Method for manufacturing light emitting device, light emitting device and display device

Abstract

This application discloses a method for fabricating a light-emitting device, the light-emitting device itself, and a display device. The fabrication method includes the following steps: providing a pre-fabricated device; applying a solution containing nano-metal oxides to one side of the pre-fabricated device to obtain an electron transport precursor layer; and within a preset time range, annealing and electro-energizing the solution located on one side of the pre-fabricated device to form an electron transport layer. This allows ligands attached to the surface of the nano-metal oxides to detach more easily under the influence of high temperature and electrical energy, effectively shortening the gap between adjacent nanoparticles, improving the crystallinity, conductivity, and stability of the electron transport layer, thereby greatly enhancing the luminous performance and lifespan of the light-emitting device. Applying the light-emitting device prepared by this method to a display device is beneficial for improving the display effect and extending the lifespan of the display device.

Description

Technical Field

[0001] This application relates to the field of optoelectronic technology, specifically to a method for fabricating a light-emitting device, and a light-emitting device and display device. Background Technology

[0002] Light-emitting devices include, but are not limited to, organic light-emitting diodes (OLEDs) and quantum dot light-emitting diodes (QLEDs). These devices have a "sandwich" structure, consisting of an anode, a cathode, and a light-emitting layer. The anode and cathode are positioned opposite each other, and the light-emitting layer is located between them. The principle of light emission is as follows: electrons are injected from the cathode into the light-emitting region, and holes are injected from the anode. Electrons and holes recombine in the light-emitting region to form excitons. These excitons then release photons through radiative transitions, thus emitting light.

[0003] In light-emitting devices, an electron transport layer is typically placed between the cathode and the light-emitting layer. Metal oxide nanoparticles are one of the materials used to prepare this electron transport layer. While nano-metal oxides possess high electron mobility and a wide electron bandgap, their surfaces contain numerous defect states, leading to less than ideal stability. Furthermore, external environmental conditions significantly affect the defect density and conductivity of nano-metal oxides, resulting in substantial fluctuations in the performance of the electron transport layer. This, in turn, negatively impacts the photoelectric performance and lifespan of the light-emitting device.

[0004] Therefore, improving the performance stability of electron transport layers containing nano-metal oxides is of great significance to the application and development of light-emitting devices. Summary of the Invention

[0005] This application provides a method for fabricating a light-emitting device, the light-emitting device itself, and a display device, in order to improve the photoelectric performance and stability of the light-emitting device.

[0006] The technical solution of this application is as follows:

[0007] In a first aspect, this application provides a method for fabricating a light-emitting device, the method comprising the following steps:

[0008] A prefabricated device is provided, and a solution containing nano-metal oxides is applied to one side of the prefabricated device to obtain an electron transport precursor layer;

[0009] Within a preset time range, the solution located on one side of the prefabricated device is subjected to annealing and electro-energizing treatment to form an electron transport layer;

[0010] When the light-emitting device is an upright structure, the prefabricated device includes an anode and a light-emitting layer stacked together, and the solution is applied to the side of the light-emitting layer away from the anode;

[0011] When the light-emitting device is an inverted structure, the prefabricated device includes a cathode, and the solution is applied to one side of the cathode.

[0012] Optionally, the annealing temperature is between 80°C and 250°C;

[0013] And / or, the preset time range is 5 min to 120 min;

[0014] And / or, the nano-metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ta2O3, ZrO2, TiLiO, ZnGaO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, InSnO, AlZnO, ZnOCl or ZnOF;

[0015] And / or, the average particle size of the nano-metal oxide is 2 nm to 15 nm.

[0016] Furthermore, the time period of the annealing process and the time period of the power-on process at least partially overlap.

[0017] Optionally, the annealing process is continuous, and the power-on process is continuous.

[0018] Optionally, the annealing process is continuous, and the energizing process is intermittent;

[0019] Alternatively, the annealing process may be intermittent, while the energizing process may be continuous;

[0020] Alternatively, the annealing process may be intermittent, and the energizing process may also be intermittent.

[0021] Furthermore, when the annealing process is continuous and the power-on process is intermittent, the interval between adjacent power-on processes is 5 to 10 minutes, and the duration of a single power-on process is 10 to 15 minutes.

[0022] Alternatively, when the annealing process is intermittent and the power-on process is continuous, the interval between adjacent annealing processes is 5 to 10 minutes, and the time for a single annealing process is 10 to 30 minutes.

[0023] Alternatively, when the annealing process is intermittent and the power-on process is intermittent, the interval between adjacent annealing processes is 5 to 20 minutes, and the duration of a single annealing process is 5 to 20 minutes; the interval between adjacent power-on processes is 5 to 20 minutes, and the duration of a single power-on process is 5 to 20 minutes.

[0024] Furthermore, the total time for the annealing process is 5 to 120 minutes, the total time for the power-on process is 5 to 120 minutes, and the total overlap time between the annealing process and the power-on process is 5 to 120 minutes.

[0025] As an alternative implementation, the annealing process is performed alternately with the power-on process.

[0026] Furthermore, the total annealing time is 5 to 60 minutes, and the total power-on time is 5 to 60 minutes;

[0027] And / or, the duration of a single power-on process is 5 to 20 minutes, and the duration of a single annealing process is 5 to 20 minutes.

[0028] Optionally, the energizing process is a constant current energizing process, a constant voltage energizing process, or an alternating energizing process;

[0029] During the energizing process, the current density of the electron transport precursor layer is 100 mA / cm². 2 Up to 300mA / cm 2 .

[0030] Optionally, when the light-emitting device is an upright structure, the fabrication method further includes the step of: after forming an electron transport layer on one side of the pre-fabricated device, forming a cathode on the side of the electron transport layer away from the light-emitting layer;

[0031] Alternatively, when the light-emitting device is an inverted structure, the fabrication method further includes the following steps:

[0032] After forming an electron transport layer on one side of the prefabricated device, a light-emitting layer is formed on the side of the electron transport layer away from the cathode; and

[0033] An anode is formed on the side of the light-emitting layer away from the electron transport layer.

