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

Abstract

The invention discloses a composite material and a preparation method thereof, a light-emitting device and a display device, and relates to the technical field of display. A composite material includes inorganic nanoparticles and a cobalt complex. According to the composite material provided by the invention, erosion of water and oxygen can be prevented, the defects of the inorganic nanoparticles can be passivated, and the performance of the inorganic nanoparticles can be improved; when the composite material is applied to a functional layer of a luminescent device, the luminous efficiency of the luminescent device can be improved.

Description

TECHNICAL FIELD

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

[0002] In the prior art, inorganic nanoparticles are often used as the material of the functional layer of the light-emitting device, such as quantum dots used as the material of the light-emitting layer, zinc oxide used as the material of the electron functional layer, and nickel oxide used as the material of the hole functional layer.

[0003] However, the inorganic nanoparticles have defects and are highly sensitive to water vapor, which can affect the carrier transport performance of the inorganic nanoparticles and result in low light-emitting efficiency of the light-emitting device. SUMMARY

[0004] Therefore, the present application provides a composite material and a preparation method thereof, a light-emitting device and a display device.

[0005] The present application provides a composite material, which comprises inorganic nanoparticles and a cobalt complex.

[0006] Correspondingly, the present application also provides a preparation method of the composite material, which comprises the following steps.

[0007] The cobalt complex and the inorganic nanoparticles are provided.

[0008] The cobalt complex and the inorganic nanoparticles are mixed to obtain the composite material.

[0009] Correspondingly, the present application also provides a light-emitting device, which comprises an anode, a functional layer and a cathode which are sequentially stacked; wherein the material of the functional layer comprises the above-mentioned composite material or the composite material prepared by the above-mentioned preparation method.

[0010] Correspondingly, the present application also provides a display device, which comprises the above-mentioned light-emitting device.

[0011] The composite material provided by the present application can prevent the inorganic nanoparticles from being eroded by water and oxygen and improve the performance of the inorganic nanoparticles; the composite material applied to the functional layer of the light-emitting device can improve the light-emitting efficiency of the light-emitting device. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0013] Figure 1 is a flow chart of a preparation method of a composite material provided by an embodiment of the present application.

[0014] Figure 2 is a structural schematic diagram of a light emitting device provided by an embodiment of the present application.

[0015] Reference signs:

[0016] Anode 10; hole functional layer 20; light emitting layer 30; electron functional layer 40; cathode 50. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope 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.

[0018] In the present application, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the direction of the drawing surface in the drawings, and "inner" and "outer" refer to the outline of the device. In addition, in the description of the present application, the term "comprising" means "including but not limited to". The words first, second, third, etc. are only used as labels and do not impose numerical requirements or establish an order.

[0019] In the present application, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following cases: A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural.

[0020] In the present application, "at least one" means one or more, and "multiple" means two or more. "One or more", "at least one of the following", or similar expressions, means any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can 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.

[0021] Various embodiments of the present application can exist in a range of forms; it should be understood that the description in a range form is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the range description has disclosed all possible sub-ranges and single values in the range. For example, it should be considered that the range description from 1 to 6 has 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 values in the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in the present text, it refers to any cited number (fraction or integer) in the indicated range.

[0022] The technical solutions of the present application are as follows:

[0023] In a first aspect, the embodiments of the present application provide a composite material, comprising inorganic nanoparticles and a cobalt complex.

[0024] The composite material provided by the present application comprises inorganic nanoparticles and a cobalt complex. The cobalt complex has strong water absorption and can adsorb water vapor to prevent water and oxygen from eroding the inorganic nanoparticles. The cobalt complex can also passivate defects of the inorganic nanoparticles to improve the performance of the inorganic nanoparticles. After the cobalt complex adsorbs water vapor, the number of free electrons in the cobalt complex increases, and electron movement occurs inside the cobalt complex, which can further improve the conductivity of the composite material. When the composite material is applied to a film layer of a light-emitting device, the light-emitting efficiency of the light-emitting device can be improved, and the service life of the light-emitting device can be prolonged.

[0025] In some embodiments, the inorganic nanoparticles have vacancy defects, and the cobalt complex can fill the vacancy defects.

[0026] In some embodiments, in the composite material, the mass ratio of the inorganic nanoparticles to the cobalt complex is 100:(5-8), for example, it can be 100:5.2, 100:5.5, 100:5.8, 100:6, 100:6.2, 100:6.5, 100:6.8, 100:7, 100:7.2, 100:7.5, 100:7.8, etc. Within the range of the mass ratio, the cobalt complex can adsorb water vapor, and the defects of the inorganic nanoparticles can be effectively passivated.

[0027] In some embodiments, the composite material consists of the inorganic nanoparticles and the cobalt complex.

[0028] In some embodiments, the cobalt complex is a porous cobalt complex. Further, the average pore size of the porous cobalt complex is 30-60 nm, for example, 32 nm, 35 nm, 38 nm, 40 nm, 42 nm, 45 nm, 48 nm, 50 nm, 52 nm, 55 nm, 58 nm, etc. Within the range of the average pore size, the cobalt complex has a large water absorption amount and a fast water absorption rate.

[0029] In some embodiments, the cobalt complex comprises an alcohol amine-cobalt complex.

[0030] In some embodiments, the alcohol amine-cobalt complex contains oxygen atoms, the vacancy defects include oxygen vacancy defects, and the oxygen atoms fill the oxygen vacancy defects. In this way, the connection between the cobalt complex and the inorganic nanoparticles is achieved. It can be understood that the oxygen atoms can come from the alcohol amine compound in the alcohol amine-cobalt complex.

[0031] In some embodiments, the alcohol amine-cobalt complex is obtained by complexing an alcohol amine compound and a cobalt salt.

[0032] Further, the alcohol amine compound comprises one or more of ethanol amine, diethanol amine, and triethanol amine. The alcohol amine compound can effectively passivate the defects of the inorganic nanoparticles.

[0033] The cobalt salt comprises one or more of cobalt chloride, cobalt bromide, cobalt iodide, and cobalt nitrate. The cobalt ions in the cobalt salt are prone to complexing with the alcohol amine compound to form a stable cobalt complex.

[0034] In some embodiments, the cobalt complex comprises Co-SHM, i.e., a complex of cobalt chloride and ethanol amine. Co-SHM has a dense hygroscopic pore size, a super-high water absorption rate, and a fast water absorption rate, and can effectively adsorb water vapor.

