CN116234405A - Light emitting device, manufacturing method of light emitting device and display device - Google Patents

Abstract

The preparation method of the light-emitting device has the advantages of simple preparation process, easiness in control and suitability for industrial production, and the light-emitting device prepared by the preparation method of the light-emitting device or the light-emitting device is applied to a display device, so that the display effect of the display device is improved and the service life of the display device is prolonged.

Description

Light emitting device, manufacturing method of light emitting device and display device

Technical Field

The application relates to the technical field of photoelectricity, in particular to a light emitting device, a preparation method of the light emitting device and a display device.

Background

Light Emitting devices include, but are not limited to, organic Light-Emitting diodes (OLEDs) and quantum dot Light Emitting diodes (Quantum Dot Light Emitting Diodes, QLEDs), which are typically "sandwich" structures comprising an anode, a Light Emitting layer, and a cathode, arranged in that order. The light emitting principle of the light emitting device is: electrons are injected into the light-emitting area from the cathode of the device, holes are injected into the light-emitting area from the anode of the device, the electrons and the holes are combined in the light-emitting area to form excitons, and photons are released from the combined excitons in a radiation transition mode, so that light is emitted.

At present, the performance of the light emitting device is reduced, such as reduced light emitting efficiency and shortened service life, during the operation process of the light emitting device. Therefore, research to improve the performance of the light emitting device is of great significance to the application and development of the light emitting device.

Disclosure of Invention

The application provides a light emitting device, a preparation method of the light emitting device and a display device, so as to improve the photoelectric property and the service life of the light emitting device.

The technical scheme of the application is as follows:

in a first aspect, the present application provides a light emitting device comprising:

an anode;

a cathode disposed opposite the anode;

A light-emitting layer disposed between the anode and the cathode; and

an electron transport layer disposed between the light emitting layer and the cathode;

wherein the material of the electron transport layer comprises a super oxygen radical scavenger and a nano metal oxide.

Further, the superoxide radical scavenger and the nano metal oxide are blended in the same layer of the electron transport layer, the hydroxyl number contained in a single molecule of the superoxide radical scavenger is not less than 4, and the dissociation constant pKa of each hydroxyl group in the superoxide radical scavenger is not less than 6.

Further, the superoxide radical scavenger comprises quercetin and/or rutin.

Further, in the material of the electron transport layer, the superoxide radical scavenger: the mass ratio of the nano metal oxide is (0.001-0.05): 1.

further, the electron transport layer comprises N nano metal oxide layers and (N-1) super oxygen radical capturing layers, wherein N is a positive integer greater than or equal to 2; the nano metal oxide layers and the super oxygen radical capturing layers are alternately arranged, and one layer of the electron transport layer close to the light emitting layer and one layer of the electron transport layer close to the cathode are both nano metal oxide layers.

Further, the material of the superoxide radical trapping layer comprises at least one of ascorbic acid, quercetin or rutin.

Further, the total thickness of the N nano metal oxide layers is 20nm to 100nm, and the thickness of each nano metal oxide layer is 5nm to 45nm; (N-1) the total thickness of the super oxygen radical trapping layers is between 0.2nm and 5nm, and the thickness of each of the super oxygen radical trapping layers is between 0.1nm and 3.0nm.

Further, the nano metal oxide is selected from ZnO and TiO ₂ 、SnO ₂ 、Ta ₂ O ₃ 、ZrO ₂ At least one of TiLiO, znGaO, znAlO, znMgO, znSnO, znLiO, inSnO, alZnO, znOCl and ZnOF.

Further, the nano metal oxide has a particle size of 2nm to 15nm.

Further, the light-emitting device further comprises a hole transport layer arranged between the anode and the light-emitting layer, wherein the hole transport layer is made of a material selected from NiO and WO ₃ 、MoO ₃ CuO, poly (9, 9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine), 3-hexyl-substituted polythiophene, poly (9-vinylcarbazole), poly [ bis (4-phenyl) (4-butylphenyl) amine]At least one of poly (N, N '-bis (4-butylphenyl) -N, N' -diphenyl-1, 4-phenylenediamine-CO-9, 9-dioctylfluorene), 4',4 "-tris (carbazol-9-yl) triphenylamine, 4' -bis (9-carbazol) biphenyl, N '-diphenyl-N, N' -bis (3-methylphenyl) -1,1 '-biphenyl-4, 4' -diamine or N, N '-diphenyl-N, N' - (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine.

Further, the material of the light-emitting layer is an organic light-emitting material or quantum dots, and the organic light-emitting material is selected from the group consisting of biaromatic materialsAt least one of a anthracene derivative, a stilbene aromatic derivative, a pyrene derivative or a fluorene derivative, a blue light-emitting TBPe fluorescent material, a green light-emitting TTPA fluorescent material, an orange light-emitting TBRb fluorescent material, and a red light-emitting DBP fluorescent material; the quantum dot is selected from at least one of II-VI compound, III-V compound, IV-VI compound and I-III-VI compound, wherein the II-VI compound is selected from at least one of CdS, cdSe, cdTe, znS, znSe, znTe, znO, hgS, hgSe, hgTe, cdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, cdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe and HgZnSTe, the III-V compound is selected from at least one of GaN, gaP, gaAs, gaSb, alN, alP, alAs, alSb, inN, inP, inAs, inSb, gaNP, gaNAs, gaNSb, gaPAs, gaPSb, alNP, alNAs, alNSb, alPAs, alPSb, inNP, inNAs, inNSb, inPAs, inPSb, gaAlNP, gaAlNAs, gaAlNSb, gaAlPAs, gaAlPSb, gaInNP, gaInNAs, gaInNSb, gaInPAs, gaInPSb, inAlNP, inAlNAs, inAlNSb, inAlPAs and InAlPSb, the IV-VI 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 and SnPbSTe, and the I-III-VI compound is selected from CuInS ₂ 、CuInSe ₂ And AgInS ₂ At least one of them.

In a second aspect, the present application provides a method for manufacturing a light emitting device, the method comprising the steps of:

providing a mixed solution comprising a superoxide radical scavenger and a nano metal oxide;

providing a laminated structure, coating the mixed solution on one side of the laminated structure, and then drying to obtain an electron transport layer;

when the light-emitting device is of a positive structure, the laminated structure is a substrate comprising an anode and a light-emitting layer, and the electron transport layer is formed on one side of the light-emitting layer away from the anode; when the light emitting device is of an inverted structure, the stacked structure is a substrate including a cathode, and the electron transport layer is formed on one side of the cathode; the number of hydroxyl groups contained in a single molecule of the superoxide radical scavenger is not less than 4, and the dissociation constant pKa of each hydroxyl group in the superoxide radical scavenger is not less than 6.

