Light emitting diode and method of manufacturing the same, and application thereof

Abstract

This invention relates to a method for fabricating a light-emitting diode (LED), comprising the following steps: sequentially depositing a bottom electrode, a light-emitting layer, an electron transport layer, and a top electrode stacked in the thickness direction on one side surface of a substrate, wherein the electron transport layer is made of ZnO or ZnMgO, and the top electrode is made of Al; coating the surface of the top electrode with an organic acid treatment agent, and thermally annealing to allow the material of the top electrode to penetrate into the material of the electron transport layer and react with the material of the electron transport layer to form an electron transport layer doped with the material of the top electrode. This invention can effectively reduce the energy level barrier between the light-emitting layer and the electron transport layer, enhance the electron injection performance of the LED, and improve the device performance of the LED.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a light-emitting diode, its manufacturing method, and its applications. Background Technology

[0002] Quantum dot light-emitting diodes (QLEDs) are widely favored in the lighting and display fields due to their advantages such as high color purity, adjustable emission color according to quantum dot size, low operating voltage, high brightness, and low manufacturing cost.

[0003] Among these, flat panel display devices require low operating voltage, high current efficiency, and high external quantum efficiency, and QLEDs, with their superior performance, have broad application prospects in this field. In recent years, a great deal of research has been conducted on the improvement of quantum dot materials and the optimization of device structures.

[0004] However, during the fabrication of light-emitting diodes, the large energy level barrier between the electron transport layer and the light-emitting layer makes electron injection difficult, resulting in reduced device efficiency. This technical defect is particularly prominent in the fabrication process of blue quantum dot light-emitting diodes. Summary of the Invention

[0005] Therefore, it is necessary to provide a light-emitting diode (LED) that can reduce the energy level barrier between the electron transport layer and the light-emitting layer, enhance electron injection, and improve device efficiency, as well as its fabrication method and applications.

[0006] This invention provides a method for manufacturing a light-emitting diode, comprising the following steps:

[0007] A bottom electrode, a light-emitting layer, an electron transport layer, and a top electrode are sequentially deposited on one side surface of a substrate and stacked in the thickness direction. The electron transport layer is made of ZnO or ZnMgO, and the top electrode is made of Al.

[0008] An organic acid treatment agent is coated on the surface of the top electrode, and thermal annealing causes the material of the top electrode to penetrate into the material of the electron transport layer and react with the material of the electron transport layer to form an electron transport layer doped with the material of the top electrode.

[0009] In one embodiment, the material of the light-emitting layer is a blue quantum dot light-emitting material.

[0010] In one embodiment, the organic acidic treatment agent includes one or more of acrylic acid, benzoic acid, glycine, alanine, aspartic acid, glutamic acid, and phenylpropionic acid.

[0011] In one embodiment, the heat annealing step includes heating the material coated with the organic acid treatment agent to 80°C to 120°C and baking it for 0.5h to 2h.

[0012] In one embodiment, the coating thickness of the organic acid treatment agent is 50 μm to 100 μm.

[0013] In one embodiment, the thermal annealing is followed by a forward aging step, with a forward aging current density of 30 mA / cm². 2 ~100mA / cm 2 The aging time is 0.5h to 2h.

[0014] In one embodiment, the thickness of the top electrode is 50 nm to 200 nm.

[0015] In one embodiment, the following steps are also included:

[0016] At least one of a hole injection layer and a hole transport layer is formed between the bottom electrode and the light-emitting layer.

[0017] In one embodiment, the substrate material is one or more of ITO, IZO, ZTO, and AZO with a bottom electrode; and / or,

[0018] The hole injection layer is made of one or more of PEDOT:PSS, HATCN, MoO3, and Cu2O; and / or,

[0019] The hole transport layer is made of one or more of the following materials: TFB, PVK, NiO, NPB, and TCTA.

[0020] The present invention also provides a light-emitting diode, which is manufactured by the light-emitting diode manufacturing method described in any of the above embodiments.

[0021] The present invention also provides a display device, including the above-described light-emitting diode.