[0035] In some embodiments, the average particle size of the inorganic nanoparticles is 5-8 nm, for example, 5.2 nm, 5.5 nm, 5.8 nm, 6 nm, 6.2 nm, 6.5 nm, 6.8 nm, 7 nm, 7.2 nm, 7.5 nm, 7.8 nm, etc. Within the range of the average particle size, the inorganic nanoparticles have a suitable size, good dispersibility, are not prone to agglomeration, and are easy to contact with the cobalt complex to passivate the defects of the inorganic nanoparticles by the alcohol amine compound in the cobalt complex.

[0036] In some embodiments, the inorganic nanoparticles include one of N-type inorganic nanoparticles, P-type inorganic nanoparticles, and quantum dot particles. It can be appreciated that when the inorganic nanoparticles are N-type inorganic nanoparticles or P-type inorganic nanoparticles, the cobalt complex can improve the carrier migration efficiency of the composite material; and when the inorganic nanoparticles are quantum dot particles, the cobalt complex can improve the light emitting performance, such as photoluminescence quantum yield, of the composite material.

[0037] It should be noted that the N-type inorganic nanoparticles refer to materials known in the art for use in an electron functional layer, the P-type inorganic nanoparticles refer to materials known in the art for use in a hole functional layer, and the quantum dots refer to materials known in the art for use in a light emitting layer.

[0038] In some embodiments, the N-type inorganic nanoparticles include one or more of first doped metal oxide particles, first non-doped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials, the first non-doped metal oxide particles include one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5, the metal oxide in the first doped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3, the doping element in the first doped metal oxide particles includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga, 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, and the IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS.

[0039] In some embodiments, the P-type inorganic nanoparticles include one or more of second doped metal oxide particles, second non-doped metal oxide particles, metal sulfides, metal selenides, and metal nitrides, the metal oxide in the second doped metal oxide particles and the metal oxide in the second non-doped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5, the doping element in the second doped metal oxide particles includes one or more of Mo, W, Ni, Cr, Cu, and V, the metal sulfides include one or more of CuS, MoS3, and WS3, the metal selenides include one or more of MoSe3 and WSe3, and the metal nitrides include P-type gallium nitride.

[0040] In some embodiments, the quantum dots can be selected from, but not limited to, one or more of single-structure quantum dots, core-shell quantum dots, and perovskite quantum dots.

[0041] The materials of the single-structure quantum dots, the core materials of the core-shell quantum dots, and the shell materials of the core-shell quantum dots can be selected from, but not limited to, one or more of II-VI compounds, IV-VI compounds, III-V compounds, and I-III-VI compounds, respectively. The shell of the core-shell quantum dots is one or more layers. The II-VI compounds can be selected from, but not limited to, 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 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, SnPbSTe. The III-V 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 compounds can be selected from, but not limited to, one or more of CuInS2, CuInSe2, and AgInS2.

[0042] As an example, the core-shell structure quantum dot can be selected from, but not limited to, 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 " / " in the above expressions such as "CdSe / ZnS" means that the substance after " / " (as a shell layer) coats the substance before " / " (as a core layer).

[0043] The perovskite quantum dot can be selected from, but not limited to, a doped or non-doped inorganic perovskite quantum dot, or an organic-inorganic hybrid perovskite quantum dot. The inorganic perovskite quantum dot has a general structure of AMX3, wherein A is a Cs + ion, M is a divalent metal cation selected from one or more of 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 X is a halide anion selected from one or more of Cl - , Br - , I - . The organic-inorganic hybrid perovskite quantum dot has a general structure of BMX3, wherein B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ wherein n≥2, M is a divalent metal cation selected from one or more of 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 X is a halide anion selected from Cl - , Br - , I- one or more of the following:

[0044] In a second aspect, referring to Figure 1 The embodiments of the present application also provide a preparation method of the composite material, comprising:

[0045] S11, providing a cobalt complex and inorganic nanoparticles;

[0046] S12, mixing the cobalt complex and the inorganic nanoparticles to obtain a composite material.

[0047] In the S11,

[0048] In some embodiments, the preparation method of the cobalt complex comprises:

[0049] S111, providing a cobalt salt solution and an alcohol amine solution, the cobalt salt solution containing a cobalt salt, and the alcohol amine solution containing an alcohol amine compound;

[0050] S112, mixing the cobalt salt solution and the alcohol amine solution to obtain a cobalt complex.

[0051] In some embodiments, the cobalt salt comprises one or more of cobalt chloride, cobalt bromide, cobalt iodide, and cobalt nitrate.

[0052] In some embodiments, the molar concentration of the cobalt salt in the cobalt salt solution is 0.5 mmol / mL to 1.2 mmol / mL, for example, it can be 0.6 mmol / mL, 0.7 mmol / mL, 0.8 mmol / mL, 0.9 mmol / mL, 1 mmol / mL, 1.1 mmol / mL, etc. Within the range of the molar concentration, the uniform dispersion of the cobalt salt can be promoted.

[0053] In some embodiments, the cobalt salt solution further comprises a first solvent.

[0054] In some embodiments, the alcohol amine compound comprises one or more of ethanol amine, diethanol amine, and triethanol amine.

[0055] In some embodiments, the molar concentration of the alcohol amine compound in the alcohol amine solution is 10 mmol / mL to 20 mmol / mL, for example, it can be 11 mmol / mL, 13 mmol / mL, 15 mmol / mL, 17 mmol / mL, 19 mmol / mL, etc. Within the range of the molar concentration, the uniform dispersion of the alcohol amine compound can be promoted.

[0056] In some embodiments, the alcohol amine solution further comprises a second solvent.

[0057] In some embodiments, the molar ratio of the cobalt salt and the alcohol amine compound is 6:(2-3), such as 6:2.1, 6:2.3, 6:2.5, 6:2.7, 6:2.9, etc. Within the range of the molar ratio, the yield of the cobalt complex is improved.

[0058] It is noted that when the cobalt salt is cobalt chloride and the alcohol amine compound is ethanol amine, the mixture of the cobalt salt solution and the alcohol amine solution is blue, and the mixture can be changed to pink by continuous stirring.

[0059] In some embodiments, after the mixture of the cobalt salt solution and the alcohol amine solution, drying is further included. For example, the mixture can be evenly spread on a petri dish, and then dried.