Further, in the mixed solution, the superoxide radical scavenger: the mass ratio of the nano metal oxide is (0.001-0.05): 1.

in a third aspect, the present application further provides a method for preparing a light emitting device, the method comprising the steps of: providing a laminated structure, alternately preparing and forming a nano metal oxide layer and a super oxygen radical trapping layer on one side of the laminated structure, wherein an initially prepared layer and a finally prepared layer are nano metal oxide layers, and N nano metal oxide layers and (N-1) super oxygen radical trapping layers forming an electron transport layer are obtained, wherein N is a positive integer greater than or equal to 2;

When the light-emitting device is of a positive structure, the laminated structure is a substrate comprising an anode and a light-emitting layer, and the electron transport layer is formed on one side of the light-emitting layer away from the anode; when the light emitting device is of an inverted structure, the stacked structure is a substrate including a cathode, and the electron transport layer is formed on one side of the cathode.

In a fourth aspect, the present application provides a display apparatus comprising a light-emitting device according to any one of the first aspects, or comprising a light-emitting device manufactured by a manufacturing method according to any one of the second or third aspects.

The application provides a light emitting device, a preparation method of the light emitting device and a display device, and the preparation method has the following technical effects:

the material of the electron transport layer of the light-emitting device comprises a superoxide radical trapping agent, and can eliminate superoxide radicals in the light-emitting device or reduce the content of the superoxide radicals in the light-emitting device, so that adverse effects of the superoxide radicals on the photoelectric performance and service life of the light-emitting device are eliminated or reduced, and the problems of reduced light-emitting efficiency and shortened service life of the QLED caused by decomposing the surface ligand of the quantum dot by the superoxide radicals are effectively solved, and in addition, the problem of charge imbalance of the QLED caused by decomposing the surface ligand of the nano metal oxide by the superoxide radicals is also solved, so that the photoelectric performance of the light-emitting device is improved, and the service life of the light-emitting device is prolonged.

The application provides two preparation methods of a light-emitting device, wherein the first method is as follows: coating a mixed solution containing a superoxide radical scavenger and a nano metal oxide on one side of the laminated structure, and then drying to form an electron transport layer; the second is: the method has the advantages that compared with the first preparation method, the electron transport layer prepared by the second preparation method can further reduce the failure risk of the superoxide radical scavenger, and the two preparation methods have the advantages of simple preparation procedures, easiness in control and suitability for industrial production.

The light-emitting device of the embodiment of the application or the light-emitting device manufactured by the manufacturing method of the light-emitting device of the embodiment of the application is applied to a display device, so that the display effect of the display device is improved and the service life of the display device is prolonged.

Drawings

Technical solutions and other advantageous effects of the present application will be made apparent from the following detailed description of specific embodiments of the present application with reference to the accompanying drawings.

Fig. 1 is a schematic structural view of a first light emitting device provided in an embodiment of the present application.

Fig. 2 is a schematic structural view of a second light emitting device provided in an embodiment of the present application.

Fig. 3 is a schematic structural view of a third light emitting device provided in an embodiment of the present application.

Fig. 4 is a schematic flow chart of a method for manufacturing a light emitting device according to an embodiment of the present application.

Fig. 5 is a schematic structural view of a fourth light emitting device provided in an embodiment of the present application.

Fig. 6 is a schematic structural view of a fifth light emitting device provided in an embodiment of the present application.

Fig. 7 is a graph of current density vs. voltage characteristics of the light emitting devices of examples 1 to 5 and the comparative example in experimental examples of the present application.

Fig. 8 is a graph showing current density-voltage characteristics of the light emitting devices of example 6, example 7, and comparative example in experimental examples of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any methods and materials similar or equivalent to those described herein can be used in the present invention. The preferred methods and materials described herein are illustrative only and should not be construed as limiting the scope of the present application.

The following description of the embodiments is not intended to limit the preferred embodiments. In addition, in the description of the present application, the term "comprising" means "including but not limited to". Various embodiments of the present application may exist in a range of forms; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; it is therefore to be understood that the range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the ranges, such as 1, 2, 3, 4, 5, and 6, wherever applicable. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.

The embodiment of the application provides a light emitting device, as shown in fig. 1, the light emitting device 1 includes an anode 11, a cathode 12, a light emitting layer 13, and an electron transport layer 14, the anode 11 is disposed opposite to the cathode 12, the light emitting layer 13 is disposed between the anode 11 and the cathode 12, and the electron transport layer 14 is disposed between the light emitting layer 13 and the cathode 12, wherein a material of the electron transport layer 14 includes a superoxide radical scavenger and a nano metal oxide.

The inventor found in the research process that nano metal oxide is one of materials for preparing electron transport layer, and because nano metal oxide has characteristics of small particle size and many surface defects, excitons are easy to generate in the electron transport layer under the excitation of electric field and light, and electrons e after exciton separation ^- Can combine with oxygen to generate superoxide radical (O) ₂ ^- Radical), the presence of superoxide radicals can adversely affect the optoelectronic properties of the light emitting device. The super-oxygen free radical is an important factor affecting the performance of the device, taking a QLED as an example, the super-oxygen free radical can decompose the surface ligand of the quantum dot in the light-emitting layer, so that the defect of the quantum dot is increased, the quantum efficiency of the quantum dot is reduced, the light-emitting efficiency of the QLED is reduced, and the service life of the QLED is shortened. In the embodiment of the application, the material based on the electron transport layer contains the superoxide radical trapping agent, so that the superoxide radical in the light-emitting device can be eliminated or the content of the superoxide radical in the light-emitting device can be reduced, thereby eliminating or reducing the adverse effect of the superoxide radical on the photoelectric performance and the service life of the light-emitting device, taking a QLED as an example, the problems that the luminous efficiency of the QLED is reduced and the service life is shortened due to the decomposition of the surface ligand of the quantum dot by the superoxide radical can be effectively improved, and in addition, the problem that the charge imbalance of the QLED is caused due to the decomposition of the surface ligand of the nano metal oxide by the superoxide radical can be also improved.

In the present embodiment, the materials of the anode 11 and the cathode 12 may be materials common in the art, for example: anode11 and the cathode 12 are independently selected from one or more of a metal, a carbon material, and a metal oxide, and the metal is selected from at least one of Al, ag, cu, mo, au, ba, ca and Mg; the carbon material is at least one selected from graphite, carbon nano tube, graphene and carbon fiber; the metal oxide may be a doped or undoped metal oxide selected from at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO. The anode 11 or cathode 12 may also be independently selected from a composite electrode of doped or undoped transparent metal oxide sandwiching a metal, including but not limited to AZO/Ag/AZO, AZO/Al/AZO, ITO/Ag/ITO, ITO/Al/ITO, znO/Ag/ZnO, znO/Al/ZnO, tiO ₂ /Ag/TiO ₂ 、TiO ₂ /Al/TiO ₂ 、ZnS/Ag/ZnS、ZnS/Al/ZnS、TiO ₂ /Ag/TiO ₂ TiO ₂ /Al/TiO ₂ At least one of them. In some embodiments of the present application, the anode 11 has a thickness of 40nm to 160nm and the cathode 12 has a thickness of 20nm to 120nm.

