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 steps of: providing a pre-fabricated device; applying a solution containing nano-metal oxides to one side of the pre-fabricated device to form an electron transport precursor layer; and subjecting the electron transport precursor layer to a charge treatment within a preset time range to form an electron transport layer. This effectively improves the crystallinity, conductivity, and stability of the electron transport layer. Applying the light-emitting device prepared by this method to a display device can improve the display effect and extend the service life 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, wherein a solution containing nano-metal oxides is applied to one side of the prefabricated device to form an electron transport precursor layer;

[0009] The electron transport precursor layer is charged to form the electron transport layer;

[0010] When the light-emitting device is an upright structure, the prefabricated device includes a bottom electrode and a light-emitting layer stacked together, the electron transport precursor layer is formed on the side of the light-emitting layer away from the bottom electrode, and the bottom electrode is an anode;

[0011] Alternatively, when the light-emitting device is an inverted structure, the prefabricated device includes a bottom electrode, the electron transport precursor layer is formed on one side of the bottom electrode, and the bottom electrode is a cathode.

[0012] Furthermore, the charging process involves making the electron transport precursor layer carry positive or negative charges, or making the electron transport precursor layer alternately carry positive and negative charges.

[0013] Furthermore, the electrification process includes the steps of: providing an external power supply, wherein a first terminal of the external power supply is connected to the bottom electrode and a second terminal of the external power supply is grounded; and turning on the external power supply to create a potential difference between the first terminal and the second terminal.

[0014] Furthermore, during the charged processing, the external power supply applies a constant voltage or AC voltage to the electron transport precursor layer;

[0015] The constant voltage value is between 10V and 30V;

[0016] The frequency of the AC voltage is from 10Hz to 200Hz, and the effective voltage value is from 10V to 30V.

[0017] Further, 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;

[0018] And / or, the average particle size of the nano-metal oxide is 2 nm to 15 nm.

[0019] Furthermore, the charging time is from 5 min to 120 min;

[0020] The electrification process is continuous.

[0021] Alternatively, the energizing process may be intermittent, with each energizing process lasting 5 to 20 minutes and the interval between adjacent energizing processes lasting 5 to 20 minutes.

[0022] Furthermore, the electron transport precursor layer is a wet film, and the preparation method further includes the step of annealing the electron transport precursor layer.

[0023] Furthermore, the annealing temperature is between 80°C and 250°C;

[0024] And / or, the annealing process takes 5 to 120 minutes.

[0025] Optionally, the annealing time period and the electrical charging time period at least partially overlap, and the annealing method and the electrical charging method are any of the following:

[0026] (a1) The annealing process is continuous, and the electrification process is continuous;

[0027] (a2) The annealing process is continuous, and the electrification process is intermittent;

[0028] (a3) The annealing process is intermittent, and the electrification process is continuous;

[0029] (a4) The annealing process is intermittent, and the electrification process is also intermittent.

[0030] Furthermore, when the annealing process is continuous and the electrification process is continuous, the overlap time between the annealing process and the electrification process is 5 min to 120 min;

[0031] Alternatively, when the annealing process is continuous and the electrification process is intermittent, the overlap time between the annealing process and the electrification process is 5 min to 115 min.

[0032] Alternatively, when the annealing process is intermittent and the electrification process is continuous, the interval between adjacent annealing processes is 5 to 10 minutes, the time of a single annealing process is 10 to 30 minutes, and the overlap time between the annealing process and the electrification process is 5 to 115 minutes.

[0033] Alternatively, when the annealing process is intermittent and the electrification process is intermittent, the interval between adjacent annealing processes is 5 to 10 minutes, the duration of a single annealing process is 10 to 30 minutes, and the overlap time between the annealing process and the electrification process is 5 to 115 minutes.

[0034] Optionally, the annealing time period and the electrical charging time period do not overlap, and the annealing method and the electrical charging method are any of the following:

[0035] (b1) The annealing process and the electrical charging process are performed alternately;

[0036] (b2) After the charging process is completed on the electron transport precursor layer, the annealing process is then performed;

[0037] For (b1), the time for a single annealing process is 5 min to 20 min.

[0038] Furthermore, 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 top electrode on the side of the electron transport layer away from the light-emitting layer, wherein the top electrode is a cathode;

[0039] Alternatively, when the light-emitting device is an inverted structure, the fabrication method further includes the following steps:

[0040] After forming an electron transport layer on one side of the preform, a light-emitting layer is formed on the side of the electron transport layer away from the bottom electrode;

[0041] A top electrode is formed on the side of the light-emitting layer away from the electron transport layer, and the top electrode is an anode;

[0042] And / or, the material of the light-emitting layer is an organic light-emitting material or quantum dots;

[0043] 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;

[0044] 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.