[0060] Further, the temperature for drying is 50-80°C, such as 55°C, 60°C, 65°C, 71°C, 75°C, etc., and the time is 10-20 minutes, such as 11 minutes, 13 minutes, 15 minutes, 17 minutes, 19 minutes, etc. In this way, under the conditions of drying, the first solvent and the second solvent are removed.

[0061] In some embodiments, when the inorganic nanoparticles are P-type or N-type inorganic nanoparticles, the preparation method of the inorganic nanoparticles includes: providing a metal salt and a base, mixing to obtain inorganic nanoparticles.

[0062] In some embodiments, the metal salt includes one or more of zinc salt, titanium salt, tin salt, tantalum salt, zirconium salt, cadmium salt, copper salt, indium salt, gallium salt, aluminum salt, magnesium salt, lithium salt, yttrium salt, lanthanum salt, cerium salt, nickel salt, molybdenum salt, tungsten salt, chromium salt, vanadium salt, cuprous salt.

[0063] In some embodiments, the metal salt includes one or more of acetate, sulfate, halide, nitrate, sulfamate, cuprous hydroxide, carbonyl salt, and tetraacetate. For example, the zinc salt includes one or more of zinc acetate, zinc sulfate, zinc chloride, zinc nitrate. The nickel salt includes one or more of nickel sulfate, nickel chloride, nickel sulfamate, nickel bromide, cuprous nickel hydroxide, carbonyl nickel, nickel nitrate, nickel acetate, and tetraacetate nickel.

[0064] In some embodiments, the base includes one or more of potassium hydroxide, lithium hydroxide, sodium hydroxide, ammonium hydroxide, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0065] In some embodiments, the molar ratio of the salt ion in the metal salt to the hydroxyl ion in the base is 1:(1-1.5), for example, it can be 1:1.1, 1:1.2, 1:1.3, 1:1.4, etc.

[0066] In some embodiments, the method of mixing the metal salt and the base comprises:

[0067] S113, providing a metal salt solution and a base solution, the metal salt solution comprising a metal salt and a third solvent, the base solution comprising a base and a fourth solvent;

[0068] S114, mixing the metal salt solution and the base solution.

[0069] In the S113,

[0070] In some embodiments, in the metal salt solution, the molar concentration of the metal salt solution is 0.1 mol / L-1 mol / L, for example, it can be 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, etc. Within the range of the molar concentration, it is beneficial for the metal salt to be fully dissolved.

[0071] In some embodiments, in the base solution, the molar concentration of the base is 0.1 mol / L-1 mol / L, for example, it can be 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, etc. Within the range of the molar concentration, it is beneficial for the base to be fully dissolved.

[0072] In the S114,

[0073] In some embodiments, the temperature for mixing the metal salt solution and the base solution is 50°C-70°C, for example, it can be 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, etc.; the time is 2h-3h, for example, it can be 2.1h, 2.3h, 2.5h, 2.7h, 2.9h, etc. In this way, under the conditions of the mixing, it is beneficial for the formation of the inorganic nanoparticles.

[0074] It can be understood that in other embodiments, when the inorganic nanoparticles are quantum dots, the quantum dots can be prepared by conventional methods in the art, such as mechanical ball milling, physical crushing, vacuum condensation, chemical reduction, photochemical method, sol-gel method, radiation reduction method, coprecipitation method, combustion synthesis method, condensation method, blasting method, high-energy processing method, hydrothermal synthesis method, radiation synthesis method, ionization evaporation precipitation method, etc.

[0075] In the S12, the cobalt complex and the inorganic nanoparticles are mixed.

[0076] In some embodiments, the mixing of the cobalt complex and the inorganic nanoparticles comprises:

[0077] S121, providing a cobalt complex dispersion liquid containing a cobalt complex and a fifth solvent, and an inorganic nanoparticle dispersion liquid containing an inorganic nanoparticle and a sixth solvent;

[0078] S122, mixing the cobalt complex dispersion liquid and the inorganic nanoparticle dispersion liquid.

[0079] In some embodiments, the mass concentration of the cobalt complex in the cobalt complex dispersion liquid is 2 mg / mL to 5 mg / mL, for example, it can be 2.2 mg / mL, 2.5 mg / mL, 2.8 mg / mL, 3 mg / mL, 3.2 mg / mL, 3.5 mg / mL, 3.8 mg / mL, 4 mg / mL, 4.2 mg / mL, 4.5 mg / mL, 4.8 mg / mL, etc. Within the range of the mass concentration, it is beneficial for the uniform dispersion of the cobalt complex.

[0080] In some embodiments, the mass concentration of the inorganic nanoparticles in the inorganic nanoparticle dispersion liquid is 20 mg / mL to 30 mg / mL, for example, it can be 21 mg / mL, 23 mg / mL, 25 mg / mL, 27 mg / mL, 29 mg / mL, etc. Within the range of the mass concentration, it is beneficial for the uniform dispersion of the inorganic nanoparticles.

[0081] In some embodiments, the first solvent, the second solvent, the third solvent, the fourth solvent, the fifth solvent, and the sixth solvent are independently selected from one or more of chlorobenzene, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, ethanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, phenylacetone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

[0082] In some embodiments, the mass ratio of the inorganic nanoparticles to the cobalt complex is 100:(5-10), for example, it can be 100:5.5, 100:6, 100:6.5, 100:7, 100:7.5, 100:8, 100:8.5, 100:9, 100:9.5, etc.

[0083] In some embodiments, the temperature for mixing the cobalt complex and the inorganic nanoparticles is 3-10°C, for example, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, etc.; the time is 5-10h, for example, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, etc. Thus, under the mixing conditions, the cobalt complex and the inorganic nanoparticles are mixed well.

[0084] In some embodiments, after mixing the cobalt complex and the inorganic nanoparticles, the method further comprises washing.

[0085] Further, the washing agent for washing can be deionized water, methanol, etc.; the number of times of washing can be 3, 5, 8, etc.

[0086] The method for preparing the composite material provided in the application is simple in operation, low in cost, and can effectively prepare the composite material.

[0087] In a third aspect, referring to Figure 2 The application also provides a light-emitting device, which comprises an anode 10, a functional layer, and a cathode 50 arranged in sequence; wherein the material of the functional layer comprises the composite material or the composite material prepared by the method.

[0088] It should be noted that, in the process of preparing the light-emitting device, after the functional layer is prepared by using the composite material, water vapor exists in the atmosphere in the process after the preparation of the functional layer, such as evaporation and packaging. In the presence of the cobalt complex, the water vapor can be prevented from entering the functional layer to affect the performance of the functional layer.

