Composite material and preparation method thereof, photoelectric device and display device

Abstract

The invention belongs to the technical field of perovskite nanocrystals, and particularly relates to a composite material and a preparation method thereof, a photoelectric device and a display device, and the composite material comprises perovskite nanocrystals and acid radical anions of VIB group elements modified on the surfaces of the perovskite nanocrystals. The invention further relates to a preparation method of the composite material, a photoelectric device and a display device. According to the technical scheme provided by the invention, the stability of the perovskite nanocrystal in different environments can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of perovskite nanocrystals, and more specifically, to a composite material, a method for preparing the composite material, an optoelectronic device, and a display device. Background Art

[0002] Perovskite nanocrystals have high photoluminescence quantum yield (PLQY), high color purity, tunable band gap and optical properties that suggest synthesis. Inspired by their excellent optical properties, people have been committed to making light-emitting diodes based on perovskite nanocrystals. The external quantum efficiency (EQE) of light-emitting diodes made of perovskite nanocrystals can reach 22%, which is close to organic electroluminescent diodes and quantum dot light-emitting diodes, but the surface of perovskite nanocrystals is unstable. Summary of the invention

[0003] The present application provides a composite material and a preparation method thereof, a composite film, an optoelectronic device and a display device.

[0004] The present invention provides a composite material, which adopts the following technical solution:

[0005] A composite material comprises a perovskite nanocrystal and an acid anion of a VIB group element modified on the surface of the perovskite nanocrystal.

[0006] Furthermore, the average particle size of the perovskite nanocrystals is 5 nm to 15 nm;

[0007] And / or, the perovskite nanocrystals are one or more of inorganic perovskite nanocrystals, organic perovskite nanocrystals and organic-inorganic hybrid perovskite nanocrystals, wherein the structure of the perovskite nanocrystals is AMX3 at the same time, wherein M is a divalent metal cation;

[0008] Optionally, A in the inorganic perovskite nanocrystal is Cs + , the divalent metal cation is selected from Pb 2+ Sn 2 + , Cu 2+ 、N i 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of, X is selected from C - Br - ,I - At least one of;

[0009] Optionally, A in the organic perovskite nanocrystal is a carboxamidine group, and the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、N i 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of, X is selected from C - Br - ,I - At least one of;

[0010] Optionally, in the organic-inorganic hybrid perovskite nanocrystal, A is selected from CH 3 (CH 2 ) n-2 NH 3+ NH 3 (CH 2 ) n NH3 2+ In one of the above, the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2 + ,Ge 2+ , Yb 2+ and Eu 2+ At least one of, X is selected from Cl - Br - ,I - At least one of;

[0011] And / or, the acid anion of the VIB group element is selected from CrO 4 2- 、MoO 4 2- , WO 4 2- At least one of .

[0012] Furthermore, in the composite material, the mass ratio of the perovskite nanocrystals to the acid anions of the Group VIB elements is (125-75):1.

[0013] The present application also provides a method for preparing a composite material, which adopts the following technical solution:

[0014] A method for preparing a composite material solution comprises the following steps:

[0015] providing a perovskite nanocrystal solution;

[0016] Providing a microemulsion, wherein the microemulsion comprises a Group VIB compound;

[0017] The perovskite nanocrystal solution is dispersed in the microemulsion and diluted, and then solid-liquid separation is performed, and the obtained solid is the composite material.

[0018] Furthermore, the perovskite nanocrystal solution is prepared by the following steps:

[0019] The perovskite nanocrystals are dispersed in a solvent, and then a precipitant is added to the obtained perovskite nanocrystal solution. After solid-liquid separation, the obtained solid is dispersed in the solvent again to obtain the perovskite nanocrystal solution.

[0020] Optionally, the solvent is selected from at least one of n-hexane, n-octane, toluene and chloroform;

[0021] The precipitant is selected from at least one of ethyl acetate, methyl acetate, methyl formate and ethyl formate.

[0022] Furthermore, the microemulsion is prepared by the following steps:

[0023] dissolving the Group VIB compound in deionized water to form an aqueous solution of the Group VIB compound;

[0024] Mixing the aqueous solution of the Group VIB compound, a surfactant, a co-surfactant and an oil phase, and subjecting the mixture to ultrasonic treatment to form the microemulsion;

[0025] Optionally, the Group VIB compound is selected from at least one of soluble chromates, soluble molybdates and soluble tungstates;

[0026] The surfactant is selected from at least one of potassium cetyl phosphate, polyethylene glycol octylphenyl ether (Triton X-100), alkylphenol polyoxyethylene (10) ether and nonylphenol polyoxyethylene ether;

[0027] The co-surfactant is selected from at least one of octanol, hexanol, butanol and pentanol;

[0028] The oil phase is selected from at least one of cyclohexane, isooctane, n-octane and heptane.

[0029] The present application also provides a photoelectric device, which adopts the following technical solution:

[0030] A photoelectric device comprises the composite material as described above or a composite material prepared by the method for preparing the composite material as described above.