[0045] Furthermore, 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;

[0046] 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;

[0047] The material of the hole injection layer is selected from at least one of poly(3,4-ethylenedioxythiophene): 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 at least one of NiOx, MoOx, WOx, or CrOx, and the transition metal chalcogenide is selected from at least one of MoSx, MoSex, WSx, WSex, or CuS.

[0048] Secondly, this application provides a light-emitting device, which is prepared by any of the preparation methods described in the first aspect.

[0049] Thirdly, this application also provides a display device, which includes a light-emitting device prepared by any of the preparation methods described in the first aspect, or a light-emitting device prepared by any of the methods described in the second aspect.

[0050] 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:

[0051] In the preparation method, a solution containing nano-metal oxides is applied to one side of the pre-fabricated device to form an electron transport precursor layer. The electron transport precursor layer is charged to form an electron transport layer, which facilitates the detachment of ligands attached to the surface of the nano-metal oxides, effectively shortens the gap between adjacent nanoparticles, improves the crystallinity, conductivity and stability of the electron transport layer, and thus greatly enhances the luminescence performance and working life of the light-emitting device.

[0052] 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.

[0053] 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

[0054] 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.

[0055] Figure 1 This is a schematic flowchart illustrating a method for fabricating a light-emitting device according to an embodiment of this application.

[0056] Figure 2 This is a schematic diagram of the structure of the first light-emitting device provided in the embodiments of this application.

[0057] 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.

[0058] 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

[0059] 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.

[0060] 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.

[0061] 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.

[0062] This application provides a method for fabricating a light-emitting device, such as... Figure 1 As shown, the preparation method includes the following steps:

[0063] S1. Provide a prefabricated device, and apply a solution containing nano-metal oxides to one side of the prefabricated device to form an electron transport precursor layer;

[0064] S2. Charge the electron transport precursor layer to form the electron transport layer.

[0065] It should be noted that the electron transport precursor layer described above can be in a wet film state or a dry film state. For example, the electron transport precursor layer can be a wet film formed by applying a solution containing nano-metal oxides to one side of a prefabricated device. Alternatively, the electron transport precursor layer can be a dry film obtained after drying a wet film formed by applying a solution containing nano-metal oxides to one side of a prefabricated device. It is understood that during or after the charging treatment of the electron transport precursor layer, the preparation method may also include other processing steps. For example, when the electron transport precursor layer is a wet film, after charging the electron transport precursor layer, the preparation method may further include a drying process to obtain a dry film electron transport layer.

[0066] The electron transport precursor layer is prepared using a solution containing nano-metal oxides. If only the precursor layer is dried to form the electron transport layer, the drying temperature should not be too high to avoid damaging the light-emitting layer and other functional layers. Therefore, the ligands on the surface of the nano-metal oxides cannot be sufficiently removed, thus failing to effectively shorten the gaps between adjacent nanoparticles. This results in a loosely arranged nanocrystal array formed by the nano-metal oxides in the electron transport layer, leading to low density. The gaps between adjacent nanoparticles create a potential barrier for electron conduction. Since the nano-metal oxides themselves have a large specific surface area and are highly reactive, the electron transport layer prepared from them exhibits poor conductivity and stability. Therefore, in the above preparation method, a technique of "electrifying the electron transport precursor layer" is used to cause the ligands attached to the surface of the nano-metal oxides to detach under the influence of electrical energy and high temperature. This shortens the gaps between adjacent nanoparticles, thereby improving the crystallinity, conductivity, and stability of the electron transport layer, which is beneficial for improving the photoelectric performance and lifespan of the light-emitting device.

[0067] 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 bottom electrode and a light-emitting layer stacked together, with an electron transport precursor layer formed on the side of the light-emitting layer away from the bottom electrode. The bottom electrode is an 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 bottom electrode, with an electron transport precursor layer formed on one side of the bottom electrode. The bottom electrode is a cathode. For example, the prefabricated device consists of a substrate and a cathode stacked together, with the electron transport precursor layer formed on the side of the cathode away from the substrate.

[0068] 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.

[0069] 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.

[0070] Specifically, in step S2, the charging process is performed within a preset time range. The "preset time range" refers to a time range set by the operator, which can be obtained through repeated experiments. Furthermore, the time range will vary depending on the type of light-emitting device. In some embodiments of this application, the charging time is from 5 min to 120 min. For example, the charging time can be 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.

