Ultrahigh-resolution QLED device and preparation method thereof

Abstract

The invention discloses an ultrahigh-resolution QLED device and a preparation method thereof, insulating layer materials are printed on any one of a substrate, a hole injection layer, a hole transport layer, a quantum dot light emitting layer and an electron transport layer in a criss-cross manner, and the printed insulating layer materials cannot perform charge transmission, so that the QLED device forms uniform array patterns, and the performance of the QLED device is improved. The QLED device with the ultrahigh resolution ratio is efficiently and simply obtained, the size of the pixel point can reach about 5 microns, another simple method is provided for breaking through a ten-thousand-level PPI pixel display technology, the preparation process is safe and free of pollution, no by-product is generated, the technological process is simple and easy to operate, and meanwhile the material utilization rate and the precision are high.

Description

Technical Field

[0001] The present application relates to an ultra-high-resolution QLED device and a method for preparing the same, and belongs to the field of light-emitting display technology. Background Art

[0002] Quantum dot light-emitting diodes (QLEDs) have excellent optoelectronic properties, such as high color purity, high luminous efficiency, and solution processability, and have broad application prospects in the field of lighting and display. In recent years, driven by emerging concepts such as smart healthcare and the "metaverse", the next generation of displays has put forward higher standards for pixel resolution to meet the ever-increasing application needs of massive information and near-eye displays. QLED uses extremely small nano-products as light emitters, and theoretically the device's luminous performance is not limited by size, so it has unique advantages in the field of high-resolution displays. Ultra-high pixel resolution QLED materials and device technologies with completely independent intellectual property rights and breakthroughs in 10,000-level PPI pixel display technology are crucial to whether my country can occupy the commanding heights and achieve technological leadership in the fierce competition of the next generation of display technology.

[0003] However, the resolution of current mainstream displays remains at tens or hundreds of microns, and it faces many severe challenges when entering the submicron or even nanometer scale. Summary of the invention

[0004] According to one aspect of the present application, a method for preparing an ultra-high resolution QLED device is provided, comprising the following steps:

[0005] S1: The substrate is ultrasonically cleaned, then dried with nitrogen and UV treated;

[0006] S2: preparing a hole injection layer, making a solution of hole injection layer material and spin coating it on the substrate, and then annealing it in air;

[0007] S3: preparing a hole transport layer, preparing a solution of hole transport layer material and spin coating the solution on the hole injection layer, and then annealing the solution in a nitrogen atmosphere;

[0008] S4: preparing a quantum dot light-emitting layer, dissolving the quantum dot material in n-octane to obtain a prefabricated solution, then spin-coating the prefabricated solution on the hole transport layer, and then annealing in a nitrogen atmosphere;

[0009] S5: preparing an electron transport layer, preparing a solution of the electron transport layer material, spin coating it on the quantum dot light-emitting layer, and vacuum drying it;

[0010] S6: Preparation of metal electrodes;

[0011] S7: Encapsulation;

[0012] The steps also include A0, specifically:

[0013] Prepare the insulating layer. On any one of the substrate, hole injection layer, hole transport layer, quantum dot light-emitting layer, and electron transport layer, print and solidify the solution containing the insulating layer material at equal intervals horizontally and vertically in turn to form a criss-cross insulating layer grid.

[0014] An electric fluid printing device is used to print the insulating layer material horizontally and evenly spaced on any one of the substrate, the hole injection layer, the hole transport layer, the quantum dot light-emitting layer, and the electron transport layer, and then baked to solidify. The insulating layer material is then printed vertically and evenly spaced, and then baked again to solidify.

[0015] The preparation method provided in the present application prepares a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a metal electrode on an anode substrate, and uses an electrofluid printing device to criss-cross print the insulating layer material on any one of the substrate, the hole injection layer, the hole transport layer, the quantum dot light-emitting layer and the electron transport layer. Since the printed insulating layer material cannot transport charges, the QLED device forms a uniform array pattern, thereby simply and efficiently realizing the preparation of ultra-high resolution QLED devices.

[0016] Optionally, the ultrasonic cleaning in step S1 is specifically:

[0017] Ultrasonic cleaning was performed with cleaning solution, ethanol, acetone, and deionized water in sequence;

[0018] Among them, ethanol and acetone can also be replaced by other solvents with the same effect. The purpose is to remove the residual chemicals on the substrate, and finally use ultrapure water to remove the solvent on it.

[0019] Preferably, the ultrasonic cleaning time is 20min to 50min;

[0020] Preferably, the substrate is made of ITO glass.

[0021] Optionally, the UV treatment time in step S1 is 15 min to 40 min.

[0022] Optionally, the hole injection layer material is selected from one of polymer PEDOT:PSS, molybdenum oxide, nickel oxide, and cuprous thiocyanate;

[0023] Preferably, the spin coating speed in step S2 is 3500 rpm to 4500 rpm, and the spin coating time is 25 s to 35 s;

[0024] Preferably, the annealing treatment time in step S2 is 30 min to 40 min, and the temperature is 150° C. to 200° C.