The nano-metal oxide may be either undoped nano-metal oxide or doped nano-metal oxide. In some embodiments of the present application, the nano-metal oxide is selected from, for example, znO, tiO ₂ 、SnO ₂ 、Ta ₂ O ₃ 、ZrO ₂ At least one of TiLiO, znGaO, znAlO, znMgO, znSnO, znLiO, inSnO and AlZnO. The surface of the nano metal oxide may be connected with or not connected with a ligand, the ligand comprises but is not limited to a carboxylic acid ligand containing hydroxyl and having 2 to 8 carbon atoms and/or an amine ligand containing hydroxyl and having 2 to 8 carbon atoms, the carboxylic acid ligand containing hydroxyl and having 2 to 8 carbon atoms is selected from at least one of acetate, propionate and acrylate, and the amine ligand containing hydroxyl and having 2 to 8 carbon atoms is selected from at least one of ethanolamine, diethanolamine and diglycolamine. The particle size of the nano metal oxide may be, for example, 2nm to 15nm. In an example of the application, the nano metal oxide is nano ZnO with the particle size of 6.0nm, the surface of the nano ZnO is connected with an acetate ligand and a hydroxyl ligand, the nano ZnO has high catalytic activity and is excited by an electric field and light to generateIf the electron transport layer has no superoxide radical scavenger, the generated superoxide radical can decompose the ligand on the surface of the nano ZnO, so that the electrical property of the nano ZnO is changed, and the charge balance of the light-emitting device is not facilitated.

In some embodiments of the present application, the material of the light emitting layer 13 is an organic light emitting material or quantum dot, and the organic light emitting material includes, but is not limited to, at least one of a biaryl anthracene derivative, a stilbene aromatic derivative, a pyrene derivative or fluorene derivative, a blue light emitting TBPe fluorescent material, a green light emitting TTPA fluorescent material, an orange light emitting TBRb fluorescent material, and a red light emitting DBP fluorescent material; the quantum dots include, but are not limited to, at least one of II-VI compound 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, hgZnSeTe and HgZnSTe, III-V compound 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, IV-VI compound selected from SnS, snSe, snTe, pbS, pbSe, pbTe, snSeS, snSeTe, snSTe, pbSeS, pbSeTe, pbSTe, snPbS, snPbSe, snPbTe, snPbSSe, snPbSeTe and SnPbSTe, and I-III-VI compound selected from CuInS ₂ 、CuInSe ₂ And AgInS ₂ At least one of them.

In some embodiments of the present application, the superoxide radical scavenger and the nano metal oxide are arranged in the same layer, the hydroxyl number contained in a single molecule of the superoxide radical scavenger is not less than 4, and the dissociation constant pKa of each hydroxyl group in the superoxide radical scavenger is not less than 6, that is, a compound with weaker acidity and stronger superoxide radical capturing performance is adopted as the superoxide radical scavenger, so as to reduce the negative influence on the property of the nano metal oxide, and prevent the suppression effect of the superoxide radical scavenger on the superoxide radical from being reduced, for example: when the surface of the nano metal oxide is connected with a ligand containing hydroxyl, a super-oxygen free radical capturing agent (such as ascorbic acid) with higher acidity can damage the ligand containing hydroxyl carried by the nano metal oxide, thereby affecting the dispersion performance of the nano metal oxide; in addition, when the material of the electron transport layer includes a superoxide radical scavenger and a nano metal oxide having an alkaline ligand attached to a surface thereof and the electron transport layer is prepared by a solution method, a nano metal oxide solution having an alkaline ligand attached to a surface thereof is prepared, and then the superoxide radical scavenger is added to the nano metal oxide solution to form an electron transport material solution, and the superoxide radical scavenger having a higher acidity is added to the alkaline nano metal oxide solution to hydrolyze, so that the superoxide radical scavenger has a limited effect of inhibiting superoxide radicals.

In some embodiments of the present application, the superoxide radical scavenger comprises quercetin and/or rutin.

In some embodiments of the present application, in the material of the electron transport layer, the superoxide radical scavenger: the mass ratio of the nano metal oxide is (0.001-0.05): 1. the content of the super-oxygen free radical scavenger is too much or too little, so that the improvement effect on the performance of the light-emitting device is limited, and if the content of the super-oxygen free radical scavenger is too little, the elimination effect on the super-oxygen free radicals in the light-emitting device is limited; if the content of the superoxide radical scavenger is too large, the effect of enhancing the electron conductivity of the electron transport layer is limited.

As an alternative embodiment, in order to prevent the suppression effect of the superoxide radical scavenger on the superoxide radical from being reduced due to the mixing effect with the nano metal oxide, in some examples of the present application, as shown in fig. 2, the electron transport layer 14 includes N nano metal oxide layers 14-1 and (N-1) superoxide radical trapping layers 14-2, where N is a positive integer of 2 or more, each nano metal oxide layer 14-1 is alternately arranged with each superoxide radical trapping layer 14-2, and one layer of the electron transport layer 14 near the light emitting layer 13 and one layer of the electron transport layer 14 near the cathode 12 are both nano metal oxide layers 14-1. In some embodiments of the present application, the material of the superoxide radical trapping layer comprises at least one of ascorbic acid, quercetin, or rutin.

In some embodiments of the present application, the total thickness of the N nano-metal oxide layers is 20nm to 100nm, and the thickness of each nano-metal oxide layer is 5nm to 45nm; the total thickness of the (N-1) superoxide radical trapping layers is between 0.2nm and 5nm, and the thickness of each superoxide radical trapping layer is between 0.1nm and 3.0nm.