[0034] Optionally, the material of the light-emitting layer is an organic light-emitting material or quantum dots;

[0035] The organic light-emitting material is selected from at least one of diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPA fluorescent materials, TBRb fluorescent materials, or DBP fluorescent materials;

[0036] The quantum dots are selected from at least one of single-component quantum dots, core-shell quantum dots, inorganic perovskite quantum dots, or organic-inorganic hybrid perovskite quantum dots; when the quantum dots are selected from single-component quantum dots or core-shell quantum dots, the material of the single-component quantum dot, the material of the core of the core-shell quantum dot, and the material of the shell of the core-shell quantum dot are independently selected from at least one of group II-VI compounds, group III-V compounds, group IV-VI compounds, or group I-III-VI compounds, wherein the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, Zn O, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgT e. At least one of HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe or HgZnSTe, the III-V group Compounds 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, GaInP At least one of Sb, InAlNP, InAlNAs, InAlNSb, InAlPAs, or InAlPSb, wherein 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, or SnPbSTe, and wherein the I-III-VI group compound is selected from at least one of CuInS2, CuInSe2, or AgInS2.

[0037] Optionally, the preparation method further includes the step of: forming a hole functional layer between the anode and the light-emitting layer, the hole functional layer including a hole injection layer and / or a hole transport layer, wherein when the hole functional layer includes a stacked hole transport layer and a hole injection layer, the hole transport layer is close to the light-emitting layer and the hole injection layer is close to the anode;

[0038] The material of the hole transport layer is selected from at least one of NiO, WO3, MoO3, CuO, poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine), 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), poly[bis(4-phenyl)(4-butylphenyl)amine], poly(N,N'-di(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene), 4,4',4”-tris(carbazole-9-yl)triphenylamine, 4,4'-di(9-carbazole)biphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine or N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine;

[0039] The material of the hole injection layer is selected from at least one of poly(3,4-vinyldioxythiophene): poly(styrene sulfonic acid), copper phthalocyanine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, transition metal oxides, or transition metal chalcogenides, wherein the transition metal oxide is selected from NiO. x MoO x WO x or CrO x At least one of the following, wherein the transition metal chalcogenide compound is selected from MoS x MoSe x WS x 、WSe x Or at least one of CuS.

[0040] Secondly, this application provides a light-emitting device, which is prepared by any of the preparation methods described in the first aspect.

[0041] Thirdly, this application also provides a display device, which includes a light-emitting device as described in any of the first aspects, or a light-emitting device prepared by any of the preparation methods described in the second aspect.

[0042] This application provides a method for fabricating a light-emitting device, the light-emitting device itself, and a display device, which have the following technical advantages:

[0043] In the preparation method, the solution containing nano-metal oxides applied to one side of the pre-fabricated device is annealed and electrically treated within a preset time range to form an electron transport layer. Under the action of high temperature and electrical energy, the ligands attached to the surface of the nano-metal oxides are more likely to detach, which can effectively shorten the gap between adjacent nanoparticles, improve the crystallinity, conductivity and stability of the electron transport layer, and thus greatly improve the luminescence performance and working life of the light-emitting device.

[0044] Compared to existing light-emitting devices (where the electron transport layer is made of nano-oxide), the electron transport layer of the light-emitting device in this application (made of the same type of nano-metal oxide) has higher density, meaning the gaps between adjacent nanoparticles are smaller. This results in higher conductivity and stability of the electron transport layer, thus leading to better overall performance of the light-emitting device in this application.

[0045] Applying the light-emitting device prepared by the method described in this application to a display device can improve the display effect and extend the service life of the display device. Attached Figure Description

[0046] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0047] Figure 1 This is a schematic flowchart illustrating a method for fabricating a light-emitting device according to an embodiment of this application.

[0048] Figure 2 This is a schematic diagram of the structure of the first light-emitting device provided in the embodiments of this application.

[0049] Figure 3 This is a schematic diagram of the structure of a second type of light-emitting device provided in an embodiment of this application.

[0050] Figure 4 This is a schematic diagram of the structure of a third type of light-emitting device provided in an embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0053] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to," and the terms "a plurality of" or "multiple layers" mean two or more layers. Various embodiments of this application may exist in a range format; 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; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0054] This application provides a method for fabricating a light-emitting device, such as... Figure 1 As shown, the post-processing method includes the following steps:

[0055] S1. Provide a prefabricated device and apply a solution containing nano-metal oxides to one side of the prefabricated device;

[0056] S2. Within a preset time range, the solution located on one side of the prefabricated device is subjected to annealing and electro-energizing treatment to form an electron transport layer.

[0057] In the above preparation method, "annealing treatment" includes all steps that enable the solution located on one side of the preform to obtain higher energy and at least remove part of the solvent, including but not limited to isothermal heat treatment steps or non-isothermal heat treatment steps (e.g., temperature gradient changes). In some embodiments of this application, "annealing treatment" refers to isothermal heat treatment at 80°C to 250°C for 5 min to 120 min. The annealing temperature can be, for example, 80°C to 100°C, 100°C to 120°C, 120°C to 140°C, 140°C to 160°C, 160°C to 180°C, 18... The annealing temperature can be 0°C to 200°C, 200°C to 220°C, 220°C to 240°C, or 240°C to 250°C, and the annealing time can be, for example, 5 min to 10 min, 10 min to 20 min, 20 min to 30 min, 30 min to 40 min, 40 min to 50 min, 50 min to 60 min, 60 min to 70 min, 70 min to 80 min, 80 min to 90 min, 90 min to 100 min, 100 min to 110 min, or 110 min to 120 min. It is understood that the solution located on one side of the prefabricated device can form a film layer in a wet film state or a dry film state after annealing.

[0058] As used in this application, "electrification processing" involves connecting a solution containing nano-metal oxides between the cathode and anode of an external power supply to form a closed loop. The solution is equivalent to the resistance in the closed loop. This application does not specifically limit the type or model of the external power supply; it can be selected according to the scale of different light-emitting devices. It should be noted that either only the solution can be connected between the cathode and anode of the external power supply, or a prefabricated device containing the solution can be connected between the cathode and anode of the external power supply. In at least one embodiment of this application, "electrification processing" includes the steps of: fixing the prefabricated device containing the solution onto a fixture, and then connecting the anode and cathode of the external power supply to opposite sides of the wet film formed by the solution.

[0059] It should be noted that when annealing only the solution located on one side of the pre-fabricated device, the solution is typically annealed using heat treatment. However, the heat treatment temperature should not be too high to avoid damaging the light-emitting layer and other functional layers. Therefore, it is impossible to thoroughly anneal the nano-metal oxides, resulting in insufficient removal of ligands on the surface of the nano-metal oxides. Consequently, the gaps between adjacent nanoparticles cannot be effectively shortened, leading to a loosely arranged nanocrystal array formed by the nano-metal oxides in the formed film, resulting in low film density. The gaps between adjacent nanoparticles create a potential barrier for electron conduction, and the nano-metal oxides themselves have a large specific surface area and are highly reactive, resulting in unsatisfactory conductivity and poor stability in the film prepared from the nano-metal oxides. Based on this, in the above preparation method, by adopting the technical means of "annealing and electro-treating the solution within a preset time range", the solution is promoted to form a film under the action of electrical energy and high temperature, while making the ligands attached to the surface of the nano metal oxide easier to detach, thereby shortening the gap between adjacent nanoparticles, and thus improving the crystallinity, conductivity and stability of the electron transport layer, which is beneficial to improving the photoelectric performance and working life of the light-emitting device.