[0022] A method for fabricating a light-emitting diode (LED) is provided. Using ZnO or ZnMgO as the electron transport layer material and Al as the top electrode material, a bottom electrode, a light-emitting layer, an electron transport layer, and a top electrode are sequentially deposited and stacked in the thickness direction on one side surface of a substrate. An organic acid treatment agent is then coated onto the surface of the top electrode, and thermal annealing is performed to induce the top electrode material to penetrate into the electron transport layer material, forming an electron transport layer doped with the top electrode material. This method increases the LUMO energy level of the electron transport layer, lowers the energy level barrier between the quantum dot light-emitting layer and the electron transport layer, enhances the electron injection capability of the LED, improves the device efficiency of the LED, and passivates surface defects in zinc oxide, further enhancing the device performance of the LED. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a light-emitting diode according to one embodiment.

[0024] Figure 2 In order to be in Figure 1 A schematic diagram of a structure coated with an organic acid treatment agent.

[0025] Figure 3 This is a comparison graph of the current density-current efficiency changes between Example 1 and Comparative Example 1.

[0026] Figure label:

[0027] 10: Light-emitting diode; 110: Substrate; 120: Bottom electrode; 130: Light-emitting layer; 140: Electron transport layer; 150: Top electrode; 160: Hole injection layer; 170: Hole transport layer; 20: Organic acid treatment agent. Detailed Implementation

[0028] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0031] One embodiment of the present invention provides a method for manufacturing a light-emitting diode 10, comprising the following steps S1 to S2.

[0032] like Figure 1 As shown, in step S1: a bottom electrode 120, a light-emitting layer 130, an electron transport layer 140, and a top electrode 150 are sequentially deposited on one side surface of the substrate 110 and stacked in the thickness direction. The electron transport layer 140 is made of ZnO or ZnMgO, and the top electrode 150 is made of Al.

[0033] ZnO possesses excellent electron transport properties and carrier balance capabilities, exhibiting high transport efficiency without emitting stray light or absorbing light emitted from the light-emitting layer 130. Using ZnO as the electron transport layer 140 can improve the luminous efficiency of the light-emitting diode 10. ZnMgO is a ternary alloy formed by doping ZnO with MgO. The incorporation of MgO further broadens the bandgap of ZnO with minimal lattice alteration, further enhancing the device quality of the light-emitting diode 10. Preferably, the electron transport layer 140 is made of nanoscale ZnO or ZnMgO.

[0034] Al is used as the material for the top electrode 150 of the light-emitting diode 10, and it has good electrical conductivity.

[0035] like Figure 2 As shown, step S2: an organic acid treatment agent 20 is coated on the surface of the top electrode 150, and thermal annealing is performed to allow the material of the top electrode 150 to penetrate into the material of the electron transport layer 140 and react with the material of the electron transport layer 140 to form an electron transport layer 140 doped with the material of the top electrode 150.

[0036] During the thermal annealing process, under the influence of the organic acid treatment agent 20, the Al atoms in the top electrode 150 are accelerated to penetrate into the electron transport layer 140, forming an aluminum-doped electron transport layer 140, namely an AlZnO electron transport layer or an AlZnMgO electron transport layer. This raises the LUMO energy level of the electron transport layer 140 and brings it close to the LUMO energy level of the light-emitting layer 130, reducing the energy level barrier between the electron transport layer 140 and the light-emitting layer 130, and improving the electron injection capability. This makes it easier for electrons to be injected into the light-emitting layer 130 after passing through the electron transport layer 140, thereby improving the device performance and efficiency of the light-emitting diode 10.

[0037] Understandably, the method for fabricating the light-emitting diode 10 of the present invention is applicable to various light-emitting materials where electron injection is difficult. For example, the material of the light-emitting layer 130 can be a quantum dot light-emitting material or an organic light-emitting material. Furthermore, when the material of the light-emitting layer 130 is a blue quantum dot light-emitting material, the improvement in device efficiency is particularly significant after adding the organic acid treatment agent 20.

[0038] Understandably, the organic acid treatment agent 20 is an anhydrous organic acid treatment agent. Using an anhydrous organic acid treatment agent can prevent moisture from damaging the device performance.

[0039] Preferably, the organic acid treatment agent 20 is selected from organic acids with weak reactivity and small molecular weight.

[0040] Preferably, an organic acid containing a carboxyl group is used as the organic acid treatment agent 20.

[0041] In a specific example, the organic acidic treatment agent 20 may be one or more of acrylic acid, benzoic acid, and phenylpropionic acid, or it may be an amino acid with a smaller R group, such as glycine, alanine, aspartic acid, and glutamic acid.