In some embodiments of the present application, the light emitting device further includes a hole transport layer disposed between the anode and the light emitting layer, the material of the hole transport layer including, but not limited to, poly (9, 9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine) (abbreviated as TFB, CAS No. 220797-16-0), 3-hexyl-substituted polythiophene (CAS No. 104934-50-1), poly (9-vinylcarbazole) (abbreviated as PVK, CAS No. 25067-59-8), poly [ bis (4-phenyl) (4-butylphenyl) amine](abbreviated as Poly-TPD, CAS number 472960-35-3), poly (N, N '-bis (4-butylphenyl) -N, N' -diphenyl-1, 4-phenylenediamine-CO-9, 9-dioctylfluorene) (abbreviated as PFB, CAS number 223569-28-6), 4 '-tris (carbazol-9-yl) triphenylamine (abbreviated as TCTA, CAS number 139092-78-7), 4' -bis (9-carbazol) biphenyl (abbreviated as CBP, CAS number 58328-31-7), N '-diphenyl-N, at least one of N' -bis (3-methylphenyl) -1,1 '-biphenyl-4, 4' -diamine (abbreviated as TPD, CAS No. 65181-78-4) and N, N '-diphenyl-N, N' - (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine (abbreviated as NPB, CAS No. 123847-85-8), and the material of the hole transporting layer may be selected from inorganic materials having hole transporting ability, including but not limited to NiO, WO ₃ 、MoO ₃ And at least one of CuO. The thickness of the hole transport layer may be, for example, 10nm to 50nm.

In an example of the present application, as shown in fig. 3, the light emitting device 1 further includes a hole transport layer 15 on the basis of the light emitting device 1 shown in fig. 2, the hole transport layer 15 being disposed between the anode 11 and the light emitting layer 13. The thickness of the hole transport layer 15 may be, for example, 10nm to 50nm.

It should be noted that, the light emitting device according to the embodiments of the present application may further include other layer structures, for example, the light emitting device may further include an electron injection layer disposed between the electron transport layer and the cathode, and the material of the electron injection layer includes, but is not limited to, at least one of an alkali metal halide including, but not limited to, liF, an alkali metal organic complex including, but not limited to, lithium 8-hydroxyquinoline, and an organic phosphine compound including, but not limited to, one or more of an organic phosphorus oxide, an organic thiophosphine compound, and an organic selenophosphine compound.

The embodiment of the application also provides a preparation method of the light-emitting device, as shown in fig. 4, the preparation method comprises the following steps:

s11, providing a mixed solution containing a superoxide radical scavenger and a nano metal oxide;

And S12, providing a laminated structure, coating the mixed solution in the step S11 on one side of the laminated structure, and then drying to obtain the electron transport layer.

In the above manufacturing method, when the light emitting device is of a front structure, the stacked structure is a substrate including an anode and a light emitting layer, and the electron transport layer is formed on a side of the light emitting layer away from the anode; when the light emitting device is of an inverted structure, the laminated structure is a substrate comprising a cathode, and the electron transport layer is formed on one side of the cathode; the hydroxyl number contained in a single molecule of the superoxide radical scavenger is not less than 4, and the hydroxyl dissociation constant of the superoxide radical scavenger is not less than 6. The compound with weaker acidity and stronger superoxide radical capturing performance is adopted as the superoxide radical capturing agent, so that the negative influence on the properties of the nano metal oxide is reduced, and the suppression effect of the superoxide radical capturing agent on the superoxide radical is prevented from being reduced.

In some embodiments of the present application, for the mixed solution of step S11, the superoxide radical scavenger: the mass ratio of the nano metal oxide is (0.001-0.05): 1. the content of the super-oxygen free radical scavenger is too much or too little, so that the improvement effect on the performance of the light-emitting device is limited, and if the content of the super-oxygen free radical scavenger is too little, the elimination effect on the super-oxygen free radicals in the light-emitting device is limited; if the content of the superoxide radical scavenger is too large, the effect of enhancing the electron conductivity of the electron transport layer is limited.

In some embodiments of the present application, step S11 includes: mixing a first solution containing nano metal oxide and a second solution containing super oxygen radical scavenger to obtain a mixed solution, wherein the solvent of the first solution comprises at least one of ethanol, butanol and ethylene glycol monomethyl ether, and the solvent of the second solution comprises at least one of methanol, ethanol, acetone and n-octanol as an example: a mixed solution is obtained by mixing a nano ZnO-ethanol solution with the concentration of 30mg/mL and a quercetin solution with the concentration of 1 mg/mL.

It should be noted that, in step S12, the mixed solution of step S11 is applied to one side of the laminated structure by a solution method, which includes, but is not limited to, spin coating, ink-jet printing, knife coating, dip-coating, dipping, spray coating, roll coating, or casting. The "drying treatment" includes all processes that can obtain higher energy from the wet film to be converted into a dry film, for example, heat treatment, standing and naturally drying, etc., wherein the "heat treatment" may be constant temperature heat treatment or non-constant temperature heat treatment (for example, temperature is changed in a gradient manner), and in one example of the present application, the "drying treatment" refers to constant temperature heat treatment at 80 ℃ for 30min.

The embodiment of the application also provides a preparation method of the light-emitting device, which comprises the following steps: providing a laminated structure, alternately preparing and forming a nano metal oxide layer and a super oxygen radical trapping layer on one side of the laminated structure, wherein the initially prepared layer and the finally prepared layer are nano metal oxide layers, and N nano metal oxide layers and (N-1) super oxygen radical trapping layers forming an electron transport layer are obtained, wherein N is a positive integer greater than or equal to 2; when the light-emitting device is of a positive structure, the laminated structure is a substrate comprising an anode and a light-emitting layer, and the electron transport layer is formed on one side of the light-emitting layer far away from the anode; when the light emitting device is of an inverted structure, the stacked structure is a substrate including a cathode, and an electron transport layer is formed on one side of the cathode. The preparation method of each nano metal oxide layer and each superoxide radical trapping layer may be, for example, a solution method.

In addition to the electron transport layer, other layers in the light emitting device are prepared by methods including, but not limited to, solution methods including, but not limited to, spin coating, ink jet printing, knife coating, dip-coating, dipping, spray coating, roll coating, or casting; the deposition method includes a chemical method including, but not limited to, a chemical vapor deposition method, a continuous ion layer adsorption and reaction method, an anodic oxidation method, an electrolytic deposition method, or a coprecipitation method, and a physical method including, but not limited to, a thermal evaporation plating method, an electron beam evaporation plating method, a magnetron sputtering method, a multi-arc ion plating method, a physical vapor deposition method, an atomic layer deposition method, or a pulsed laser deposition method. If the film layer is prepared by adopting a solution method, a drying treatment procedure is added to convert a wet film prepared by the solution method into a dry film.

