several of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga, and Sn. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS. The organic electron functional materials include one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds.

[0036] Correspondingly, the present application also provides a method for preparing a light-emitting device, including the following steps:

[0037] Providing a light-emitting device preform, the light-emitting device preform including a first electrode;

[0038] Providing a second solvent and a third mixed material of a composite material, the composite material including quantum dots and amino-functionalized MXene, and disposing the third mixed material on the light-emitting device preform to form a light-emitting layer;

[0039] Forming a second electrode on the light-emitting layer to obtain a light-emitting device.

[0040] Optionally, in some embodiments of the present application, the light-emitting device preform includes a stacked first electrode and a first carrier functional layer. The disposing the third mixed material on the light-emitting device preform includes: disposing the third mixed material on the first carrier functional layer; and / or

[0041] The forming a second electrode on the light-emitting layer includes: forming a second carrier functional layer and a second electrode on the light-emitting layer; and / or

[0042] The mass ratio of the quantum dots to the amino-functionalized MXene is 1:(1-5); and / or

[0043] The molar ratio of the amino acid to MXene in the amino acid-functionalized MXene is (1-5):1; and / or

[0044] The average particle size of the quantum dots is 5-20 nm; and / or

[0045] The mass concentration of the third hybrid material is 20-40 mg / ml.

[0046] Correspondingly, the present application also provides a display device, and the display device includes the above-mentioned light-emitting device.

[0047] The composite material of the present application includes quantum dots and amino acid-functionalized MXene, which can improve the stability of the composite material and thus improve the lifespan of the light-emitting device. Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0049] Figure 1 is a schematic structural diagram of a light-emitting device provided by an embodiment of the present application;

[0050] Figure 2 is a flowchart of a preparation method of a light-emitting device provided by an embodiment of the present application.

[0051] Reference Signs:

[0052] Light-emitting device 100; First electrode 10; Light-emitting layer 20; Second electrode 30; First carrier functional layer 40; Second carrier functional layer 50. Detailed Embodiments

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing particular embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] In this application, unless otherwise stated, the orientation terms such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the drawings; while "inner" and "outer" refer to the outline of the device. Additionally, in the description of this application, the term "comprising" means "including but not limited to". The use of terms such as first, second, third, etc. is merely for identification purposes and does not impose a numerical requirement or establish an order.

[0056] In this application, "and / or" describes the association relationship of associated objects and indicates that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, or B exists alone. Where A and B can be singular or plural.

[0057] In this application, "at least one" means one or more, and "a plurality" means two or more. "One or more", "at least one of the following (items)" or similar expressions refer to any combination of these items, including any combination of single (item) or plural (items). For example, "at least one of (item) a, b, or c", or, "at least one of (item) a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0058] In this application, when forming another layer "on" a certain layer, the so-called "on" is a broad concept, which can mean that the formed another layer is adjacent to a certain layer, or there can be other spacer structure layers between the another layer and a certain layer. For example, when forming a second electrode "on" the first carrier functional layer, the so-called "on" can mean that the formed second electrode is adjacent to the first carrier functional layer, or there can be other spacer structure layers between the second electrode and the first carrier functional layer, such as a light-emitting layer.

[0059] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0060] To improve the stability of quantum dot light-emitting devices, organic encapsulating materials are usually used to treat quantum dots. However, some organic materials may decompose, fade, etc. under long-term use or high-temperature environments, thereby affecting the performance and lifespan of quantum dots.

[0061] Amino acid molecules have specific functional groups and molecular structures such as amino and carboxyl groups, and can effectively chemically bond with quantum dots and MXene. Amino acid-functionalized MXene has excellent electrical conductivity and can serve as an efficient carrier transport channel.

[0062] The technical solution of the present application is as follows:

[0063] In a first aspect, an embodiment of the present application provides a composite material, including quantum dots and amino acid-functionalized MXene.

[0064] In the composite material provided by the present application, the composite material includes quantum dots and amino acid-functionalized MXene. The surface of amino acid-functionalized MXene has positive and negative charges, and the quantum dots also have charged surface groups. The two can attract each other through electrostatic interaction. This electrostatic interaction can make the quantum dots evenly distributed on the surface of amino acid-functionalized MXene, thereby improving the stability of the composite material; amino acid-functionalized MXene can inhibit the occurrence of adverse reactions such as the photodegradation and surface oxidation of quantum dots, thereby extending the lifespan of quantum dots and maintaining their stable electroluminescent performance.