[0042] In a specific example, the thermal annealing step includes heating the material coated with the organic acid treatment agent 20 to 80°C–120°C and baking it for 0.5–2 hours. During the thermal annealing process, under the catalytic action of the organic acid treatment agent 20, Al atoms in the top electrode 150 are accelerated to diffuse into the electron transport layer 140, causing a chemical reaction between the material of the electron transport layer 140 and the Al atoms. Under these thermal annealing conditions, the formed AlZnO electron transport layer or AlZnMgO electron transport layer significantly improves the device efficiency of the light-emitting diode 10.

[0043] In a specific example, the coating thickness of the organic acid treatment agent 20 is 50 μm to 100 μm. The organic acid treatment agent 20 is coated on the top electrode 150, and the coating area covers the entire light-emitting region. If the coating thickness of the organic acid treatment agent 20 is too thick, the content of the organic acid treatment agent 20 will be too high, and the organic acid treatment agent 20 will diffuse into other functional layers outside the electron transport layer 140 and the top electrode 150, which will adversely affect the device performance of the light-emitting diode 10. If the coating thickness of the organic acid treatment agent 20 is too thin, the content of the organic acid treatment agent 20 will be too low, which is not conducive to promoting the diffusion of Al atoms in the top electrode 150 into the electron transport layer 140. Within this coating thickness range, it is possible to ensure that the organic acid treatment agent 20 can effectively promote the diffusion of Al atoms in the top electrode 150 into the electron transport layer 140, without diffusing into other functional layers and causing adverse effects on the device.

[0044] Understandably, if the raw material of the organic acid treatment agent 20 is a solid powder, the organic acid treatment agent 20 can be dissolved in a first organic solvent before being coated onto the top electrode 150. The first organic solvent can be, but is not limited to, alcohols.

[0045] Understandably, after the organic acid treatment agent 20 is coated on the top electrode 150, the distribution of the organic acid treatment agent can be made more uniform by spreading, rotating or oscillating.

[0046] In a specific example, the thermal annealing is followed by a forward aging step, through which the device performance of the light-emitting diode 10 can be continuously enhanced as the storage time increases.

[0047] Furthermore, during the forward aging process, the bottom electrode 120 is connected to the positive terminal of the power supply, and the top electrode 150 is connected to the negative terminal of the power supply. The current density for forward aging is 30 mA / cm². 2~100mA / cm 2 The aging time is 0.5h to 2h. Under these conditions, the forward aging effect of LED 10 is optimal.

[0048] Understandably, when the light-emitting layer 130 and the electron transport layer 140 are sequentially deposited on the bottom electrode 120, the materials of the light-emitting layer 130 and the electron transport layer 140 are prepared into solutions and coated onto preset positions to form films.

[0049] In a specific example, the material of the light-emitting layer 130 is dissolved in a second organic solvent to prepare a solution, which is then deposited onto the bottom electrode 120. The second organic solvent is then evaporated to form the light-emitting layer 130. Further, the material of the light-emitting layer 130 is prepared as a solution with a concentration of 10 mg / mL to 20 mg / mL. The second organic solvent may be, but is not limited to, alcohols.

[0050] In a specific example, the material of the electron transport layer 140 is dissolved in a third organic solvent to prepare a solution, which is then deposited onto the light-emitting layer 130. The third organic solvent is then evaporated to form the electron transport layer 140. Further, the material of the electron transport layer 140 is prepared as a solution with a concentration of 20 mg / mL to 40 mg / mL. The third organic solvent may be, but is not limited to, alcohols.

[0051] In a specific example, the thickness of the top electrode 150 is 50 nm to 200 nm. Within this thickness range, after coating with the organic acid treatment agent 20, Al atoms can quickly penetrate into the electron transport layer 140 without adversely affecting the resistance of the top electrode 150.

[0052] Furthermore, above the electron transport layer 140, with The top electrode 150 is formed by thermally depositing metallic Al at a certain rate. Furthermore, the thermal deposition method can be vacuum evaporation.

[0053] In a specific example, the material of the substrate 110 is one or more of ITO, IZO, ZTO, and AZO, which has a bottom electrode 120. Understandably, the substrate 110 can be cleaned and dried before depositing other functional layers on it. Specifically, the substrate 110 can be cleaned by wiping, blowing dust, or ultrasonic cleaning, and dried by light exposure or heating.