[0031] Furthermore, the optoelectronic device includes a light-emitting layer, and the material of the light-emitting layer includes the composite material as described above or a composite material prepared by the method for preparing the composite material as described above.

[0032] Furthermore, the photoelectric device further comprises an anode layer, a hole functional layer, an electron functional layer and a cathode layer;

[0033] The hole functional layer is disposed between the anode layer and the light emitting layer;

[0034] The electronic functional layer is disposed between the light emitting layer and the cathode layer;

[0035] Optionally, the material of the anode layer and / or cathode layer includes at least one of a metal, a carbon material and a metal oxide, the metal includes at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes at least one of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes a doped or undoped metal oxide, including at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO 2 / Ag / TiO 2 and TiO 2 / Al / TiO 2 At least one of; and / or

[0036] Optionally, the hole functional layer includes a hole injection layer and / or a hole transport layer, and the material of the hole injection layer and / or the hole transport layer includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60; and / or

[0037] Optionally, the electronic functional layer includes an electron transport layer, and the material of the electron transport layer includes inorganic materials and / or organic materials. The inorganic material is selected from at least one of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped element includes at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material is selected from at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, and hydroxyquinoline compounds.

[0038] The present application also provides a display device, which adopts the following technical solution:

[0039] A display device comprises the optoelectronic device as described above.

[0040] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0041] The composite material provided in the present application can improve the stability of perovskite nanocrystals in high temperature and humid environments, and can also enhance the direct radiation recombination capability of the composite film formed by the composite material and extend the service life of the composite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the solutions in the present application or the prior art, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 is a flow chart of a method for preparing a composite material according to an embodiment of the present application;

[0044] Figure 2 is a schematic structural diagram of an optoelectronic device according to an embodiment of the present application;

[0045] Figure 3 1 is a PXRD diagram of the composite material of the embodiment of the present application and a conventional composite material;

[0046] Figure 4 It is the UV-Vis absorption spectrum and the photoluminescence emission spectrum of the composite material of the embodiment of the present application and the conventional composite material;

[0047] Figure 5a to Figure 5e They are respectively photoluminescence attenuation curves of the composite materials of composite material embodiments 1 to 4 and composite material comparative example 1;

[0048] Figure 6 is a HRTEM image of the light-emitting layer of an embodiment of the present application;

[0049] Figure 7 This is the HRTEM image of a conventional light-emitting layer;

[0050] Figure 8 It is a fluorescence attenuation curve diagram of the composite material of the embodiment of the present application and the conventional composite material.

[0051] Reference numerals:

[0052] 1. Anode layer; 2. Hole functional layer; 3. Light-emitting layer; 4. Electron transport layer; 5. Cathode layer. DETAILED DESCRIPTION

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0054] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0055] Perovskite nanocrystals (NCs) have been developed as materials for the light-emitting layer of light-emitting diodes due to their excellent optical properties such as high photoluminescence quantum yield (PLQY), high color purity, tunable band gap, and simple synthesis. 3 The external quantum efficiency (EQE) of the light-emitting diodes of NCs (X=Cl, Br, I) can reach 22%, which is close to that of organic light-emitting diodes and quantum dot light-emitting diodes.

[0056] However, due to the ionic nature and dynamic bonding of organic ligands on the surface of all-inorganic cesium lead halide perovskite nanocrystals, light-emitting diode devices with light-emitting layers prepared from all-inorganic cesium lead halide perovskite nanocrystals suffer from ion migration and carrier capture caused by defects, which causes existing perovskite nanocrystal light-emitting diodes to generate Joule heating and emission layer degradation, leading to a serious decrease in electroluminescence (EL) efficiency and reduced operating stability of optoelectronic devices.

[0057] At present, inorganic layer passivation is usually used to improve the surface stability of perovskite nanocrystals, that is, a shell structure is formed outside the core structure formed by the perovskite nanomaterial by an ultra-stable inorganic outer layer material. However, due to the incompatibility between the inner core of the perovskite nanomaterial and the metal oxide outer shell, the encapsulation of the perovskite nanomaterial inner core by the metal oxide shell is difficult to control, resulting in uneven shell layer, poor dispersion of the perovskite nanocrystals on the light-emitting layer, and poor film uniformity of the light-emitting layer.

[0058] Based on the above-mentioned defects of the prior art, an embodiment of the present application provides a composite material, including perovskite nanocrystals and acid anions of group VIB elements modified on the surface of the perovskite nanocrystals.

[0059] The composite material provided in the embodiment of the present application forms a ligand containing an acid anion of a Group VIB element on the surface of the perovskite nanocrystal, thereby introducing the acid anion of the Group VIB element into the surface of the perovskite nanocrystal, thereby suppressing the defect state on the surface of the perovskite nanocrystal and improving the stability of the perovskite nanocrystal in a high temperature and humid environment. In addition, by introducing the acid anion of the Group VIB element into the surface of the perovskite nanocrystal, the direct radiation recombination ability of the composite film formed by the composite material can be improved and the service life of the composite film can be extended.