[0065] In addition, by adjusting the type and quantity of amino acid molecules, the surface energy level of MXene can be changed, so that amino acid-functionalized MXene can regulate the surface energy level of quantum dots, reduce interface defects and energy loss, enhance the injection and transport efficiency of carriers, improve the brightness of electroluminescence, reduce energy consumption, and improve the overall performance. By optimizing the structure of amino acid molecules, the regulation effect on electroluminescence performance can be further enhanced. For example, by introducing appropriate substituents or changing the configuration of amino acid molecules, fine regulation of the energy level of quantum dots, carrier injection and transport efficiency can be achieved.

[0066] Amino acid-functionalized MXene can change the surface charge state of quantum dots, affect the internal electron distribution and energy transfer process in quantum dots, and the energy groups in amino acid molecules can undergo energy transfer with quantum dots, thus changing the excitation energy and emission energy of quantum dots. By selecting different types of amino acids, precise regulation of the surface charge of quantum dots can be achieved, and then their emission wavelength and emission intensity can be regulated. By changing the concentration of amino acid molecules and reaction conditions, precise regulation of the size and morphology of quantum dots can be achieved, and then their emission wavelength and emission intensity can be regulated.

[0067] Through the interaction between amino acid-functionalized MXene and biomolecules, the compatibility between quantum dots and the biological environment can be enhanced.

[0068] In some embodiments, the surface of the quantum dots in the composite material is connected to the amino acid-functionalized MXene through at least one of electrostatic attraction, covalent bond and hydrogen bond.

[0069] In some embodiments, the mass ratio of the quantum dots to the amino acid-functionalized MXene is 1:(1 - 5), for example, it can be 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, etc. Within the range of the molar ratio, the luminescence efficiency, electrical conductivity and biocompatibility of the composite material can be improved, thereby improving the injection and transport efficiency of carriers, and the interface engineering between amino acid-functionalized MXene and quantum dots can also be optimized.

[0070] In some embodiments, the molar ratio of amino acids to MXene in the amino acid-functionalized MXene is (1 - 5):1, for example, it can be 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, etc. Within the range of the molar ratio, the luminescence efficiency, electrical conductivity and biocompatibility of the composite material can be improved, thereby improving the injection and transport efficiency of carriers, and the interface engineering between amino acid-functionalized MXene and quantum dots can also be optimized.

[0071] In some embodiments, the amino acid in the amino acid-functionalized MXene can be selected from, but not limited to, hydrophobic amino acids. Thus, the hydrophobic amino acids have good electrical properties, which can improve the electrical properties of MXene, and further enhance the properties of the composite material.

[0072] In some embodiments, the hydrophobic amino acids include one or more of tryptophan, phenylalanine, valine, leucine, isoleucine, proline, alanine, and methionine. These amino acids have good electrical properties, which can effectively improve the electrical properties of MXene.

[0073] In some embodiments, the chemical general formula of MXene in the amino acid-functionalized MXene is M n+1 X n T x , where M is selected from transition metal elements, and the transition metal elements are selected from one or more of Ti, Nb, V, Mo, Zr, Hf, Ta, Cr, and Sc; X is selected from one or more of C and N; T x is a surface active functional group, and the surface active functional group includes one or more of -OH, -O, -F, -Cl, and -Br, where 0 < x ≤ 2; n is any integer among 1, 2, and 3.

[0074] In some embodiments, the Mxene includes Ti3C2T x , Ti2CT x , TiNbCT x , Ti3CNT x , Ta4C3T x , Nb2CT x , Nb4C3T x , V2CT x , Mo2CT x , Ti4N3T x , and Cr2CT x , where 0 < x ≤ 2.

[0075] In some embodiments, the material of the quantum dots can be selected from, but not limited to, one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials.

[0076] The material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots can be respectively selected from, but not limited to, one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The shell of the core-shell structure quantum dots is one or more layers. The II-VI group compounds can be selected from, but not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds can be selected from, but not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The III-V group compounds can be selected from, but not limited to, one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The I-III-VI group compounds can be selected from, but not limited to, one or more of CuInS2, CuInSe2, and AgInS2.

[0077] As an example, the quantum dots of the core-shell structure include one or more of CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS, and InP / ZnSe / ZnS. In the expressions such as CdSe / ZnS above, the " / " indicates that the substance after " / " (as the shell layer) coats the substance before " / " (as the core layer).

[0078] The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors. The general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs + ions, M is a divalent metal cation selected from Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ and one or more of them, and X is a halogen anion selected from Cl - , Br - , I - and one or more of them. The general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation selected from Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2 + , Eu 2+ and one or more of them, and X is a halogen anion selected from Cl - , Br - , I -one or more of the above.

[0079] In some embodiments, the average particle size of the quantum dots is 5 - 20 nm.

