Light-emitting device, preparation method thereof and display device

Abstract

The invention discloses a light-emitting device, a preparation method thereof and a display device. According to the light-emitting device, the first electron transport layer close to the light-emitting layer comprises a long carbon chain ligand with the carbon atom number of 4-12, and the second ligand connected to the second electron transport layer comprises one or more of a short chain ligand with the carbon atom number of 1-3 or a hydroxyl ligand. Through the ligand arrangement of the first electron transport layer and the second electron transport layer, the distance between the electronic function layer and the light-emitting layer can be increased, the recombination efficiency of the light-emitting layer can be improved, the damage to the electronic function layer can be avoided, the service life of the light-emitting device can be prolonged, and the dissolution and penetration damage and the like of a film layer prepared in advance can be avoided; therefore, the film forming quality of the electronic function layer is improved, the possibility of current leakage of the light-emitting device is reduced, and the service life of the light-emitting device is prolonged.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a light-emitting device and a method for preparing the same, and a display device. Background Art

[0002] Currently, widely used light-emitting devices include organic light-emitting diodes (OLEDs) and quantum dot light-emitting diodes (QLEDs). The traditional OLED and QLED device structures mainly include a first electrode, a hole functional layer, a light-emitting layer, an electron functional layer, and a second electrode. Under the action of the electric field, the holes generated by the first electrode of the light-emitting device and the electrons generated by the second electrode move and are injected into the hole transport layer and the electron transport layer respectively, and finally migrate to the light-emitting layer. When the two meet in the light-emitting layer, energy excitons are generated, and visible light is finally generated.

[0003] Since the electron transport layer is in contact with the light-emitting layer and the second electrode at the same time, there are interface problems between the electron transport layer and the light-emitting layer and between the electron transport layer and the second electrode. When solving the interface problem between the electron transport layer and the light-emitting layer, it often brings about the interface problem between the electron transport layer and the second electrode, or when solving the interface problem between the electron transport layer and the second electrode, it brings about the interface problem between the electron transport layer and the light-emitting layer. Interface problems will affect the life of the light-emitting device, etc.

[0004] Therefore, how to solve the problem of the two interfaces between the electron transport layer and the adjacent film layer in the light-emitting device is an important strategy to improve the life of the light-emitting device. Summary of the invention

[0005] In view of this, the present application provides a light-emitting device and a method for preparing the same, and a display device, aiming to solve the interface problem between the electron transport layer and the adjacent film layer.

[0006] The embodiment of the present application is implemented as follows: a light-emitting device is provided, comprising a first electrode and a second electrode arranged opposite to each other; a light-emitting layer arranged between the first electrode and the second electrode; and an electronic functional layer arranged between the second electrode and the light-emitting layer; wherein the electronic functional layer comprises a stacked first electron transport layer and a second electron transport layer, the first electron transport layer being arranged close to one side of the light-emitting layer, and the second electron transport layer being arranged close to one side of the second electrode, wherein the material of the first electron transport layer comprises a first inorganic material, a first ligand being connected to the first inorganic material, the first ligand comprising a long carbon chain ligand having 4 to 12 carbon atoms, and the material of the second electron transport layer comprises a second inorganic material, a second ligand being connected to the second inorganic material, the second ligand comprising one or more of a short chain ligand having 1 to 3 carbon atoms or a hydroxyl ligand.

[0007] Optionally, in some embodiments of the present application, the electronic functional layer is composed of the first electron transport layer and the second electron transport layer; and / or, the molar percentage of the long carbon chain ligand with a carbon number of 4 to 12 in all ligands connected to the surface of the first inorganic material is greater than or equal to 20%; in the first electron transport layer, the mass percentage of carbon element is greater than or equal to 10%; and / or, the long carbon chain ligand with a carbon number of 4 to 12 includes a carboxylic acid ligand with a carbon number of 4 to 12, a carbon atom The short-chain ligands with carbon atoms of 1 to 3 include one or more of phosphate ligands with carbon atoms of 4 to 12, thiol ligands with carbon atoms of 4 to 12 or amine ligands with carbon atoms of 4 to 12; and / or, in the second electron transport layer, the molar percentage of the hydroxyl ligands is less than or equal to 10%; and / or, the short-chain ligands with carbon atoms of 1 to 3 include one or more of carboxylic acid ligands with carbon atoms of 1 to 3, phosphate ligands with carbon atoms of 1 to 3, thiol ligands with carbon atoms of 1 to 3 or amine ligands with carbon atoms of 1 to 3.

[0008] Optionally, in some embodiments of the present application, the carboxylic acid ligand having 4 to 12 carbon atoms includes one or more of butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, n-octanoic acid, n-decanoic acid, undecanoic acid, and lauric acid; and / or, the phosphate ligand having 4 to 21 carbon atoms includes one or more of n-hexyl phosphate, 1-octyl phosphate, 1-decyl phosphate, and n-dodecyl phosphate; and / or, the thiol ligand having 4 to 12 carbon atoms includes one or more of butanethiol, 1-pentanethiol, 1-hexanethiol, 1-heptanethiol, n-octanethiol, isooctanethiol, 1-decanethiol, 1-undecanethiol, and 1-dodecanethiol; and / or, the 4 The amine ligands having 1 to 12 carbon atoms include one or more of n-butylamine, pentylamine, hexylamine, heptylamine, n-octylamine, decylamine, 1-aminoundecane and dodecylamine; and / or the carboxylic acid ligands having 1 to 3 carbon atoms include one or more of formic acid ligands, acetic acid ligands and propionic acid ligands; and / or the phosphate ligands having 1 to 3 carbon atoms include phosphate ligands; and / or the thiol ligands having 1 to 3 carbon atoms include one or more of sulfhydryl ligands, methyl mercaptan ligands, ethyl mercaptan ligands and 1-propanethiol ligands; and / or the amine ligands having 1 to 3 carbon atoms include one or more of amine ligands, methylamine ligands, ethylamine ligands and propylamine ligands.

[0009] Optionally, in some embodiments of the present application, the first inorganic material includes at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3, and ZrO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, the doping element is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, the IIB-VIA semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the IIIB-VA semiconductor material is selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material is selected from at least one of CuInS and CuGaS; and / or the thickness of the first electron transport layer is 5 ~40nm; and / or, the second inorganic material includes at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3, and ZrO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, the doping element is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, the IIB-VIA semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the IIIB-VA semiconductor material is selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material is selected from at least one of CuInS and CuGaS; and / or, the thickness of the second electron transport layer is 5 to 40nm.

[0010] Optionally, in some embodiments of the present application, the first inorganic material is selected from Al-doped ZnO, and the second inorganic material is selected from doped ZnO or undoped ZnO, wherein the doping element included in the doped ZnO is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, and the second ligand includes a hydroxyl ligand.

[0011] Optionally, in some embodiments of the present application, the material of the light-emitting layer is selected from one or more of organic light-emitting materials or quantum dot light-emitting materials; the organic light-emitting material is selected from at least one of diaromatic anthracene derivatives, distilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, TBPe fluorescent materials emitting blue light, TTPA fluorescent materials emitting green light, TBRb fluorescent materials emitting orange light and DBP fluorescent materials emitting red light; the quantum dot light-emitting material is selected from at least one of single-structure quantum dots, core-shell structure quantum dots and perovskite semiconductor materials, and the single-structure quantum dots are selected from II-VI compounds, IV-VI compounds, III-V compounds and I-III- At least one of the Group VI compounds, the Group II-VI compound being selected from the group consisting 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, At least one of HgZnSeS, HgZnSeTe and HgZnSTe, the IV-VI group compound is selected from at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, the III-V group compound is selected from at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, at least one of 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 Group I-III-VI compound is at least one of CuInS, CuInSe and AgInS;The core of the quantum dots of the core-shell structure is selected from any one of the above-mentioned single-structure quantum dots, and the shell material of the quantum dots of the core-shell structure is selected from at least one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS and ZnS; the perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the general structural formula of the inorganic perovskite semiconductor is AMX3, wherein A is Cs; + ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2 + , Yb 2+ 、Eu 2+ At least one of, X is a halogen anion selected from Cl - Br - ,I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ 、Eu 2+ At least one of, X is a halogen anion selected from Cl - Br - ,I - At least one of; and / or,

[0012] The first electrode and the second electrode are independently selected from metal electrodes, carbon electrodes, doped or undoped metal oxide electrodes and composite electrodes; wherein the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Ni, Ir and Mg; the material of the carbon electrode is selected from at least one of graphite, carbon nanotubes, graphene and carbon fiber; the material of the doped or undoped metal oxide electrode is selected from ITO, FTO, ATO, AZO, GZO, IZO, MZO, ITZO, ICO, At least one of AMO, SnO2, In2O3, Cd:ZnO, F:SnO2, In:SnO2, and Ga:SnO2; the material of the composite electrode is selected from at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS; and / or,

[0013] The light-emitting device further comprises a hole functional layer, which is arranged between the first electrode and the light-emitting layer. The hole functional layer comprises at least one layer of a hole injection layer and a hole transport layer. The material of the hole transport layer is selected from arylamine, polyaniline, polypyrrole, poly(p-phenylene vinylene) and its derivatives, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, poly(N-vinyl carbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octyl)-1,1'-biphenyl compound, poly(p-carbazolyl ... Fluorene) and its derivatives, poly (spirofluorene) and its derivatives, doped or undoped NiO, MoO3, WO3, V2O5, CrO3, CuO, MoS2, MoSe2, WS3, WSe3, CuS, CuSCN one or more; wherein the aromatic amine is selected from 4,4'-bis (9-carbazole) biphenyl, poly (9,9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine), poly (N,N'-bis (4-butylphenyl) -N,N'-bis (phenyl) benzidine), N,N'-bis (4- (N,N'-diphenyl-amino) phenyl )-N,N'-diphenylbenzidine, poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine), 4,4',4"-tri(carbazol-9-yl)triphenylamine, 4,4',4"-tri(N-carbazolyl)-triphenylamine, 4,4',4"-tri(N-3-methylphenyl-N-phenylamino)triphenylamine, 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'- One or more of diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, Spiro-NPB, Spiro-TPD, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, Spiro-NPB; the poly(p-)phenylene vinylene and its derivatives are selected from one or more of poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene];The material of the hole injection layer is selected from poly(ethylenedioxythiophene): polystyrene sulfonate, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, copper phthalocyanine, poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine), polyarylamine, poly(N-vinylcarbazole), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine, 4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl, 4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine, 4,4' ,4"-tri(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[(di-4-tolylamino)phenylcyclohexane, 4,4',4"-tri(diphenylamino)triphenylamine doped with F4-TCNQ, p-doped phthalocyanine, F4-TCNQ doped N,N'-diphenyl-N,N'-di(1-naphthyl)-1,1'-biphenyl-4,4"-diamine, transition metal oxides, transition metal sulfur compounds, one or more thereof; wherein the transition metal oxides include one or more of NiO, MoO2, WO3, and CuO; the metal sulfur compounds include one or more of MoS2, MoSe2, WS3, WSe3, and CuS;