[0089] In the light-emitting device provided in the application, the material of the functional layer comprises inorganic nanoparticles and a cobalt complex. The cobalt complex has high water absorption rate and fast water absorption efficiency, can effectively absorb the water vapor in the functional layer, avoids the influence of the water vapor on the light-emitting device, thereby improving the photoelectric efficiency of the light-emitting device and prolonging the service life of the light-emitting device.

[0090] In some embodiments, the light-emitting device comprises a light-emitting diode.

[0091] In some embodiments, the functional layer comprises one or more of a hole functional layer 20, a light-emitting layer 30, and an electron functional layer 40. The hole functional layer 20 is arranged between the anode 10 and the light-emitting layer 30, and the electron functional layer 40 is arranged between the light-emitting layer 30 and the cathode 50.

[0092] In some embodiments, the thickness of the light-emitting layer 30 is 20-60 nm, for example, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, etc. In the thickness range, the light-emitting layer 30 has good light-emitting performance.

[0093] In some embodiments, the thickness of the hole functional layer 20 and the electron functional layer 40 is 30-120 nm, for example, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, etc. In the thickness range, the hole functional layer 20 has good hole migration performance, and the electron functional layer 40 has good electron migration performance.

[0094] Further, the hole functional layer 20 includes one or more of a hole injection layer and a hole transport layer.

[0095] The electron functional layer 40 includes one or more of an electron injection layer and an electron transport layer.

[0096] In some embodiments, the anode 10 and the cathode 50 each independently include one or more of a metal, a carbon material, and a metal oxide; the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes one or more of graphite, carbon nanotube, graphene, and carbon fiber; and the metal oxide includes a metal oxide electrode or a composite electrode with a metal sandwiched between doped or undoped transparent metal oxides, the material of the metal oxide electrode includes one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, and the composite electrode includes 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. In the above, “ / ” represents a stacked structure, for example, AZO / Ag / AZO represents a composite electrode including an AZO layer, an Ag layer, and an AZO layer stacked in sequence.

[0097] In some embodiments, the material of the light-emitting layer 30 includes the above-mentioned composite material, organic light-emitting material, or quantum dot.

[0098] The inorganic nanoparticles in the composite material are quantum dots.

[0099] The organic light emitting material can be selected from, but not limited to, one or several of CBP:Ir(mppy)3 (4,4'-bis(N-carbazole)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine iridium(III)]), TCTX:Ir(mmpy) (4,4',4"-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridine iridium]), diaryl anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescent materials, TTA materials, TADF (thermally activated delayed) materials, polymers containing B-N covalent bonding, HLCT (hybrid localized charge transfer excited state) materials, Exciplex (excited complex) light emitting materials.

[0100] The quantum dots can be selected from, but not limited to, one or several of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dot materials.

[0101] The material of the single-structure quantum dot, the core material of the core-shell structure quantum dot and the shell material of the core-shell structure quantum dot can be selected from, but not limited to, one or more of II-VI compounds, IV-VI compounds, III-V compounds and I-III-VI compounds. The shell of the core-shell structure quantum dot is one or more layers. The II-VI compounds can be selected from, but not limited to, 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 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, SnPbSTe. The III-V 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 compounds can be selected from, but not limited to, one or more of CuInS2, CuInSe2 and AgInS2.

[0102] As an example, the core-shell structure quantum dot can be selected from, but not limited to, 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 " / " in the above expressions such as "CdSe / ZnS" means that the substance after " / " (as a shell layer) coats the substance before " / " (as a core layer).

[0103] The perovskite quantum dot material can be selected from, but not limited to, doped or non-doped inorganic perovskite quantum dots, or organic-inorganic hybrid perovskite quantum dots. The structure general formula of the inorganic perovskite quantum dot is AMX3, wherein A is Cs + ion, M is a divalent metal cation selected from one or more of 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 X is a halide anion selected from one or more of Cl - , Br - , I - . The structure general formula of the organic-inorganic hybrid perovskite quantum dot is BMX3, wherein B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , wherein n≥2, M is a divalent metal cation selected from one or more of 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 X is a halide anion selected from one or more of Cl - , Br - , I.

[0104] In some embodiments, the material of the hole function layer 20 includes one or more of the following: the above-mentioned composite material, 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'-di(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[bi(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], 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 derivatives thereof, derivative of PEDOT:PSS doped with s-MoO3, poly(N-vinylcarbazole) and derivatives thereof, polymethacrylate and derivatives thereof, poly(9,9-octylfluorene) and derivatives thereof, poly(spirofluorene) and derivatives thereof, N,N'-di(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro NPB, nanopolycrystalline diamond, microcrystalline cellulose, and tetracyanoquinodimethane, doped graphene, undoped graphene, second doped metal oxide particles, second undoped metal oxide particles, metal sulfide, metal selenide, and metal nitride, the metal oxide in the second doped metal oxide particles and the metal oxide in the second undoped metal oxide particles each independently including one or more of MoO3, WO3, NiO, CrO3, CuO, V2O5, the doping element in the second doped metal oxide particles including one or more of Mo, W, Ni, Cr, Cu, V, the metal sulfide including one or more of CuS, MoS3, WS3, the metal selenide including one or more of MoSe3, WSe3, and the metal nitride including P-type gallium nitride;The inorganic nanoparticles in the composite material are P-type inorganic nanoparticles.

[0105] In some embodiments, the material of the electronic functional layer 40 comprises one or more of the above-mentioned composite material, 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2,2'-(1,3-phenyl)di[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetrakis[(m-pyridyl)-phen-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine, 1,3-bis(3,5-dipyridin-3-ylphenyl)benzene, n,n'-bis(naphthalen-1-yl)-n,n'-bis(phenyl)benzidine, first doped metal oxide particles, first undoped metal oxide particles, Group IIB-VIA semiconductor material, Group IIIA-VA semiconductor material, and Group IB-IIIA-VIA semiconductor material, the material of the first undoped metal oxide particles comprising one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, the metal oxide in the first doped metal oxide particles comprising one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, Al2O3, the doping element in the first doped metal oxide particles comprising one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga, the Group IIB-VIA semiconductor material comprising one or more of ZnS, ZnSe, CdS, the Group IIIA-VA semiconductor material comprising one or more of InP, GaP, and the Group IB-IIIA-VIA semiconductor material comprising one or more of CuInS, CuGaS; the inorganic nanoparticles in the composite material are N-type inorganic nanoparticles.