[0080] In a second aspect, an embodiment of the present application further provides a method for preparing a composite material, including the following steps:

[0081] S11, providing a first hybrid material including amino-functionalized MXene, quantum dots, and a first solvent, and obtaining a composite material after reaction.

[0082] In the step S11: In some embodiments, the mass ratio of the quantum dots to the amino-functionalized MXene is 1:(1 - 5), for example, it can be 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, etc. Within the molar ratio range, the luminescence efficiency, conductivity, and biocompatibility of the material of the light-emitting layer can be improved, thereby improving the injection and transport efficiency of carriers, and the interface engineering between the amino-functionalized MXene and the quantum dots can also be optimized.

[0083] In some embodiments, the molar ratio of the amino acid to the MXene in the amino-functionalized MXene is (1 - 5):1, for example, it can be 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, etc. Within the molar ratio range, the luminescence efficiency, conductivity, and biocompatibility of the material of the light-emitting layer can be improved, thereby improving the injection and transport efficiency of carriers, and the interface engineering between the amino-functionalized MXene and the quantum dots can also be optimized.

[0084] In some embodiments, the first solvent includes one or more of n-octane, dimethylformamide, ethanol, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

[0085] In some embodiments, the mass concentration of the first hybrid material is 20 - 40 mg / ml, for example, it can be 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, etc.

[0086] In some embodiments, the reaction temperature of the first hybrid material is 180 - 200 °C, for example, it can be 182 °C, 184 °C, 186 °C, 188 °C, 190 °C, 192 °C, 194 °C, 196 °C, 198 °C, etc. The heating time is 0.5 - 1 h, for example, it can be 0.55 h, 0.6 h, 0.65 h, 0.7 h, 0.75 h, 0.8 h, 0.85 h, 0.9 h, 0.95 h, etc. In this way, the effective reaction between the amino acid-functionalized MXene and the quantum dots can be promoted, and the purity of the product can be improved.

[0087] In some embodiments, the reaction process of the first hybrid material is carried out under an inert protective atmosphere, and the inert gas includes nitrogen, helium, neon, argon, krypton, xenon, and radon. Under the inert protective atmosphere, the contact between the quantum dots and MXene and reactive gases such as oxygen can be effectively isolated, and the reaction between surface defects and active sites and reactive gases can be reduced, thereby improving the luminescence performance and stability of the quantum dots and MXene. In addition, introducing an inert gas can also control the reaction pressure, thereby affecting the surface modification process of the quantum dots and amino acid-functionalized MXene, and optimizing the product structure and properties.

[0088] In some embodiments, the reaction of the first hybrid material further includes separation, and the separation method is a method used for separation in the prior art in this field.

[0089] In at least one embodiment, the separation method includes centrifugal separation and filtration separation. The rotation speed of the centrifugation is 5000 - 8000 rpm, for example, it can be 5500 rpm, 6000 rpm, 6500 rpm, 7000 rpm, 7500 rpm, etc. The centrifugation time is 5 - 10 min, for example, it can be 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min, 9.5 min, etc. In this way, agglomeration can be reduced, surface defects of the product can be removed, the physical properties of the product can be optimized, and the purity of the product can be improved, thereby improving the luminescence performance and stability of the quantum dots.

[0090] In some embodiments, the separation process further includes washing with a detergent. In this way, the obtained composite material is purer.

[0091] In some embodiments, the detergent is an alcohol, exemplarily, methanol, ethanol, propanol, butanol.

[0092] In some embodiments, the preparation method of the amino acid-functionalized MXene includes:

[0093] Providing a second hybrid material including MXene, amino acid, and a polar solvent, and obtaining amino acid-functionalized MXene after reaction.

[0094] In some embodiments, the polar solvent includes, but is not limited to, polar solvents of alcohols. Exemplarily, ethanol, isopropanol, and methanol.

[0095] In some embodiments, the mass concentration of the second mixed material is 0.3 - 0.8 mg / ml.

[0096] In some embodiments, the reaction of the second mixed material includes heating, and the temperature of the heating is 40 - 60 °C, and the time is 48 - 60 h.

[0097] In some embodiments, the heating temperature of the second mixed material is 40 - 60 °C. For example, it can be 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, 52 °C, 54 °C, 56 °C, 58 °C, etc. The heating time of the second mixed material is 48 - 60 h. For example, it can be 49 h, 50 h, 51 h, 52 h, 53 h, 54 h, 55 h, 56 h, 57 h, 58 h, 59 h, etc. Thus, the synthesis process of MXene and amino acid can be promoted, and the purity of the product can be improved.