[0014] Correspondingly, an embodiment of the present application also provides a method for preparing a light-emitting device, the preparation method comprising: providing a preset device, the preset device comprising a second electrode; arranging an electronic functional layer on the preset device; arranging a light-emitting layer on the electronic functional layer; forming a first electrode on the light-emitting layer; or, the preparation method comprises: providing a preset device, the preset device comprising a stacked first electrode and a light-emitting layer; forming an electronic functional layer on the preset device; forming a second electrode on the electronic functional layer; wherein the electronic functional layer comprises a first electron transport layer and a second electron transport layer, the first electron transport layer is arranged close to one side of the light-emitting layer, and the second electron transport layer is arranged close to one side of the second electrode; wherein the material of the first electron transport layer comprises a first inorganic material, a first ligand is connected to the first inorganic material, the first ligand comprises a long carbon chain ligand with a carbon number of 4 to 12, and the material of the second electron transport layer comprises a second inorganic material, a second ligand is connected to the second inorganic material, and the second ligand comprises one or more of a short chain ligand with a carbon number of 1 to 3 or a hydroxyl ligand.

[0015] Optionally, in some embodiments of the present application, the forming of the electronic functional layer on the preset device includes forming a first electron transport layer and forming a second electron transport layer; wherein, the forming of the first electron transport layer includes: providing a first solution, the first solution includes a first inorganic material and a first solvent, the first inorganic material is connected to the first ligand; and, setting the second solution to obtain the first electron transport layer; wherein, the forming of the second electron transport layer includes: providing a second solution, the second solution includes a second inorganic material and a second solvent; and, setting the second solution to obtain the second electron transport layer.

[0016] Optionally, in some embodiments of the present application, in the first solution, the concentration of the first inorganic material is 10 to 50 mg / mL; and / or, the first solvent is selected from a non-polar solvent; and / or, the molar percentage of the long carbon chain ligand with 4 to 12 carbon atoms in the first ligand is greater than or equal to 20%; and / or, the long carbon chain ligand with 4 to 12 carbon atoms includes one or more of a carboxylic acid ligand with 4 to 12 carbon atoms, a phosphate ligand with 4 to 12 carbon atoms, a thiol ligand with 4 to 12 carbon atoms, or an amine ligand with 4 to 12 carbon atoms; and / or, the first inorganic material includes a metal oxide, a doped metal oxide, At least one of the semiconductor materials of Group IIB-VIA, Group IIIB-VA and Group IB-IIIB-VIA, the metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3 and ZrO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2 and SnO2, the doping element is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y and In, the semiconductor materials of Group IIB-VIA are selected from at least one of ZnS, ZnSe and CdS; the IIIB-VA semiconductor The conductor material is selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material is selected from at least one of CuInS and CuGaS; and / or, in the second solution, the concentration of the second inorganic material is 10 to 50 mg / mL; and / or, the second solvent is selected from polar solvents; and / or, the short-chain ligand having 1 to 3 carbon atoms includes a hydroxyl ligand; and / or, the second inorganic material includes at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, and the metal oxide is selected from At least one of ZnO, TiO2, SnO2, BaO, Ga2O3, and ZrO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, the doping element is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, the IIB-VIA semiconductor family material is selected from at least one of ZnS, ZnSe, and CdS; the IIIB-VA semiconductor family material is selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material is selected from at least one of CuInS and CuGaS.

[0017] Optionally, in some embodiments of the present application, the non-polar solvent includes one or more of n-hexane, cyclohexane, n-pentane, isopentane, n-octane, and n-nonane; and / or, the polar solvent includes one or more of ethanol, isopropanol, n-butanol, and n-pentanol; and / or, the carboxylic acid ligand with a carbon number of 4 to 12 includes one or more of butyric acid, valeric acid, hexanoic acid, heptanoic acid, n-octanoic acid, n-decanoic acid, undecanoic acid, and lauric acid; and / or, the phosphate ligand with a carbon number of 4 to 21 includes n-hexyl The amine ligands having 4 to 12 carbon atoms include one or more of butylamine, pentylamine, hexylamine, heptylamine, 1-aminoundecane and dodecylamine.

[0018] Optionally, in some embodiments of the present application, before forming the second electron transport layer, the second inorganic material is also prepared, including: providing a fourth solution, the fourth solution including a second metal source and a fourth solvent; adding a second base to the fourth solution, mixing and reacting to obtain the second inorganic material; wherein the molar ratio of the metal element in the second metal source to the second base is 1:(0.8~1.1).

[0019] Correspondingly, an embodiment of the present application further provides a display device, comprising the above-mentioned light-emitting device.

[0020] The light-emitting device of the present application includes a long carbon chain ligand with a carbon number of 4 to 12 in the first electron transport layer close to the light-emitting layer, and the second ligand connected to the second electron transport layer includes one or more of a short chain ligand with a carbon number of 1 to 3 or a hydroxyl ligand. By setting the ligands of the first electron transport layer and the second electron transport layer, the distance between the electronic functional layer and the light-emitting layer can be increased, the recombination efficiency of the light-emitting layer can be improved, damage to the electronic functional layer can be avoided, the life of the light-emitting device can be improved, and dissolution and penetration damage to a previously prepared film layer can be avoided, thereby improving the film quality of the electronic functional layer, reducing the possibility of leakage in the light-emitting device, and improving the life of the light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A structural schematic diagram of an embodiment of a light emitting device is provided for the present application;

[0023] Figure 2 A schematic diagram of a process of an embodiment of a method for preparing a light-emitting device provided in the present application;

[0024] Figure 3 A schematic diagram of another embodiment of a method for preparing a light-emitting device provided in the present application;

[0025] Figure 4 AFM surface morphology image;

[0026] Figure 5 is a dissolution state diagram of aluminum-doped zinc oxide corresponding to device comparative example 3;

[0027] Figure numerals: 100 - light-emitting device; 10 - first electrode; 20 - second electrode; 30 - light-emitting layer; 40 - electron functional layer; 41 - first electron transport layer; 42 - second electron transport layer; 50 - hole functional layer, hole injection layer 51, hole transport layer 52. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words such as "upper" and "lower" used are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the stated range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the stated range.

[0029] In this application, "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0030] In the present application, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0031] The present application provides a light emitting device, referring to Figure 1 , Figure 1 The present application provides a structural schematic diagram of an embodiment of a light-emitting device, wherein the light-emitting device 100 includes a first electrode 10 and a second electrode 20 that are relatively arranged, and a light-emitting layer 30 that is arranged between the first electrode 10 and the second electrode 20, and an electronic functional layer 40 that is arranged between the second electrode 20 and the light-emitting layer 30.

[0032] Among them, the electronic functional layer 40 includes a first electron transport layer 41 and a second electron transport layer 42, the first electron transport layer 41 is arranged close to the side of the light-emitting layer 30, and the second electron transport layer 42 is arranged close to the side of the second electrode 20, wherein the material of the first electron transport layer 41 includes a first inorganic material, a first ligand is connected to the first inorganic material, and the first ligand includes a long carbon chain ligand with a carbon number of 4 to 12, and the material of the second electron transport layer includes a second inorganic material, a second ligand is connected to the second inorganic material, and the second ligand includes one or more of a short chain ligand or a hydroxyl ligand with a carbon number of 1 to 3.

[0033] In this embodiment, in the first electron transport layer 41 close to the light-emitting layer 30, the surface of the first inorganic material is connected with a long carbon chain ligand with a carbon number of 4 to 12, which can improve the recombination efficiency of the light-emitting layer 30, avoid damage to the electronic functional layer 40, and reduce electron injection and electron mobility. In the second electron transport layer 42 close to the second electrode 20, the surface of the second inorganic material is connected with one or more short chain ligands or hydroxyl ligands with a carbon number of 1 to 3, which can improve electron mobility and promote electron transport, thereby improving the efficiency of the light-emitting device 100. In addition, the setting of the ligands in the first electron transport layer 41 and the second electron transport layer 42 can avoid dissolution and penetration damage to a previously prepared film layer, thereby improving the film quality of the electronic functional layer 40, reducing the possibility of leakage of the light-emitting device 100, and improving the efficiency and life of the light-emitting device 100.

[0034] Specifically, in the first electron transport layer 41 close to the light-emitting layer 30, the surface of the first inorganic material is connected with a long carbon chain ligand with 4 to 12 carbon atoms, which can increase the distance between the electronic functional layer 40 and the light-emitting layer 30, which is equivalent to inserting a thinner insulating barrier layer between the electronic functional layer 40 and the light-emitting layer 30, so that the excitons generated in the light-emitting layer 30 will not continue to transfer to the energy level position of the electronic functional layer 40, that is, the excitons are restricted in the area of ​​the light-emitting layer 30, and the non-radiative recombination of the excitons at the trap energy level on the surface of the first electron transport layer 41 close to the light-emitting layer 30 is reduced, thereby improving the recombination efficiency of the light-emitting layer 30 and avoiding damage to the electronic functional layer 40; in addition, it can also reduce the electron injection and electron mobility to a certain extent, thereby improving the carrier balance in the light-emitting device 100 of the electron injection excess type and improving the luminescence performance.