[0054] In a specific example, the following steps are also included:

[0055] At least one of a hole injection layer 160 and a hole transport layer 170 is formed between the bottom electrode 120 and the light-emitting layer 130.

[0056] In a specific example, the material of the hole injection layer 160 may be, but is not limited to, one or more of PEDOT:PSS, HATCN, MoO3, and Cu2O.

[0057] In a specific example, the material of the hole transport layer 170 is one or more of TFB, PVK, NiO, NPB, and TCTA.

[0058] Understandably, the hole injection layer 160 is located between the bottom electrode 120 and the light-emitting layer 130, and the hole transport layer 170 is located between the hole injection layer 160 and the light-emitting layer 130.

[0059] In a specific example, the material of the hole injection layer 160 is dissolved in a fourth organic solvent to prepare a solution, which is then deposited onto the bottom electrode 120, and the fourth organic solvent is evaporated to form the hole injection layer 160. Further, the material of the hole injection layer 160 is prepared as a solution with a concentration of 10 mg / mL to 20 mg / mL. The fourth organic solvent may be, but is not limited to, alcohols.

[0060] In a specific example, the material of the hole transport layer 170 is dissolved in a fifth organic solvent to prepare a solution, which is then deposited onto the hole injection layer 160. The fifth organic solvent is then evaporated to form the hole transport layer 170. Further, the material of the hole transport layer 170 is prepared as a solution with a concentration of 8 mg / mL to 20 mg / mL. The fifth organic solvent may be, but is not limited to, chlorobenzene, etc.

[0061] Furthermore, the hole transport layer 170 can also be two layers, with the first hole transport layer located between the hole injection layer 160 and the light-emitting layer 130, and the second hole transport layer located between the first hole transport layer and the light-emitting layer 130. The second hole transport layer also functions as an electron blocking layer.

[0062] In this process, the material of the first hole transport layer is dissolved and prepared into a solution, which is then deposited onto the hole injection layer 160, and the solvent is evaporated to form the first hole transport layer. Further, the material of the first hole transport layer is prepared into a solution with a concentration of 8 mg / mL to 12 mg / mL.

[0063] The material of the second hole transport layer is dissolved and prepared into a solution, which is then deposited onto the first hole transport layer, and the solvent is evaporated to form the second hole transport layer. Further, the material of the second hole transport layer is prepared into a solution with a concentration of 8 mg / mL to 12 mg / mL.

[0064] Understandably, after forming any one of the hole injection layer 160, hole transport layer 170, light emission layer 130 and electron transport layer 140, the edge of the substrate 110 is wiped to expose the bottom electrode 120 on the substrate 110.

[0065] Understandably, the method for manufacturing the light-emitting diode 10 in any of the above embodiments also includes a device packaging step.

[0066] An embodiment of the present invention also provides a light-emitting diode 10, which is manufactured by the method for manufacturing a light-emitting diode 10 in any of the above examples.

[0067] An embodiment of the present invention also provides a display device, including the light-emitting diode 10 described above.

[0068] One embodiment of the present invention provides a method for fabricating a light-emitting diode 10. ZnO or ZnMgO is used as the material for the electron transport layer 140, and Al is used as the material for the top electrode 150. After depositing and forming a bottom electrode 120, a light-emitting layer 130, an electron transport layer 140, and a top electrode 150 stacked in the thickness direction sequentially on one side surface of a substrate 110, an organic acid treatment agent 20 is coated on the surface of the top electrode 150, followed by thermal annealing. Under the catalytic action of the organic acid treatment agent 20, Al atoms are accelerated to penetrate downwards into the material of the electron transport layer 140, forming an aluminum-doped electron transport layer 140, i.e., an AlZnO ETL layer or an AlZnMgO ETL layer. This increases the LUMO energy level of the electron transport layer 140, lowers the energy level barrier between the light-emitting layer 130 and the electron transport layer 140, enhances the electron injection capability of the light-emitting diode 10, and improves the performance of the light-emitting diode 10. Furthermore, the addition of organic acid treatment agent 20 can passivate the surface defects of the electron transport layer 140 material, further enhancing the device performance of the light-emitting diode 10.