[0060] Furthermore, the annealing and electro-energizing processes are performed in an inert gas atmosphere. "Inert gas" refers to a type of gas that is chemically inert, does not react with the electron transport precursor layer and other functional layers, and possesses the property of isolating oxygen and water. Inert gases are selected from at least one of nitrogen, helium, neon, argon, krypton, or xenon. After the annealing and electro-energizing processes are performed within a preset time range, other processing steps can be carried out, such as drying, to form a dry film electron transport layer.

[0061] Specifically, in step S1, the application method of the solution containing nano-metal oxides includes, but is not limited to, at least one of spin coating, coating, inkjet printing, blade coating, dip-coating, immersion, spraying, roller coating, or casting. When the light-emitting device is a positive structure, the prefabricated device includes a stacked anode and a light-emitting layer, and the solution is applied to the side of the light-emitting layer away from the anode. For example, the prefabricated device consists of a substrate, an anode, and a light-emitting layer stacked sequentially, or the prefabricated device consists of a substrate, an anode, a hole functional layer, and a light-emitting layer stacked sequentially. When the light-emitting device is an inverted structure, the prefabricated device includes a cathode, and the solution is applied to one side of the cathode. For example, the prefabricated device consists of a stacked substrate and a cathode, and the solution is applied to the side of the cathode away from the substrate.

[0062] The nano-metal oxide can be an undoped nano-metal oxide or a doped nano-metal oxide. In some embodiments of this application, the nano-metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ta2O3, ZrO2, TiLiO, ZnGaO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, InSnO, AlZnO, ZnOCl, or ZnOF. The average particle size of the nano-metal oxide can be, for example, 2 nm to 15 nm, 2 nm to 4 nm, 2 nm to 6 nm, 2 nm to 8 nm, 2 nm to 10 nm, 4 nm to 10 nm, or 10 nm to 15 nm, or 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm.

[0063] The solution containing nano-metal oxides may be, for example, a product containing nano-metal oxides prepared by a solution method, wherein the solvent includes, but is not limited to, at least one of water, ethanol, propanol, butanol, hexanol, n-octane, n-hexane, or ethylene glycol monomethyl ether.

[0064] In step S2, the "preset time range" refers to a time range set by the operator. This time range can be obtained through repeated experiments, and the time range will vary depending on the type of light-emitting device. In some embodiments of this application, the "preset time range" refers to 5 minutes to 120 minutes.

[0065] In some embodiments of this application, the energizing process is a constant current energizing process, a constant voltage energizing process, or an alternating energizing process; during the energizing process, the current density of the solution located on one side of the prefabricated device is 100 mA / cm². 2 Up to 300mA / cm 2 For example, it could be 100mA / cm 2 Up to 150 mA / cm 2 150mA / cm 2 Up to 200mA / cm 2 200mA / cm 2 Up to 250mA / cm 2 Or 250mA / cm 2 Up to 300mA / cm 2 .

[0066] It is understandable that, under the premise of constant energization time, appropriately increasing the current density of the solution located on one side of the prefabricated device can improve the ligand removal effect on the surface of the nano-metal oxide, thereby increasing the degree of gap reduction between adjacent nanoparticles, and thus improving the conductivity and stability of the electron transport layer.

[0067] In some embodiments of this application, the annealing time period and the power-on time period overlap at least partially.

[0068] In at least one embodiment of this application, the annealing process is continuous, and the power-on process is also continuous. It is understood that the time periods of the annealing process and the power-on process may partially overlap or completely overlap.

[0069] In at least one embodiment of this application, the annealing process is continuous, while the power-on process is intermittent. The interval between adjacent power-on processes can be 5 to 10 minutes, and the duration of a single power-on process can be 10 to 15 minutes. For example, the interval between adjacent power-on processes can be 5 to 6 minutes, 6 to 7 minutes, 7 to 8 minutes, 8 to 9 minutes, or 9 to 10 minutes, and the duration of a single power-on process can be 10 to 11 minutes, 11 to 12 minutes, 12 to 13 minutes, 13 to 14 minutes, or 14 to 15 minutes.

[0070] In at least one embodiment of this application, the annealing process is intermittent, while the power-on process is continuous. The interval between adjacent annealing processes is 5 to 10 minutes, and the time for a single annealing process is 10 to 30 minutes. For example, the interval between adjacent annealing processes can be 5 to 6 minutes, 6 to 7 minutes, 7 to 8 minutes, 8 to 9 minutes, or 9 to 10 minutes, and the time for a single annealing process can be 10 to 15 minutes, 15 to 20 minutes, 20 to 25 minutes, or 25 to 30 minutes.

[0071] In at least one embodiment of this application, the annealing process is intermittent, and the power-on process is intermittent, with the interval between adjacent annealing processes being 5 to 20 minutes and the duration of a single annealing process being 5 to 20 minutes; the interval between adjacent power-on processes being 5 to 20 minutes and the duration of a single power-on process being 5 to 20 minutes.

[0072] In at least one embodiment of this application, the total time for the annealing process is 5 to 120 minutes, the total time for the power-on process is 5 to 120 minutes, and the total overlap time between the annealing process and the power-on process is 5 to 120 minutes. The total time for the annealing process can be, for example, 5 to 10 minutes, 10 to 20 minutes, 20 to 30 minutes, 30 to 40 minutes, 40 to 50 minutes, 50 to 60 minutes, 60 to 70 minutes, 70 to 80 minutes, 80 to 90 minutes, 90 to 100 minutes, 100 to 110 minutes, or 110 to 120 minutes. Similarly, the total time for the power-on process can be, for example, 5 to 10 minutes, 10 to 20 minutes, 20 to 30 minutes, 30 to 40 minutes, 40 to 50 minutes, 50 to 60 minutes, or 60 minutes. The total overlap time between the annealing process and the power-on process can be, for example, 5 min to 10 min, 10 min to 20 min, 20 min to 30 min, 30 min to 40 min, 40 min to 50 min, 50 min to 60 min, 60 min to 70 min, 70 min to 80 min, 80 min to 90 min, 90 min to 100 min, 100 min to 110 min, or 110 min to 120 min.

[0073] As an alternative embodiment, in at least one embodiment of this application, annealing and power-on processes are performed alternately.