[0060] In some embodiments, the average particle size of the perovskite nanocrystals is 5 nm to 15 nm. Specifically, the average particle size of the perovskite nanocrystals can be set to any one of 5 nm, 10 nm, and 15 nm or a range formed between any two values.

[0061] In some embodiments, the perovskite nanocrystal is one of an inorganic perovskite nanocrystal, an organic perovskite nanocrystal, and an organic-inorganic hybrid perovskite nanocrystal, wherein the structure of the perovskite nanocrystal is AMX 3 , wherein M is a divalent metal cation.

[0062] When the perovskite nanocrystal is an inorganic perovskite nanocrystal, the general structural formula of the perovskite nanocrystal is AMX 3 , wherein A is Cs + , the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of the following, wherein X is a halogen anion, which is Cl - Br - and I - At least one of .

[0063] When the perovskite nanocrystal is an organic perovskite nanocrystal, the general structural formula of the perovskite nanocrystal is AMX 3 , wherein A is carbamimidoyl (FA), and the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of the following, wherein X is a halogen anion, which is Cl - Br - and I - At least one of .

[0064] When the perovskite nanocrystal is an organic-inorganic hybrid perovskite nanocrystal, the general structural formula of the perovskite nanocrystal is AMX 3 , wherein A is an organic amine cation (for example: CH 3 (CH 2 )n-2 NH 3+ NH 3 (CH 2 ) n NH3 2+ ), the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of the following, wherein X is a halogen anion, which is Cl - Br - and I - At least one of .

[0065] In some embodiments, the acid anion of the VIB group element is selected from CrO 4 2- 、MoO 4 2- , WO 4 2- At least one of .

[0066] In this embodiment, the perovskite nanomaterial is preferably an inorganic cesium lead halide perovskite nanomaterial, and its general structural formula is CrPbX 3 The divalent metal cation is lead ion (Pb 2+ ); the acid anion of the VIB group element reacts with the free Pb on the surface of the inorganic cesium lead halide perovskite nanomaterial in the solvent 2+ The ions react with each other to form PbCrO 4 or PbMoO 4 or PbWO 4 The ligands are fixed on the surface of perovskite nanocrystals, thereby passivating the surface of perovskite nanocrystals.

[0067] In the embodiment of the present application, since the ligand on the surface of the perovskite nanocrystal is Pb 2+ The ions interact with the acid anions of group VIB elements in the solvent to form a passivation structure that fits the surface of the perovskite nanocrystals. While improving the stability of the perovskite nanocrystals, it enables the core structure formed by the perovskite nanocrystals to form a uniform shell structure, thereby improving the dispersion uniformity of the perovskite nanocrystals on the film layer and improving the thin film uniformity of the light-emitting layer.

[0068] In some embodiments, in the composite material, the mass ratio of the perovskite nanocrystals to the acid anions of the VIB group elements is (125-75):1. Specifically, in the composite material, the mass ratio of the perovskite nanocrystals to the acid anions of the VIB group elements is 125:1; or, the mass ratio of the perovskite nanocrystals to the acid anions of the VIB group elements is 100:1; or, the mass ratio of the perovskite nanocrystals to the acid anions of the VIB group elements is 80:1; or, the mass ratio of the perovskite nanocrystals to the acid anions of the VIB group elements is 75:1.

[0069] See also Figure 1 As shown, based on the above composite material, the embodiment of the present application further provides a method for preparing a composite material, which is used to prepare the above composite material, comprising the following steps:

[0070] Step S100, providing a perovskite nanocrystal solution.

[0071] Step S200, providing a microemulsion, wherein the microemulsion contains a Group VIB compound.

[0072] Step S300, dispersing the perovskite nanocrystal solution in the microemulsion to dilute it, and then performing solid-liquid separation, and the obtained solid is the composite material.

[0073] The embodiment of the present application processes the perovskite nanomaterial through the preparation method of the above-mentioned composite material, and utilizes the properties of the microemulsion method to reduce the long-chain oleylamine and oleic acid in the surface ligands of the perovskite nanocrystals, so that the metal cations become free, and then the microemulsion method is used to induce the VIB group acid anions formed by the VIB group compounds to combine with the free metal cations, so that the ligands containing the VIB group acid anions can be fixed on the surface of the perovskite nanocrystals, so that the ligands have strong adhesion to resist the decomposition of water and oxygen, thereby improving the stability of the perovskite nanocrystals in high temperature and humid environments; because the ligands have strong adhesion, they can form a uniformly distributed encapsulation outside the perovskite nanocrystal core, improve the uniformity of the shell layer, and improve the dispersion uniformity of the perovskite nanocrystals on the light-emitting layer, thereby improving the uniformity of the light-emitting layer film formed by the perovskite nanocrystals.

[0074] In some embodiments, the perovskite nanocrystal solution in step S100 is prepared by the following steps:

[0075] The perovskite nanocrystals are dispersed in a solvent, and then a precipitant is added to the obtained perovskite nanocrystal solution. After solid-liquid separation, the obtained solid is dispersed in the solvent again to obtain the perovskite nanocrystal solution.