[0071] It is understood that, within a preset time range, the live-line processing can be continuous or intermittent. In some embodiments of this application, within a preset time range, the live-line processing is intermittent, with the duration of a single live-line processing session being 5 to 20 minutes, and the interval between adjacent live-line processing sessions being 5 to 20 minutes. For example, the duration of a single live-line processing session can be 5 to 8 minutes, 8 to 10 minutes, 10 to 15 minutes, or 15 to 20 minutes, and the interval between adjacent live-line processing sessions can be, for example, 5 to 8 minutes, 8 to 10 minutes, 10 to 12 minutes, 12 to 15 minutes, or 15 to 20 minutes.

[0072] In some embodiments of this application, “charge processing” includes all processes that enable the electron transport precursor layer to carry positive or negative charges, or to alternately carry positive and negative charges. It is understood that the charge processing may enable only the electron transport precursor layer to carry charges, or may enable the entire prefabricated device containing the electron transport precursor layer to carry charges, or may enable a portion of the layers (including the electron transport precursor layer) in the prefabricated device containing the electron transport precursor layer to carry charges.

[0073] In some embodiments of this application, the charging process includes the steps of: providing an external power supply, a first terminal of which is connected to the bottom electrode and a second terminal of which is grounded; turning on the external power supply; and establishing a potential difference between the first terminal and the second terminal, thereby causing the prefabricated device containing the electron transport precursor layer to carry either a positive or negative charge, or for the prefabricated device containing the electron transport precursor layer to alternately carry both positive and negative charges. The embodiments of this application do not specifically limit the type and model of the external power supply; it can be selected according to the different scales of the light-emitting devices.

[0074] In at least one embodiment of this application, the “charged processing” includes the steps of: fixing a prefabricated device containing an electron transport precursor layer onto a fixture, then connecting a first end of an external power supply to a bottom electrode located on one side of the prefabricated device, grounding a second end of the external power supply, turning on the external power supply, and having a potential difference between the first end and the second end.

[0075] Furthermore, during the electrification process, an external power supply applies a constant voltage or AC voltage to the electron transport precursor layer. When the external power supply applies a constant voltage to the electron transport precursor layer, the first terminal can be positive and the second terminal negative, causing the prefabricated device containing the electron transport precursor layer to carry a positive charge; alternatively, the first electrode can be negative and the second electrode positive, causing the prefabricated device containing the electron transport precursor layer to carry a negative charge. When the external power supply applies an AC voltage to the electron transport precursor layer, the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges.

[0076] Optionally, when an external power supply applies a constant voltage to the electron transport precursor layer, the constant voltage value is between 10V and 30V, for example, 10V to 15V, 15V to 20V, 20V to 25V, or 25V to 30V. As used in this application, "voltage value" refers only to the specific magnitude of the voltage and does not indicate the direction of the voltage. It is understood that, under the premise of a constant charging time, a constant voltage value that is too high or too low will have limited effect on improving the overall performance of the light-emitting device. If the voltage value is too low, the removal effect on the ligands on the surface of the nano-metal oxide will be limited, thus limiting the reduction of the gap between adjacent nanoparticles, and consequently limiting the improvement effect on the conductivity and stability of the electron transport layer; if the voltage value is too high, it may cause a certain degree of damage to the organic functional layer and / or the light-emitting layer.

[0077] Optionally, when an external power supply applies an AC voltage to the electron transport precursor layer, the frequency of the AC voltage is 10Hz to 200Hz, the effective voltage value is 10V to 30V, and the frequency of the AC voltage is, for example, 10Hz to 30Hz, 30Hz to 50Hz, 50Hz to 80Hz, 80Hz to 100Hz, 100Hz to 120Hz, 120Hz to 150Hz, 150Hz to 180Hz, or 180Hz to 200Hz, and the effective voltage value is, for example, 10V to 15V, 15V to 20V, 20V to 25V, or 25V to 30V.

[0078] In some embodiments of this application, the electron transport precursor layer is a wet film, and the preparation method further includes the step of annealing the electron transport precursor layer. "Annealing" includes all processes that enable the wet film electron transport precursor layer to obtain higher energy while at least partially removing the solvent, including but not limited to isothermal heat treatment processes or non-isothermal heat treatment processes (e.g., temperature gradient changes). In some embodiments of this application, "annealing" refers to isothermal heat treatment at 80°C to 250°C for 5 to 120 minutes. 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, or 180°C to 250°C. The annealing temperature can be 0℃, 200℃ to 220℃, 220℃ to 240℃, or 240℃ to 250℃, 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.