[0098] In some embodiments, after the reaction of the second mixed material and before obtaining the amino acid-functionalized MXene, separation and drying are further included; the temperature of the drying is 60 - 100 °C, and the time of the drying is 12 - 24 h.

[0099] In some embodiments, the temperature of the drying is 60 - 100 °C. For example, it can be 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, etc. The time of the drying is 12 - 24 h. For example, it can be 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, etc. Thus, the volatilization of the solvent can be accelerated and the purity of the particles can be maintained.

[0100] In a third aspect, please refer to Figure 1 , an embodiment of the present application provides a light-emitting device 100, including a first electrode 10, a light-emitting layer 20, and a second electrode 30 which are stacked. The material of the light-emitting layer 20 includes the above composite material. In some embodiments, the thickness of the light-emitting layer 20 is 20 - 50 nm.

[0101] In some embodiments, the light-emitting device 100 further includes one or several of a first carrier function layer 40 and a second carrier function layer 50. The first carrier function layer 40 is disposed between the first electrode 10 and the light-emitting layer 20, and the second carrier function layer 50 is disposed between the second electrode 30 and the light-emitting layer 20.

[0102] In some embodiments, the first charge carrier functional layer 40 is a hole functional layer, and the second charge carrier functional layer 50 is an electron functional layer.

[0103] In other embodiments, the second charge carrier functional layer 50 is an electron functional layer, and the first charge carrier functional layer 40 is a hole functional layer.

[0104] In some embodiments, the materials of the first electrode 10 and the second electrode 30 independently include one or more of metals, carbon materials, and metal oxides; the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include metal oxide electrodes or composite electrodes with a metal sandwiched between doped or undoped transparent metal oxides. The materials of the metal oxide electrodes include one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, and the composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2. Herein, " / " represents a stacked structure. For example, AZO / Ag / AZO represents a composite electrode including a sequentially stacked AZO layer, Ag layer, and AZO layer.

[0105] In some embodiments, the electron functional layer includes one or more of an electron injection layer and an electron transport layer.

[0106] In some embodiments, the hole functional layer includes one or more of a hole injection layer and a hole transport layer.

[0107] In some embodiments, the material of the electronic functional layer includes one or more of inorganic electronic functional materials and organic electronic functional materials. The inorganic electronic functional materials include one or more of metal oxides, doped metal oxides, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The metal oxides include one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxides in the doped metal oxides include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The dopants in the doped metal oxides include one or several of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga, and Sn. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS. The organic electronic functional materials include one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds.

[0108] In some embodiments, the materials of the hole functional layer include 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green light-emitting material, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-phenylene vinylene), poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro-NPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinodimethane, doped graphene, undoped graphene, transition metal oxides, transition metal sulfides, transition metal stannides, doped or undoped zinc oxide, barium oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc selenide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, or one or more of them.

[0109] In a fourth aspect, please refer to Figure 2 , embodiments of the present application further provide a method for preparing a light-emitting device 100, including:

[0110] S111. Provide a light-emitting device preform, the light-emitting device preform including a first electrode 10;

[0111] S112. Provide a second solvent and a third mixed material of a composite material, the composite material including quantum dots and amino-functionalized MXene, and dispose the third mixed material on the light-emitting device preform to form a light-emitting layer 20;

[0112] S113. Form a second electrode 30 on the light-emitting layer 20 to obtain a light-emitting device 100.

[0113] In the manufacturing method of the light-emitting device 100 provided in this application, the light-emitting layer 20 is prepared from a solution composed of amino-functionalized MXene and quantum dots. The amino-functionalized MXene and the quantum dots can interact with each other through electrostatic forces, covalent bonds, and hydrogen bonds, enabling the quantum dots to be evenly distributed on the surface of the amino-functionalized MXene, thereby improving the stability of the quantum dots, contributing to extending the lifespan of the light-emitting device and maintaining its stable electroluminescent performance.

[0114] In S111:

[0115] In some embodiments, the light-emitting device preform includes a stacked first electrode 10 and a first carrier functional layer 40, and disposing the third mixed material on the light-emitting device preform includes: disposing the third mixed material on the first carrier functional layer 40.

[0116] In S112:

[0117] In some embodiments, the mass concentration of the third mixed material is 20 - 40 mg / ml, and for example, it can be 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, etc. Within this concentration range, the luminous efficiency of the light-emitting device can be enhanced, the energy level structure of the light-emitting device can be optimized, the carrier injection and transport efficiency can be enhanced, the biocompatibility of the light-emitting device can be improved, and the interfaces of the functional layers in the light-emitting device can be optimized.