[0076] In this embodiment, the perovskite nanocrystals are prepared by the following steps:

[0077] Cesium acetate (CH 3 COOCs and lead acetate trihydrate (Pb(CH 3 COO 2 ·3H 2 O) was mixed with octadecene (ODE), oleic acid (OA) and oleylamine (OAm) in a three-necked flask to form a mixed solution.

[0078] The mixed solution was first evacuated at 120° C. and then nitrogen was introduced, and this process was repeated several times to remove the air and moisture in the three-necked flask.

[0079] Keep N 2 Under atmosphere, the temperature was adjusted to 170° C., and benzoyl bromide was added to form a crude reaction solution, which was allowed to stand.

[0080] The crude reaction solution after standing was cooled to room temperature, and ethyl acetate was added to obtain a crude perovskite nanocrystal solution.

[0081] After the crude perovskite nanocrystal solution is centrifuged, the precipitate is taken to obtain the perovskite nanocrystal.

[0082] In some embodiments, the solvent is selected from at least one of n-hexane, n-octane, toluene and chloroform.

[0083] In some embodiments, the precipitant is selected from at least one of ethyl acetate, methyl acetate, methyl formate and ethyl formate.

[0084] In this embodiment, the perovskite nanocrystals in step S100 are prepared by the following steps:

[0085] dispersing the prepared perovskite nanocrystals in a toluene solution to form a perovskite nanocrystal solution;

[0086] Ethyl acetate is added to the obtained perovskite nanocrystal solution, and after solid-liquid separation, the obtained solid is dispersed in a toluene solution again to obtain the perovskite nanocrystal solution.

[0087] In some embodiments, after the step of adding a precipitant to the obtained perovskite nanocrystal solution and before the step of solid-liquid separation, the method further comprises the following steps:

[0088] The obtained perovskite nanocrystal solution is centrifuged at least twice to remove the upper impurity solution.

[0089] In the embodiment of the present application, the stored perovskite nanocrystal solution is centrifuged before preparing the composite material to remove impurities and improve the purity of the perovskite nanocrystals, so as to facilitate the subsequent modification of the perovskite nanocrystals.

[0090] In some embodiments, the microemulsion in step S200 is prepared by the following steps:

[0091] The Group VIB compound is dissolved in deionized water to form an aqueous solution of the Group VIB compound.

[0092] The aqueous solution of the VIB group compound, a surfactant, a co-surfactant and an oil phase are mixed and ultrasonically treated to form the microemulsion.

[0093] In some embodiments, the Group VIB compound is selected from CrO 4 2- Chromates with MoO as anion 4 2- Molybdate with WO as anion 4 2- At least one of the tungstates with an anion, in this embodiment, the VIB group compound is K 2 MoO 4 .

[0094] In some embodiments, the surfactant is selected from at least one of potassium cetyl phosphate, polyethylene glycol octylphenyl ether (Triton X-100), alkylphenol polyoxyethylene (10) ether and nonylphenol polyoxyethylene ether. In this embodiment, the surfactant is potassium cetyl phosphate.

[0095] In some embodiments, the co-surfactant is selected from at least one of octanol, n-hexanol, n-butanol and n-pentanol. In this embodiment, the co-surfactant is octanol.

[0096] In some embodiments, the oil phase is selected from at least one of cyclohexane, isooctane, n-octane and heptane. In this embodiment, the oil phase is cyclohexane.

[0097] In some embodiments, the solvent includes at least one of n-hexane, n-octane, toluene and chloroform.

[0098] In some embodiments, in the step of mixing the aqueous solution of the group VIB compound, the surfactant, the co-surfactant and the oil phase and performing ultrasonic treatment to form the microemulsion, the volume of the aqueous solution of the group VIB compound can be increased to increase the concentration of the acid ions of the group VIB elements in the microemulsion, so that after the perovskite nanocrystal solution is subsequently diluted with the microemulsion, the mass ratio of the perovskite nanocrystals to the acid ions in the obtained composite material can be increased, thereby improving the stability of the perovskite nanocrystals in a high temperature and humid environment.

[0099] In some embodiments, in the step S300, after the step of dispersing the perovskite nanocrystal solution in the microemulsion for dilution, the step further includes: stirring the perovskite nanocrystal solution dispersed in the microemulsion to obtain a diluted perovskite nanocrystal solution.

[0100] In some embodiments, the duration of the stirring is 1 to 30 minutes. Specifically, the duration of the stirring can be set to any one of 1 minute, 5 minutes, 10 minutes, and 30 minutes, or a range formed between any two values.

[0101] In the embodiment of the present application, the perovskite nanocrystal solution dispersed in the microemulsion is stirred sufficiently so that the microemulsion can fully contact the surface of the perovskite nanocrystal, thereby reducing the amount of the long-chain oleylamine oleic acid ligand of the perovskite nanocrystal. 2+ Metal cations are free in the mixed solution and induce MoO 4 2- The anions in the mixed solution react with the free Pb 2+ The metal cations pair to form PbMoO 4 The surface of the perovskite nanocrystals is modified, and as the stirring time is gradually prolonged, the mass ratio of the perovskite nanocrystals to the acid ions in the composite material is increased, thereby improving the stability of the perovskite nanocrystals in a high temperature and humid environment.