[0106] In a fourth aspect, the embodiments of the present application further provide a display device, which comprises the light-emitting device.

[0107] The display device can be any electronic product with display function, including but not limited to smart phones, tablet computers, notebook computers, digital cameras, digital camcorders, smart wearable devices, smart weighing electronic scales, vehicle-mounted displays, televisions or e-book readers, wherein the smart wearable device can be a smart bracelet, a smart watch, a virtual reality (VR) helmet, etc.

[0108] The application will be specifically described below through specific examples, and the following examples are only part of the application and are not a limitation of the application.

[0109] Example 1

[0110] This embodiment provides a composite material comprising N-type inorganic nanoparticle zinc oxide and ethanolamine-cobalt chloride complex, and the preparation method is as follows:

[0111] Dissolve 8 mmol of CoCl2 in an ethanol solvent to form a cobalt salt solution of 0.8 mmol / mL, dissolve 3.3 mmol of ethanolamine in an ethanol solvent to form an ethanolamine solution of 16 mmol / mL, mix the cobalt salt solution and the ethanolamine solution, and stir to form a blue complex; then add 3 mL of deionized water, and continuously stir to change the color to pink; uniformly spread on a glass plate, and then dry at 70℃ for 15 min to obtain an ethanolamine-cobalt chloride complex, which is dissolved in ethanol to obtain an ethanolamine-cobalt chloride complex dispersion;

[0112] Dissolve zinc acetate in an ethanol solution to obtain a metal salt solution of 0.5 mol / mL, dissolve lithium hydroxide in a DMSO solution to obtain an alkali solution of 0.5 mol / mL, mix the metal salt solution and the alkali solution, and stir for 5 min, then transfer to a flask, keep the hydrothermal reaction temperature at 60℃, and naturally cool after reaction for 2 h, then take out and suction filter, wash with ethanol and n-octane three times, and then dry to obtain inorganic zinc oxide nanoparticles, which are dissolved in ethanol to obtain a zinc oxide dispersion;

[0113] Mix the ethanolamine-cobalt chloride complex dispersion and the zinc oxide dispersion, wherein the mass ratio of the ethanolamine-cobalt chloride complex to the zinc oxide is 8:100, stir for 30 min to fully dissolve, continue to stir in a low-temperature environment of 5℃ for 8 h after the addition is completed, and then repeatedly suction filter and wash with deionized water and methanol to obtain a composite material.

[0114] Example 2

[0115] This embodiment is basically the same as Example 1, and the only difference is that the mass ratio of the ethanolamine-cobalt chloride complex to the zinc oxide in this embodiment is 10:100.

[0116] Example 3

[0117] This example is substantially identical to Example 1, except that in this example the mass ratio of the ethanolamine-cobalt chloride complex to zinc oxide is 5:100.

[0118] Example 4

[0119] This example is substantially identical to Example 1, except that in this example the reaction time of the ethanolamine-cobalt chloride complex and zinc oxide is 10 h.

[0120] Example 5

[0121] This example is substantially identical to Example 1, except that in this example the reaction time of the ethanolamine-cobalt chloride complex and zinc oxide is 5 h.

[0122] Example 6

[0123] This example is substantially identical to Example 1, except that in this example the reaction temperature of the ethanolamine-cobalt chloride complex and zinc oxide is 10 °C.

[0124] Example 7

[0125] This example is substantially identical to Example 1, except that in this example the reaction temperature of the ethanolamine-cobalt chloride complex and zinc oxide is 3 °C.

[0126] Example 8

[0127] This example is substantially identical to Example 1, except that in this example the ethanolamine in the ethanolamine solution is 4 mmol.

[0128] Example 9

[0129] This example is substantially identical to Example 1, except that in this example the ethanolamine in the ethanolamine solution is 2.67 mmol.

[0130] Example 10

[0131] This example is substantially identical to Example 1, except that in this example CoCl2 is replaced by CoBr2.

[0132] Example 11

[0133] This example is substantially identical to Example 1, except that in this example ethanolamine is replaced by diethanolamine.

[0134] Example 12

[0135] This example is substantially identical to Example 1, except that in this example N-type inorganic nanoparticle zinc oxide is replaced by N-type inorganic nanoparticle titanium dioxide.

[0136] Example 13

[0137] This example is basically the same as Example 1, except that in this example, the N-type inorganic nanoparticle zinc oxide is replaced by P-type inorganic nanoparticle nickel oxide.

[0138] Example 14

[0139] This example is basically the same as Example 1, except that in this example, the N-type inorganic nanoparticle zinc oxide is replaced by CdZnS quantum dots.

[0140] Comparative Example 1

[0141] This comparative example provides a material comprising N-type inorganic nanoparticle zinc oxide.

[0142] Comparative Example 2

[0143] This comparative example provides a material comprising N-type inorganic nanoparticle titanium dioxide.

[0144] Comparative Example 3

[0145] This comparative example provides a material comprising P-type inorganic nanoparticle nickel oxide.

[0146] Comparative Example 4

[0147] This comparative example provides a material comprising CdZnS quantum dots.

[0148] The carrier mobility (electron mobility for Examples 1-12 and Comparative Examples 1-2, and hole mobility for Example 13 and Comparative Example 3) of the composite materials of Examples 1-13 and Comparative Examples 1-3 was tested, and the photoluminescence quantum yield (PLQY) of the composite materials of Example 14 and Comparative Example 4 was tested, and the results are shown in Table 1.

[0149] The testing method for carrier mobility is as follows: the current density-voltage curve of the half device (single-carrier transport thin film device HOD / EOD) of the light-emitting device was tested, wherein the structure of the EOD is anode / quantum dot light-emitting layer / electron transport layer / cathode, and the material of the electron transport layer is the composite material of Examples 1-12 and Comparative Examples 1-2; the structure of the HOD is anode / hole transport layer / quantum dot light-emitting layer / cathode, and the material of the hole transport layer is the composite material of Example 13 and Comparative Example 3; the space charge limited current (SCLC) region in the current density-voltage curve is obtained, and then the carrier mobility is calculated according to the formula J = (9 / 8)ε r 0μ e V 2 / d 3 , wherein J represents the current density, with the unit of mA cm-2 ; ε r denotes the relative dielectric constant, and ε0denotes the vacuum dielectric constant; μ e denotes the electron mobility, and the unit is cm 2 V -1 s -1 ; V denotes the driving voltage, and the unit is V; d denotes the film thickness, and the unit is m.