[0074] Furthermore, the total annealing time is 5 to 60 minutes, the total power-on time is 5 to 60 minutes, the total annealing time is, for example, 5 to 10 minutes, 10 to 20 minutes, 20 to 30 minutes, 30 to 40 minutes, 40 to 50 minutes, or 50 to 60 minutes, and the total power-on time is, for example, 5 to 10 minutes, 10 to 20 minutes, 20 to 30 minutes, 30 to 40 minutes, 40 to 50 minutes, or 50 to 60 minutes.

[0075] Furthermore, the time for a single power-on process is 5 to 20 minutes, the time for a single annealing process is 5 to 20 minutes, the time for a single power-on process is, for example, 5 to 8 minutes, 8 to 10 minutes, 10 to 15 minutes, or 15 to 20 minutes, and the time for a single annealing process is, for example, 5 to 8 minutes, 8 to 10 minutes, 10 to 15 minutes, or 15 to 20 minutes.

[0076] In some embodiments of this application, when the light-emitting device is an upright structure, the fabrication method further includes the step of: after forming an electron transport layer on one side of the pre-fabricated device, forming a cathode on the side of the electron transport layer away from the light-emitting layer. It is understood that when the light-emitting device is an upright structure, the pre-fabricated device can be a stacked structure including an anode, a hole functional layer, and a light-emitting layer. Therefore, the fabrication method further includes the step of: providing an anode, and sequentially forming a hole functional layer and a light-emitting layer on one side of the anode, wherein the hole functional layer includes a hole transport layer and / or a hole injection layer. When the hole functional layer includes a hole transport layer and a hole injection layer, the hole injection layer is closer to the anode, and the hole transport layer is closer to the light-emitting layer.

[0077] In one embodiment of this application, when the light-emitting device is an upright structure, the fabrication method further includes the following steps:

[0078] S1. Provide a substrate and form an anode on one side of the substrate;

[0079] S2. A hole injection layer is formed on the side of the anode away from the substrate;

[0080] S3. A hole transport layer is formed on the side of the hole injection layer away from the anode;

[0081] S4. A light-emitting layer is formed on the side of the hole transport layer away from the hole injection layer;

[0082] S5. Apply a solution containing nano-metal oxide to the side of the light-emitting layer away from the hole transport layer. Within a preset time range, anneal and energize the solution on one side of the prefabricated device to obtain the electron transport layer.

[0083] S6. A cathode is formed on the side of the electron transport layer away from the light-emitting layer.

[0084] In some other embodiments of this application, when the light-emitting device is an inverted structure, the fabrication method further includes the following steps:

[0085] After forming an electron transport layer on one side of the prefabricated device, a light-emitting layer is formed on the side of the electron transport layer away from the cathode; and

[0086] An anode is formed on the side of the light-emitting layer away from the electron transport layer.

[0087] Furthermore, when the light-emitting device has an inverted structure, the fabrication method further includes the step of forming a hole functional layer between the anode and the light-emitting layer. The hole functional layer includes a hole injection layer and / or a hole transport layer. When the hole functional layer includes a stacked hole transport layer and a hole injection layer, the hole transport layer is close to the light-emitting layer, and the hole injection layer is close to the anode. It can be understood that "forming a hole functional layer between the anode and the light-emitting layer" means first forming the hole functional layer on the side of the light-emitting layer away from the electron transport layer, and then forming the anode on the side of the hole functional layer away from the light-emitting layer. Furthermore, when the hole functional layer includes a hole injection layer and a hole transport layer, the hole transport layer, the hole injection layer, and the light-emitting layer are formed sequentially on the side of the light-emitting layer away from the electron transport layer.

[0088] In one embodiment of this application, when the light-emitting device is an inverted structure, the fabrication method includes the following steps:

[0089] S1', Provide a substrate, and form a cathode on one side of the substrate;

[0090] S2' Apply a solution containing nano-metal oxides to the side of the cathode away from the substrate, and then anneal and energize the solution on one side of the prefabricated device within a preset time range, and then dry it to obtain an electron transport layer.

[0091] S3', A light-emitting layer is formed on the side of the electron transport layer away from the cathode;

[0092] S4'. A hole transport layer is formed on the side of the light-emitting layer away from the electron transport layer.

[0093] S5'. A hole injection layer is formed on the side of the hole transport layer away from the light-emitting layer;

[0094] S6', An anode is formed on the side of the hole injection layer away from the hole transport layer.

[0095] It should be noted that, apart from the electron transport layer, the preparation methods for other films in the light-emitting device include, but are not limited to, solution methods and deposition methods. Solution methods include, but are not limited to, spin coating, coating, inkjet printing, blade coating, dip-coating, immersion, spraying, roller coating, or casting. Deposition methods include chemical methods and physical methods. Chemical methods include, but are not limited to, chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, or co-precipitation. Physical methods include, but are not limited to, thermal evaporation deposition, electron beam evaporation deposition, magnetron sputtering, multi-arc ion plating, physical vapor deposition, atomic layer deposition, or pulsed laser deposition. When using solution methods to prepare films, an annealing process is required to convert the wet film into a dry film.

[0096] It is understandable that the fabrication method of light-emitting devices may also include other steps, such as encapsulation after the various layers of the light-emitting device are fabricated.

[0097] This application also provides a light-emitting device, which is prepared using any of the above-described fabrication methods, such as... Figure 2 As shown, 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 and cathode 12 are disposed opposite each other, the light-emitting layer 13 is disposed between the anode 11 and cathode 12, and the electron transport layer 14 is disposed between the cathode 12 and the light-emitting layer 13. It is understood that the light-emitting device includes, but is not limited to, OLED or QLED, and the light-emitting device can be a normal or inverted structure. Compared to existing light-emitting devices (where the electron transport layer is made of nano-metal oxide), the electron transport layer (made of the same nano-metal oxide) of the light-emitting device in this embodiment has higher density, meaning the gaps between adjacent nanoparticles are smaller, resulting in higher conductivity and stability of the electron transport layer. Therefore, the overall performance of the light-emitting device in this embodiment is better.

[0098] In the light-emitting device of this application embodiment, the materials of the anode 11, cathode 12, and light-emitting layer 13 can be materials commonly used in the art, such as:

[0099] The materials of the anode 11 and the cathode 12 are independently selected from at least one of metal, carbon material or metal oxide. The metal is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca or Mg; the carbon material is selected from at least one of graphite, carbon nanotube, graphene or carbon fiber; the metal oxide can be a doped or undoped metal oxide, for example selected from at least one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO) or magnesium-doped zinc oxide (MZO). The anode 11 or cathode 12 may also be selected from composite electrodes consisting of a metal sandwiched between doped or undoped transparent metal oxides. These composite electrodes include, but are not limited to, 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, ZnS / Al / ZnS, TiO2 / Ag / TiO2, or TiO2 / Al / TiO2. The thickness of the anode 11 may, for example, be from 40 nm to 160 nm, and the thickness of the cathode 12 may, for example, be from 20 nm to 120 nm.