In an example of the present application, the manufacturing method of the light emitting device 1 as shown in fig. 3 includes the steps of:

s10, providing an anode, and preparing and forming a hole transport layer on one side of the anode;

s20, coating a quantum dot-n-octane solution on one side of the hole transport layer far away from the anode in the step S10, and carrying out constant-temperature heat treatment to obtain a dry film state light-emitting layer;

s30, coating a super-oxygen free radical trapping agent solution on one side of the first nano metal oxide layer far away from the light-emitting layer in the step S20, and performing constant-temperature heat treatment to obtain a first super-oxygen free radical trapping layer in a dry film state;

s40, coating a nano metal oxide solution on one side of the first super oxygen free radical capturing layer far away from the first nano metal oxide layer in the step S30, and performing constant temperature heat treatment to obtain a second nano metal oxide layer in a dry film state;

s50, repeating the operation of the step S30 and the step S40 to obtain N nano metal oxide layers and (N-1) super oxygen radical trapping layers which form an electron transport layer;

and S60, evaporating cathode materials on one side of the electron transport layer far away from the light emitting layer in the step S50, and then packaging to obtain the light emitting device.

The embodiment of the application also provides a display device, which comprises any one of the electroluminescent devices in the embodiment of the application. The display device may be any electronic product with a display function, including but not limited to a smart phone, a tablet computer, a notebook computer, a digital camera, a digital video camera, a smart wearable device, a smart weighing electronic scale, a vehicle-mounted display, a television set or an electronic book reader, wherein the smart wearable device may be, for example, a smart bracelet, a smart watch, a Virtual Reality (VR) helmet, etc.

The technical solutions and technical effects of the present application are described in detail below by means of specific examples, comparative examples and experimental examples, and the following examples are only some examples of the present application and are not intended to limit the present application in any way.

Example 1

The present embodiment provides a light emitting device and a method for manufacturing the same, wherein the light emitting device is a quantum dot light emitting diode with a front-mounted structure, and as shown in fig. 5, the light emitting device 1 includes a substrate 10, an anode 11, a hole injection layer 16, a hole transport layer 15, a light emitting layer 13, an electron transport layer 14, and a cathode 12, which are sequentially disposed in a bottom-to-top direction.

The materials and thicknesses of the respective layers in the light emitting device 1 are as follows:

the material of the substrate 10 is glass with the thickness of 0.4mm;

the anode 11 is made of ITO and has a thickness of 50nm;

the cathode 12 is made of Ag and has a thickness of 100nm;

the luminescent layer 13 is made of CdSe/ZnS quantum dots, and the thickness is 20nm;

the hole injection layer 16 is made of PEDOT PSS with the thickness of 20nm;

the hole transport layer 15 is made of TFB and has a thickness of 20nm;

the material of the electron transport layer 14 is composed of nano ZnO with a particle size of 5nm and quercetin: the mass ratio of the nano ZnO is 0.02:1.

the preparation method of the light-emitting device in the embodiment comprises the following steps:

S1.1, providing a substrate, sputtering ITO on one side of the substrate to obtain an ITO layer, then sequentially ultrasonically cleaning the substrate containing the ITO by using acetone for 15min, ultrasonically cleaning the substrate by using a cleaning agent for 15min, ultrasonically cleaning the substrate by using deionized water for 15min and ultrasonically cleaning the substrate by using isopropanol for 15min, and performing surface treatment by using ultraviolet-ozone for 5min after drying to obtain the substrate containing an anode;

s1.2, spin-coating PEDOT/PSS aqueous solution (CAS number 155090-83-8) on one side of the anode far from the substrate in an air environment at normal temperature and normal pressure, and then performing heat treatment at 150 ℃ for 15min to obtain a hole injection layer;

s1.3, spin-coating TFB (CAS number 223569-31-1) -chlorobenzene solution with concentration of 8mg/mL on one side of the hole injection layer far away from the anode in the step S1.2 under the nitrogen environment of normal temperature and normal pressure, and then placing the solution in a constant temperature heat treatment mode for 30 minutes at 150 ℃ to obtain a hole transport layer;

s1.4, spin-coating a CdSe/ZnS quantum dot-n-octane solution with the concentration of 30mg/mL on one side of the hole transport layer far away from the hole injection layer in the step S1.3 under the nitrogen environment at normal temperature and normal pressure, and then performing heat treatment at 80 ℃ for 20min to obtain a luminescent layer;

s1.5, mixing an equal volume of nano ZnO-ethanol solution (the nano ZnO concentration is 50 mg/mL) and a quercetin solution (the quercetin concentration is 1mg/mL, and a solvent is methanol) in a nitrogen environment at normal temperature and normal pressure to obtain a mixed solution, spin-coating the mixed solution on one side of the luminescent layer far away from the hole transport layer in the step S1.4, and then placing the mixed solution at 80 ℃ for heat treatment for 30min to obtain an electron transport layer;

S1.6, evaporating Ag on one side of the electron transport layer far away from the light-emitting layer in the step S1.5 to obtain a cathode, and then packaging by adopting epoxy resin and a cover glass to obtain the light-emitting device.

Example 2

The present embodiment provides a light emitting device and a method for manufacturing the same, which differ from the light emitting device of embodiment 1 only in that: the material of the electron transport layer is replaced by' the material of the electron transport layer is composed of nano ZnO with the particle size of 5nm and quercetin: the mass ratio of the nano ZnO is 0.001:1".

The preparation method of this example differs from that of example 1 only in that: the step S1.5 is replaced by "under nitrogen atmosphere at normal temperature and normal pressure", equal volumes of nano ZnO-ethanol solution (nano ZnO concentration is 50 mg/mL) and quercetin solution (quercetin concentration is 0.05mg/mL, solvent is methanol) are mixed to obtain a mixed solution, the mixed solution is spin-coated on one side of the light emitting layer far away from the hole transport layer in the step S1.4, and then the mixed solution is subjected to heat treatment at 80 ℃ for 30min to obtain an electron transport layer.

Example 3

The present embodiment provides a light emitting device and a method for manufacturing the same, which differ from the light emitting device of embodiment 1 only in that: the material of the electron transport layer is replaced by' the material of the electron transport layer is composed of nano ZnO with the particle size of 5nm and quercetin: the mass ratio of the nano ZnO is 0.05:1".

The preparation method of this example differs from that of example 1 only in that: the step S1.5 is replaced by "under nitrogen atmosphere at normal temperature and normal pressure", equal volumes of nano ZnO-ethanol solution (nano ZnO concentration is 50 mg/mL) and quercetin solution (quercetin concentration is 2.5mg/mL, solvent is methanol) are mixed to obtain a mixed solution, the mixed solution is spin-coated on one side of the light emitting layer far away from the hole transport layer in the step S1.4, and then the mixed solution is subjected to heat treatment at 80 ℃ for 30min to obtain an electron transport layer.

Example 4

The present embodiment provides a light emitting device and a method for manufacturing the same, which differ from the light emitting device of embodiment 1 only in that: the material of the electron transport layer is replaced by' the material of the electron transport layer is composed of nano ZnO with the grain diameter of 5nm and quercetin, and the nano ZnO: the mass ratio of the quercetin is 0.1:1".