[0150] The test method of photoluminescence quantum yield (PLQY) is as follows: an Edinburgh Instruments steady-state fluorescence spectrometer is used for testing, the model of the instrument is FS5, and the accessory corresponding to the measurement of the fluorescence quantum yield is SC-30.

[0151] Table 1

[0152]

[0153]

[0154] It can be known from Table 1 that:

[0155] It can be obtained from Examples 1-3 and Comparative Example 1 that the addition of the cobalt complex to the inorganic nanoparticles to form a composite material can effectively prevent the erosion of the composite material by water and oxygen and promote the exertion of the beneficial properties of the inorganic nanoparticles, such as the electron mobility of the N-type inorganic nanoparticles.

[0156] It can be obtained from Examples 1, 4-7 and Comparative Example 1 that within the temperature and time ranges of the reaction of the cobalt complex provided in the application and the inorganic nanoparticles, the carrier mobility of the composite material prepared is much higher than that of Comparative Example 1, and the performance is obviously improved.

[0157] It can be obtained from Examples 1, 8-11 and Comparative Example 1 that the types and proportions of the cobalt salt and the alcohol amine compound in the cobalt complex provided in the application cause certain differences in the influence of the cobalt complex on the properties of the inorganic nanoparticles, and within the range provided in the application, the carrier mobility effect of the composite material is better when the ratio of the cobalt salt and the alcohol amine compound is relatively high.

[0158] It can be obtained from Examples 1, 12-14 and Comparative Examples 1-4 that no matter whether the inorganic nanoparticles are N-type inorganic nanoparticles, P-type inorganic nanoparticles or quantum dots, the addition of the cobalt complex can effectively improve the performance of the composite material, for the N-type inorganic nanoparticles, the electron mobility of the composite material can be effectively improved, for the P-type inorganic nanoparticles, the hole mobility of the composite material can be effectively improved, and for the quantum dots, the photoluminescence quantum yield of the composite material can be effectively improved.

[0159] Device Example 1

[0160] The present embodiment provides a light-emitting device, and the preparation method is as follows:

[0161] The ITO conductive glass was cleaned with a cleaning agent to preliminarily remove the stains on the surface, and then was sequentially ultrasonically cleaned in deionized water, acetone, anhydrous ethanol, and deionized water for 20 min, respectively, to remove the impurities on the surface, and finally was blown dry with high-purity nitrogen to form an ITO anode;

[0162] An ethanol dispersion of nickel oxide was provided, which was spin-coated on the ITO anode at a speed of 3000 rpm for 30 s, and was heated at 150°C for 30 min to form a 30 nm hole transport layer;

[0163] A quantum dot solution of CdZnS with a mass concentration of 10 mg / mL was prepared, which was spin-coated on the hole transport layer at a speed of 3000 rpm for 30 s, and was heated at 80°C for 10 min to form a 40 nm light-emitting layer;

[0164] The composite material prepared in Example 1 was dissolved in ethanol, which was spin-coated on the light-emitting layer at a speed of 4000 rpm for 30 s, and was then heated at 80°C for 30 min to form an 80 nm electron transport layer;

[0165] Ag was evaporated on the electron transport layer by thermal evaporation, at a vacuum degree of not higher than 3x10 -4 Pa, a speed of 1 angstrom / s, a time of 1000 s, and a thickness of 100 nm to form a cathode;

[0166] Packaging to obtain a light-emitting device.

[0167] Device Examples 2-12

[0168] Device Examples 2-12 are basically the same as Device Example 1, except that the composite material of Example 1 is replaced by the composite material of Examples 2-12 in Device Examples 2-12.

[0169] Device Example 13

[0170] Device Example 13 is basically the same as Device Example 1, except that the material of the electron transport layer in Device Example 13 is zinc oxide without ethanolamine-cobalt chloride complex, and the material of the hole transport layer is the composite material of Example 13.

[0171] Device Example 14

[0172] Device Example 14 is basically the same as Device Example 1, except that the material of the electron transport layer in Device Example 13 is zinc oxide without ethanolamine-cobalt chloride complex, and the material of the light-emitting layer is the composite material of Example 14.

[0173] Device Example 15

[0174] Device Example 15 is substantially the same as Device Example 1, except that the material of the hole transport layer in Device Example 15 is the composite material of Example 13, and the material of the light-emitting layer in Device Example 15 is the composite material of Example 14.

[0175] Device Example 16

[0176] Device Example 16 is substantially the same as Device Example 1, except that the thickness of the electron transport layer in Device Example 16 is 120 nm.

[0177] Device Example 17

[0178] Device Example 17 is substantially the same as Device Example 1, except that the thickness of the electron transport layer in Device Example 17 is 40 nm.

[0179] Device Comparative Examples 1-2

[0180] Device Comparative Examples 1-2 are substantially the same as Device Example 1, except that the composite material of Example 1 is replaced by the material of Comparative Examples 1-2, respectively.

[0181] The external quantum efficiency EQE and the lifetime T95@1000nit of the light-emitting devices of Device Examples 1-17 and Device Comparative Examples 1-2 are tested, respectively, and the results are shown in Table 2.

[0182] The test method of the external quantum efficiency EQE is as follows: the ratio of the number of electron-hole pairs injected into the quantum dots to the number of emitted photons, with a unit of %, which is an important parameter for measuring the advantages and disadvantages of electroluminescent devices, and can be obtained by using an EQE optical testing instrument. The specific calculation formula is as follows:

[0183]

[0184] wherein η e is the light output coupling efficiency, η r is the ratio of the number of recombined carriers to the number of injected carriers, χ is the ratio of the number of excitons to the total number of excitons, K R is the radiative process rate, and K NR is the non-radiative process rate.

[0185] Test conditions: performed at room temperature, with an air humidity of 30-60%.