[0100] The material of the light-emitting layer 13 is selected from organic light-emitting materials or quantum dots. The thickness of the light-emitting layer 13 can be, for example, 20 nm to 60 nm. Organic light-emitting materials include, but are not limited to, at least one of diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPA fluorescent materials, TBRb fluorescent materials, or DBP fluorescent materials.

[0101] Quantum dots include, but are not limited to, at least one of red, green, or blue quantum dots, and include, but are not limited to, at least one of single-component quantum dots, core-shell structured quantum dots, inorganic perovskite quantum dots, or organic-inorganic hybrid perovskite quantum dots. The particle size of quantum dots can be, for example, 5 nm to 10 nm.

[0102] When the quantum dot is selected from single-component quantum dots or core-shell structured quantum dots, the material of the single-component quantum dot, the material of the core of the core-shell structured quantum dot, and the material of the shell of the core-shell structured quantum dot are independently selected from at least one of group II-VI compounds, group III-V compounds, group IV-VI compounds, or group I-III-VI compounds, wherein the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, and ZnS. At least one of the following: eS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, or HgZnSTe, wherein the III-V compound is selected from GaN, GaP, GaAs, GaSb, Al N, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, I nNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InA The group IV-VI compound is selected from at least one of lNAs, InAlNSb, InAlPAs, or InAlPSb, wherein the group 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, or SnPbSTe, and the group I-III-VI compound is selected from at least one of CuInS2, CuInSe2, or AgInS2.

[0103] For inorganic perovskite quantum dots, the general structural formula is AMX3, where A is Cs. + Ions, where M is a divalent metal cation, and M includes, but is not limited to, Pb. 2+ Sn 2+ Cu 2+ Ni 2+ Cd2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Or Eu 2+ X is a halide anion, including but not limited to Cl. - ,Br - or I - .

[0104] For organic-inorganic hybrid perovskite quantum dots, the general structural formula is BMX3, where B is an organic amine cation, including but not limited to CH3(CH2). n -2NH 3+ (n≥2) or NH3(CH2) n NH3 2+ (n≥2), M is a divalent metal cation, and M includes, but is not limited to, Pb. 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Or Eu 2+ X is a halide anion, including but not limited to Cl. - ,Br - or I - .

[0105] It is understood that when the material of the light-emitting layer includes quantum dots, the material of the light-emitting layer also includes ligands attached to the surface of the quantum dots. The ligands include, but are not limited to, at least one of amine ligands, carboxylic acid ligands, thiol ligands, (oxy)phosphine ligands, phospholipids, lecithin, or polyvinylpyridine. Amine ligands are selected from at least one of oleylamine, n-butylamine, n-octylamine, octaamine, or 1,2-ethylenediamine. Carboxylic acid ligands are selected from at least one of oleic acid, acetic acid, butyric acid, valeric acid, hexanoic acid, arachidic acid, decacaric acid, undecenoic acid, tetradecanoic acid, or stearic acid. Thiol ligands are selected from at least one of ethanethiol, propanethiol, mercaptoethanol, benzenethiol, octylthiol, octaalkylthiol, dodecylthiol, or octadecylthiol. (oxy)phosphine ligands are selected from at least one of trioctylphosphine or trioctylphosphine oxide.

[0106] To achieve better photoelectric performance and lifespan, in some embodiments of this application, such as... Figure 3As shown, the light-emitting device 1 further includes a hole functional layer 15, which is disposed between the anode 11 and the light-emitting layer 13. The hole functional layer 15 includes a hole injection layer and / or a hole transport layer. When the hole functional layer includes a stacked hole transport layer and a hole injection layer, the hole transport layer is closer to the light-emitting layer, and the hole injection layer is closer to the anode. The thickness of the hole functional layer 15 can be, for example, from 20 nm to 100 nm.

[0107] Materials used in hole transport layers include, but are not limited to, poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB, CAS No. 220797-16-0), 3-hexyl-substituted polythiophene (CAS No. 104934-50-1), poly(9-vinylcarbazole) (PVK, CAS No. 25067-59-8), poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD, CAS No. 472960-35-3), poly(N,N'-bis(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene) (PFB, CAS No. 223569-28-6), and 4,4',4”-tris(carb) The hole transport layer may be selected from at least one of the following: TCTA (9-carbazole) triphenylamine (CAS No. 139092-78-7), 4,4'-bis(9-carbazole)biphenyl (CBP, CAS No. 58328-31-7), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD, CAS No. 65181-78-4), or N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB, CAS No. 123847-85-8); furthermore, the hole transport layer material may also be selected from inorganic materials with hole transport capabilities, including but not limited to at least one of NiO, WO3, MoO3, or CuO.

[0108] The hole injection layer material includes, but is not limited to, poly(3,4-vinyldioxythiophene): poly(styrene sulfonic acid) (CAS No. 155090-83-8), copper phthalocyanine (CuPc, CAS No. 147-14-8), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4-TCNQ, CAS No. 29261-33-4), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene (HATCN, CAS No. 105598-27-4), transition metal oxides, or transition metal chalcogenides, wherein the transition metal oxide may be NiO. x MoO x WOx or CrO x At least one of them, the metal chalcogenide compound can be MoS x MoSe x WS x 、WSe x Or at least one of CuS.

[0109] It should be noted that the light-emitting device may also include other layer structures. For example, the light-emitting device may also include an electron injection layer, which is disposed between the electron transport layer and the cathode. The material of the electron injection layer includes, but is not limited to, at least one of alkali metal halides, alkali metal organo-complexes, or organophosphorus compounds. Alkali metal halides include, but are not limited to, LiF. Alkali metal organo-complexes include, but are not limited to, lithium 8-hydroxyquinoline. Organophosphorus compounds include, but are not limited to, at least one of organophosphorus oxides, organothiophosphorus compounds, or organoselenophosphorus compounds.

[0110] This application also provides a display device, which includes a light-emitting device prepared by any of the preparation methods described in this application. The display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0111] The technical solutions and effects of this application will be described in detail below through specific embodiments. The following embodiments are only some embodiments of this application and are not intended to limit this application.