[0118] In some embodiments, the second solvent includes one or more of n-octane, dimethylformamide, ethanol, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

[0119] In S113:

[0120] In some embodiments, forming the second electrode 30 on the light-emitting layer 20 includes: forming a second carrier functional layer 50 and the second electrode 30 on the light-emitting layer 20.

[0121] In a fifth aspect, an embodiment of the present application further provides a display device, and the display device includes the above-mentioned light-emitting device 100.

[0122] The display device may be any electronic product with a display function, and the electronic product includes but is not limited to a smart phone, a tablet computer, a notebook computer, a digital camera, a digital video camera, a smart wearable device, a smart weighing electronic scale, a vehicle-mounted display, a television, or an e-book reader. Among them, the smart wearable device may be, for example, a smart bracelet, a smart watch, a virtual reality (VR) helmet, etc.

[0123] The present application will be specifically described below through specific embodiments. The following embodiments are only partial embodiments of the present application and do not limit the present application.

[0124] Embodiment 1

[0125] This embodiment provides a light-emitting device, and the preparation method is as follows:

[0126] Dissolve 17.62 mg of L-tryptophan and 12.75 mg of Ti3C2T x (molar ratio of 1:1) in 50 ml of methanol, mix and heat at 60 °C for 48 h, then wash, filter, and dry to obtain amino acid-functionalized MXene;

[0127] Dissolve quantum dots with CdZnSeS as the core and ZnS as the shell in n-octane to prepare a quantum dot solution with a concentration of 20 mg / mL. Weigh 1 mL of the quantum dot solution and 20 mg of the above-mentioned amino acid-functionalized MXene, mix and heat at 190 °C under a nitrogen atmosphere for 0.8 h, then centrifuge, filter, and wash to obtain a composite material.

[0128] This embodiment also provides a light-emitting device, and the preparation method is as follows:

[0129] Provide ITO glass, dip a cotton swab in a small amount of soapy water and wipe the ITO surface to remove visible impurities on the surface. Then ultrasonically clean with deionized water, acetone, ethanol, and isopropanol for 15 min, and then dry with nitrogen for use to obtain an ITO anode with a thickness of 100 nm;

[0130] Inkjet print PEDOT:PSS ink on the above ITO substrate to form a hole injection layer with a thickness of 30 nm;

[0131] The TFB ink is inkjet printed on the above hole injection layer to form a hole transport layer with a thickness of 25 nm;

[0132] The above composite material is dissolved in n-octane, and then 50 μL is sucked with a pipette and dropped on the hole functional layer, followed by spin coating at a rotation speed of 3000 rpm for 50 s. Then annealing is carried out at an annealing temperature of 120 °C for 15 min to form a light-emitting layer with a thickness of 30 nm;

[0133] 40 μL of zinc oxide ethanol solution with a concentration of 25 mg / mL is sucked with a pipette, set on the light-emitting layer, and spin-coated at a rotation speed of 3000 rpm for 30 s, and annealed at 130 °C for 10 min to form an electron functional layer with a thickness of 70 nm;

[0134] On the electron functional layer, the Ag target is turned on, and the Ag target is evaporated at a rate of to form a cathode with a thickness of 30 nm;

[0135] Encapsulation is carried out to obtain a light-emitting device.

[0136] Example 2

[0137] This example is basically the same as Example 1, except that in this example, the quantum dots with CdZnSeS as the core and ZnS as the shell are replaced by quantum dots with CdS as the core and ZnSe as the shell.

[0138] Example 3

[0139] This example is basically the same as Example 1, except that in this example, the quantum dots with CdZnSeS as the core and ZnS as the shell are replaced by CdSe quantum dots.

[0140] Example 4

[0141] This example is basically the same as Example 1, except that in this example, 1 mL of quantum dot solution is weighed and mixed with 60 mg of amino acid-functionalized MXene.

[0142] Example 5

[0143] This example is basically the same as Example 1, except that in this example, 1 mL of quantum dot solution is weighed and mixed with 100 mg of amino acid-functionalized MXene.

[0144] Example 6

[0145] This example is basically the same as Example 1, except that in this example, L-tryptophan is replaced by L-aspartic acid.

[0146] Example 7

[0147] This example is basically the same as Example 1, except that in this example, L-tryptophan is replaced with alanine.

[0148] Example 8

[0149] This example is basically the same as Example 1, except that in this example, L-tryptophan is replaced with glutamic acid.

[0150] Example 9

[0151] This example is basically the same as Example 1, except that in this example, Ti3C2T x is replaced with V2CT x .

[0152] Example 10

[0153] This example is basically the same as Example 1, except that in this example, Ti3C2T x is replaced with Cr2CT2.