[0186] The test method of the lifetime T95@1000nit is: the time required for the luminance of the device to reduce to a certain percentage of the highest luminance under the driving of constant current or voltage, the time for the luminance to reduce to 95% of the highest luminance is defined as T95, and the lifetime is the measured lifetime. In order to shorten the test period, the device lifetime test is usually carried out by accelerating the device aging at high luminance, and the lifetime at high luminance is obtained by fitting the high luminance through the extended exponential decay luminance decay fitting formula, such as the lifetime at 1000nit is T95@1000nit. The specific calculation formula is as follows:

[0187]

[0188] Wherein, T95 L is the lifetime at low luminance, T95 H is the measured lifetime at high luminance, L H is the highest luminance of the device, L L is 1000nit, and A is the acceleration factor. In the experiment, the value of A is 1.7 obtained by measuring the lifetime of several groups of QLED devices at the rated luminance.

[0189] Table 2

[0190]

[0191]

[0192] It can be seen from Table 2 that:

[0193] It can be obtained from device examples 1-3 and device comparative example 1 that the composite material is applied to the film layer of the light-emitting device, under the action of the cobalt complex in the composite material adsorbing water vapor, preventing water and oxygen from eroding, and passivating the defects of the inorganic nanoparticles, the external quantum efficiency and the service life of the light-emitting device are effectively improved;

[0194] It can be obtained from device examples 1, 4-7 and device comparative example 1 that within the temperature and time range of the reaction of the cobalt complex and the inorganic nanoparticles provided in the application, the composite material prepared is applied to the light-emitting device, and the external quantum efficiency and the service life are both much higher than those of device comparative example 1, and the performance of the light-emitting device is obviously improved;

[0195] It can be obtained from device examples 1, 8-11 and device comparative example 1 that the types and proportions of the cobalt salt and the alcohol amine compound in the cobalt complex provided in the application have different effects on the performance of the light-emitting device. Within the range provided in the application, when the ratio of the cobalt salt to the alcohol amine compound in device example 8 is relatively high, the external quantum efficiency of the light-emitting device is relatively high, and the service life is also relatively long;

[0196] As can be seen from device examples 1, 12 to 15 and device comparative examples 1 to 2, the cobalt complex and different inorganic nanoparticles can be composited and applied to different film layers of the light-emitting device, such as composited with N-type inorganic nanoparticles for the electronic functional layer, composited with P-type inorganic nanoparticles for the hole functional layer, and composited with quantum dots for the light-emitting layer. All of these can promote the beneficial properties of each film layer, thereby improving the external quantum efficiency of the light-emitting device and extending the service life of the light-emitting device.

[0197] It can be seen from device embodiments 1, 16 to 17 and device comparative example 1 that, within the thickness range of the electronic functional layer provided in this application, the external quantum efficiency and service life of device embodiments 1, 16 to 17 are significantly improved compared with device comparative example 1.

[0198] The above is a detailed introduction to the composite materials and their preparation methods, light-emitting devices, and display devices provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the methods and core ideas of the present application. At the same time, for technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A composite material, characterized by, The inorganic nanoparticles and the cobalt complex are included.

2. The composite material of claim 1, wherein, a mass ratio of the inorganic nanoparticles to the cobalt complex in the composite material is 100:(5-8); and / or the inorganic nanoparticles have vacancy defects, and the cobalt complex fills the vacancy defects; and / or the cobalt complex is a porous cobalt complex; and / or the cobalt complex includes an alcohol amine-cobalt complex; and / or an average particle size of the inorganic nanoparticles is 5-8 nm; and / or the inorganic nanoparticles include one of N-type inorganic nanoparticles, P-type inorganic nanoparticles, and quantum dots.

3. The composite material of claim 2, wherein, an average pore size of the porous cobalt complex is 30-60 nm; and / or the alcohol amine-cobalt complex contains oxygen atoms, the vacancy defects include oxygen vacancy defects, and the oxygen atoms fill the oxygen vacancy defects; and / or alcohol amine compounds in the alcohol amine-cobalt complex include one or more of ethanol amine, diethanol amine, and triethanol amine; and / or cobalt salts in the alcohol amine-cobalt complex include one or more of cobalt chloride, cobalt bromide, cobalt iodide, and cobalt nitrate; and / or the cobalt complex includes Co-SHM.

4. The composite material of claim 2, wherein, the N-type inorganic nanoparticles include one or more of first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials, the first undoped metal oxide particles include one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5, the metal oxide in the first doped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3, the doped element in the first doped metal oxide particles includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga, 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, and the IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS; and / or The P-type inorganic nanoparticles comprise one or more of second doped metal oxide particles, second non-doped metal oxide particles, metal sulfides, metal selenides and metal nitrides, the metal oxide in the second doped metal oxide particles and the metal oxide in the second non-doped metal oxide particles each independently comprise one or more of MoO3, WO3, NiO, CrO3, CuO, V2O5, the doping element in the second doped metal oxide particles comprises one or more of Mo, W, Ni, Cr, Cu, V, the metal sulfides comprise one or more of CuS, MoS3, WS3, the metal selenides comprise one or more of MoSe3, WSe3, and the metal nitrides comprise P-type gallium nitride; and / or The quantum dots are selected from one or more of single-structure quantum dots, core-shell quantum dots, and perovskite quantum dots; the material of the single-structure quantum dots, the core material of the core-shell quantum dots, and the shell material of the core-shell quantum dots are each selected from one or more of II-VI compounds, IV-VI compounds, III-V compounds, and I-III-VI compounds; the shell of the core-shell quantum dots is one or more layers; the II-VI 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 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 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; and the I-III-VI compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2.The core-shell structure quantum dot is 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 quantum dot is selected from doped or non-doped inorganic perovskite quantum dot or organic-inorganic hybrid perovskite quantum dot; the inorganic perovskite quantum dot has a general structure of AMX3, wherein A is Cs; + ion; the organic-inorganic hybrid perovskite quantum dot has a general structure of BMX3, wherein B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , wherein n≥2, M is a divalent metal cation selected from one or more of 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 X is a halide anion selected from one or more of Cl - , Br - , I - .

5. A method of producing a composite material, characterized by, Comprise: providing a cobalt complex and inorganic nanoparticles; mixing the cobalt complex and the inorganic nanoparticles to obtain a composite material.

6. The production method according to claim 5, wherein The preparation method of the cobalt complex comprises: providing a cobalt salt solution containing a cobalt salt and an alcohol amine solution containing an alcohol amine compound; mixing the cobalt salt solution and the alcohol amine solution to obtain a cobalt complex.