[0102] Based on the preparation method of the above composite material, an embodiment of the present application further provides a composite film, which is prepared by the preparation method of the above composite material. In this embodiment, the composite film is used for the light-emitting layer of an optoelectronic device.

[0103] The composite film provided in the embodiment of the present application adopts the preparation method of the composite material to improve the uniformity of the film and the stability in a high temperature or humid environment; in addition, since the composite material is MoO 4 2-The perovskite nanocrystals modified with acid anions suppress the defect states on the surface of the perovskite nanocrystals, thereby improving the direct radiation recombination ability of the composite film and extending the service life of the composite film.

[0104] Based on the above-mentioned composite film, an embodiment of the present application also provides a photoelectric device, comprising a stacked anode layer 1, a light-emitting layer 3 and a cathode layer 5, wherein the light-emitting layer 3 comprises the composite material as described above in the claim or a composite material prepared by the method for preparing the composite material as described above.

[0105] In some embodiments, the optoelectronic device further includes a hole functional layer 2 and an electron functional layer 4 , wherein the hole functional layer 2 is disposed between the anode layer 1 and the light-emitting layer 3 ; and the electron functional layer 4 is disposed between the light-emitting layer 3 and the cathode layer 5 .

[0106] In some embodiments, the optoelectronic device comprises:

[0107] The anode layer 1 and the cathode layer 5 are arranged opposite to each other.

[0108] The hole functional layer 2 is disposed between the anode layer 1 and the cathode layer 5 and is disposed close to the anode layer 1 .

[0109] The electronic functional layer 4 is disposed between the anode layer 1 and the cathode layer 5 and is disposed close to the cathode layer 5 .

[0110] The light-emitting layer 3 is disposed between the hole functional layer 2 and the electron functional layer 4 .

[0111] In some embodiments, the material of the anode layer 1 and / or the cathode layer 5 includes at least one of a metal, a carbon material and a metal oxide, wherein the metal includes at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes at least one of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes a doped or undoped metal oxide, including at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO 2 / Ag / TiO 2 and TiO 2 / Al / TiO 2 At least one of .

[0112] The hole functional layer 2 includes a hole injection layer and / or a hole transport layer, and the material of the hole injection layer and / or the hole transport layer includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tri(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60.

[0113] The electronic functional layer 4 includes an electron transport layer, and the material of the electron transport layer includes inorganic materials and / or organic materials. The inorganic material is selected from at least one of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped element includes at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material is selected from at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, and hydroxyquinoline compounds.

[0114] In this embodiment, the photoelectric device is an upright photoelectric device, and the structure of the photoelectric device is anode layer 1 / hole functional layer 2 / light-emitting layer 3 / electron functional layer 4 / cathode layer 5. In other embodiments, the photoelectric device can also be an inverted photoelectric device, and the structure of the photoelectric device is cathode layer 5 / electron functional layer 4 / light-emitting layer 3 / hole functional layer 2 / anode layer 1.

[0115] The optoelectronic device provided in the embodiment of the present application adopts the above-mentioned composite film as the light-emitting layer, which can improve the film uniformity of the light-emitting layer and improve the direct radiation recombination ability of the light-emitting layer, thereby improving the device efficiency of the optoelectronic device. In addition, it can also increase the service life of the light-emitting layer, thereby increasing the service life of the optoelectronic device.

[0116] An embodiment of the present application further provides a display device, which includes the above-mentioned optoelectronic device.

[0117] The display device can be any electronic product with a display function, including but not limited to smart phones, tablet computers, laptops, digital cameras, digital video cameras, smart wearable devices, smart weighing electronic scales, car displays, televisions or e-book readers, among which smart wearable devices can be, for example, smart bracelets, smart watches, virtual reality (VR) helmets, etc.

[0118] The present application is described in detail below through specific embodiments. The following embodiments are only partial embodiments of the present application and are not limitations of the present application.

[0119] Composite material example 1

[0120] Step (1), providing CsPbBr 3 Nanocrystal solution:

[0121] Wherein, the perovskite nanocrystal solution is prepared by the following steps:

[0122] 0.5 mmol of cesium acetate (CH 3 COOCs and 1.0 mmol of lead acetate trihydrate (Pb(CH 3 COO 2 ·3H 2 O) was mixed with 25 mL of octadecene (ODE), 4.0 mL of oleic acid (OA), and 5.0 mL of oleylamine (OAm) in a 100 mL three-necked flask to form a mixed solution;

[0123] The mixed solution was first evacuated at 120°C for 15 minutes and then nitrogen was introduced for 10 minutes, and this process was repeated three times to remove air and moisture from the three-necked flask;

[0124] Keep N 2 Under atmosphere, the temperature was adjusted to 170 °C, and 4 mmol of benzoyl bromide was added to form a crude reaction solution, which was allowed to stand for 5 s;