The preparation method of this example differs from that of example 1 only in that: the step S1.5 is replaced by 'under the nitrogen environment at normal temperature and normal pressure', equal volumes of nano ZnO-ethanol solution (the nano ZnO concentration is 50 mg/mL) and quercetin solution (the quercetin concentration is 5mg/mL, and the solvent is methanol) are mixed to obtain a mixed solution, the mixed solution is spin-coated on one side of the luminescent layer far away from the hole transport layer in the step S1.4, and then the mixed solution is subjected to heat treatment at 80 ℃ for 30min to obtain an electron transport layer.

Example 5

The present embodiment provides a light emitting device and a method for manufacturing the same, which differ from the light emitting device of embodiment 1 only in that: the electron transport layer material is replaced by an electron transport layer material which is composed of nano ZnO with the particle size of 5nm and ascorbic acid, wherein the nano ZnO: the mass ratio of the ascorbic acid is 0.02:1".

The preparation method of this example differs from that of example 1 only in that: the step S1.5 is replaced by "under nitrogen atmosphere at normal temperature and normal pressure, equal volumes of nano ZnO-ethanol solution (nano ZnO concentration is 50 mg/mL) and ascorbic acid solution (ascorbic acid concentration is 1mg/mL, solvent is methanol) are mixed to obtain a mixed solution, the mixed solution is spin-coated on one side of the light-emitting layer far away from the hole transport layer in the step S1.4, and then the mixed solution is subjected to heat treatment at 80 ℃ for 30min to obtain an electron transport layer.

Example 6

The embodiment provides a light emitting device and a preparation method thereof, wherein the light emitting device is a quantum dot light emitting diode with a forward structure, as shown in fig. 6, in a bottom-to-top direction, the light emitting device 1 comprises a substrate 10, an anode 11, a hole injection layer 16, a hole transport layer 15, a light emitting layer 13, an electron transport layer 14 and a cathode 12, wherein the electron transport layer 14 is composed of a first nano ZnO layer 14-1-1, a super oxygen radical capturing layer 14-2 and a second nano ZnO layer 14-1-2 which are alternately stacked, the first nano ZnO layer 14-1-1 is close to the light emitting layer 13, and the second nano ZnO layer 14-1-2 is close to the cathode 12.

The materials and thicknesses of the respective layers in the light emitting device 1 are as follows:

the material of the substrate 10 is glass with the thickness of 0.4mm;

the anode 11 is made of ITO and has a thickness of 50nm;

the cathode 12 is made of Ag and has a thickness of 100nm;

the luminescent layer 13 is made of CdSe/ZnS quantum dots, and the thickness is 20nm;

the hole injection layer 16 is made of PEDOT PSS with the thickness of 20nm;

the hole transport layer 15 is made of TFB and has a thickness of 20nm;

the materials of the first nano ZnO layer 14-1-1 and the second nano ZnO layer 14-1-2 are nano ZnO with the particle size of 5nm, and the thicknesses of the first nano ZnO layer 14-1-1 and the second nano ZnO layer are 20nm;

the material of the superoxide radical trapping layer 14-2 was quercetin, with a thickness of 2nm.

The preparation method of the light-emitting device in the embodiment comprises the following steps:

s2.1, providing a substrate, sputtering ITO on one side of the substrate to obtain an ITO layer, then sequentially ultrasonically cleaning the substrate containing the ITO by using acetone for 15min, ultrasonically cleaning the substrate by using a cleaning agent for 15min, ultrasonically cleaning the substrate by using deionized water for 15min and ultrasonically cleaning the substrate by using isopropanol for 15min, and performing surface treatment by using ultraviolet-ozone for 5min after drying to obtain the substrate containing the anode;

s2.2, spin-coating PEDOT/PSS aqueous solution (CAS number 155090-83-8) on one side of the anode far from the substrate in an air environment at normal temperature and normal pressure, and then performing heat treatment at 150 ℃ for 15min to obtain a hole injection layer;

S2.3, spin-coating TFB (CAS number 223569-31-1) -chlorobenzene solution with concentration of 8mg/mL on one side of the hole injection layer far away from the anode in the step S2.2 under the nitrogen environment of normal temperature and normal pressure, and then placing the solution in a constant temperature heat treatment mode for 30 minutes at 150 ℃ to obtain a hole transport layer;

s2.4, spin-coating a CdSe/ZnS quantum dot-n-octane solution with the concentration of 30mg/mL on one side of the hole transport layer far away from the hole injection layer in the step S2.3 under the nitrogen environment at normal temperature and normal pressure, and then performing heat treatment at 80 ℃ for 20min to obtain a luminescent layer;

s2.5, spin-coating a nano ZnO-ethanol solution with the concentration of 15mg/mL on one side of the luminescent layer far away from the hole transport layer in the step S2.4 under the nitrogen environment at normal temperature and normal pressure, and then performing heat treatment at 80 ℃ for 10min to obtain a first nano ZnO layer 14-1-1; spin-coating a quercetin solution with concentration of 1mg/mL on one side of the first nano ZnO layer 14-1-1 far away from the light-emitting layer, and then placing the quercetin solution at 80 ℃ for heat treatment for 5min to obtain a superoxide radical capturing layer 14-2; spin-coating a nano ZnO-ethanol solution with the concentration of 15mg/mL on one side of the super oxygen free radical capture layer 14-2 far away from the light-emitting layer, and then placing the nano ZnO-ethanol solution at 80 ℃ for heat treatment for 10min to obtain a second nano ZnO layer 14-1-2, wherein the first nano ZnO layer 14-1-1, the super oxygen free radical capture layer 14-2 and the second nano ZnO layer 14-1-2 form an electron transport layer;

S2.6, evaporating Ag on one side of the electron transport layer far away from the light-emitting layer in the step S2.5 to obtain a cathode, and then packaging by adopting epoxy resin and a cover glass to obtain the light-emitting device.

Example 7

The present embodiment provides a light emitting device and a method for manufacturing the same, which differ from the light emitting device of embodiment 6 only in that: the electron transport layer is formed by alternately stacking a first nano ZnO layer, a first superoxide radical trapping layer, a second nano ZnO layer, a second superoxide radical trapping layer and a third nano ZnO layer, wherein the first nano ZnO layer is close to the light emitting layer, and the third nano ZnO layer is close to the cathode; the first nano ZnO layer, the second nano ZnO layer and the third nano ZnO layer are all made of nano ZnO with the grain diameter of 5nm and the thickness of 15nm; the material of the first superoxide radical trapping layer and the material of the second superoxide radical trapping layer are quercetin, and the thickness of the first superoxide radical trapping layer and the second superoxide radical trapping layer are 1nm.