7. The production method according to claim 6, wherein Comprise: the cobalt salt comprises one or more of cobalt chloride, cobalt bromide, cobalt iodide, and cobalt nitrate; and / or the alcohol amine compound comprises one or more of ethanol amine, diethanol amine, and triethanol amine; and / or the molar ratio of the cobalt salt to the alcohol amine compound is 6:(2-3); and / or in the cobalt salt solution, the molar concentration of the cobalt salt is 0.5 mmol / mL-1.2 mmol / mL; and / or in the alcohol amine solution, the molar concentration of the alcohol amine compound is 10 mmol / mL-20 mmol / mL.

8. The production method according to claim 5, wherein The mixing of the cobalt complex and the inorganic nanoparticles comprises: providing a cobalt complex dispersion containing a cobalt complex and an inorganic nanoparticle dispersion containing inorganic nanoparticles; mixing the cobalt complex dispersion and the inorganic nanoparticle dispersion.

9. The preparation method of claim 8, wherein in the cobalt complex dispersion, the mass concentration of the cobalt complex is 2 mg / mL-5 mg / mL; and / or in the inorganic nanoparticle dispersion, the mass concentration of the inorganic nanoparticles is 20 mg / mL-30 mg / mL; and / or the mass ratio of the inorganic nanoparticles to the cobalt complex is 100:(5-10); and / or the temperature for mixing the cobalt complex and the inorganic nanoparticles is 3°C-10°C, and the time is 5 h-10 h.

10. A light emitting device, characterized in that: Comprise an anode, a functional layer and a cathode arranged in sequence; wherein the material of the functional layer comprises the composite material of any one of claims 1-4, or is prepared by the preparation method of any one of claims 5-9.

11. The light emitting device of claim 10, wherein the first and second light emitting layers are formed of a material having a band gap of 2.0 eV or more. The functional layer comprises one or more of a hole functional layer, a light emitting layer, and an electron functional layer, the hole functional layer is arranged between the anode and the light emitting layer, and the electron functional layer is arranged between the light emitting layer and the cathode.

12. The light emitting device of claim 11, wherein, The material of the light-emitting layer comprises the composite material, organic light-emitting material or quantum dot; the inorganic nanoparticles in the composite material are quantum dots; the organic light-emitting material is selected from one or more of 4,4'-bis(N-carbazole)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine iridium (III)], 4,4',4"-tris(carbazole-9-yl) triphenylamine: tris[2-(p-tolyl)pyridine iridium], diaryl anthracene derivative, stilbene aromatic derivative, pyrene derivative, fluorene derivative, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescent material, TTA material, TADF material, polymer containing B-N covalent bond, HLCT material, Exciplex light-emitting material; the quantum dot is selected from one or more of single-structure quantum dot, core-shell structure quantum dot and perovskite quantum dot; the material of the single-structure quantum dot, the core material of the core-shell structure quantum dot and the shell material of the core-shell structure quantum dot are respectively selected from one or more of II-VI group compound, IV-VI group compound, III-V group compound and I-III-VI group compound; the shell of the core-shell structure quantum dot is one or more layers; the II-VI group compound is 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 compound is selected from one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe.The III-V compound is 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 compound is selected from one or more of CuInS2, CuInSe2, and AgInS2; the core-shell quantum dot is 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 quantum dot is selected from a doped or undoped inorganic perovskite quantum dot, or an organic-inorganic hybrid perovskite quantum dot; the inorganic perovskite quantum dot has a general structure of AMX3, where A is Cs + ion; the organic-inorganic hybrid perovskite quantum dot has a general structure of 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 one or more of 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 X is a halide anion selected from one or more of Cl - , Br - , I - ; and / or The material of the hole functional layer comprises one or more of the composite material of any one of claims 1-9, 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'-di(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-buty lphenyl)diphenylamine)], poly(4-butylphenyl-diphenylamine), poly[bi s(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], 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 derivatives thereof, derivatives of PEDOT:PSS doped with s-MoO3, poly(N-vinylcarbazole) and derivatives thereof, polymethacrylate and derivatives thereof, poly(9,9-octylfluorene) and derivatives thereof, poly(spirofluorene) and derivatives thereof, N,N'-di(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro NPB, nanopolycrystalline diamond, microcrystalline cellulose, and tetracyanoquinodimethane, doped graphene, undoped graphene, second doped metal oxide particles, second undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides, the metal oxide in the second doped metal oxide particles and the metal oxide in the second undoped metal oxide particles each independently comprising one or more of MoO3, WO3, NiO, CrO3, CuO, V2O5, the doping element in the second doped metal oxide particles comprising one or more of Mo, W, Ni, Cr, Cu, V, the metal sulfides comprising one or more of CuS, MoS3, WS3, the metal selenides comprising one or more of MoSe3, WSe3, the metal nitrides comprising P-type gallium nitride;The inorganic nanoparticles in the composite material are P-type inorganic nanoparticles; and / or; The material of the electron functional layer comprises one or more of the composite material of any one of claims 1-9, 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2,2'-(1,3-phenyl)di[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetrakis[(m-pyridyl)-phen-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]dipyridine, 1,3-bis(3,5-dipyrid-3-ylphenyl)benzene, n,n'-bis(naphthalen-1-yl)-n,n'-bis(phenyl)benzidine, first doped metal oxide particles, first non-doped metal oxide particles, group IIB-VIA semiconductor material, group IIIA-VA semiconductor material, and group IB-IIIA-VIA semiconductor material, the material of the first non-doped metal oxide particles comprises one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, the metal oxide in the first doped metal oxide particles comprises one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, Al2O3, the doping element in the first doped metal oxide particles comprises one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga, the group IIB-VIA semiconductor material comprises one or more of ZnS, ZnSe, CdS, the group IIIA-VA semiconductor material comprises one or more of InP, GaP, and the group IB-IIIA-VIA semiconductor material comprises one or more of CuInS, CuGaS; the inorganic nanoparticles in the composite material are N-type inorganic nanoparticles; and / or The anode and the cathode each independently comprise one or more of a metal, a carbon material, and a metal oxide; the metal comprises one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material comprises one or more of graphite, carbon nanotube, graphene, and carbon fiber; the metal oxide comprises a metal oxide electrode or a composite electrode with a metal sandwiched between doped or undoped transparent metal oxides, the material of the metal oxide electrode comprises one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, the composite electrode comprises 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 thickness of the light-emitting layer is 20-60 nm; and / or The thickness of the hole functional layer is 30-120 nm; and / or The thickness of the electron functional layer is 30-120 nm.

13. A display device comprising: The light-emitting device as claimed in any one of claims 10-12.

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