[0125] The crude reaction solution was cooled to room temperature after standing, and 5 mL of ethyl acetate was added to obtain a crude perovskite nanocrystal solution;

[0126] The crude solution of perovskite nanocrystals was centrifuged at 12000 rpm for 5 min, and the precipitate was dispersed in a toluene solution to form CsPbBr 3 Nanocrystal stock solution;

[0127] Add 2 mL of CsPbBr 33 mL of ethyl acetate was added to the nanocrystal stock solution and centrifuged at least twice at 10,000 rpm to remove the upper impurity solution, and then toluene was added to the precipitate to form CsPbBr 3 Nanocrystal solution, the CsPbBr 3 The concentration of the nanocrystal solution was 0.2 mol / L and the volume was 5 ml;

[0128] Step (2), providing a microemulsion:

[0129] Wherein, the microemulsion is prepared by the following steps:

[0130] 0.1 mol of K 2 MoO 4 Dissolve in 2 mL of deionized water to form K 2 MoO 4 Aqueous solution;

[0131] Dissolve 0.2 mmol of potassium cetyl phosphate in 4 mL of cyclohexane, and then add 0.5 mL of octanol to form a potassium cetyl phosphate-cyclohexane solution;

[0132] Take 100 μl of K 2 MoO 4 The aqueous solution was mixed with 4.5 mL of potassium cetyl phosphate-cyclohexane solution and subjected to ultrasonic treatment to form a transparent and uniform microemulsion;

[0133] Step (3): take 18 mL of the microemulsion prepared by the method of step (2) above, add 2 mL of 0.2 mol / L concentration of CsPbBr 3 The nanocrystal solution was immediately dispersed in 18 ml of microemulsion for dilution and stirred for 30 min to obtain a diluted CsPbBr3 nanocrystal solution. 3 The concentration of the nanocrystal solution was 0.02 mol / L;

[0134] Step (4), centrifugation is performed at a speed of 12000 rpm for 5 min, and after solid-liquid separation, the solid obtained is the composite material, wherein CsPbBr in the composite material 3 The mass ratio of molybdate ion to molybdate ion is 75:1.

[0135] Composite material example 2

[0136] The difference between this embodiment and composite material embodiment 1 is that in step (2), 40 μl of K 2 MoO 4 The aqueous solution was mixed with 4.5 mL of potassium cetyl phosphate-cyclohexane solution and subjected to ultrasonic treatment to form a transparent and uniform microemulsion;

[0137] In the step (4), centrifugation is performed at a speed of 12000 rpm for 5 minutes, and after solid-liquid separation, the solid obtained is the composite material, wherein CsPbBr in the composite material 3 The mass ratio of molybdate ion to molybdate ion is 125:1.

[0138] Composite material example 3

[0139] The difference between this embodiment and composite material embodiment 1 is that in step (2), 60 μl of K 2 MoO 4 The aqueous solution was mixed with 4.5 mL of potassium cetyl phosphate-cyclohexane solution and subjected to ultrasonic treatment to form a transparent and uniform microemulsion;

[0140] In the step (4), centrifugation is performed at a speed of 12000 rpm for 5 minutes, and after solid-liquid separation, the solid obtained is the composite material, wherein CsPbBr in the composite material 3 The mass ratio of molybdate ion to molybdate ion is 100:1.

[0141] Composite material example 4

[0142] The difference between this embodiment and composite material embodiment 1 is that in step (2), 90 μl of K 2 MoO 4 The aqueous solution was mixed with 4.5 mL of potassium cetyl phosphate-cyclohexane solution and subjected to ultrasonic treatment to form a transparent and uniform microemulsion;

[0143] In the step (4), centrifugation is performed at a speed of 12000 rpm for 5 minutes, and after solid-liquid separation, the solid obtained is the composite material, wherein CsPbBr in the composite material 3 The mass ratio of molybdate ion to molybdate ion is 80:1.

[0144] Composite material comparative example 1

[0145] Comparative Example 1 is conventional CsPbBr 3 Nanocrystal solution.

[0146] Composite film embodiment 1

[0147] Step (1), using the composite material prepared in the composite material embodiment 1 as the luminescent layer ink to prepare the luminescent layer.

[0148] Composite film comparative example 1

[0149] Step (1), using conventional CsPbBr3 nanocrystal solution as the light-emitting layer ink to prepare the light-emitting layer.

[0150] Performance test results analysis:

[0151] (i) Perform X-ray powder diffraction analysis on the composite materials prepared in Composite Material Example 1 and Composite Material Comparative Example 1, respectively, and record the analysis results in Figure 3 ,according to Figure 3 It can be seen that the modified perovskite nanomaterial used in Composite Example 1 shows a diffraction peak similar to that of the conventional perovskite nanomaterial in Composite Comparative Example 1, indicating that the use of microemulsion to treat CsPbBr 3 The modification of nanocrystals does not destroy CsPbBr 3 The crystal structure of the nanocrystals, and the modified perovskite nanomaterial of the composite material embodiment 1 has better phase purity, and its diffraction light intensity is higher than that of the conventional CsPbBr 3 Nanocrystals.