[0069] The present invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, all raw materials in the following specific embodiments can be obtained from commercially available sources.

[0070] Among them, PEDOT:PSS was purchased from Heraeus, model AI4083;

[0071] TFB was purchased from American Dye Source, model number 223569-31-1;

[0072] PVK was purchased from American Dye Source, model number 139092-78-7;

[0073] B-QDs was acquired from Mesolight Inc.

[0074] ZnO NPs were acquired from Mesolight Inc.

[0075] Acrylic acid was purchased from Mesolight Inc.

[0076] Example 1:

[0077] (1) Cleaning the substrate (including the bottom electrode): First, wipe the ITO substrate with a lint-free cloth soaked in detergent for 1 minute, and blow away the dust on the substrate with an N2 air gun. Place the wiped substrate in the detergent and heat it to 80°C. Ultrasonically treat it for 20 minutes. Then, ultrasonically clean the substrate in ultrapure water, acetone, and isopropanol for 15 minutes each. Finally, perform UV treatment on the cleaned ITO substrate for 15 minutes.

[0078] (2) Preparation of the hole injection layer: After thoroughly mixing PEDOT:PSS, filter it through a 0.45μm filter. Use a pipette to pipette 150μL of the filtered PEDOT:PSS solution onto the bottom electrode of the ITO substrate. Spin coat the solution at 5000rpm for 60s under atmospheric conditions until a film is formed. Wipe the edges of the ITO / PEDOT:PSS substrate with a cotton swab soaked in deionized water to expose the electrode at the substrate edge. Then place it on an annealing plate and heat it to 150℃ for 15min. Then remove it and transfer it to a nitrogen glove box that is isolated from water and oxygen to cool it.

[0079] (3) Fabrication of the first hole transport layer: TFB powder was dissolved in the organic solvent chlorobenzene to form a solution with a concentration of 8 mg / mL. The prepared TFB solution was filtered with a 0.2 μm filter to remove impurities. The ITO / PEDOT:PSS substrate was adsorbed onto the stage using a spin coater. 60 μL of TFB solution taken with a pipette was added dropwise at a uniform speed to the middle of the ITO / PEDOT:PSS substrate at a speed of 3000 rpm. After the solution was spin-coated for 45 s to form a film, the ITO / PEDOT:PSS / TFB substrate was placed on an annealing plate and heated to 150 °C and maintained for 30 min. Then it was removed and transferred to a nitrogen glove box isolated from water and oxygen to cool.

[0080] (4) Fabrication of the second hole transport layer: Dissolve PVK powder in the organic solvent chlorobenzene to form a solution with a concentration of 8 mg / mL. Filter the prepared PVK solution with a 0.2 μm filter to remove impurities. Then, use a spin coater to adsorb the ITO / PEDOT:PSS / TFB substrate onto the stage. Add 60 μL of PVK solution taken with a pipette at a uniform rate to the middle of the ITO / PEDOT:PSS / TFB substrate at a speed of 4000 rpm. After the solution has been spin-coated for 45 s to form a film, place the ITO / PEDOT:PSS / TFB / PVK substrate on an annealing plate and heat it to 150°C and maintain it for 30 min. Then, remove it and transfer it to a nitrogen glove box that is isolated from water and oxygen to cool it.

[0081] (5) Fabrication of the luminescent layer: Filter the 18 mg / mL B-QDs solution through a 0.2 μm PTFE filter. Then, use a spin coater to adsorb the ITO / PEDOT:PSS / TFB / PVK substrate onto the stage. Take 60 μL of the filtered B-QDs solution with a pipette and add it dropwise at a constant speed to the middle of the substrate at a speed of 2500 rpm. Spin coat for 45 s until the solution forms a film.

[0082] (6) Fabrication of the electron transport layer: An ethanol solution of ZnO NPs with a concentration of 30 mg / ml was filtered through a 0.2 μm filter to remove impurities. 60 μL of the filtered solution was then pipetted onto the middle of the ITO / PEDOT:PSS / TFB / QDs substrate. The solution was then spin-coated at 3000 rpm for 45 s until a film was formed. The edges of the ITO / PEDOT:PSS / TFB / QDs / ZnO substrate were then wiped with a cotton swab soaked in a small amount of chlorobenzene or toluene solution to expose the electrodes at the edges. The substrate was then transferred to an annealing plate and heated to 60 °C for 30 min. Finally, it was removed and transferred to a nitrogen glove box to cool in an oxygen-free environment.