[0035] It can be understood that in the first electron transport layer 41, the surface of the first inorganic material is connected with a long carbon chain ligand with a carbon number of 4 to 12, so that the material of the first electron transport layer 41 has good solubility and dispersibility in non-polar solvents. In the second electron transport layer 42, the surface of the second inorganic material is connected with one or more short chain ligands or hydroxyl ligands with a carbon number of 1 to 3, which can increase the surface polarity of the second inorganic material, so that it has good solubility and dispersibility in polar solvents. When the first electron transport layer 41 and the second electron transport layer 42 are prepared by a solution method, after one of the first prepared layers of the first electron transport layer 41 and the second electron transport layer 42 is prepared, the film layer prepared later avoids dissolving and penetrating damage to the first prepared film layer during the preparation process, thereby improving the film quality of the electronic functional layer 40, reducing the possibility of leakage of the light-emitting device 100, and thus improving the efficiency and life of the light-emitting device 100.

[0036] For example, after preparing the first electron transport layer 41, when preparing the second electron transport layer 42 on the first electron transport layer 41 by a solution method, the solvent used may be a polar solvent, which will not dissolve or damage the first electron transport layer 41. After preparing the second electron transport layer 42, when preparing the first electron transport layer 41 on the second electron transport layer 42 by a solution method, the solvent used may be a non-polar solvent, which will not dissolve or damage the second electron transport layer 42.

[0037] It can be understood that the polar solvent and the non-polar solvent can be polar or non-polar solvents known in the art. For example, the polar solvent can include one or more of ethanol, isopropanol, n-butanol, n-pentanol, etc., and the non-polar solvent can include one or more of n-hexane, n-octane, n-nonane, etc.

[0038] Specifically, the long carbon chain ligand with 4 to 12 carbon atoms includes one or more of a carboxylic acid ligand with 4 to 12 carbon atoms, a phosphate ligand with 4 to 12 carbon atoms, a thiol ligand with 4 to 12 carbon atoms, or an amine ligand with 4 to 12 carbon atoms.

[0039] Furthermore, the carboxylic acid ligand having 4 to 12 carbon atoms includes one or more of butyric acid, valeric acid, hexanoic acid, heptanoic acid, n-octanoic acid, n-decanoic acid, undecanoic acid, lauric acid and the like.

[0040] The phosphate ligand having 4 to 21 carbon atoms includes one or more of n-hexyl phosphate, 1-octyl phosphate, 1-decyl phosphate, n-dodecyl phosphate and the like.

[0041] The thiol ligand having 4 to 12 carbon atoms includes one or more of butyl mercaptan, 1-pentyl mercaptan, 1-hexyl mercaptan, 1-heptyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, 1-decyl mercaptan, 1-undecanethiol, 1-dodecanethiol and the like.

[0042] The amine ligand having 4 to 12 carbon atoms includes one or more of n-butylamine, pentylamine, hexylamine, heptylamine, n-octylamine, decylamine, 1-aminoundecane, dodecylamine and the like.

[0043] In this embodiment, the long-chain ligand with 4 to 12 carbon atoms can form a steric hindrance effect, has good stability and relatively good charge conductivity, and avoids poor charge conductivity that hinders electron transfer, thereby causing the operating voltage of the light-emitting device 100 to be too high.

[0044] In one embodiment, the molar percentage of the long carbon chain ligand with carbon number of 4 to 12 in all the ligands connected to the surface of the first inorganic material is greater than or equal to 20%. Specifically, it can be 20% to 50%, 20% to 30%, 30% to 40%, 40% to 50%, 20% to 70%, 20% to 80%, 20% to 90%, etc. It can be understood that the ligands connected to the surface of the first inorganic material, in addition to the long carbon chain ligand with carbon number of 4 to 12, also include other ligands. Specifically, the ligand can be introduced by the reaction precursor, or by the ligand introduced by the additionally added ligand reagent or ligand solvent, such as acetate ligand, hydroxyl ligand, etc. The molar percentage of the long carbon chain ligand to all the ligands is greater than or equal to 20%, that is, the number of the long carbon chain ligand accounts for a percentage of the total number of ligands greater than or equal to 20%, which can prevent the surface contact between the first inorganic material and the material of the light-emitting layer 30 through the steric hindrance effect.

[0045] In one embodiment, in the first electron transport layer 41, the mass percentage of the carbon (C) element is greater than or equal to 10%, and can be specifically 10-15%, 10-15%, 15-18%, 18-20%, 20-25%, 25-30%, etc. Further, in a specific embodiment, the mass percentage of the carbon element is 10-18%, and can be specifically 10-16%, 12-16%, 12-14%, 10-12%, 16-18%, etc. It can be understood that in the first electron transport layer 41, the larger the mass percentage of the carbon (C) element, the larger the proportion of ligands with longer chain lengths.

[0046] In one embodiment, the first inorganic material includes at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide being selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3 and ZrO2; the metal oxide in the doped metal oxide being selected from at least one of ZnO and TiO2, the doping element being selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y and In; the IIB-VIA semiconductor material being selected from at least one of ZnS, ZnSe and CdS; the IIIB-VA semiconductor material being selected from at least one of InP and GaP; and the IB-IIIB-VIA semiconductor material being selected from at least one of CuInS and CuGaS.

[0047] In one embodiment, the first inorganic material is selected from the doped metal oxide, in which the molar ratio of the metal oxide to the doping element can be (100-3):1, such as (100-5):1, (80-10):1, (80-10):1, (60-10):1, (60-30):1, (40-30):1, (30-20):1, (20-10):1, (10-5):1, etc.

[0048] In a specific embodiment, the first inorganic material is selected from doped or undoped ZnO.

[0049] Furthermore, the doping element in the doped ZnO is selected from Al, which can improve the film morphology of the first electron transport layer 41 and make it smoother. In addition, the first electron transport layer 41 with a smoother surface is more conducive to setting other film layers on the first electron transport layer 41, such as improving the thickness uniformity of other film layers, and will not cause tailing or poor contact.

[0050] In one embodiment, the second inorganic material in the second electron transport layer 42 includes at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3, and ZrO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, the doping element is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, the IIB-VIA semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the IIIB-VA semiconductor material is selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material is selected from at least one of CuInS and CuGaS.

[0051] In a specific embodiment, the second inorganic material is selected from doped or undoped ZnO.

[0052] It is understandable that the second inorganic material may be the same as the first inorganic material or different from the first inorganic material. In a specific embodiment, the first inorganic material is selected from doped or undoped ZnO, and the second inorganic material is selected from doped or undoped ZnO.

[0053] In one embodiment, the second ligand comprises a hydroxyl ligand.

[0054] Furthermore, in the second electron transport layer 42, the molar percentage of the hydroxyl ligand is less than or equal to 10%, or the molar percentage of the hydroxyl ligand in the second ligand is less than or equal to 10%, specifically greater than 0 and less than 1%, 1-10%, 1-8%, 3-8%, 3-6%, 5-6%, etc. The range of the molar percentage of the hydroxyl ligand can improve the dispersibility and solubility of the material of the second electron transport layer 42 in polar solvents while avoiding a greater negative impact on electron transport. Specifically, the oxygen in the hydroxyl ligand in contact with the second electrode 20 may have a certain negative effect on electron transport, such as oxidizing the metal in the second electrode 20.

[0055] In one embodiment, the second ligand comprises a short-chain ligand having 1 to 3 carbon atoms.

[0056] Furthermore, the short-chain ligand with 1 to 3 carbon atoms may also include one or more of a carboxylic acid ligand with 1 to 3 carbon atoms, a phosphate ligand with 1 to 3 carbon atoms, a thiol ligand with 1 to 3 carbon atoms, or an amine ligand with 1 to 3 carbon atoms.

[0057] Specifically, the carboxylic acid ligand having 1 to 3 carbon atoms includes one or more of formic acid ligand, acetic acid (acetic acid) ligand, and propionic acid ligand.

[0058] The phosphate ligand having 1 to 3 carbon atoms includes phosphate ligands and the like.

[0059] The thiol ligand having 1 to 3 carbon atoms includes one or more of a thiol ligand, a methylthiol ligand, an ethylthiol ligand, and a 1-propanethiol ligand.

[0060] The amine ligand having 1 to 3 carbon atoms includes one or more of an amino ligand, a methylamine ligand, an ethylamine ligand, and a propylamine ligand.

[0061] In this embodiment, the short-chain ligand with a shorter chain length is connected to the second inorganic material. On the one hand, it can improve the electron mobility of the second electron transport layer 42 and promote electron transport. On the other hand, it can increase the surface polarity of the second inorganic material, making it have better solubility and dispersibility in polar solvents.

[0062] In one embodiment, the electronic functional layer 40 is composed of the first electron transport layer 41 and the second electron transport layer 42. The electronic functional layer 40 includes a double-layer structure, which can improve the interface problem between the electronic functional layer 40 and the second electrode 20, and the interface problem between the electronic functional layer 40 and the light-emitting layer 30 on the basis of improving electron injection and transport, and can also avoid the problem of dissolution damage during stacking preparation, thereby improving the efficiency and life of the light-emitting device 100.

[0063] In one embodiment, the thickness of the first electron transport layer 41 is 5-40 nm, specifically 5-35 nm, 10-35 nm, 10-30 nm, 15-30 nm, 15-25 nm, 20-25 nm, etc.

[0064] In one embodiment, the thickness of the second electron transport layer 42 is 5-40 nm, specifically 5-35 nm, 10-35 nm, 10-30 nm, 15-30 nm, 15-25 nm, 20-25 nm, etc.

[0065] In one embodiment, the material of the light-emitting layer 30 is selected from one or more of organic light-emitting materials and quantum dot light-emitting materials.

[0066] The organic light-emitting material is selected from at least one of diaromatic anthracene derivatives, distyrene aromatic derivatives, pyrene derivatives or fluorene derivatives, TBPe fluorescent materials emitting blue light, TTPA fluorescent materials emitting green light, TBRb fluorescent materials emitting orange light, and DBP fluorescent materials emitting red light.