[0152] (ii) Performing Fenton performance tests on composite material example 1 and composite material comparative example 1 respectively, and plotting their UV-Vis absorption spectra and photoluminescence emission spectra, and recording them in Figure 4 ,according to Figure 4 It can be seen that the modified perovskite nanomaterial of composite material embodiment 1 is compared with the conventional perovskite nanocrystal of composite material comparison example 1, and the shape of the curve of the absorption spectrum is basically the same as the curve of the emission spectrum. According to the light absorption rate curve, based on the photo-Fenton principle, photons are energy quanta, and the energy size is inversely proportional to the wavelength. Therefore, it can be seen that when the wavelength is about 500nm, the photoluminescence intensity of the modified perovskite nanomaterial of composite material embodiment 1 is enhanced by about 15%. According to the photoluminescence intensity curve, it can be seen that the photoluminescence quantum yield (PLQY) of the modified perovskite nanomaterial of composite material embodiment 1 increases from 85% to 94%. Therefore, according to Figure 4 It can be shown that the modified perovskite nanomaterial of composite material embodiment 1 can significantly increase the direct radiation recombination ability of perovskite nanoparticles.

[0153] (III) The time required for the modified perovskite nanomaterials prepared from the composite material examples 1 to 4 and the composite material comparative example 1 to decay from the initial fluorescence emission intensity of 1 a.u. by using a life aging device, and the time required for the decay is plotted into a photoluminescence decay curve, which is recorded as Figure 5a to Figure 5e ;in, Figure 5a The photoluminescence attenuation curve of the composite material prepared in the corresponding composite material example 1, Figure 5b The photoluminescence attenuation curve of the composite material prepared in the composite material example 2 is as follows: Figure 5c The photoluminescence attenuation curve of the composite material prepared in the corresponding composite material embodiment 3 is as follows: Figure 5dThe photoluminescence attenuation curve of the composite material prepared in Composite Material Example 4 is as follows: Figure 5e The photoluminescence attenuation curve of the composite material prepared in Comparative Example 1 of the composite material is shown in FIG. Figures 5a to 5d As shown in FIG. 1 , it can be seen that the average photoluminescence lifetime of the modified perovskite nanomaterials prepared in Composite Material Examples 1 to 4 is 13.56 ns, while the average photoluminescence lifetime of the conventional perovskite nanocrystals in Composite Material Comparative Example 1 is 6.5 ns. In addition, according to Figures 5a to 5d As the mass ratio of CsPbBr3 nanocrystals to molybdate ions in the composite material increases, the average photoluminescence lifetime of the modified perovskite nanomaterials also gradually increases, which is greater than that of conventional perovskite nanocrystals (such as Figure 5e ), therefore, it can be shown that the lifetime of the modified perovskite nanomaterials prepared in composite material embodiments 1 to 4 is significantly improved.

[0154] (IV) The light-emitting layer of the composite film example 1 and the light-emitting layer of the composite film comparison example 1 were placed in a high humidity (relative humidity, RH=75%) and high temperature (constant temperature 60° C.) environment, and their HRTEM images were recorded after 30 days. Figure 6 (corresponding to composite film embodiment 1), Figure 7 (corresponding to the composite film comparative example 1) shows that after 30 days, the light-emitting layer of the composite film comparative example 1 has serious agglomeration phenomenon, while the light-emitting layer of the composite film embodiment 1 is still in a relatively stable dispersed arrangement. Figure 6 , Figure 7 It can be shown that the light-emitting layer of the composite film embodiment 1 has good stability in a high temperature and high humidity environment.

[0155] (V) The photoluminescence intensity of the modified perovskite nanomaterial of the composite film example 1 and the conventional perovskite nanocrystal of the composite film comparison example 1 were tested respectively, and the test results were recorded in Figure 8 In, according to Figure 8 As shown in FIG. 1 , the photoluminescence intensity of the modified perovskite nanomaterial of the composite material example 1 becomes 35% of the original after annealing, maintaining sufficient photoluminescence intensity, while the photoluminescence intensity of the conventional perovskite nanocrystal of the composite material comparative example 1 becomes 8% of the original after annealing. Therefore, according to Figure 8 It can be shown that the light-emitting layer of Example 1 can effectively suppress the surface trap states of the nanocrystals to enhance the direct radiation recombination ability of the perovskite nanocrystals.

[0156] In summary, the composite material provided in the embodiment of the present application uses the ligand of the acid anion of the VIB group element to modify the surface of the perovskite nanocrystal, which can increase the direct radiation recombination ability of the perovskite nanocrystal; can inhibit the defect state on the surface of the perovskite nanocrystal to improve the stability of the light-emitting layer in a high temperature and humid environment, and can extend the service life of the perovskite nanocrystal, thereby improving the direct radiation recombination ability of the composite film prepared by using the composite material, the stability in a high temperature and humid environment and the service life, thereby improving the device efficiency and service life of the optoelectronic device.