[0112] Example 1

[0113] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. The fabrication method includes the following steps:

[0114] S1.1 Under normal temperature and pressure atmospheric environment, a 0.5 mm glass substrate is provided. ITO is sputtered on one side of the glass substrate to obtain an ITO layer with a thickness of 40 nm. The surface of the ITO layer is wiped with a cotton swab dipped in a small amount of soapy water to remove visible impurities. Then, the substrate including ITO is ultrasonically cleaned with deionized water for 15 min, ultrasonically cleaned with acetone for 15 min, ultrasonically cleaned with ethanol for 15 min, and ultrasonically cleaned with isopropanol for 15 min in sequence. After drying, it is surface treated with ultraviolet-ozone for 15 min to obtain a glass substrate including an anode.

[0115] S1.2 Under normal temperature and pressure atmospheric conditions, spin-coat the side of the anode away from the glass substrate in step S1.1 with PEDOT:PSS aqueous solution, and then place it at 150℃ for constant temperature heat treatment for 15 min to obtain a hole injection layer with a thickness of 20nm.

[0116] S1.3 Under a nitrogen atmosphere at normal temperature and pressure, spin-coat the side of the hole injection layer away from the anode in step S1.2 with TFB-chlorobenzene solution, and then heat-treat at 150°C for 30 min to obtain a hole transport layer with a thickness of 30 nm.

[0117] S1.4 Under a nitrogen atmosphere at normal temperature and pressure, spin-coat a CdZnSe / CdZnS / ZnS quantum dot-n-octane solution with a concentration of 10 mg / mL on the side of the hole transport layer away from the hole injection layer in step S1.3, and then place it under constant temperature heat treatment at 100℃ for 5 min to obtain a light-emitting layer with a thickness of 20 nm.

[0118] S1.5. Under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (5 nm particle size)-ethanol solution is spin-coated onto the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The prefabricated device containing the wet film is fixed using a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first and second sides facing each other. The device is then subjected to continuous annealing at a constant temperature of 150°C for 60 minutes. During the annealing process, the wet film is continuously energized with a constant current for 60 minutes using an external power supply, with a current density of 200 mA / cm². 2 An electron transport layer with a thickness of 50 nm was obtained;

[0119] S1.6, at an air pressure of 4×10 -6 In a vacuum environment of mbar, Ag is deposited on the side of the electron transport layer away from the light-emitting layer in step S1.5 to obtain a cathode with a thickness of 100 nm. Then, it is encapsulated with epoxy resin and a glass plate to obtain... Figure 4 The light-emitting device shown has the structure shown.

[0120] Please see Figure 4 In the direction from bottom to top, the light-emitting device 1 includes a glass substrate 10, an anode 11, a hole functional layer 15, a light-emitting layer 13, an electron transport layer 14 and a cathode 12 stacked sequentially. The hole functional layer 15 is composed of a hole injection layer 151 and a hole transport layer 152 stacked together, with the hole injection layer 151 close to the anode 11 and the hole transport layer 152 close to the light-emitting layer 13.

[0121] Example 2

[0122] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The prefabricated device containing the wet film is fixed with a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other. Then, it is subjected to continuous isothermal heat treatment at a constant temperature of 150°C for 60 min. During the annealing process, the wet film is continuously subjected to 200 mA / cm at a frequency of 50 Hz using an external power supply." 2 "A rectangular alternating current treatment for 60 minutes was performed to obtain an electron transport layer with a thickness of 50 nm."

[0123] Example 3

[0124] This embodiment provides a method for preparing a light-emitting device and the resulting light-emitting device. Compared with the method for preparing a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The pre-fabricated device containing the wet film is fixed with a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other. Then, it is continuously annealed at a constant temperature of 150°C for 60 min. During the annealing process, the wet film is intermittently energized with a constant current for 60 min using an external power supply. The current density of the wet film during the energizing process is 200 mA / cm²". 2 The interval between adjacent energizing processes was 10 minutes, and the duration of a single energizing process was 10 minutes, resulting in an electron transport layer with a thickness of 50 nm.

[0125] Example 4

[0126] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The prefabricated device containing the wet film is fixed with a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other. Then, it is subjected to continuous annealing at a constant temperature of 150°C for 60 min. During the annealing process, the electron transport precursor layer is intermittently powered at a frequency of 50 Hz and a voltage of 200 mA / cm²." 2 A rectangular alternating current treatment was performed for 60 minutes, with an interval of 10 minutes between adjacent treatments, and a single treatment session lasting 10 minutes, resulting in an electron transport layer with a thickness of 50 nm.

[0127] Example 5

[0128] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The prefabricated device containing the wet film is fixed with a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other. The wet film is continuously energized with a constant current for 60 minutes using an external power supply. During the energizing process, the current density of the electron transport precursor layer is 200 mA / cm²." 2 During the power-on process, the wet film was subjected to intermittent annealing for 60 minutes at a temperature of 150°C. The interval between adjacent annealing processes was 5 minutes, and the duration of each annealing process was 15 minutes, resulting in an electron transport layer with a thickness of 50 nm.

[0129] Example 6

[0130] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a nano-ZnO (particle size of 5nm)-ethanol solution with a concentration of 30mg / mL is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film; a prefabricated device containing the wet film is fixed with a clamp; the anode of an external power supply is connected to the first side (left side) of the wet film, and the cathode of an external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other; the wet film is continuously subjected to a frequency of 50Hz at 200mA / cm using an external power supply." 2 The wet film was subjected to rectangular alternating current treatment for 60 minutes, and during the current treatment, it was intermittently annealed for 60 minutes at a temperature of 150°C. The interval between adjacent annealing treatments was 5 minutes, and the time for a single annealing treatment was 15 minutes, resulting in an electron transport layer with a thickness of 50 nm.

[0131] Example 7

[0132] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film; a prefabricated device containing the wet film is fixed with a clamp; the anode of an external power supply is connected to the first side (left side) of the wet film, and the cathode of an external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other; the wet film is intermittently energized with a constant current for 60 minutes using an external power supply, and the current density of the wet film during the energizing process is 200 mA / cm²". 2 The wet film was subjected to intermittent annealing for 60 minutes at a temperature of 150°C. The annealing and energizing processes were alternated, with an interval of 15 minutes between adjacent energizing processes and a single energizing process of 5 minutes. The interval between adjacent annealing processes was 5 minutes, and the single annealing process was 15 minutes, resulting in an electron transport layer with a thickness of 50 nm.