[0067] The quantum dot luminescent material can be selected from at least one of a single structure quantum dot, a core-shell structure quantum dot and a perovskite semiconductor material. The single structure quantum dot is selected from at least one of a II-VI group compound, a IV-VI group compound, a III-V group compound and a I-III-VI group compound. The II-VI group compound is selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdS At least one of dZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe and HgZnSTe, and the IV-VI group compound is selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, Sn At least one of PbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, and the III-V compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb , GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs and InAlPSb, the I-III-VI group compound is selected from at least one of CuInS, CuInSe and AgInS; the core of the quantum dots of the core-shell structure is selected from any one of the above-mentioned single-structure quantum dots, and the shell material of the quantum dots of the core-shell structure is selected from at least one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS and ZnS;

[0068] The perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the inorganic perovskite semiconductor has a general structural formula of AMX3, wherein A is Cs + ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ 、Eu 2+ At least one of, X is a halogen anion selected from Cl - Br - ,I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ 、Eu 2+ At least one of, X is a halogen anion selected from Cl - Br - ,I - When n=2, the inorganic metal halide octahedron MX6 4- The metal cation M is located at the center of the halogen octahedron, and the organic amine cation B fills the gap between the octahedrons to form an infinitely extended three-dimensional structure. When n>2, the inorganic metal halide octahedron MX6 connected by the top-sharing method 4- It extends in two dimensions to form a layered structure, with an organic amine cation bilayer (protonated monoamine) or an organic amine cation monolayer (protonated diamine) inserted between the layers, and the organic layer and the inorganic layer overlap to form a stable two-dimensional layered structure.

[0069] In a specific embodiment, the material of the light-emitting layer 30 is selected from the quantum dot light-emitting material.

[0070] The thickness of the light emitting layer 30 may be 15 to 40 nm, specifically 15 to 35 nm, 25 to 35 nm, 25 to 30 nm, 30 to 40 nm, etc.

[0071] In one embodiment, the light emitting device 100 may further include a hole functional layer 50, and the hole functional layer 50 is disposed between the first electrode 10 and the light emitting layer 30. The hole functional layer 50 may include a hole injection layer 51 and / or a hole transport layer 52. When the hole functional layer 50 includes two layers, the hole injection layer 51 and the hole transport layer 52, the hole injection layer 51 is disposed close to the first electrode 10, and the hole transport layer 52 is disposed close to the light emitting layer 30.

[0072] In one embodiment, the thickness of the hole injection layer 51 may be 20-200 nm, specifically 20-150 nm, 80-150 nm, 80-120 nm, etc. The thickness of the hole transport layer 52 may be 30-180 nm, specifically 30-150 nm, 50-150 nm, 50-120 nm, 80-120 nm, 80-100 nm, etc.

[0073] The material of the hole transport layer 52 is selected from arylamine, polyaniline, polypyrrole, poly(p-)phenylene vinylene and its derivatives, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, poly(N-vinylcarbazole) (PVK) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped or undoped NiO, MoO3, WO3, V2O5, CrO3, CuO, MoS2, MoSe2, WS3, WSe3 , CuS, CuSCN; wherein the aromatic amine is selected from 4,4'-bis(9-carbazole)biphenyl (CBP), poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine) (poly-TPD), N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTPD), poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine) (PFB), 4 ,4',4"-tri(carbazol-9-yl)triphenylamine (TCATA), 4,4',4"-tri(N-carbazol-9-yl)triphenylamine (TCTA), 4,4',4"-tri(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine (α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl- One or more of 4,4'-diamine (NPB), Spiro-NPB, Spiro-TPD, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro(spiro-TPD), and spiro-NPB; the poly(p-)phenylene vinylene and its derivatives are selected from one or more of poly(phenylene vinylene) (PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MOMO-PPV).

[0074] The material of the hole injection layer 51 is a material having hole injection capability, selected from poly(ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN), copper phthalocyanine (CuPc ), poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine) (TFB), polyarylamine, poly(N-vinylcarbazole), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), 4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA), 4,4',4"-tri(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[(di-4-tolylamino)phenylcyclohexane (TAPC), 4,4',4"-tri(diphenylamino)triphenylamine (TDATA) doped with F4-TCNQ, p-doped phthalocyanine (e.g., F4-TCNQ-doped zinc phthalocyanine (ZnPc)), F4-TCNQ-doped N,N'-diphenyl-N,N'-di(1-naphthyl)-1,1'-biphenyl-4,4"-diamine (α-NPD), transition metal oxides, transition metal sulfur compounds; wherein the transition metal oxides include one or more of NiO, MoO2, WO3, CuO; the metal sulfur compounds include one or more of MoS2, MoSe2, WS3, WSe3, CuS.

[0075] In one embodiment, the first electrode 10 and the second electrode 20 are independently selected from metal electrodes, carbon electrodes, doped or undoped metal oxide electrodes and composite electrodes; wherein the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Ni, Ir and Mg; the material of the carbon electrode is selected from at least one of graphite, carbon nanotubes, graphene and carbon fiber; the material of the doped or undoped metal oxide electrode is selected from ITO, FTO, ATO, AZO, GZO, IZO, MZO, I At least one of TZO, ICO, AMO, SnO2, In2O3, Cd:ZnO, F:SnO2, In:SnO2, and Ga:SnO2; the material of the composite electrode is selected from at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS. Wherein, " / " represents a stacked structure, for example, the composite electrode AZO / Ag / AZO represents an electrode of a composite structure of three stacked layers consisting of an AZO layer, an Ag layer, and an AZO layer.

[0076] In one embodiment, the first electrode 10 is an anode, and the second electrode 20 is a cathode.

[0077] In one embodiment, the first electrode 10 is composed of a conductive material with a relatively high work function, and may be composed of a doped or undoped metal oxide, such as ITO, IZO, ITZO, ICO, SnO2, In2O3, Cd:ZnO, F:SnO2, In:SnO2, Ga:SnO2 or AZO, etc.; or in addition to the above-mentioned metal oxides, it may be composed of a metal material including nickel (Ni), platinum (Pt), gold (Au), silver (Ag), iridium (Ir) or CNT.

[0078] In one embodiment, the second electrode 20 is composed of a conductive material with a relatively low work function, which may be one or more of Ca, Ba, Ca / Al, LiF / Ca, LiF / Al, BaF2 / Al, CsF / Al, CaCO3 / Al, BaF2 / Ca / Al, Al, Mg, Au:Mg or Ag:Mg.

[0079] It is understandable that, in addition to the above-mentioned functional layers, the light-emitting device 100 may also be provided with some functional layers conventionally used in light-emitting devices to help improve the performance of the light-emitting device, such as an electron blocking layer, an electron injection layer, a hole blocking layer and / or an interface modification layer.

[0080] It can be understood that the material and thickness of each layer of the light-emitting device 100 can be set and adjusted accordingly according to the light-emitting requirements of the light-emitting device 100 .

[0081] The light emitting device 100 further includes a substrate (not shown), which may also be referred to as a substrate. The substrate may be a rigid substrate or a flexible substrate. The rigid substrate may be a ceramic material or various glass materials. The flexible substrate may be a substrate formed of materials such as polyimide film (PI) and its derivatives, polyethylene naphthalate (PEN), phosphoenolpyruvic acid (PEP) or diphenylene ether resin. In one embodiment, the material of the substrate includes glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyether sulfone, or a combination thereof.

[0082] It can be understood that when the first electrode 10 or the second electrode 20 is connected to the substrate, it can be called a bottom electrode, and the one away from the substrate is a top electrode, wherein the thickness of the bottom electrode can be 20 to 200 nm, and the thickness of the top electrode can be 40 to 190 nm.

[0083] It can be understood that the light emitting device 100 can be an upright light emitting device or an inverted light emitting device. When the light emitting device 100 is an upright light emitting device, the substrate is combined with a side of the first electrode 10 away from the light emitting layer 30. When the light emitting device 100 is an inverted light emitting device, the substrate is combined with a side of the second electrode 20 away from the light emitting layer 30.

[0084] The present application also provides a method for preparing a light-emitting device to prepare a light-emitting device with good luminous efficiency.

[0085] See also Figure 2 , Figure 2 The present invention provides a flow chart of a method for preparing a light-emitting device according to an embodiment of the present invention, which specifically includes the following steps:

[0086] Step S11: providing a preset device, wherein the preset device includes a second electrode;

[0087] Step S12: forming an electronic functional layer on the preset device;

[0088] Step S13: forming a stacked light-emitting layer and a first electrode on the electronic functional layer.

[0089] The light-emitting device prepared in this embodiment is an inverted device.

[0090] See also Figure 3 , Figure 3A schematic flow chart of another embodiment of a method for preparing a light-emitting device provided in the present application specifically includes the following steps:

[0091] Step S21: providing a preset device, wherein the preset device includes a stacked first electrode and a light-emitting layer;

[0092] Step S22: forming an electronic functional layer on the preset device;

[0093] Step S23: forming a second electrode on the electronic functional layer.

[0094] The light-emitting device prepared in this embodiment is an upright device.

[0095] In the above two embodiments, the electronic functional layer includes a first electron transport layer and a second electron transport layer, the first electron transport layer is arranged close to the light emitting layer, and the second electron transport layer is arranged close to the second electrode;

[0096] Among them, the material of the first electron transport layer includes a first inorganic material, a first ligand is connected to the first inorganic material, and the first ligand includes a long carbon chain ligand with a carbon number of 4 to 12; the material of the second electron transport layer includes a second inorganic material, a second ligand is connected to the second inorganic material, and the second ligand includes one or more of a short chain ligand or a hydroxyl ligand with a carbon number of 1 to 3.

[0097] In the above two embodiments, in the first electron transport layer close to the light-emitting layer 30, the surface of the first inorganic material is connected with a long carbon chain ligand with a carbon number of 4 to 12, which can improve the recombination efficiency of the light-emitting layer, avoid damage to the electronic functional layer, and reduce electron injection and electron mobility, while in the second electron transport layer close to the second electrode, the surface of the second inorganic material is connected with one or more of a short chain ligand or a hydroxyl ligand with a carbon number of 1 to 3, which can improve electron mobility and promote electron transport, thereby improving the efficiency of the light-emitting device. In addition, the setting of the ligands in the first electron transport layer and the second electron transport layer can avoid dissolution and penetration damage to a previously prepared film layer, thereby improving the film quality of the electronic functional layer, reducing the possibility of leakage of the light-emitting device, and thus improving the efficiency and life of the light-emitting device.