[0079] In some embodiments of this application, the time period of annealing and the time period of electrical charging at least partially overlap, and the annealing and electrical charging methods are any of the following:

[0080] (a1) The annealing process is continuous, and the electrification process is continuous;

[0081] (a2) The annealing process is continuous, and the electrification process is intermittent;

[0082] (a3) The annealing process is intermittent, and the electrification process is continuous;

[0083] (a4) The annealing process is intermittent, and the electrification process is also intermittent.

[0084] In at least one embodiment of this application, the annealing process is continuous, and the electrification process is also continuous. The overlap time between the annealing and electrification processes is 5 min to 120 min, 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. The annealing time is, for example, 5 min to 120 min, the annealing temperature is, for example, 80°C to 250°C, and the electrification time is, for example, 5 min to 120 min.

[0085] In at least one embodiment of this application, the annealing process is continuous, while the electrification process is intermittent. The overlap time between the annealing and electrification processes is 5 min to 115 min, 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, or 100 min to 115 min. The annealing time is, for example, 5 min to 120 min, the annealing temperature is, for example, 80°C to 250°C, the electrification time is, for example, 5 min to 120 min, the time of a single electrification process is, for example, 5 min to 20 min, and the interval between adjacent electrification processes is, for example, 5 min to 20 min.

[0086] In at least one embodiment of this application, the annealing process is intermittent and the electrification process is continuous, the interval between adjacent annealing processes is 5 min to 10 min, the time of a single annealing process is 10 min to 30 min, the overlap time between the annealing process and the electrification process is 5 min to 115 min, and the temperature of the annealing process is, for example, 80°C to 250°C. The interval between annealing processes is, for example, 5 to 6 minutes, 6 to 7 minutes, 7 to 8 minutes, 8 to 9 minutes, or 9 to 10 minutes; the time for a single annealing process is, for example, 10 to 15 minutes, 15 to 20 minutes, 20 to 25 minutes, or 25 to 30 minutes; the overlap time between annealing and live-line treatment is, 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, or 100 to 115 minutes. The time for live-line treatment is, for example, 5 to 120 minutes.

[0087] In at least one embodiment of this application, the annealing process is intermittent, and the electrification process is intermittent. The interval between adjacent annealing processes is 5 to 10 minutes, the duration of a single annealing process is 10 to 30 minutes, the overlap time between annealing and electrification processes is 5 to 115 minutes, and the annealing temperature is, for example, 80°C to 250°C. The electrification process takes, for example, 5 to 120 minutes, the duration of a single electrification process is, for example, 5 to 20 minutes, and the interval between adjacent electrification processes is, for example, 5 to 20 minutes.

[0088] In other embodiments of this application, the annealing time period and the electrical charging time period do not overlap, and the annealing method and the electrical charging method are any of the following:

[0089] (b1) Annealing and electrical charging are performed alternately;

[0090] (b2) After the charging process is completed on the electron transport precursor layer, the annealing process is then performed.

[0091] It is understandable that for (b1), both the annealing and the electrification processes are intermittent, with the electrification process lasting for, for example, 5 to 120 minutes and the single electrification process lasting for, for example, 5 to 20 minutes, the annealing process lasting for, for example, 5 to 120 minutes and the single annealing process lasting for, for example, 5 to 20 minutes.

[0092] For (b2), the energizing process can be continuous or intermittent, and similarly, the annealing process can also be continuous or intermittent. The energizing time is, for example, 5 to 120 minutes, and the annealing time is, for example, 5 to 120 minutes.

[0093] It should be noted that the annealing and electrical treatment are carried out 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 has the property of isolating oxygen and water. Inert gases are selected from at least one of nitrogen, helium, neon, argon, krypton or xenon.

[0094] In some embodiments of this application, when the light-emitting device is a positively oriented structure, the fabrication method further includes the step of forming a top electrode on the side of the electron transport layer away from the light-emitting layer, wherein the top electrode is a cathode. It is understood that when the light-emitting device is a positively oriented structure, the prefabricated device can be a stacked structure comprising 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. 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.

[0095] In at least one embodiment of this application, when the light-emitting device is a positively positioned structure, the fabrication method includes the following steps:

[0096] S1. Provide a substrate and form an anode on one side of the substrate;

[0097] S2. A hole injection layer is formed on the side of the anode away from the substrate;

[0098] S3. A hole transport layer is formed on the side of the hole injection layer away from the anode;

[0099] S4. A light-emitting layer is formed on the side of the hole transport layer away from the hole injection layer;

[0100] S5. Apply a solution containing nano-metal oxides to the side of the light-emitting layer away from the hole transport layer to obtain an electron transport precursor layer in a wet film state. Then, within a preset time range, perform annealing and charging treatment on the electron transport precursor layer to make the electron transport precursor layer carry positive or negative charges, or to make the electron transport precursor layer alternately carry positive and negative charges to obtain an electron transport layer.