[0083] (7) Fabrication of the top electrode: The above ITO / PEDOT:PSS / TFB / QDs / ZnO substrate is transferred to a high vacuum deposition chamber (vacuum degree ≤ 1×10-6 mbar) to... A thermally deposited aluminum cathode was achieved at a rate of 100 nm, wherein a mask was used to define the contact area between the top Al layer and the electron transport layer and to form a 0.04 cm layer. 2 The effective light-emitting area of ​​the device.

[0084] (8) Adding organic acid treatment agent: Coat the surface of the top electrode with an 80μm thick layer of anhydrous acrylic surfactant, heat to 80℃ and anneal for 1 hour, and perform positive aging treatment. The positive aging current density is 60mA / cm. 2 The aging time is 1 hour.

[0085] Comparative Example 1:

[0086] Comparative Example 1 is the same as Step 1 to Step (7) of Example 1, except that Comparative Example 1 does not have Step (8).

[0087] (1) Cleaning the substrate (including the bottom electrode): First, wipe the ITO substrate with a lint-free cloth soaked in detergent for 1 minute, and blow away the dust on the substrate with an N2 air gun. Place the wiped substrate in the detergent and heat it to 80°C. Ultrasonically treat it for 20 minutes. Then, ultrasonically clean the substrate in ultrapure water, acetone, and isopropanol for 15 minutes each. Finally, perform UV treatment on the cleaned ITO substrate for 15 minutes.

[0088] (2) Preparation of the hole injection layer: After thoroughly mixing PEDOT:PSS, filter it through a 0.45μm filter. Use a pipette to pipette 150μL of the filtered PEDOT:PSS solution onto the bottom electrode of the ITO substrate. Spin coat the solution at 5000rpm for 60s under atmospheric conditions until a film is formed. Wipe the edges of the ITO / PEDOT:PSS substrate with a cotton swab soaked in deionized water to expose the electrode at the substrate edge. Then place it on an annealing plate and heat it to 150℃ for 15min. Then remove it and transfer it to a nitrogen glove box that is isolated from water and oxygen to cool it.

[0089] (3) Fabrication of the first hole transport layer: TFB powder was dissolved in the organic solvent chlorobenzene to form a solution with a concentration of 8 mg / ml. The prepared TFB solution was filtered with a 0.2 μm filter to remove impurities. The ITO / PEDOT:PSS substrate was adsorbed onto the stage using a spin coater. 60 μL of TFB solution was taken with a pipette and added dropwise at a constant speed to the middle of the ITO / PEDOT:PSS substrate at a speed of 3000 rpm. After the solution was spin-coated for 45 s to form a film, the ITO / PEDOT:PSS / TFB substrate was placed on an annealing plate and heated to 150 °C and maintained for 30 min. Then it was removed and transferred to a nitrogen glove box isolated from water and oxygen to cool.

[0090] (4) Fabrication of the second hole transport layer: Dissolve PVK powder in the organic solvent chlorobenzene to form a solution with a concentration of 8 mg / ml. Filter the prepared PVK solution with a 0.2 μm filter to remove impurities. Then, use a spin coater to adsorb the ITO / PEDOT:PSS / TFB substrate onto the stage. Add 60 μL of PVK solution taken with a pipette at a uniform rate to the middle of the ITO / PEDOT:PSS / TFB substrate at a speed of 4000 rpm. After the solution is spin-coated for 45 s to form a film, place the ITO / PEDOT:PSS / TFB / PVK substrate on an annealing plate and heat it to 150°C and maintain it for 30 min. Then, remove it and transfer it to a nitrogen glove box that is isolated from water and oxygen to cool it.

[0091] (5) Fabrication of the luminescent layer: Filter the 18 mg / mL B-QDs solution through a 0.2 μm PTFE filter. Then, use a spin coater to adsorb the ITO / PEDOT:PSS / TFB / PVK substrate onto the stage. Take 60 μL of the filtered B-QDs solution with a pipette and add it dropwise at a constant speed to the middle of the substrate at a speed of 2500 rpm. Spin coat for 45 s until the solution forms a film.