[0098] In step S12 and step S22, forming an electronic functional layer on the preset device includes:

[0099] A first electron transport layer is formed, and a second electron transport layer is formed, wherein the first electron transport layer is formed on a side close to the light-emitting layer, and the second electron transport layer is formed on a side away from the light-emitting layer.

[0100] It is understandable that the first electron transport layer may be formed first, and then the second electron transport layer may be formed on the first electron transport layer; or the second electron transport layer may be formed first, and then the first electron transport layer may be formed on the second electron transport layer.

[0101] Wherein, the forming of the first electron transport layer specifically includes:

[0102] Step S31: providing a first solution, wherein the first solution includes a first inorganic material and a first solvent;

[0103] Wherein, the surface of the first inorganic material is connected with a long carbon chain ligand having 4 to 12 carbon atoms;

[0104] Step S32: setting the first solution to form a wet film, and drying to obtain the first electron transport layer.

[0105] In one embodiment, in the first solution, the concentration of the first inorganic material is 10-50 mg / mL, specifically 10-45 mg / mL, 15-45 mg / mL, 15-40 mg / mL, 20-40 mg / mL, 20-35 mg / mL, 25-35 mg / mL, etc.

[0106] The forming of the second electron transport layer specifically includes:

[0107] Step S41: providing a second solution, wherein the second solution includes a second inorganic material and a second solvent;

[0108] Step S42: setting the second solution to form a wet film, and drying to obtain the second electron transport layer.

[0109] In this embodiment, the first electron transport layer and the second electron transport layer are formed by a solution method. In the first electron transport layer close to the light-emitting layer, the surface of the first inorganic material is connected with the long carbon chain ligand with 4 to 12 carbon atoms, which can increase the distance between the electronic functional layer and the light-emitting layer, which is equivalent to inserting a thin insulating barrier layer between the electronic functional layer and the light-emitting layer, so that the excitons generated in the light-emitting layer will not continue to transfer to the energy level position of the electronic functional layer, that is, limit the excitons in the area of ​​the light-emitting layer, reduce the non-radiative recombination of the excitons at the trap energy level on the surface of the first electron transport layer close to the light-emitting layer, thereby improving the recombination efficiency of the light-emitting layer and avoiding damage to the electronic functional layer; in addition, it can also reduce the electron injection and electron mobility to a certain extent, thereby improving the carrier balance in the light-emitting device of the electron injection excess type and improving the luminescence performance. In the second electron transport layer close to the second electrode, the surface of the second inorganic material is connected with a short chain ligand with 1 to 3 carbon atoms, which can improve the electron mobility, promote electron transport, and thus improve the efficiency of the light-emitting device.

[0110] In this embodiment, the description of the first inorganic material, the second inorganic material, the long carbon chain ligand with 4 to 12 carbon atoms, the short chain ligand with 1 to 3 carbon atoms, etc. can refer to the corresponding content in the light-emitting device 100 described above, and will not be repeated here.

[0111] Specifically, the first solvent can be selected from non-polar solvents, and specifically can include one or more of n-hexane, cyclohexane, n-pentane, isopentane, n-octane, n-nonane, etc. The second solvent can be selected from polar solvents, and specifically can include one or more of ethanol, isopropanol, n-butanol, n-pentanol, etc. It can be understood that the first solvent can be a single solvent or a mixed solvent, and the second solvent can be a single solvent or a mixed solvent.

[0112] In one embodiment, in the second solution, the concentration of the second inorganic material is 10-50 mg / mL, specifically 10-45 mg / mL, 15-45 mg / mL, 15-40 mg / mL, 20-40 mg / mL, 20-35 mg / mL, 25-35 mg / mL, etc.

[0113] In the above-mentioned forming of the first electron transport layer and forming of the second electron transport layer, a drying step is included. The drying can be heating drying, the heating drying temperature is 60 to 150° C., and the time is 1 min to 30 min. The drying can be vacuum drying, and the vacuum drying pressure is 10 -1 ~10 -2Pa, the temperature is 0-30°C, for example, it can be at room temperature of about 25°C.

[0114] In one embodiment, before forming the first electron transport layer, the method further includes preparing a first electron transport material, specifically including:

[0115] Step S51: providing a third solution, wherein the third solution comprises a first metal source, a first ligand solvent and a third solvent, wherein the carbon chain length of the first ligand solvent is 4 to 12 carbon atoms;

[0116] Step S52: adding the first base to the third solution, mixing and reacting to obtain the first inorganic material connected with the first ligand solvent.

[0117] In step S51:

[0118] In one embodiment, the first metal source includes a first main metal source, and the first main metal source includes one or more of a first zinc source and a first titanium source; wherein the first zinc source may include at least one of diethyl zinc, zinc oleate, zinc stearate, zinc acetate, zinc laurate and zinc oxide, and the first titanium source may include one or more of tetrabutyl titanate, isopropyl titanate, titanyl sulfate, titanium tetrachloride, etc.

[0119] Furthermore, the first metal source also includes a first doping metal source, which may include one or more of a Mg source, a Ca source, a Li source, a Ga source, an Al source, a Co source, a Mn source, a Zr source, a W source, a Ti source, a Y source, an In source, etc. Specifically, the first doping metal source may be selected from corresponding metal salts and hydrates thereof, etc., which are not limited here.

[0120] In one embodiment, the first doping metal source includes an aluminum (Al) source, and the aluminum source includes one or more of aluminum acetate and its hydrate, aluminum nitrate and its hydrate, aluminum sulfate and its hydrate, and aluminum chloride and its hydrate.

[0121] In a specific embodiment, the first doping metal source includes a magnesium (Mg) source, and the magnesium source includes one or more of magnesium acetate and its hydrate, magnesium nitrate and its hydrate, magnesium sulfate and its hydrate, and magnesium chloride and its hydrate.

[0122] In one embodiment, the molar ratio of the metal element in the first main metal source to the first doping element in the first doping metal source is (100-3):1, for example, (100-5):1, (80-10):1, (80-10):1, (60-10):1, (60-30):1, (40-30):1, (30-20):1, (20-10):1, (10-5):1, etc.

[0123] The first ligand solvent includes one or more of a carboxylic acid solvent having 4 to 12 carbon atoms, a thiol solvent having 4 to 12 carbon atoms, an amine solvent having 4 to 12 carbon atoms, and a phosphoric acid solvent having 4 to 12 carbon atoms.

[0124] Specifically, the carboxylic acid solvent with 4 to 12 carbon atoms includes one or more of butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, n-octanoic acid, n-decanoic acid, undecanoic acid, dodecanoic acid (lauric acid), etc. The thiol solvent with 4 to 12 carbon atoms includes one or more of butyl mercaptan, hexyl mercaptan, 1-heptyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, 1-decyl mercaptan, 1-undecyl mercaptan, 1-dodecanethiol, 1-pentyl mercaptan, etc. The amine solvent with 4 to 12 carbon atoms includes one or more of n-butylamine, pentylamine, hexylamine, heptylamine, n-octylamine, decylamine, 1-aminoundecane, dodecylamine, etc. The phosphoric acid solvent with 4 to 12 carbon atoms includes one or more of n-hexyl phosphoric acid, 1-octyl phosphoric acid, 1-decyl phosphoric acid, n-dodecyl phosphoric acid, etc.

[0125] In one embodiment, the first metal source includes a first metal cation and a first anion, wherein the first metal cation includes a first main metal and a first doping metal. The molar ratio of the first ligand solvent to the first anion is greater than or equal to 2:5, that is, greater than or equal to 40%, specifically 40% to 60%, 60% to 70%, 70% to 80%, etc. The molar ratio of the first ligand solvent to the first anion can make the molar percentage of the long-chain ligand connected to the surface of the first inorganic material finally formed greater than or equal to 20% of all ligands.

[0126] The third solvent may include one or more of dimethyl sulfoxide, N,N-dimethylformamide, methanol, ethanol, and tetrahydrofuran.

[0127] In one embodiment, the first metal source, the first ligand solvent and the third solvent are stirred and condensed under reflux at 20 to 80° C. for 1 to 8 hours to obtain the third solution.

[0128] In step S52:

[0129] In one embodiment, the molar ratio of the metal element in the first metal source to the hydroxide in the first base is 1:(0.5-2), specifically 1:(0.5-1.5), 1:(1.0-1.5), 1:(1.1-1.5), 1:(1.1-1.3), etc.

[0130] The first base may include one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia water, tetramethylammonium hydroxide, and one or more of hydrates thereof.

[0131] It is understandable that the first base can be added in the form of an alkaline solution. Specifically, the solvent in the alkaline solution can include one or more of dimethyl sulfoxide, N,N-dimethylformamide, methanol, ethanol, and tetrahydrofuran. It is understandable that the solvent in the alkaline solution can be the same as or different from the third solvent. In a specific embodiment, the base is added to the corresponding solution and stirred at room temperature for 1 to 8 hours to obtain the alkaline solution. Among them, the alkaline solution can also be called an oxygen precursor.

[0132] In one embodiment, the mixing reaction time can be 0.1 to 10 hours, specifically 0.1 to 1 hour, 1 to 3 hours, 3 to 5 hours, 5 to 8 hours, 8 to 10 hours, etc. The mixing reaction temperature can be 20 to 80°C, specifically 20 to 40°C, 40 to 60°C, 60 to 80°C, etc. In a specific embodiment, the mixing reaction is specifically: mixing at 20 to 80°C, stirring and condensing and refluxing for 0.1 to 10 hours.

[0133] It is understandable that after the mixing reaction, purification may be performed to obtain the first inorganic material. Specifically, the purification may be performed by repeated centrifugation and dispersion using ethanol and n-octane.

[0134] In one embodiment, before forming the second electron transport layer, the method further includes preparing a second electron transport material, specifically including:

[0135] Step S61: providing a fourth solution, wherein the fourth solution includes a second metal source and a fourth solvent;

[0136] Step S62: adding a second base to the fourth solution, mixing and reacting to obtain a second inorganic material.

[0137] Wherein, in step S61:

[0138] The second metal source includes a second main metal source, and the second main metal source includes one or more of a second zinc source and a second titanium source; wherein the second zinc source may include at least one of zinc acetate, zinc chloride and zinc oxide, and the second titanium source may include one or more of isopropyl titanate, titanyl sulfate, titanium tetrachloride, etc.