The preparation method of this example differs from that of example 6 only in that: replacing the step S2.5 with 'under the nitrogen environment at normal temperature and normal pressure', spin-coating a nano ZnO-ethanol solution with the concentration of 12mg/mL on the side, far away from the hole transport layer, of the luminescent layer in the step S2.4, and then placing the nano ZnO-ethanol solution in the temperature of 80 ℃ for heat treatment for 10min to obtain a first nano ZnO layer; spin-coating a quercetin solution with the concentration of 1mg/mL on one side of the first nano ZnO layer far away from the light-emitting layer, and then placing the quercetin solution at 80 ℃ for heat treatment for 5min to obtain a first superoxide radical capturing layer; spin-coating a nano ZnO-ethanol solution with the concentration of 12mg/mL on one side of the first superoxide radical capturing layer far away from the light-emitting layer, and then placing the nano ZnO-ethanol solution at 80 ℃ for heat treatment for 10min to obtain a second nano ZnO layer; spin-coating a quercetin solution with the concentration of 0.5mg/mL on one side of the second nano ZnO layer far away from the first superoxide radical trapping layer, and then placing the quercetin solution at 80 ℃ for heat treatment for 5min to obtain a second superoxide radical trapping layer; and spin-coating a nano ZnO-ethanol solution with the concentration of 12mg/mL on one side of the second superoxide radical capturing layer far away from the second nano ZnO layer, and then placing the nano ZnO-ethanol solution at 80 ℃ for heat treatment for 10min to obtain a third nano ZnO layer.

Comparative example

The present comparative example provides a light emitting device differing from the light emitting device of embodiment 1 only in that: the material of the electron transport layer was replaced with "nano ZnO having a particle diameter of 5 nm", and the thickness of the electron transport layer was 50nm.

The preparation method of this example differs from that of example 1 only in that: and replacing the step S1.5 with 'under the nitrogen environment at normal temperature and normal pressure', spin-coating 30mg/mL of nano ZnO-ethanol solution on one side of the luminescent layer far away from the hole transport layer in the step S1.4, and then placing the nano ZnO-ethanol solution at 80 ℃ for heat treatment for 30min to obtain the electron transport layer.

Experimental example

Performance tests were performed on the light emitting devices of examples 1 to 7 and comparative examples using a Friedel-crafts FPD optical property measuring apparatus, which is an efficiency test system constructed by LabView-controlled QE-PRO spectrometer, keithley 2400 and Keithley 6485, capable of measuring parameters such as voltage, current, luminance, light emission spectrum, etc. of the obtained light emitting device and obtaining key parameters such as external quantum dot efficiency, power efficiency, etc. by calculation, maximum external quantum efficiency (EQE _max (percent) Table 1 below, and the current density-voltage characteristic curves of the light emitting devices of examples 1 to 7 and comparative examples are shown in FIGS. 7 and 8, further, the light emitting devices of examples 1 to 7 and comparative examples were obtained with a life test apparatus such that the luminance was attenuated from 100% to 95 at a luminance of 1000 nit (nit)% time required (T95-1K, h), T95-1K of the light emitting devices of examples 1 to 7 and comparative examples are detailed in Table 1 below:

table 1 results of performance tests of light emitting devices of examples 1 to 7 and comparative examples

As can be seen from table 1, the light emitting devices of examples 1 to 7 have comprehensive properties significantly superior to those of the light emitting device of the comparative example, and it is fully illustrated that the material of the electron transport layer contains the superoxide radical scavenger, which can eliminate superoxide radicals in the light emitting device or reduce the content of superoxide radicals in the light emitting device, and effectively avoid the superoxide radicals to decompose the surface ligand of the quantum dot and the surface ligand of the nano ZnO, thereby improving the light emitting efficiency of the light emitting device and prolonging the service life of the light emitting device.

The light emitting devices of embodiments 1 to 3 have better photoelectric properties and service lives than those of embodiment 4, for example: the EQEmax of the light emitting device of example 1 is 1.3 times that of the light emitting device of example 4, and T95-1K of the light emitting device of example 1 is 1.5 times that of the light emitting device of example 4, indicating that when the superoxide radical scavenger is in the material of the electron transport layer: the mass ratio of the nano metal oxide is (0.001-0.05): 1, the comprehensive performance of the light-emitting device is improved, and if the content of the superoxide radical trapping agent is excessive, the enhancement effect on the electron conduction capacity of the electron transport layer is limited.

The overall performance of the light emitting device of example 1 was more excellent than that of example 5, indicating that: when the superoxide radical scavenger and the nano ZnO are arranged in the same layer, a compound (e.g. quercetin) with weaker acidity and stronger superoxide radical scavenger is adopted to be doped in the electron transport layer, so that negative influence of the superoxide radical scavenger on the conductivity of the nano metal oxide can be reduced on the premise of ensuring ideal inhibition effect on the superoxide radicals; when a compound with higher acidity (such as ascorbic acid) is used as a superoxide radical scavenger, the ascorbic acid is added into an alkaline nano ZnO-ethanol solution to be hydrolyzed in the preparation process, so that the inhibition effect on superoxide radicals is limited, and the improvement effect on the luminous efficiency and the service life of a luminous device is limited.

The overall performance of example 6 and example 7 is better than that of examples 1 to 5, for example: the EQEmax of the light emitting device of example 6 is 1.1 times that of the light emitting device of example 3, and T95-1K of the light emitting device of example 6 is 4.7 times that of the light emitting device of example 3, indicating that the electron transport layer is configured in a multi-layered structure, and the nano metal oxide layers and the super oxygen radical trapping layer are alternately arranged, the performance of the electron transport layer is not adversely affected, and the problem that the super oxygen radical trapping agent has a reduced suppression effect on super oxygen radicals due to the mixing effect with the nano metal oxide can be prevented, thereby further improving the light emitting efficiency and the service life of the light emitting device.

As can be seen from fig. 7 and 8, the current densities of the light emitting devices of examples 1 to 7 and the comparative example all tended to rise with the rise of the driving voltage at the driving voltage of 1.0V to 9.0V, and the difference in the current densities at the same driving voltage was small, indicating that the addition of the superoxide radical scavenger in the electron transport layer did not adversely affect the current and brightness of the light emitting device.

The light emitting device, the method for manufacturing the light emitting device and the display device provided in the embodiments of the present application are described in detail above. The principles and embodiments of the present application are described herein with reference to specific examples, the description of which is only for aiding in understanding the technical solution of the present application and its core ideas; those of ordinary skill in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the scope of the corresponding technical solutions of the embodiments of the present application.