[0157] Obviously, the embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to perform equivalent replacement of some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is similarly within the scope of patent protection of this application.

Claims

1. A composite material, It is characterized in that The invention comprises a perovskite nanocrystal and an acid anion of a VIB group element modified on the surface of the perovskite nanocrystal.

2. The composite material according to claim 1, It is characterized in that The average particle size of the perovskite nanocrystals is 5nm to 15nm; And / or, the perovskite nanocrystals include one or more of inorganic perovskite nanocrystals, organic perovskite nanocrystals and organic-inorganic hybrid perovskite nanocrystals, wherein the general structural formula of the perovskite nanocrystals is AMX 3 , M is a divalent metal cation; Optionally, A in the inorganic perovskite nanocrystal is Cs + , the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2 + 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of, X is selected from Cl - Br - ,I - At least one of; Optionally, A in the organic perovskite nanocrystal is a carboxamidine group, and the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of, X is selected from Cl - Br - ,I - At least one of; Optionally, in the organic-inorganic hybrid perovskite nanocrystal, A is an organic amine cation selected from CH 3 (CH 2 ) n-2 NH 3 + or [NH 3 (CH 2 ) n NH 3 ] 2+ , wherein n≥2, the divalent metal cation is selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2 + 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ and Eu 2+ At least one of, X is selected from Cl - Br - ,I - At least one of; And / or, the acid anion of the VIB group element is selected from CrO 4 2- 、MoO 4 2- , WO 4 2- At least one of .

3. The composite material according to claim 1, It is characterized in that The mass ratio of the perovskite nanocrystal to the acid anion of the VIB group element is (125-75):

1.

4. A method for preparing a composite material, It is characterized in that The following steps are involved: providing a perovskite nanocrystal solution; Providing a microemulsion, wherein the microemulsion comprises a Group VIB compound; The perovskite nanocrystal solution is dispersed in the microemulsion to form a mixed solution, and then solid-liquid separation is performed to obtain a solid that is the composite material.

5. The method for preparing the composite material according to claim 4, It is characterized in that The perovskite nanocrystal solution is prepared by the following steps: dispersing the perovskite nanocrystals in a solvent, adding a precipitant to the obtained perovskite nanocrystal solution, and dispersing the precipitate in the solvent again after solid-liquid separation to obtain the perovskite nanocrystal solution; Optionally, the solvent is selected from at least one of n-hexane, n-octane, toluene and chloroform; The precipitant is selected from at least one of ethyl acetate, methyl acetate, ethyl formate and methyl formate.

6. The method for preparing the composite material according to claim 4, It is characterized in that The microemulsion is prepared by the following steps: The microemulsion is prepared by the following steps: dissolving the Group VIB compound in deionized water to form an aqueous solution of the Group VIB compound; Mixing the aqueous solution of the Group VIB compound, a surfactant, a co-surfactant and an oil phase, and subjecting the mixture to ultrasonic treatment to form the microemulsion; Optionally, the Group VIB compound is selected from at least one of soluble chromates, soluble molybdates and soluble tungstates; The surfactant is selected from at least one of potassium cetyl phosphate, polyethylene glycol octylphenyl ether (Triton X-100), alkylphenol polyoxyethylene (10) ether and nonylphenol polyoxyethylene ether; The co-surfactant is selected from at least one of octanol, hexanol, butanol and pentanol; The oil phase is selected from at least one of cyclohexane, isooctane, n-octane and heptane.

7. A photoelectric device, It is characterized in that The optoelectronic device comprises the composite material according to any one of claims 1 to 3 or the composite material prepared by the preparation method according to any one of claims 4 to 6.

8. The optoelectronic device according to claim 7, Its only characteristic is that The optoelectronic device comprises a light-emitting layer, and the material of the light-emitting layer comprises the composite material according to any one of claims 1 to 3 or the composite material prepared by the preparation method according to any one of claims 4 to 6.

9. The optoelectronic device according to claim 8, It is characterized in that The photoelectric device also includes an anode, a hole functional layer, an electron functional layer and a cathode; The hole functional layer is disposed between the anode and the light emitting layer; The electronic functional layer is disposed between the light emitting layer and the cathode; Optionally, the material of the anode layer and / or cathode layer includes at least one of a metal, a carbon material and a metal oxide, the metal includes at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes at least one of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes a doped or undoped metal oxide, including at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO 2 / Ag / TiO 2 and TiO 2 / Al / TiO 2 At least one of; Optionally, the hole functional layer includes a hole injection layer and / or a hole transport layer, and the material of the hole injection layer and / or the hole transport layer includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60; Optionally, the electronic functional layer includes an electron transport layer, and the material of the electron transport layer includes inorganic materials and / or organic materials. The inorganic material is selected from at least one of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped element includes at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material is selected from at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, and hydroxyquinoline compounds.

10. A display device, It is characterized in that The display device comprises the optoelectronic device according to any one of claims 7 to 9.

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