[0101] S6. A cathode is formed on the side of the electron transport layer away from the light-emitting layer.

[0102] In some other embodiments of this application, when the light-emitting device is an inverted structure, the fabrication method further includes the following steps:

[0103] 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 bottom electrode; and

[0104] A top electrode is formed on the side of the light-emitting layer away from the electron transport layer, and the top electrode is the anode.

[0105] 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.

[0106] In at least one embodiment of this application, when the light-emitting device is an inverted structure, the fabrication method includes the following steps:

[0107] S1', Provide a substrate, and form a cathode on one side of the substrate;

[0108] S2' Apply a solution containing nano-metal oxides to the side of the cathode away from the substrate to obtain an electron transport precursor layer in a wet film state. Then, within a preset time range, perform annealing and charging treatment on the electron transport precursor layer to make the electron transport precursor layer carry positive or negative charges, or to make the electron transport precursor layer alternately carry positive and negative charges to obtain an electron transport layer.

[0109] S3', A light-emitting layer is formed on the side of the electron transport layer away from the cathode;

[0110] S4'. A hole transport layer is formed on the side of the light-emitting layer away from the electron transport layer.

[0111] S5'. A hole injection layer is formed on the side of the hole transport layer away from the light-emitting layer;

[0112] S6', An anode is formed on the side of the hole injection layer away from the hole transport layer.

[0113] It should be noted that, apart from the electron transport layer, the preparation methods for other films in light-emitting devices 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 coating, 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, a drying process is required to convert the wet film into a dry film.

[0114] 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.

[0115] 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 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 normally oriented structure or an inverted structure. Compared to existing light-emitting devices (where the electron transport layer is made of nano-metal oxide), the electron transport layer of the light-emitting device in this embodiment has higher density, i.e., smaller gaps between adjacent nanoparticles, resulting in higher conductivity and stability of the electron transport layer, thus leading to better overall performance of the light-emitting device in this embodiment.

[0116] 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:

[0117] 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.

[0118] 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.

[0119] 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.

[0120] When the quantum dots are selected from single-component quantum dots or core-shell structured quantum dots, the materials of the single-component quantum dots, the core of the core-shell structured quantum dots, and the shell of the core-shell structured quantum dots 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, ZnSeS, and ZnS. At least one of the following: eTe, 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, AlN, Al P, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNS b. InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlN At least one of As, 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, and wherein the I-III-VI compound is selected from at least one of CuInS2, CuInSe2, or AgInS2.

[0121] 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+ 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 - .

[0122] 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 - .

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] This application also provides a display device, which includes a light-emitting device prepared by any of the preparation methods described in this application, or any of the light-emitting devices 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.

[0129] 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.

[0130] Example 1

[0131] This embodiment provides a method for fabricating a light-emitting device and the resulting light-emitting device. The fabrication method includes the following steps:

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] S1.5 Under a nitrogen atmosphere at normal 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 stacked structure containing an electron transport precursor layer (wet film).

[0137] S1.6 Under a nitrogen atmosphere at normal temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer. An external power supply is provided, and the first end of the external power supply is connected to the anode, while the second end of the external power supply is grounded. Then, the stacked structure is continuously annealed at a constant temperature of 150°C for 60 minutes. During the annealing process, the external power supply applies a constant voltage of +25V to the electron transport precursor layer to continuously charge it for 60 minutes. This allows the entire prefabricated device containing the electron transport precursor layer to carry a positive charge during the annealing process, resulting in an electron transport layer with a thickness of 50nm.

[0138] S1.7, 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 S1.6 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.

[0139] 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 function layer 15, a light-emitting layer 13, an electron transport layer 14 and a cathode 12 stacked sequentially. The hole function 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.

[0140] Example 2

[0141] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "in a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, and then it is placed at a constant temperature of 150°C for continuous annealing for 60 minutes. During the annealing process, the external power supply applies a constant voltage of -25V to the electron transport precursor layer for continuous charging for 60 minutes, so that the prefabricated device containing the electron transport precursor layer carries a negative charge during the heating and annealing process, and an electron transport layer with a thickness of 50nm is obtained."