[0133] Example 8

[0134] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a nano-ZnO (particle size of 5nm)-ethanol solution with a concentration of 30mg / mL is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film; a prefabricated device containing the wet film is fixed with a clamp; the anode of an external power supply is connected to the first side (left side) of the wet film, and the cathode of an external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other; the wet film is intermittently powered by an external power supply at a frequency of 50Hz and a voltage of 200mA / cm²". 2 The wet film was subjected to rectangular alternating current treatment for 60 min, followed by intermittent annealing at 150℃ for 60 min. The annealing and current treatments were alternated, with an interval of 15 min between adjacent current treatments and a single current treatment duration of 5 min. The interval between adjacent annealing treatments was 5 min, and the single annealing treatment duration was 15 min, resulting in an electron transport layer with a thickness of 50 nm.

[0135] Example 9

[0136] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The prefabricated device containing the wet film is fixed with a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other. Then, it is continuously annealed at a constant temperature of 150°C for 60 min. During the annealing process, the wet film is continuously energized with a constant current for 60 min using an external power supply. During the energizing process, the current density of the electron transport precursor layer is 400 mA / cm²." 2 "An electron transport layer with a thickness of 50 nm was obtained."

[0137] Example 10

[0138] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. Compared with the method for fabricating a light-emitting device provided in Embodiment 1, the only difference in this embodiment is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a 30 mg / mL nano-ZnO (particle size 5 nm)-ethanol solution is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film. The prefabricated device containing the wet film is fixed with a clamp. The anode of the external power supply is connected to the first side (left side) of the wet film, and the cathode of the external power supply is connected to the second side (right side) of the wet film, with the first side and the second side facing each other. Then, it is continuously annealed at a constant temperature of 150°C for 60 min. During the annealing process, the wet film is continuously subjected to a 400 mA / cm² frequency of 50 Hz by an external power supply." 2 "A rectangular alternating current treatment for 60 minutes was performed to obtain an electron transport layer with a thickness of 50 nm."

[0139] Comparative Example

[0140] This comparative example provides a method for preparing a light-emitting device and the resulting light-emitting device. Compared with the method for preparing a light-emitting device provided in Example 1, the only difference in the method for preparing a light-emitting device in this comparative example is that step S1.5 is replaced with "under a nitrogen atmosphere at room temperature and pressure, a nano ZnO (particle size of 5 nm)-ethanol solution with a concentration of 30 mg / mL is spin-coated on the side of the light-emitting layer away from the hole transport layer in step S1.4 to obtain a wet film, and then the film is continuously annealed at a constant temperature of 150°C for 60 min to obtain an electron transport layer with a thickness of 50 nm".

[0141] Experimental Example

[0142] The performance of the light-emitting devices in Examples 1 to 10 and the comparative examples was tested, and the maximum external quantum efficiency (EQE) of each light-emitting device on the day of packaging completion was compared. max The luminance decayed from 100% to 95% (LT95@1000nit,h) and the time required for the luminance to decay from 100% to 95% were compared, as well as the EQE of each light-emitting device after 30 days of packaging. max And LT95@1000nit.

[0143] The voltage, current, brightness, emission spectrum and other parameters of each light-emitting device were detected using the FPD optical property measurement equipment (an efficiency testing system built by LabVIEW-controlled QE-PRO spectrometer, Keithley 2400 and Keithley 6485). Then, key parameters such as external quantum efficiency and power efficiency were calculated, and the lifespan of each light-emitting device was tested using a lifetime testing equipment.

[0144] Specifically, the external quantum efficiency was tested using the integrating sphere method; the lifetime test employed the constant current method. Under a constant current (2mA), the brightness change of each light-emitting device was measured using a silicon photonics system. The time (T95, h) required for the brightness to decay from 100% to 95% was recorded, and the LT95@1000nit of each light-emitting device was calculated. The experimental results are detailed in Table 1 below:

[0145] Table 1. Performance test results of the light-emitting devices in Examples 1 to 10 and the comparative examples.

[0146]

[0147]

[0148] As shown in Table 1, the overall performance of the light-emitting devices in Examples 1 to 10 is significantly better than that of the light-emitting devices in the comparative examples. Taking Example 2 as an example, on the day of packaging, the EQE of the light-emitting device in Example 2 is significantly higher. max EQE of the light-emitting device in the comparison max The LT95@1000nit of the light-emitting device in Example 5 is 2.2 times that of the control device, and the LT95@1000nit of the light-emitting device in Example 5 is 3.7 times that of the control device in Example 5; after being packaged and placed for 30 days, the EQE of the light-emitting device in Example 5 is 2.2 times that of the control device in Example 5. max EQE of the light-emitting device in the comparison max The luminous efficacy of the light-emitting device in Example 5 is 3.7 times that of the light-emitting device in the comparative example, and the LT95@1000nit of the light-emitting device in Example 5 is 15.2 times that of the light-emitting device in the comparative example. Comparing the performance test data on the day of packaging and after 30 days of packaging, it can be seen that the luminous efficacy and operating life of the light-emitting devices in Examples 1 to 11 show relatively small changes and ideal stability within 30 days of packaging, while the EQE of the light-emitting device in the comparative example is much lower. max The LT95@1000nit of the light-emitting device in the comparative example decreased by 51%, and the LT95@1000nit of the light-emitting device decreased by 75%. This fully demonstrates that during the preparation of the electron transport layer, annealing and energizing the wet film within a preset time range can improve the crystallinity and stability of the electron transport layer, thereby improving the luminescent performance and working life of the light-emitting device.

[0149] The performance test data of the light-emitting devices in Examples 1, 2, 9 and 10 show that the overall performance of the light-emitting devices in Examples 1 and 2 is better than that in Examples 9 and 10, and Example 2 is the best. This fully demonstrates that, under the premise that the power-on processing time is constant, appropriately increasing the current density of the wet film is beneficial to further improving the overall performance of the light-emitting devices.

[0150] The performance test data of the light-emitting devices in Examples 1 and 2, 3 and 4, 5 and 6, 7 and 8, 9 and 10 show that, compared with constant current conditions, alternating current conditions are more conducive to improving the overall performance of the light-emitting devices. The reason may be that, under alternating current conditions, the electrical properties of the charge carried by nano-ZnO oscillate continuously, which is more conducive to the ligand detachment on the surface of nano-ZnO and the phase aggregation between nanoparticles, which further helps to improve the density and stability of the electron transport layer.

[0151] The performance test data of the light-emitting devices in Examples 1 to 10 show that the method of treating the wet film by continuous isothermal heat treatment combined with continuous power supply treatment is most beneficial to improving the light-emitting performance and working life of the light-emitting devices. The methods of treating the electron transport precursor layer by intermittent isothermal heat treatment combined with continuous power supply treatment, continuous isothermal heat treatment combined with intermittent power supply treatment, and intermittent isothermal heat treatment combined with intermittent power supply treatment can all improve the overall performance of the light-emitting devices to a certain extent and save energy consumption.