[0154] Example 11

[0155] This example is basically the same as Example 1, except that in this example, the heating temperature of the quantum dot solution and the amino acid-functionalized MXene is 180 °C.

[0156] Example 12

[0157] This example is basically the same as Example 1, except that in this example, the heating temperature of the quantum dot solution and the amino acid-functionalized MXene is 200 °C.

[0158] Example 13

[0159] This example is basically the same as Example 1, except that in this example, the heating time of the quantum dot solution and the amino acid-functionalized MXene is 0.5 h.

[0160] Example 14

[0161] This example is basically the same as Example 1, except that in this example, the heating time of the quantum dot solution and the amino acid-functionalized MXene is 1 h.

[0162] Example 15

[0163] This example is basically the same as Example 1, except that in this example, the molar ratio of L-tryptophan and Ti3C2T x is 2.5:1.

[0164] Example 16

[0165] This example is basically the same as Example 1, except that in this example, the molar ratio of L-tryptophan to Ti3C2T x is 5:1.

[0166] Example 17

[0167] This example is basically the same as Example 1, except that in this example, the heating temperature of L-tryptophan and Ti3C2T x is 40 °C.

[0168] Example 18

[0169] This example is basically the same as Example 1, except that in this example, the heating temperature of L-tryptophan and Ti3C2T x is 55 °C.

[0170] Example 19

[0171] This example is basically the same as Example 1, except that in this example, the heating time of L-tryptophan and Ti3C2T x is 55 h.

[0172] Example 20

[0173] This example is basically the same as Example 1, except that in this example, the inverted light-emitting device is prepared in the order of cathode, electron functional layer, light-emitting layer, hole functional layer, and anode. x is 60 h.

[0174] Example 21

[0175] This example is basically the same as Example 1, except that in this example, the inverted light-emitting device is prepared in the order of cathode, electron functional layer, light-emitting layer, hole functional layer, and anode.

[0176] Comparative Example 1

[0177] This comparative example is basically the same as Example 1, except that in this comparative example, the quantum dot solution is directly disposed on the hole functional layer to form a light-emitting layer.

[0178] Comparative Example 2

[0179] This comparative example is basically the same as Example 1, except that in this comparative example, the amino acid-functionalized MXene is replaced with MXene.

[0180] Comparative Example 3

[0181] This comparative example is basically the same as Example 1, except that in this comparative example, the amino acid-functionalized MXene is replaced with oleic acid.

[0182] Comparative Example 4

[0183] This comparative example is basically the same as Example 20, except that in this comparative example, the quantum dot solution is directly disposed on the hole functional layer to form a light-emitting layer.

[0184] The fluorescence quantum yield PLQY of the composite materials of Examples 1 to 20 and Comparative Examples 1 to 4 was tested, and the external quantum efficiency EQE and T95@1000 nits of the light-emitting devices were tested. The test results are shown in Table 1.

[0185] Among them, the fluorescence quantum yield PLQY was tested using a steady-state fluorescence spectrometer from Edinburgh Instruments. The model of the instrument is FS5, and the accessory corresponding to the measured fluorescence quantum yield is SC-30.

[0186] Among them, the maximum external quantum efficiency EQE max The test method is as follows: Using a FushiDA FPD optical property measurement device, an efficiency test system built by controlling a QE PRO spectrometer, a Keithley 2400, and a Keithley 6485 through LabView, parameters such as voltage, current, brightness, and emission spectrum were measured, and the maximum external quantum efficiency EQE of the device was obtained through calculation. max The specific calculation formula is as follows:

[0187]

[0188] In the formula, ηe is the light output coupling efficiency, ηr is the ratio of the number of recombined carriers to the number of injected carriers, χ is the ratio of the number of excitons generating photons to the total number of excitons, KR is the radiation process rate, and KNR is the non-radiation process rate.

[0189] The maximum brightness L max And the lifetime T95@1000 nit test method is as follows: In CDA gas, under the drive of a constant current or voltage, the time taken for the brightness of the device to decay to a certain proportion of the maximum brightness is measured. The time when the brightness decays to 95% of the maximum brightness is defined as T95, and this lifetime is the measured lifetime. To shorten the lifetime test cycle, the device lifetime test is usually carried out by accelerating the device aging at high brightness, and the lifetime at low brightness is obtained by fitting through a decay fitting formula. For example, the lifetime at 1000 nits is denoted as T95@1000 nits, and the calculation formula is:

[0190]

[0191] Among them, T95 L Is the lifetime at low brightness, generally taking the lifetime at 1000 nits, T95 H Is the lifetime at high brightness, that is, the measured lifetime, L H Is the maximum brightness to which the device is accelerated, L LGenerally, it is 1000 nits. A is the acceleration factor, taking 1.7. Among them,

[0192] The constant current is 1 mA.