[0142] Example 3

[0143] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "in a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, and then it is placed at a constant temperature of 150°C for continuous annealing for 60 minutes. During the annealing process, the external power supply applies a constant voltage of 8V to the electron transport precursor layer for continuous charging for 60 minutes, so that the prefabricated device containing the electron transport precursor layer carries a positive charge as a whole, and an electron transport layer with a thickness of 50nm is obtained."

[0144] Example 4

[0145] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "in a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, and then it is placed at a constant temperature of 150°C for continuous annealing for 60 minutes. During the annealing process, the external power supply applies a constant voltage of 40V to the electron transport precursor layer for continuous charging for 60 minutes, so that the prefabricated device containing the electron transport precursor layer carries a positive charge as a whole, and an electron transport layer with a thickness of 50nm is obtained."

[0146] Example 5

[0147] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "in a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, and then it is placed at a constant temperature of 150°C for continuous annealing for 60 minutes. During the annealing process, the external power supply applies a rectangular AC voltage (frequency of 50Hz) of -25V to +25V to the electron transport precursor layer for continuous charging for 60 minutes, so that the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges to obtain an electron transport layer with a thickness of 50nm".

[0148] Example 6

[0149] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "in a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, and then it is continuously annealed at a constant temperature of 150°C for 60 minutes. During the annealing process, the external power supply is turned on to intermittently charge the electron transport precursor layer with constant voltage (voltage is positive 25V) for 60 minutes. During the charging process, the prefabricated device containing the electron transport precursor layer carries a positive charge as a whole. The interval between adjacent charging processes is 10 minutes, and the time for a single charging process is 10 minutes, thereby obtaining an electron transport layer with a thickness of 50nm."

[0150] Example 7

[0151] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "In a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, and the second end of the external power supply is grounded. Then, it is placed at a constant temperature of 150°C for continuous annealing for 60 minutes. During the annealing process, the external power supply is turned on, and a rectangular AC voltage (frequency of 50Hz, voltage of -25V to +25V) is applied to the electron transport precursor layer for intermittent charging for 60 minutes. During the charging process, the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges. The interval between adjacent charging processes is 10 minutes, and the time for a single charging process is 10 minutes, thereby obtaining an electron transport layer with a thickness of 50nm."

[0152] Example 8

[0153] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "In a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, the external power supply is turned on, and a constant voltage of +25V is applied to the electron transport precursor layer for continuous charging treatment for 60 minutes, so that the prefabricated device containing the electron transport precursor layer carries a positive charge as a whole. During the charging treatment, the electron transport precursor layer is subjected to intermittent isothermal (150°C) annealing treatment for 60 minutes for heating annealing process. The interval between adjacent annealing treatments is 5 minutes, and the time of a single annealing treatment is 15 minutes, to obtain an electron transport layer with a thickness of 50nm."

[0154] Example 9

[0155] 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 S1.6 is replaced with "In a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first terminal of the external power supply is connected to the anode, the second terminal of the external power supply is grounded, the external power supply is turned on, and a rectangular AC voltage (frequency of 50Hz, voltage of -25V to positive) is applied to the electron transport precursor layer." The device is continuously charged at 25V for 60 minutes, so that the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges. During the charging process, the electron transport precursor layer is subjected to intermittent isothermal (150℃) annealing for 60 minutes as a heating annealing process, so that the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges. The interval between adjacent isothermal heat treatments is 5 minutes, and the time of a single isothermal heat treatment is 15 minutes, to obtain an electron transport layer with a thickness of 50nm.

[0156] Example 10

[0157] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "In a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, the external power supply is turned on, and a constant voltage of +25V is applied to the electron transport precursor layer for intermittent charging treatment for 60 minutes. During the charging treatment, the prefabricated device containing the electron transport precursor layer carries a positive charge as a whole, and the electron transport precursor layer is subjected to intermittent isothermal (150°C) annealing treatment for 60 minutes. The charging treatment and annealing treatment are performed alternately, with a single charging treatment time of 5 minutes and a single annealing treatment time of 15 minutes, to obtain an electron transport layer with a thickness of 50nm."

[0158] Example 11

[0159] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "In a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer, an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, the external power supply is turned on, and a rectangular AC voltage (frequency of 50Hz, voltage of -25V to +25V) is applied to the electron transport precursor layer for intermittent charging treatment for 60 minutes. During the charging treatment, the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges, and the electron transport precursor layer is subjected to intermittent isothermal (150℃) annealing treatment for 60 minutes. The charging treatment and annealing treatment are performed alternately, with a single charging treatment time of 5 minutes and a single annealing treatment time of 15 minutes, to obtain an electron transport layer with a thickness of 50nm."