[0139] Furthermore, the second metal source also includes a second doping metal source, and the second doping metal source may include one or more of a Mg source, a Ca source, a Li source, a Ga source, an Al source, a Co source, a Mn source, a Zr source, a W source, a Ti source, a Y source, an In source, etc. Specifically, the second doping metal source may be selected from corresponding metal salts and hydrates thereof, etc., which are not limited here.

[0140] The fourth solvent may include one or more of dimethyl sulfoxide, N,N-dimethylformamide, methanol, ethanol, and tetrahydrofuran.

[0141] Furthermore, the fourth solution may also include a second ligand solvent, which includes one or more of a carboxylic acid solvent with 1 to 3 carbon atoms, a phosphoric acid solvent with 1 to 3 carbon atoms, a thiol solvent with 1 to 3 carbon atoms, or an amine solvent with 1 to 3 carbon atoms.

[0142] Specifically, the carboxylic acid solvent with 1 to 3 carbon atoms includes one or more of formic acid, acetic acid (acetic acid), and propionic acid. The phosphoric acid solvent with 1 to 3 carbon atoms includes phosphoric acid. The thiol solvent with 1 to 3 carbon atoms includes one or more of methyl mercaptan solvent, ethyl mercaptan solvent, and 1-propanethiol solvent. The amine ligand with 1 to 3 carbon atoms includes one or more of amino ligand, methylamine ligand, ethylamine ligand, and propylamine ligand.

[0143] In one embodiment, the second metal source includes a second metal cation and a second anion, wherein the second metal cation may include a second main metal, or include a second main metal and a second doping metal. The molar ratio of the second ligand solvent to the second anion is greater than or equal to 2:5, that is, greater than or equal to 40%, specifically 40% to 60%, 60% to 70%, 70% to 80%, etc.

[0144] In one embodiment, the second metal source and the fourth solvent are stirred at room temperature of 20 to 30° C. for 1 to 8 hours to obtain the fourth solution.

[0145] In step S62:

[0146] The molar ratio of the metal element in the second metal source to the second base is 1:(0.8-1.1), specifically 1:(0.8-1.05), 1:(0.85-1.05), 1:(0.85-1.00), 1:(0.90-1.00), 1:(0.90-0.95), etc. The molar ratio can make the molar percentage of the hydroxyl ligand in the formed second electron transport layer less than or equal to 10%. It can be understood that the hydroxide ions in the base will first react with the metal ions to form hydroxides, and then condense to form oxides, while the uncondensed hydroxides and excess hydroxides are connected to the surface of the formed oxide as surface ligands, that is, to form the hydroxyl ligands.

[0147] The second base may include one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, aqueous ammonia, tetramethylammonium hydroxide, and one or more of hydrates thereof.

[0148] It is understandable that the second base can be added in the form of an alkaline solution. Specifically, the solvent in the alkaline solution can include one or more of dimethyl sulfoxide, N,N-dimethylformamide, methanol, ethanol, and tetrahydrofuran. It is understandable that the solvent in the alkaline solution can be the same as or different from the fourth solvent. In a specific embodiment, the base is added to the corresponding solution and stirred at room temperature for 1 to 8 hours to obtain the alkaline solution.

[0149] In one embodiment, the mixing reaction time may be 1 to 48 hours, specifically 1 to 40 hours, 10 to 40 hours, 10 to 30 hours, 20 to 30 hours, etc. The mixing reaction temperature may be room temperature (20 to 40° C.).

[0150] It is understandable that after the mixing reaction, purification may be performed to obtain the second inorganic material. Specifically, the purification may be performed by repeated centrifugation and dispersion using ethanol and n-octane.

[0151] In one embodiment, the method for preparing the light-emitting device further includes: forming a hole functional layer between the light-emitting layer and the first electrode.

[0152] Among them, the first electrode, the second electrode, the light-emitting layer, the hole functional layer, etc. can all refer to the relevant contents in the light-emitting device 100 described above, and will not be repeated here.

[0153] In the light-emitting device provided in the present application, the preparation of the first electrode, the second electrode, the light-emitting layer, the hole functional layer and other film layers can be achieved by conventional techniques in the art, such as chemical methods or physical methods. Among them, the chemical method includes chemical vapor deposition, continuous ion layer adsorption and reaction method, anode electrode oxidation method, electrolytic deposition method, and coprecipitation method. The physical method includes physical plating method and solution method, among which the physical plating method includes: thermal evaporation coating method, electron beam evaporation coating method, magnetron sputtering method, multi-arc ion plating method, physical vapor deposition method, atomic layer deposition method, pulsed laser deposition method, etc.; the solution method can be spin coating, printing method, inkjet printing method, blade coating method, printing method, dip pulling method, immersion method, spraying method, roll coating method, casting method, slit coating method and strip coating method, etc.

[0154] It is understandable that the method for preparing the light-emitting device may further include a packaging step, and the packaging step may refer to packaging methods known in the art. For example, the packaging material used for packaging may be selected from at least one of UV glue, metal film, and glass glue. In a specific embodiment, the packaging material may be acrylic resin or epoxy resin. The packaging may be machine packaging or manual packaging, and may be sealed with ultraviolet curing glue. The concentration of oxygen and water in the environment of the packaging step is less than 0.1ppm to ensure the stability of the light-emitting device.

[0155] The present application also relates to a display device, which includes the light-emitting device provided in the present application, or includes the light-emitting device prepared by the method for preparing the light-emitting device provided in the present application. The display device can be any electronic product with a display function, including but not limited to smart phones, tablet computers, laptop computers, digital cameras, digital video cameras, smart wearable devices, smart weighing electronic scales, car displays, televisions or e-book readers, wherein the smart wearable device can be, for example, a smart bracelet, a smart watch, a virtual reality (VR) helmet, etc.

[0156] 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.

[0157] Device Example 1

[0158] The device embodiment provides a quantum dot light emitting diode and a method for preparing the same, which specifically includes the following steps.

[0159] Step 1: providing a substrate with a bottom electrode, wherein the bottom electrode is ITO;

[0160] Step 2: Spin-coat PEDOT:PSS on the bottom electrode at a speed of 4000 rpm for 30 seconds, and dry to remove the solvent to obtain a hole injection layer with a thickness of 90 nm;

[0161] Step 3: In an inert atmosphere, spin-coat TFB (concentration of 8 mg / mL) on the hole injection layer at a speed of 3000 rpm for 30 s, and dry to remove the solvent to obtain a hole transport layer with a thickness of 80 nm;

[0162] Step 4: Blue quantum dots (CdZnSe / ZnSe / CdZnS / ZnS) are arranged on the hole transport layer to obtain a light-emitting layer with a thickness of 15 nm.

[0163] Step 5: Prepare the first electron transport layer on the light-emitting layer: add 10mmol zinc acetate dihydrate and 1mmol aluminum chloride hexahydrate to 30ml dimethyl sulfoxide, add 9.2mmol dodecanoic acid, stir at 50℃ and condense under reflux for 2 hours to obtain a metal precursor; add 11mmol lithium hydroxide to 30ml ethanol and stir at room temperature for 2 hours to obtain an oxygen precursor; mix the metal precursor and oxygen precursor at 70℃, stir and condense under reflux for 10 hours, repeatedly centrifuge and disperse with ethanol and n-octane to obtain a purified n-octane solution of aluminum-doped zinc oxide. Deposit the above n-octane solution of aluminum-doped zinc oxide on the quantum dot light-emitting layer, remove the solvent to form a first electron transport layer with a thickness of 15nm.

[0164] Step 6: Prepare a second electron transport layer on the first electron transport layer: add 10 mmol zinc acetate dihydrate to 30 ml dimethyl sulfoxide, stir at room temperature for 2 hours to obtain a zinc precursor; add 11 mmol lithium hydroxide to 30 ml ethanol and stir at room temperature for 2 hours to obtain an oxygen precursor; mix the zinc precursor and the oxygen precursor at room temperature and stir for 20 hours, repeatedly centrifuge and disperse with ethanol and heptane to obtain a purified zinc oxide ethanol solution. The above zinc oxide ethanol solution is deposited on the first electron transport layer, and after removing the solvent, a 15 nm thick second electron transport layer is formed.

[0165] Step 7: By thermal evaporation, the vacuum degree is not higher than 3×10 -4 Pa, Ag was evaporated on the electron transport layer to obtain a top electrode with a thickness of 60 nm, and then encapsulated.

[0166] Device Example 2

[0167] This device embodiment is substantially the same as device embodiment 1, with the only difference being that in step 5, in preparing the first electron transport layer, hydrated gallium nitrate is used instead of aluminum chloride hexahydrate.

[0168] Device Example 3

[0169] This device embodiment is substantially the same as device embodiment 1, with the only difference being that in step 5, in preparing the first electron transport layer, dodecylamine is used instead of dodecanoic acid.

[0170] Device Example 4

[0171] This device embodiment is substantially the same as device embodiment 1, with the only difference being that in step 5, in preparing the first electron transport layer, 1-undecanethiol is used instead of dodecanoic acid.

[0172] Device Example 5

[0173] This device embodiment is substantially the same as device embodiment 1, with the only difference being that in step 5, in preparing the first electron transport layer, n-dodecyl phosphoric acid is used instead of dodecanoic acid.

[0174] Device Example 6

[0175] This device example is substantially the same as device example 1, except that in step 5, in preparing the first electron transport layer, 1 mmol of dodecanoic acid, 1 mmol of n-octanoic acid and 1 mmol of 1-undecanethiol are used instead of 3 mmol of dodecanoic acid.

[0176] Device Example 7

[0177] This device embodiment is substantially the same as device embodiment 1, with the only difference being that 10 mmol of dodecanoic acid is added during the preparation of the first electron transport layer in step 5.

[0178] Device Example 8

[0179] This device example is substantially the same as device example 1, with the only difference being that in step 5, 4.6 mmol of dodecanoic acid is added during the preparation of the first electron transport layer.

[0180] Device Example 9

[0181] This device embodiment is substantially the same as device embodiment 1, except that in step 6, 15 mmol of lithium hydroxide is added.