[0193] Table 1

[0194]

[0195]

[0196] It can be seen from Table 1 that:

[0197] Compared with the light-emitting devices of Comparative Examples 1, 3, and 4, the fluorescence quantum yield PLQY of the composite materials of Examples 1 to 21 on the 30th day is higher, and the light-emitting devices have higher maximum external quantum efficiency and longer lifespan. It can be seen that the composite materials of the present application can effectively improve the stability, external quantum efficiency, and lifespan of the devices. The reason may be that the electrostatic interaction, covalent bond, and hydrogen bond between the amino acid-functionalized MXene and the quantum dots enhance the stability of the light-emitting layer material, inhibit the photo-degradation and surface oxidation of the quantum dots, and reduce the interface defects and energy loss of the light-emitting layer.

[0198] Compared with the light-emitting device of Comparative Example 2, the fluorescence quantum yield PLQY of the composite material of Example 1 on the 30th day, the maximum external quantum efficiency, and the lifespan of the light-emitting device are higher. It can be seen that the quantum dots modified with amino acid-functionalized MXene of the present application have better performance than the quantum dots modified with MXene. The reason may be that the amino acid molecules have specific functional groups and molecular structures, which can effectively chemically bond with the quantum dots and MXene, thereby improving the stability of the light-emitting layer material. At the same time, the amino acid molecules can change the surface energy level of MXene, and then change the surface energy level of the quantum dots, reducing the interface defects and energy loss of the light-emitting layer.

[0199] The composite materials, light-emitting devices, their preparation methods, and display devices provided by the embodiments of the present application have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, based on the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A composite material, characterized in that: It includes quantum dots and amino acid-functionalized MXene.

2. The composite material according to claim 1, characterized in that: In the composite material, the surface of the quantum dots is connected to the amino acid-functionalized MXene through at least one of electrostatic attraction, covalent bond, and hydrogen bond; and / or The mass ratio of the quantum dots to the amino acid-functionalized MXene is 1:(1 - 5); and / or The molar ratio of the amino acid to MXene in the amino acid-functionalized MXene is (1 - 5):1; and / or The average particle size of the quantum dots is 5 - 20 nm.

3. The composite material according to claim 1 or 2, characterized in that: The amino acid in the amino acid-functionalized MXene includes hydrophobic amino acids; and / or The chemical formula of MXene in the amino acid-functionalized MXene is M n+1 X n T x , where M is selected from transition metal elements, and the transition metal elements are selected from one or more of Ti, Nb, V, Mo, Zr, Hf, Ta, Cr, Sc; X is selected from one or more of C and N; T x is a surface-active functional group, and the surface-active functional group includes one or more of -OH, -O, -F, -Cl, -Br, where 0 < x ≤ 2; n is any integer among 1, 2, and 3; and / or The material of the quantum dots is selected from one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials; the materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are respectively selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds; the shell layer of the core-shell structure quantum dots is one or more layers; the II-VI group compounds are selected from one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds are selected from one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V group compounds are selected from one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the I-III-VI group compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2;The quantum dots of the core-shell structure are selected from one or more of CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS and InP / ZnSe / ZnS; the perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs + ion, M is a divalent metal cation selected from 2+ Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ Ge 2+ Yb 2+ Eu - one or more of Cl - Br - I n-2 one or more of; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation selected from CH3(CH2) 3+ NH n or [NH3(CH2) 2+ NH3] 2+ where n≥2, M is a divalent metal cation selected from 2+ Pb 2 + Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ Ge 2+ Yb - Eu - I - one or more of Cl - Br - I - one or more of.

4. The composite material according to claim 3, characterized in that: The hydrophobic amino acids include one or more of tryptophan, phenylalanine, valine, leucine, isoleucine, proline, alanine, and methionine; and / or The Mxene includes Ti3C2T x , Ti2CT x , TiNbCT x , Ti3CNT x , Ta4C3T x , Nb2CT x , Nb4C3T x , V2CT x , Mo2CT x , Ti4N3T x and Cr2CT x or more than one of them, where 0 < x ≤ 2.

5. A method for preparing a composite material, characterized in that, It includes the following steps: Provide a first mixed material including amino acid-functionalized MXene, quantum dots, and a first solvent, and obtain a composite material after reaction.