[0160] Example 12

[0161] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "under a nitrogen atmosphere at room temperature and pressure, the electron transport precursor layer is continuously annealed at a constant temperature (150°C) for 60 minutes to form a dry film. Then, a fixture is used to fix the stacked structure containing the dry film. An external power supply is provided, and the first end of the external power supply is connected to the anode, and the second end of the external power supply is grounded. The external power supply is turned on, and a rectangular AC voltage (frequency of 50Hz, voltage of -25V to +25V) is applied to the dry film to continuously charge it for 60 minutes. During the charging process, the prefabricated device containing the dry film alternately carries positive and negative charges to obtain an electron transport layer with a thickness of 50nm."

[0162] Example 13

[0163] 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 the method for fabricating a light-emitting device in this embodiment is that step S1.6 is replaced with "In a nitrogen atmosphere at room temperature and pressure, a jig is used to fix the stacked structure containing the electron transport precursor layer (wet film), an external power supply is provided, and the first end of the external power supply is connected to the anode, the second end of the external power supply is grounded, the external power supply is turned on, and a rectangular AC voltage (frequency of 50Hz, voltage of -25V to +25V) is applied to the electron transport precursor layer for continuous charging treatment for 60 minutes. During the charging treatment, the prefabricated device containing the electron transport precursor layer alternately carries positive and negative charges. After the charging treatment is completed, the prefabricated device is subjected to continuous isothermal (150℃) annealing treatment for 60 minutes to form an electron transport layer with a thickness of 50nm."

[0164] Comparative Example

[0165] This comparative example provides a method for preparing a light-emitting device and the obtained 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 S1.6 is replaced with "continuous isothermal (150°C) annealing treatment of the electron transport precursor layer for 60 min under nitrogen atmosphere at room temperature and pressure to obtain an electron transport layer with a thickness of 50 nm".

[0166] Experimental Example

[0167] The performance of the light-emitting devices in Examples 1 to 13 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.

[0168] 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.

[0169] 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 required for the brightness to decay from 100% to 95% (LT95, h) was recorded, and the time required for the brightness of each light-emitting device to decay from 100% to 95% at 1000 nits (LT95@1000nit, h) was calculated. The experimental results are detailed in Table 1 below:

[0170] Table 1 shows the performance test results of the light-emitting devices in Examples 1 to 13 and the comparative examples.

[0171]

[0172] As shown in Table 1, the overall performance of the light-emitting devices in Examples 1 to 11 is significantly better than that of the light-emitting devices in the comparative examples. Taking Example 5 as an example, on the day of packaging, the EQE of the light-emitting device in Example 5 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 3.4 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 14.7 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 within 30 days of packaging, the luminous efficacy and operating life of the light-emitting devices in Examples 1 to 11 show relatively small changes and ideal stability, while the EQE of the light-emitting device in the comparative example is significantly 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 annealing and charging the electron transport precursor layer within a preset time range during the preparation of the electron transport layer can improve the crystallinity and stability of the electron transport layer, thereby improving the luminescent performance and working life of the light-emitting device.

[0173] The performance test data of the light-emitting devices in Examples 1 to 4 show that the overall performance of the light-emitting devices in Examples 1 and 2 is better than that in Examples 3 and 4, and Example 2 is the best. This fully demonstrates that, under the premise that the charging time is constant, appropriately increasing the voltage value is beneficial to further improve the overall performance of the light-emitting devices.

[0174] The performance test data of the light-emitting devices in Examples 1 and 5, Examples 6 and 7, Examples 8 and 9, and Examples 10 and 11 show that, compared with constant voltage conditions for charged treatment, alternating voltage conditions for charged treatment are more conducive to improving the overall performance of the light-emitting devices. The reason may be that, under alternating voltage conditions, the electrical properties of the charge carried by nano-ZnO continuously oscillate, which is more conducive to the ligand detachment on the surface of nano-ZnO and the phase aggregation between nanoparticles, and further conducive to improving the density and stability of the electron transport layer.

[0175] The performance test data of the light-emitting devices in Examples 1, 5, and 6 to 11 show that the method of treating the electron transport precursor layer by continuous isothermal heat treatment combined with continuous charging treatment is most beneficial to improving the light-emitting performance and working life of the light-emitting device. The methods of treating the electron transport precursor layer by intermittent isothermal heat treatment combined with continuous charging treatment, continuous isothermal heat treatment combined with intermittent charging treatment, and intermittent isothermal heat treatment combined with intermittent charging treatment can all improve the overall performance of the light-emitting device to a certain extent and save energy consumption.