Claims (15)

1. A light emitting device, comprising:

an anode;

a cathode disposed opposite the anode;

A light-emitting layer disposed between the anode and the cathode; and

an electron transport layer disposed between the light emitting layer and the cathode;

wherein the material of the electron transport layer comprises a super oxygen radical scavenger and a nano metal oxide.

2. The light-emitting device according to claim 1, wherein the super-oxygen radical scavenger and the nano-metal oxide are blended in the same layer as the electron transport layer, wherein a single molecule of the super-oxygen radical scavenger contains a hydroxyl group number of not less than 4, and wherein each hydroxyl group in the super-oxygen radical scavenger has a dissociation constant pKa of not less than 6.

3. The light-emitting device according to claim 2, wherein the superoxide radical scavenger comprises quercetin and/or rutin.

4. A light-emitting device according to claim 2 or 3, wherein in the material of the electron transport layer, the superoxide radical scavenger: the mass ratio of the nano metal oxide is (0.001-0.05): 1.

5. the light-emitting device according to claim 1, wherein the electron transport layer comprises N nano-metal oxide layers and (N-1) super-oxygen radical trapping layers, wherein N is a positive integer of 2 or more; the nano metal oxide layers and the super oxygen radical capturing layers are alternately arranged, and one layer of the electron transport layer close to the light emitting layer and one layer of the electron transport layer close to the cathode are both nano metal oxide layers.

6. The light-emitting device according to claim 5, wherein the material of the superoxide radical trapping layer comprises at least one of ascorbic acid, quercetin, or rutin.

7. The light-emitting device according to claim 5 or 6, wherein a total thickness of N of the nano metal oxide layers is 20nm to 100nm, and a thickness of each of the nano metal oxide layers is 5nm to 45nm; (N-1) the total thickness of the super oxygen radical trapping layers is between 0.2nm and 5nm, and the thickness of each of the super oxygen radical trapping layers is between 0.1nm and 3.0nm.

8. A light emitting device according to claim 2 or 5 wherein the nano metal oxide is selected from ZnO, tiO ₂ 、SnO ₂ 、Ta ₂ O ₃ 、ZrO ₂ At least one of TiLiO, znGaO, znAlO, znMgO, znSnO, znLiO, inSnO, alZnO, znOCl and ZnOF.

9. The light-emitting device according to claim 8, wherein the nano metal oxide has a particle size of 2nm to 15nm.

10. The light-emitting device according to claim 2 or 5, further comprising a hole-transporting layer provided between the anode and the light-emitting layer, wherein a material of the hole-transporting layer is selected from NiO, WO ₃ 、MoO ₃ CuO, poly (9, 9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine), 3-hexyl-substituted polythiophene, poly (9-vinylcarbazole), poly [ bis (4-phenyl) (4-butylphenyl) amine]At least one of poly (N, N '-bis (4-butylphenyl) -N, N' -diphenyl-1, 4-phenylenediamine-CO-9, 9-dioctylfluorene), 4',4 "-tris (carbazol-9-yl) triphenylamine, 4' -bis (9-carbazol) biphenyl, N '-diphenyl-N, N' -bis (3-methylphenyl) -1,1 '-biphenyl-4, 4' -diamine or N, N '-diphenyl-N, N' - (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine.

11. A light-emitting device according to claim 2 or 5, wherein,the material of the light-emitting layer is an organic light-emitting material or quantum dots, and the organic light-emitting material is at least one selected from a biaryl anthracene derivative, a stilbene aromatic derivative, a pyrene derivative or fluorene derivative, a TBPe fluorescent material emitting blue light, a TTPA fluorescent material emitting green light, a TBRb fluorescent material emitting orange light and a DBP fluorescent material emitting red light; the quantum dot is selected from at least one of II-VI compound, III-V compound, IV-VI compound and I-III-VI compound, wherein the II-VI compound is selected from at least one of CdS, cdSe, cdTe, znS, znSe, znTe, znO, hgS, hgSe, hgTe, cdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, cdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe and HgZnSTe, the III-V compound is selected from at least one of GaN, gaP, gaAs, gaSb, alN, alP, alAs, alSb, inN, inP, inAs, inSb, gaNP, gaNAs, gaNSb, gaPAs, gaPSb, alNP, alNAs, alNSb, alPAs, alPSb, inNP, inNAs, inNSb, inPAs, inPSb, gaAlNP, gaAlNAs, gaAlNSb, gaAlPAs, gaAlPSb, gaInNP, gaInNAs, gaInNSb, gaInPAs, gaInPSb, inAlNP, inAlNAs, inAlNSb, inAlPAs and InAlPSb, the IV-VI 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 and SnPbSTe, and the I-III-VI compound is selected from CuInS ₂ 、CuInSe ₂ And AgInS ₂ At least one of them.

12. A method of manufacturing a light emitting device, comprising the steps of:

providing a mixed solution comprising a superoxide radical scavenger and a nano metal oxide;

providing a laminated structure, coating the mixed solution on one side of the laminated structure, and then drying to obtain an electron transport layer;

when the light-emitting device is of a positive structure, the laminated structure is a substrate comprising an anode and a light-emitting layer, and the electron transport layer is formed on one side of the light-emitting layer away from the anode; when the light emitting device is of an inverted structure, the stacked structure is a substrate including a cathode, and the electron transport layer is formed on one side of the cathode; the number of hydroxyl groups contained in a single molecule of the superoxide radical scavenger is not less than 4, and the dissociation constant pKa of each hydroxyl group in the superoxide radical scavenger is not less than 6.

13. The method of claim 12, wherein in the mixed solution, the superoxide radical scavenger: the mass ratio of the nano metal oxide is (0.001-0.05): 1.

14. a method of manufacturing a light emitting device, the method comprising the steps of: providing a laminated structure, alternately preparing and forming a nano metal oxide layer and a super oxygen radical trapping layer on one side of the laminated structure, wherein the initially prepared layer and the finally prepared layer are nano metal oxide layers, N nano metal oxide layers and (N-1) super oxygen radical trapping layers are formed, N is a positive integer greater than or equal to 2, and an electron transport layer is obtained;

When the light-emitting device is of a positive structure, the laminated structure is a substrate comprising an anode and a light-emitting layer, and the electron transport layer is formed on one side of the light-emitting layer away from the anode; when the light emitting device is of an inverted structure, the stacked structure is a substrate including a cathode, and the electron transport layer is formed on one side of the cathode.

15. A display device characterized in that it comprises the light-emitting device according to any one of claims 1 to 11 or the light-emitting device produced by the production method according to any one of claims 12 to 14.

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