[0182] Device Comparison Example 1

[0183] The device comparative example is basically the same as device embodiment 1, with the only difference being that the first electron transport layer is prepared only according to step 5 with a thickness of 30 nm, and step 6 is not performed. The finally formed light-emitting device only includes the first electron transport layer and does not include the second electron transport layer.

[0184] Device Comparison Example 2

[0185] This device embodiment is basically the same as device embodiment 1, with the only difference being that: step 5 is not performed, and only the preparation of the second electron transport layer in step 6 is performed, and a second electron transport layer with a thickness of 30 nm is formed. The light-emitting device finally formed only includes the second electron transport layer, and does not include the first electron transport layer.

[0186] Device Comparison Example 3

[0187] This device embodiment is substantially the same as device embodiment 1, except that in step 5, dodecanoic acid is not added.

[0188] Test 1

[0189] According to the preparation method of step 5 in device embodiment 1, a first electron transport layer is prepared, and its material is aluminum-doped zinc oxide, namely AZO.

[0190] According to the preparation method of step 5 in device embodiment 2, a first electron transport layer is prepared, and its material is gallium-doped zinc oxide, namely ZnGaO.

[0191] According to the preparation method of step 5 in device embodiment 1, lithium chloride is used instead of aluminum chloride hexahydrate to prepare a first electron transport layer of lithium-doped zinc oxide (ie, LiZnO).

[0192] According to the preparation method of step 5 in device embodiment 1, magnesium nitrate is used instead of aluminum chloride hexahydrate to prepare a first electron transport layer of magnesium-doped zinc oxide (ie, ZnMgO).

[0193] According to the preparation method of step 5 in device embodiment 1, aluminum chloride hexahydrate is not used, and zinc acetate dihydrate is used as the metal source to obtain a first electron transport layer of zinc oxide (ZnO).

[0194] The first electron transport layers of AZO, ZnGaO, LiZnO, ZnMgO and ZnO were respectively subjected to AFM (atomic force microscope) inspection, see Figure 4 , Figure 4 AFM surface morphology.

[0195] Depend on Figure 4 It can be seen that according to the preparation method of step 5 in Example 1, among the doped or undoped zinc oxide film layers prepared, the roughness of the LiZnO and ZnGaO film layers is relatively large, while the roughness of the ZnO, AZO, and ZnMgO is relatively small and the data are similar, but from the film layer morphology, the aluminum-doped zinc oxide (AZO) is relatively smoother.

[0196] Test 2

[0197] According to the preparation method of step 5 in device embodiment 1, a first electron transport layer is prepared, and its material is aluminum-doped zinc oxide, namely AZO. XPS (X-ray photoelectron spectroscopy) element analysis is performed on the first electron transport layer, and the mass percentage of carbon C element is 15%.

[0198] Test 3

[0199] According to the device comparative example 3, the aluminum-doped zinc oxide is prepared without adding dodecanoic acid in step 5. The solubility test of the doped zinc oxide is performed, see Figure 5 , Figure 5 3 is a dissolution state diagram of aluminum-doped zinc oxide corresponding to device comparative example 3. As can be seen from the figure, aluminum-doped zinc oxide is clear in the polar solvent ethanol, but turbid and insoluble in the non-polar solvent n-octane, that is, aluminum-doped zinc oxide is soluble in polar solvents but not in non-polar solvents.

[0200] It can be understood that in device comparative example 3, the material of the first electron transport layer prepared in step 5 is dissolved in polar materials such as ethanol, and in the subsequent step 6 for preparing the second electron transport layer, an ethanol solution of zinc oxide is provided on the first electron transport layer, and the solvent ethanol therein may cause dissolution and penetration damage to the material of the first electron transport layer that has been formed. In the embodiment of the present application, by connecting long-chain ligands such as dodecanoic acid to the surface of aluminum-doped zinc oxide, the solubility in ethanol is reduced, thereby improving the overall reduction or even avoidance of dissolution and penetration damage and improving the film quality.

[0201] Test 4

[0202] The quantum dot light-emitting diodes of device embodiments 1-9 and device comparison examples 1-3 were tested, specifically including the turn-on voltage V@1nit, the maximum device efficiency CE@max at a current of 2mA, and the device life T95-1000 nit. The test data are shown in Table 1.

[0203] Among them, device life: the time required for the brightness of the device to decrease to a certain proportion of the maximum brightness when driven by a constant current or voltage. The time when the brightness drops to 95% of the maximum brightness is defined as T95, and this life is the measured life. In order to shorten the test cycle, the device life test is usually carried out by accelerating device aging at high brightness with reference to the OLED device test, and the life under high brightness is obtained by fitting the extended exponential decay brightness attenuation fitting formula, for example: the life under 1000nit is calculated as T95-1000 nit. The specific calculation formula is as follows:

[0204]

[0205] Where T95 L For lifespan at low brightness, T95 H is the measured lifetime under high brightness, L H To accelerate the device to the highest brightness, L L is 1000nit, A is the acceleration factor, for OLED, the value is usually 1.6~2. In this experiment, the lifespan of several groups of QLED devices at rated brightness was measured and the A value was 1.7.

[0206] The life test system is used to carry out life test on the corresponding devices. The test conditions are: at room temperature and the air humidity is 30-60%.

[0207] Table 1

[0208]

[0209]

[0210] It can be seen from Table 1 that compared with the single-layer electron transport layer in device comparison examples 1 and 2, the light-emitting devices of device embodiments 1-9 can have a smaller turn-on voltage (V@1nit) while also having better current efficiency CE@max and life T95-1000 nit, indicating that the use of a double-layer electron transport layer in the present application can improve the operating voltage of the light-emitting device and has a significant effect on improving the luminous efficiency and life.

[0211] Compared with device example 1, the device life T95-1000 nit of device example 2 is shorter, which may be due to the better surface flatness of the first electron transport layer formed by aluminum-doped zinc oxide (AZO) in device example 1, thereby reducing and avoiding the burning point phenomenon and avoiding local short circuits caused by uneven interfaces, thereby improving the life of the device.

[0212] Compared with device example 1, the device life T95-1000 nit of device example 9 is shorter, which may be due to the high content of hydroxyl ligands in the second electron transport layer close to the second electrode, causing oxidation damage to the second electrode, thereby reducing the life.

[0213] The light-emitting device and its preparation method, and the display device provided in the embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A light emitting device, characterized in that: include: A first electrode and a second electrode arranged opposite to each other; A light-emitting layer is disposed between the first electrode and the second electrode; An electronic functional layer, disposed between the second electrode and the light-emitting layer; The electronic functional layer includes a stacked first electron transport layer and a second electron transport layer, the first electron transport layer is arranged close to the light-emitting layer, and the second electron transport layer is arranged close to the second electrode, wherein the material of the first electron transport layer includes a first inorganic material, a first ligand is connected to the first inorganic material, and the first ligand includes a long carbon chain ligand with a carbon number of 4 to 12, and the material of the second electron transport layer includes a second inorganic material, a second ligand is connected to the second inorganic material, and the second ligand includes one or more of a short chain ligand with a carbon number of 1 to 3 or a hydroxyl ligand.

2. The light emitting device according to claim 1, characterized in that: The electronic functional layer consists of the first electron transport layer and the second electron transport layer; and / or, The molar percentage of the long carbon chain ligand having 4 to 12 carbon atoms in all ligands connected to the surface of the first inorganic material is greater than or equal to 20%; In the first electron transport layer, the mass percentage of carbon element is greater than or equal to 10%; and / or, The long carbon chain ligand with 4 to 12 carbon atoms includes one or more of a carboxylic acid ligand with 4 to 12 carbon atoms, a phosphate ligand with 4 to 12 carbon atoms, a thiol ligand with 4 to 12 carbon atoms or an amine ligand with 4 to 12 carbon atoms; and / or, In the second electron transport layer, the molar percentage of the hydroxyl ligand is less than or equal to 10%; and / or, The short-chain ligand with 1 to 3 carbon atoms includes one or more of a carboxylic acid ligand with 1 to 3 carbon atoms, a phosphate ligand with 1 to 3 carbon atoms, a thiol ligand with 1 to 3 carbon atoms, or an amine ligand with 1 to 3 carbon atoms.

3. The light emitting device according to claim 2, characterized in that: The carboxylic acid ligand having 4 to 12 carbon atoms includes one or more of butyric acid, valeric acid, caproic acid, heptanoic acid, n-octanoic acid, n-decanoic acid, undecanoic acid, and lauric acid; and / or, The phosphate ligand having 4 to 21 carbon atoms includes one or more of n-hexyl phosphate, 1-octyl phosphate, 1-decyl phosphate, and n-dodecyl phosphate; and / or, The thiol ligand having 4 to 12 carbon atoms includes one or more of butyl mercaptan, 1-pentyl mercaptan, 1-hexyl mercaptan, 1-heptyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, 1-decyl mercaptan, 1-undecanethiol, and 1-dodecanethiol; and / or, The amine ligand having 4 to 12 carbon atoms includes one or more of n-butylamine, pentylamine, hexylamine, heptylamine, n-octylamine, decylamine, 1-aminoundecane, and dodecylamine; and / or, The carboxylic acid ligand having 1 to 3 carbon atoms includes one or more of formic acid ligand, acetic acid ligand and propionic acid ligand; and / or, The phosphate ligand having 1 to 3 carbon atoms includes a phosphate ligand; and / or, The thiol ligand having 1 to 3 carbon atoms includes one or more of a thiol ligand, a methylthiol ligand, an ethylthiol ligand, and a 1-propanethiol ligand; and / or, The amine ligand having 1 to 3 carbon atoms includes one or more of an amino ligand, a methylamine ligand, an ethylamine ligand, and a propylamine ligand.

4. The light emitting device according to claim 1, characterized in that: The first inorganic material comprises at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide being selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3 and ZrO2; the metal oxide in the doped metal oxide being selected from at least one of ZnO, TiO2 and SnO2, the doping element being selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y and In, the IIB-VIA semiconductor material being selected from at least one of ZnS, ZnSe and CdS; the IIIB-VA semiconductor material being selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material being selected from at least one of CuInS and CuGaS; and / or, The thickness of the first electron transport layer is 5 to 40 nm; and / or, The second inorganic material comprises at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide being selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3 and ZrO2; the metal oxide in the doped metal oxide being selected from at least one of ZnO, TiO2 and SnO2, the doping element being selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y and In, the IIB-VIA semiconductor material being selected from at least one of ZnS, ZnSe and CdS; the IIIB-VA semiconductor material being selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material being selected from at least one of CuInS and CuGaS; and / or, The thickness of the second electron transport layer is 5-40 nm.