[0176] The performance test data of the light-emitting devices in Examples 5, 12 and 13 show that, compared with annealing the electron transport precursor layer before charging it, or charging it before annealing it, annealing and charging the electron transport precursor layer within a preset time range is more beneficial to improving the overall performance of the light-emitting device. The reason may be that, under the dual effects of high temperature and electrical energy, the ligands attached to the surface of the nano-metal oxide are more likely to detach, further shortening the gap between adjacent nanoparticles, thereby further improving the crystallinity, conductivity and stability of the electron transport layer.

[0177] 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: A prefabricated device is provided, wherein a solution containing nano-metal oxides is applied to one side of the prefabricated device to form an electron transport precursor layer; The electron transport precursor layer is charged to form the electron transport layer; The charging process involves making the electron transport precursor layer carry positive or negative charges, or making the electron transport precursor layer alternately carry positive and negative charges. The electron transport precursor layer is a wet film, and the preparation method further includes the steps of: annealing the electron transport precursor layer, wherein the annealing time period at least partially overlaps with the charging time period, or the annealing and charging are performed alternately; the charging includes the steps of: providing an external power supply, wherein a first terminal of the external power supply is connected to the bottom electrode, and a second terminal of the external power supply is grounded; and turning on the external power supply to create a potential difference between the first terminal and the second terminal. The electrification treatment and the annealing treatment are performed in an inert gas atmosphere; When the light-emitting device is an upright structure, the prefabricated device includes a bottom electrode and a light-emitting layer stacked together, the electron transport precursor layer is formed on the side of the light-emitting layer away from the bottom electrode, and the bottom electrode is an anode; the fabrication method further includes the step of: after forming an electron transport layer on one side of the prefabricated device, forming a top electrode on the side of the electron transport layer away from the light-emitting layer, and the top electrode is a cathode; Alternatively, when the light-emitting device is an inverted structure, the prefabricated device includes a bottom electrode, the electron transport precursor layer is formed on one side of the bottom electrode, and the bottom electrode is a cathode; the fabrication method further includes the following steps: After forming an electron transport layer on one side of the preform, a light-emitting layer is formed on the side of the electron transport layer away from the bottom electrode; A top electrode is formed on the side of the light-emitting layer away from the electron transport layer, and the top electrode is the anode.

2. The preparation method according to claim 1, characterized in that, During the electrification process, the external power supply applies a constant voltage or AC voltage to the electron transport precursor layer. The constant voltage value is between 10V and 30V; The frequency of the AC voltage is from 10Hz to 200Hz, and the effective voltage value is from 10V to 30V.

3. The preparation method according to claim 1, characterized in that, 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.

4. The preparation method according to claim 1, characterized in that, The duration of the electrification process is from 5 minutes to 120 minutes. The electrification process is continuous; or the electrification process is intermittent, with the duration of a single electrification process being 5 to 20 minutes and the interval between adjacent electrification processes being 5 to 20 minutes.

5. The preparation method according to claim 4, characterized in that, The annealing temperature is between 80°C and 250°C; And / or, the annealing process takes 5 to 120 minutes.

6. The preparation method according to claim 1, characterized in that, When the annealing time period and the electrical charging time period at least partially overlap, the annealing method and the electrical charging method are any of the following: (a1) The annealing process is continuous, and the electrification process is continuous; (a2) The annealing process is continuous, and the electrification process is intermittent; (a3) The annealing process is intermittent, and the electrification process is continuous; (a4) The annealing process is intermittent, and the electrification process is intermittent.

7. The preparation method according to claim 6, characterized in that, When the annealing process is continuous and the electrification process is continuous, the overlap time between the annealing process and the electrification process is 5 min to 120 min. Alternatively, when the annealing process is continuous and the electrification process is intermittent, the overlap time between the annealing process and the electrification process is 5 min to 115 min. Alternatively, when the annealing process is intermittent and the electrification process is continuous, the interval between adjacent annealing processes is 5 to 10 minutes, the time of a single annealing process is 10 to 30 minutes, and the overlap time between the annealing process and the electrification process is 5 to 115 minutes. Alternatively, when the annealing process is intermittent and the electrification process is intermittent, the interval between adjacent annealing processes is 5 to 10 minutes, the duration of a single annealing process is 10 to 30 minutes, and the overlap time between the annealing process and the electrification process is 5 to 115 minutes.

8. The preparation method according to claim 1, characterized in that, When the annealing process and the electrification process are performed alternately, the time for a single annealing process is 5 to 20 minutes.

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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