6. The preparation method according to claim 5, characterized in that, The mass ratio of the quantum dots to the amino acid-functionalized MXene is 1:(1 - 5); and / or The molar ratio of the amino acid to MXene in the amino acid-functionalized MXene is (1 - 5):1; and / or The average particle size of the quantum dots is 5 - 20 nm; and / or The first solvent includes one or more of n-octane, dimethylformamide, ethanol, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol; and / or The mass concentration of the first mixed material is 20 - 40 mg / ml.

7. The preparation method according to claim 5, characterized in that, The reaction temperature of the first mixed material is 180 - 200 °C, and the reaction time of the first mixed material is 0.5 - 1 h; and / or The reaction process of the first mixed material is carried out under an inert protective atmosphere.

8. The preparation method according to claim 5, characterized in that, The preparation method of the amino acid-functionalized MXene includes: Provide a second mixed material including MXene, amino acid, and a polar solvent, and obtain amino acid-functionalized MXene after reaction.

9. The preparation method according to claim 8, characterized in that, The reaction of the second mixed material includes heating, and the heating temperature is 40 - 60 °C, and the time is 48 - 60 h; and / or After the reaction of the second mixed material and before obtaining the amino acid-functionalized MXene, it further includes separation and drying; the drying temperature is 60 - 100 °C, and the drying time is 12 - 24 h; and / or The polar solvent includes one or more of ethanol, isopropanol, and methanol; and / or The mass concentration of the second mixed material is 0.3 - 0.8 mg / ml.

10. A light-emitting device, characterized in that: It includes a first electrode, a light-emitting layer, and a second electrode arranged in a stacked manner. The material of the light-emitting layer includes the composite material according to any one of claims 1 - 4, or the composite material prepared by the preparation method according to any one of claims 5 - 9.

11. The light-emitting device according to claim 10, characterized in that: The light-emitting device further includes a first charge function layer and / or a second charge function layer. The first charge function layer is disposed between the first electrode and the light-emitting layer, and the second charge function layer is disposed between the light-emitting layer and the second electrode.

12. The light-emitting device according to claim 11, characterized in that: The materials of the first electrode and the second electrode independently include one or more of metals, carbon materials, and metal oxides; the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include a metal oxide electrode or a composite electrode with a metal sandwiched between doped or undoped transparent metal oxides. The materials of the metal oxide electrode include one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, and the composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or The first carrier functional layer includes a hole functional layer, and the material of the hole functional layer includes one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent material, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-phenylene vinylene), poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro-NPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinodimethane, doped graphene, undoped graphene, transition metal oxide, transition metal sulfide, transition metal stannide, doped or undoped zinc oxide, barium oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc selenide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, quinoxaline compound, imidazole compound, triazine compound, fluorene-containing compound, hydroxyquinoline compound; and / or The second carrier functional layer includes an electron functional layer. The material of the electron functional layer includes one or more of inorganic electron functional materials and organic electron functional materials. The inorganic electron functional materials include one or more of metal oxides, doped metal oxides, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The metal oxides include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5. The metal oxides in the doped metal oxides include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, Al2O3. The dopants in the doped metal oxides include one or several of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga, Sn. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, CdS. The IIIA-VA group semiconductor materials include one or more of InP, GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS, CuGaS. The organic electron functional materials include one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds.

13. A method for preparing a light-emitting device, characterized in that, It includes the following steps: Providing a light-emitting device preform, the light-emitting device preform including a first electrode; Providing a third hybrid material including a second solvent and a composite material, the composite material including quantum dots and amino-functionalized MXene; Disposing the third hybrid material on the light-emitting device preform to form a light-emitting layer; Forming a second electrode on the light-emitting layer to obtain a light-emitting device.

14. The preparation method according to claim 13, characterized in that, The light-emitting device preform includes a stacked first electrode and a first carrier functional layer. The disposing the third hybrid material on the light-emitting device preform includes: disposing the third hybrid material on the first carrier functional layer; and / or The forming the second electrode on the light-emitting layer includes: forming a second carrier functional layer and a second electrode on the light-emitting layer; and / or The mass ratio of the quantum dots to the amino-functionalized MXene is 1:(1-5); and / or The molar ratio of the amino acid to the MXene in the amino-functionalized MXene is (1-5):1; and / or The average particle size of the quantum dots is 5-20 nm; and / or The mass concentration of the third hybrid material is 20-40 mg / ml; and / or The second solvent includes one or several of n-octane, dimethylformamide, ethanol, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, cresol.

15. A display device, characterized in that: The display device includes a light-emitting device as described in any one of claims 10 to 12, or a light-emitting device manufactured by the manufacturing method as described in any one of claims 13 to 14.

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