5. The light emitting device according to claim 1, characterized in that: The first inorganic material is selected from Al-doped ZnO, and the second inorganic material is selected from doped ZnO or undoped ZnO, wherein the doping element included in the doped ZnO is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, and the second ligand includes a hydroxyl ligand.

6. The light emitting device according to claim 1, characterized in that: The material of the light-emitting layer is an organic light-emitting material or a quantum dot light-emitting material; the organic light-emitting material is selected from at least one of diaromatic anthracene derivatives, distilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, TBPe fluorescent materials emitting blue light, TTPA fluorescent materials emitting green light, TBRb fluorescent materials emitting orange light and DBP fluorescent materials emitting red light; the quantum dot light-emitting material is selected from at least one of single-structure quantum dots, core-shell structure quantum dots and perovskite semiconductor materials, the single-structure quantum dots are selected from at least one of II-VI compounds, IV-VI compounds, III-V compounds and I-III-VI compounds, the II- Group VI compounds are selected from 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, HgZn The IV-VI group compound is selected from at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, and the III-V group compound is selected from at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, at least one of GaPAs, GaPSb, AlNPs, AlNAs, AlNSb, AlPAs, AlPSb, InNPs, InNAs, InNSb, InPAs, InPSb, GaAlNPs, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNPs, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNPs, InAlNAs, InAlNSb, InAlPAs and InAlPSb, and the Group I-III-VI compound is at least one of CuInS, CuInSe and AgInS;The core of the quantum dots of the core-shell structure is selected from any one of the above-mentioned single-structure quantum dots, and the shell material of the quantum dots of the core-shell structure is selected from at least one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS and ZnS; the perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the general structural formula of the inorganic perovskite semiconductor is AMX3, wherein A is Cs; + ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2 + Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ 、Eu 2+ At least one of, X is a halogen anion selected from Cl - Br - ,I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ , Cu 2+ 、Ni 2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ 、Eu 2+ At least one of, X is a halogen anion selected from Cl - Br - ,I - At least one of; and / or, The first electrode and the second electrode are independently selected from metal electrodes, carbon electrodes, doped or undoped metal oxide electrodes and composite electrodes; wherein the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Ni, Ir and Mg; the material of the carbon electrode is selected from at least one of graphite, carbon nanotubes, graphene and carbon fiber; the material of the doped or undoped metal oxide electrode is selected from ITO, FTO, ATO, AZO, GZO, IZO, MZO, ITZO, ICO, At least one of AMO, SnO2, In2O3, Cd:ZnO, F:SnO2, In:SnO2, and Ga:SnO2; the material of the composite electrode is selected from at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS; and / or, The light-emitting device further comprises a hole functional layer, which is arranged between the first electrode and the light-emitting layer. The hole functional layer comprises at least one layer of a hole injection layer and a hole transport layer. The material of the hole transport layer is selected from arylamine, polyaniline, polypyrrole, poly(p-phenylene vinylene) and its derivatives, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, poly(N-vinyl carbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octyl)-1,1'-biphenyl compound, poly(p-carbazolyl ... Fluorene) and its derivatives, poly (spirofluorene) and its derivatives, doped or undoped NiO, MoO3, WO3, V2O5, CrO3, CuO, MoS2, MoSe2, WS3, WSe3, CuS, CuSCN one or more; wherein the aromatic amine is selected from 4,4'-bis (9-carbazole) biphenyl, poly (9,9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine), poly (N,N'-bis (4-butylphenyl) -N,N'-bis (phenyl) benzidine), N,N'-bis (4- (N,N'-diphenyl-amino) phenyl )-N,N'-diphenylbenzidine, poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine), 4,4',4"-tri(carbazol-9-yl)triphenylamine, 4,4',4"-tri(N-carbazolyl)-triphenylamine, 4,4',4"-tri(N-3-methylphenyl-N-phenylamino)triphenylamine, 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'- One or more of diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, Spiro-NPB, Spiro-TPD, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, Spiro-NPB; the poly(p-)phenylene vinylene and its derivatives are selected from one or more of poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene];The material of the hole injection layer is selected from poly(ethylenedioxythiophene): polystyrene sulfonate, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, copper phthalocyanine, poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine), polyarylamine, poly(N-vinylcarbazole), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine, 4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl, 4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine, 4,4' ,4"-tri(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[(di-4-tolylamino)phenylcyclohexane, 4,4',4"-tri(diphenylamino)triphenylamine doped with F4-TCNQ, p-doped phthalocyanine, F4-TCNQ doped N,N'-diphenyl-N,N'-di(1-naphthyl)-1,1'-biphenyl-4,4"-diamine, transition metal oxides, transition metal sulfur compounds; wherein the transition metal oxides include one or more of NiO, MoO2, WO3, and CuO; the metal sulfur compounds include one or more of MoS2, MoSe2, WS3, WSe3, and CuS.; 7. A method for preparing a light emitting device, characterized in that: The preparation method comprises: Providing a preset device, the preset device comprising a second electrode; Providing an electronic functional layer on the preset device; Disposing a light-emitting layer on the electronic functional layer; forming a first electrode on the light-emitting layer; or, The preparation method comprises: Providing a preset device, the preset device comprising a stacked first electrode and a light-emitting layer; forming an electronic functional layer on the preset device; forming a second electrode on the electronic functional layer; The electronic functional layer includes a first electron transport layer and a second electron transport layer, the first electron transport layer is arranged close to the light-emitting layer, and the second electron transport layer is arranged close to the second electrode; the material of the first electron transport layer includes a first inorganic material, a first ligand is connected to the first inorganic material, and the first ligand includes a long carbon chain ligand with a carbon number of 4 to 12; the material of the second electron transport layer includes a second inorganic material, a second ligand is connected to the second inorganic material, and the second ligand includes one or more of a short chain ligand with a carbon number of 1 to 3 or a hydroxyl ligand.

8. The preparation method according to claim 7, characterized in that: The forming of the electronic functional layer on the preset device includes forming a first electron transport layer and forming a second electron transport layer; Wherein, the forming of the first electron transport layer comprises: Providing a first solution, wherein the first solution includes a first inorganic material and a first solvent, and the first inorganic material is connected to the first ligand; and arranging the second solution to obtain the first electron transport layer; The forming of the second electron transport layer comprises: providing a second solution, wherein the second solution comprises a second inorganic material and a second solvent; and arranging the second solution to obtain the second electron transport layer.

9. The preparation method according to claim 8, characterized in that: In the first solution, the concentration of the first inorganic material is 10 to 50 mg / mL; and / or, The first solvent is selected from a non-polar solvent; and / or, The molar percentage of the long carbon chain ligand having 4 to 12 carbon atoms in the first ligand is greater than or equal to 20%; and / or, The long carbon chain ligand with 4 to 12 carbon atoms includes one or more of a carboxylic acid ligand with 4 to 12 carbon atoms, a phosphate ligand with 4 to 12 carbon atoms, a thiol ligand with 4 to 12 carbon atoms or an amine ligand with 4 to 12 carbon atoms; and / or, The first inorganic material comprises at least one of a metal oxide, a doped metal oxide, a IIB-VIA semiconductor material, a IIIB-VA semiconductor material and an IB-IIIB-VIA semiconductor material, the metal oxide being selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3 and ZrO2; the metal oxide in the doped metal oxide being selected from at least one of ZnO, TiO2 and SnO2, the doping element being selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y and In, the IIB-VIA semiconductor material being selected from at least one of ZnS, ZnSe and CdS; the IIIB-VA semiconductor material being selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material being selected from at least one of CuInS and CuGaS; and / or, In the second solution, the concentration of the second inorganic material is 10 to 50 mg / mL; and / or, The second solvent is selected from polar solvents; and / or, The second inorganic material includes at least one of metal oxide, doped metal oxide, IIB-VIA semiconductor material, IIIB-VA semiconductor material and IB-IIIB-VIA semiconductor material, the metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ga2O3, and ZrO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, the doping element is selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y, and In, the IIB-VIA semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the IIIB-VA semiconductor material is selected from at least one of InP and GaP; the IB-IIIB-VIA semiconductor material is selected from at least one of CuInS and CuGaS.

10. The preparation method according to claim 9, characterized in that: The non-polar solvent includes one or more of n-hexane, cyclohexane, n-pentane, isopentane, n-octane and n-nonane; and / or, The polar solvent includes one or more of ethanol, isopropanol, n-butanol, and n-pentanol; and / or, The carboxylic acid ligand having 4 to 12 carbon atoms includes one or more of butyric acid, valeric acid, caproic acid, heptanoic acid, n-octanoic acid, n-decanoic acid, undecanoic acid, and lauric acid; and / or, The phosphate ligand having 4 to 21 carbon atoms includes one or more of n-hexyl phosphate, 1-octyl phosphate, 1-decyl phosphate, and n-dodecyl phosphate; and / or, The thiol ligand having 4 to 12 carbon atoms includes one or more of butyl mercaptan, 1-pentyl mercaptan, 1-hexyl mercaptan, 1-heptyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, 1-decyl mercaptan, 1-undecanethiol, and 1-dodecanethiol; and / or, The amine ligand having 4 to 12 carbon atoms includes one or more of n-butylamine, pentylamine, hexylamine, heptylamine, n-octylamine, decylamine, 1-aminoundecane, and dodecylamine.

11. The preparation method according to claim 10, characterized in that: Before forming the second electron transport layer, the second inorganic material is prepared, including: providing a fourth solution, wherein the fourth solution includes a second metal source; adding a second base to the fourth solution, mixing and reacting to obtain the second inorganic material; Wherein, the molar ratio of the metal element in the second metal source to the second base is 1:(0.8-1.1).

12. A display device, characterized in that: A light-emitting device comprising the light-emitting device as described in any one of claims 1 to 6, or a light-emitting device manufactured by the method for manufacturing the light-emitting device as described in any one of claims 7 to 11.

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