[0092] (6) Fabrication of the electron transport layer: An ethanol solution of ZnO NPs with a concentration of 30 mg / ml was filtered through a 0.2 μm filter to remove impurities. 60 μL of the filtered solution was then pipetted onto the middle of the ITO / PEDOT:PSS / TFB / QDs substrate. The solution was then spin-coated at 3000 rpm for 45 s until a film was formed. The edges of the ITO / PEDOT:PSS / TFB / QDs / ZnO substrate were then wiped with a cotton swab soaked in a small amount of chlorobenzene or toluene solution to expose the electrodes at the edges. The substrate was then transferred to an annealing plate and heated to 60 °C for 30 min. Finally, it was removed and transferred to a nitrogen glove box to cool in an oxygen-free environment.

[0093] (7) Fabrication of the top electrode: The above ITO / PEDOT:PSS / TFB / QDs / ZnO substrate is transferred to a high vacuum deposition chamber (vacuum degree ≤ 1×10-6 mbar) to... A thermally deposited aluminum cathode was achieved at a rate of 100 nm, wherein a mask was used to define the contact area between the top Al layer and the electron transport layer and to form a 0.04 cm layer. 2 The effective light-emitting area of ​​the device.

[0094] The light-emitting diodes prepared in Example 1 and Comparative Example 1 were subjected to IVL testing. The testing method was as follows: the voltage of the device was scanned, the current and the brightness at the corresponding current were recorded, and the current efficiency was calculated from the brightness, current and light-emitting area.

[0095] Test results are as follows Figure 3 It can be seen that after coating the top electrode of the light-emitting diode with an organic acid treatment agent, the current efficiency is significantly enhanced, and the organic acid treatment agent is beneficial to enhancing the electron injection capability of the light-emitting diode.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for manufacturing a light-emitting diode, characterized in that, Includes the following steps: A bottom electrode, a light-emitting layer, an electron transport layer, and a top electrode are sequentially deposited on one side surface of a substrate and stacked in the thickness direction. The electron transport layer is made of ZnO or ZnMgO, and the top electrode is made of Al. An organic acid treatment agent is coated on the surface of the top electrode, and thermal annealing causes the material of the top electrode to penetrate into the material of the electron transport layer and react with the material of the electron transport layer to form an electron transport layer doped with the material of the top electrode.

2. The method for manufacturing a light-emitting diode according to claim 1, characterized in that, The material of the light-emitting layer is blue quantum dot light-emitting material.

3. The method for manufacturing a light-emitting diode according to claim 1, characterized in that, The organic acidic treatment agent includes one or more of acrylic acid, benzoic acid, glycine, alanine, aspartic acid, glutamic acid, and phenylpropionic acid.

4. The method for manufacturing a light-emitting diode according to claim 1, characterized in that, The hot annealing step includes heating the material coated with the organic acid treatment agent to 80°C to 120°C and baking it for 0.5h to 2h.

5. The method for manufacturing a light-emitting diode according to claim 1, characterized in that, The coating thickness of the organic acid treatment agent is 50 μm to 100 μm.

6. The method for manufacturing a light-emitting diode according to any one of claims 1 to 5, characterized in that, Following thermal annealing is a forward aging step, with a current density of 30 mA / cm². 2 ~100mA / cm 2 The aging time is 0.5h to 2h.

7. The method for manufacturing a light-emitting diode according to any one of claims 1 to 5, characterized in that, The thickness of the top electrode is 50nm to 200nm.

8. The method for manufacturing a light-emitting diode according to any one of claims 1 to 5, characterized in that, It also includes the following steps: At least one of a hole injection layer and a hole transport layer is formed between the bottom electrode and the light-emitting layer.

9. The method for manufacturing a light-emitting diode according to claim 8, characterized in that, The substrate material is one or more of ITO, IZO, ZTO, and AZO with a bottom electrode; and / or, The hole injection layer is made of one or more of PEDOT:PSS, HATCN, MoO3, and Cu2O; and / or, The hole transport layer is made of one or more of the following materials: TFB, PVK, NiO, NPB, and TCTA.

10. A light-emitting diode, characterized in that, It is manufactured by the method of manufacturing a light-emitting diode as described in any one of claims 1 to 9.

11. A display device, characterized in that, Includes the light-emitting diode as described in claim 10.

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