[0152] The foregoing has provided a detailed description of a method for fabricating a light-emitting device, the light-emitting device itself, and a display device, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for fabricating a light-emitting device, characterized in that, The preparation method includes the following steps: Provide a prefabricated device, wherein a solution comprising nano-metal oxides is applied to one side of the prefabricated device; and Within a preset time range, the solution located on one side of the prefabricated device is subjected to annealing and electro-energizing treatment to form an electron transport layer; Wherein, the time period of the annealing treatment and the time period of the power-on treatment overlap at least partially, or the annealing treatment and the power-on treatment are performed alternately; the power-on treatment includes the steps of: fixing the prefabricated device including the solution on a fixture, and then connecting the anode and cathode of the external power supply to the two opposite sides of the wet film formed by the solution respectively; The energizing process and the annealing process are performed in an inert gas atmosphere; When the light-emitting device is an upright structure, the prefabricated device includes an anode and a light-emitting layer stacked together, and the solution is applied to the side of the light-emitting layer away from the anode; the preparation method further includes the step of: after forming an electron transport layer on the side of the prefabricated device, forming a cathode on the side of the electron transport layer away from the light-emitting layer; Alternatively, when the light-emitting device is an inverted structure, the prefabricated device includes a cathode, and the solution is applied to one side of the cathode; the preparation method further includes the following steps: After forming an electron transport layer on one side of the prefabricated device, a light-emitting layer is formed on the side of the electron transport layer away from the cathode; and An anode is formed on the side of the light-emitting layer away from the electron transport layer.

2. The preparation method according to claim 1, characterized in that, The annealing temperature is between 80°C and 250°C; And / or, the preset time range is 5 min to 120 min; And / or, the nano-metal oxide is selected from at least one of ZnO, TiO2, SnO2, BaO, Ta2O3, ZrO2, TiLiO, ZnGaO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, InSnO, AlZnO, ZnOCl or ZnOF; And / or, the average particle size of the nano-metal oxide is 2 nm to 15 nm.

3. The preparation method according to claim 1, characterized in that, When the time period of the annealing process overlaps at least partially with the time period of the power-on process, the annealing process is continuous and the power-on process is continuous.

4. The preparation method according to claim 1, characterized in that, When the time period of the annealing process and the time period of the power-on process overlap at least partially, the annealing process is continuous and the power-on process is intermittent. Alternatively, the annealing process may be intermittent, while the energizing process may be continuous; Alternatively, the annealing process may be intermittent, and the energizing process may also be intermittent.

5. The preparation method according to claim 4, characterized in that, When the annealing process is continuous and the power-on process is intermittent, the interval between adjacent power-on processes is 5 to 10 minutes, and the duration of a single power-on process is 10 to 15 minutes. Alternatively, when the annealing process is intermittent and the power-on process is continuous, the interval between adjacent annealing processes is 5 to 10 minutes, and the time for a single annealing process is 10 to 30 minutes. Alternatively, when the annealing process is intermittent and the power-on process is intermittent, the interval between adjacent annealing processes is 5 to 20 minutes, and the duration of a single annealing process is 5 to 20 minutes; the interval between adjacent power-on processes is 5 to 20 minutes, and the duration of a single power-on process is 5 to 20 minutes.

6. The preparation method according to any one of claims 3 to 5, characterized in that, The total time for the annealing process is 5 to 120 minutes, the total time for the power-on process is 5 to 120 minutes, and the total overlap time between the annealing process and the power-on process is 5 to 120 minutes.

7. The preparation method according to claim 1, characterized in that, When the annealing process and the power-on process are performed alternately, the total time for the annealing process is 5 to 60 minutes, and the total time for the power-on process is 5 to 60 minutes. And / or, the duration of a single power-on process is 5 to 20 minutes, and the duration of a single annealing process is 5 to 20 minutes.

8. The preparation method according to claim 1, characterized in that, The power-on process can be a constant current power-on process, a constant voltage power-on process, or an alternating power-on process. During the energizing process, the current density of the solution located on one side of the prefabricated device is 100 mA / cm². 2 Up to 300mA / cm 2 .

9. The preparation method according to claim 1, characterized in that, The material of the light-emitting layer is an organic light-emitting material or quantum dots; The organic light-emitting material is selected from at least one of diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPA fluorescent materials, TBRb fluorescent materials, or DBP fluorescent materials; The quantum dots are selected from at least one of single-component quantum dots, core-shell quantum dots, inorganic perovskite quantum dots, or organic-inorganic hybrid perovskite quantum dots; when the quantum dots are selected from single-component quantum dots or core-shell quantum dots, the material of the single-component quantum dot, the material of the core of the core-shell quantum dot, and the material of the shell of the core-shell quantum dot are independently selected from group II-VI compounds, group III-V compounds, group IV-VI compounds, or group I compounds. III At least one of group II-VI compounds, wherein the group II-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, CdHgT At least one of e, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, or HgZnSTe, wherein the III-V compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, G At least one of aNP, 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, or InAlPSb, wherein 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, or SnPbSTe, wherein the I III The group VI compound is selected from at least one of CuInS2, CuInSe2 or AgInS2.

10. The preparation method according to claim 1, characterized in that, The preparation method further includes the step of forming a hole functional layer between the anode and the light-emitting layer, wherein the hole functional layer includes a hole injection layer and / or a hole transport layer, and when the hole functional layer includes a stacked hole transport layer and a hole injection layer, the hole transport layer is close to the light-emitting layer and the hole injection layer is close to the anode. The hole transport layer is made of at least one of NiO, WO3, MoO3, CuO, poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine), 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), poly[bis(4-phenyl)(4-butylphenyl)amine], poly(N,N'-di(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene), 4,4',4''-tris(carbazole-9-yl)triphenylamine, 4,4'-di(9-carbazole)biphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine or N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine; The material of the hole injection layer is selected from at least one of poly(3,4-vinyldioxythiophene): poly(styrene sulfonic acid), copper phthalocyanine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, transition metal oxides, or transition metal chalcogenides, wherein the transition metal oxide is selected from NiO. x MoO x WO x or CrO x At least one of the following, wherein the transition metal chalcogenide compound is selected from MoS x MoSe x WS x 、WSe x Or at least one of CuS.

11. A light-emitting device, characterized in that, The light-emitting device is prepared by the preparation method described in any one of claims 1 to 10.

12. A display device, characterized in that, The display device includes a light-emitting device prepared by the preparation method according to any one of claims 1 to 10, or a light-emitting device according to claim 11.

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