[0025] Optionally, the hole transport layer material is selected from one or a mixture of polymer TFB, cross-linked TFB, Poly:TPD, PVK;

[0026] Preferably, the concentration of TFB solution is 8-10 mg / ml;

[0027] Preferably, the annealing treatment in step S3 is performed for 30 min to 40 min at a temperature of 150° C. to 200° C.

[0028] Optionally, the quantum dot material is selected from one of cadmium-based quantum dot materials, InP quantum dot materials, rare earth quantum dot materials, and halogen perovskite quantum dot materials;

[0029] The concentration of the prefabricated solution is 10 to 30 mg / ml;

[0030] Preferably, the spin coating speed in step S4 is 1500 rpm to 2500 rpm, and the spin coating time is 25 s to 35 s;

[0031] Preferably, the annealing treatment in step S4 is performed for 5 min to 10 min at a temperature of 100° C. to 250° C.

[0032] Optionally, the electron transport layer material is selected from one of ZnO nanoparticles, ZnMgO nanoparticles, ZnO or ZnMgO nanoparticles doped with polymers such as PVP or PVK, ZnS nanoparticles, and ZnO nanoparticles with metal cations;

[0033] Preferably, the concentration of the prepared ZnMgO solution is 20-30 mg / ml;

[0034] Preferably, the spin coating speed in step S5 is 3500 rpm to 4500 rpm, and the spin coating time is 25 s to 35 s;

[0035] Preferably, the vacuum drying treatment time in step S5 is 10 min to 20 min.

[0036] Optionally, in step S6, one or more of Au, Ag, and Al are selected as metal electrodes and are evaporated on the electron transport layer.

[0037] Optionally, the insulating layer material is selected from one of Teflon, PMMA and PVDF;

[0038] Preferably, in step A0, a baking treatment is selected for curing, and the baking treatment temperature is 80° C. to 100° C. and the time is 30 min to 40 min.

[0039] The present application also provides an ultra-high-resolution QLED device, comprising an insulating layer, wherein the insulating layer is located on any one of a substrate, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, and an electron transport layer.

[0040] It should be noted that the types of quantum dots in the functional layers, spin coating speed, solution concentration, solvent selection, annealing temperature and annealing time used in the manufacturing process of the quantum dot light-emitting devices mentioned in this application are not completely fixed and can be adjusted appropriately according to actual needs.

[0041] The beneficial effects of this application include:

[0042] The present application provides an ultra-high-resolution QLED device and a preparation method thereof, wherein an insulating layer material is criss-cross printed on any one of a substrate, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, and an electron transport layer. Since the printed insulating layer material cannot transport charges, the QLED device forms a uniform array pattern, and an ultra-high-resolution QLED device is obtained efficiently and simply, and the pixel size can reach about 5um, providing another simple method for breaking through the 10,000-level PPI pixel display technology. The preparation process is safe and pollution-free, does not generate by-products, and the process flow is simple and easy to operate, while the material utilization rate and precision are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the structure of a QLED device obtained in one embodiment of the present application;

[0044] Figure 2 This is a microscope image of an insulating layer printed by electrofluid in one embodiment of the present application.

[0045] List of parts and reference numerals:

[0046] 1. Substrate; 2. Hole injection layer; 3. Hole transport layer; 4. Insulating layer; 5. Quantum dot light-emitting layer; 6. Electron transport layer; 7. Metal electrode. DETAILED DESCRIPTION

[0047] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0048] like Figure 1 As shown, according to one embodiment of the present application, a method for preparing an ultra-high resolution QLED device is provided, comprising the following steps:

[0049] S1: ultrasonically clean the ITO glass substrate 1 with a cleaning solution, ethanol, acetone, and deionized water for 20 minutes, then blow dry with nitrogen and treat with UV for 15 minutes;

[0050] S2: Prepare the hole injection layer 2 by spin coating the PEDOT:PSS solution onto the substrate 1 at 4000 rpm for 30 seconds, and then anneal at 150°C in air for 30 minutes;

[0051] S3: preparing the hole transport layer 3, spin coating 8 mg / ml TFB solution on the hole injection layer 2 at 3000 rpm for 30 seconds, and then annealing at 150° C. for 30 minutes in a nitrogen atmosphere;

[0052] S4: preparing a quantum dot light-emitting layer 5, dissolving a cadmium-based quantum dot material in n-octane to obtain a prefabricated solution with a concentration of 30 mg / ml, then spin-coating the prefabricated solution on the hole transport layer 3 at 2000 rpm for 30 seconds, and then annealing at 100° C. for 5 minutes in a nitrogen atmosphere;

[0053] The step A0 is also included, specifically:

[0054] Prepare the insulating layer 4, use an electrofluidic printing device to print the Teflon solution on the quantum dot light-emitting layer 5 at equal intervals in the horizontal direction, then bake it at 80° C. for 30 minutes, then print the Teflon solution at equal intervals in the vertical direction, and bake it at 80° C. for 30 minutes again to form a criss-cross insulating layer grid;

[0055] The prepared insulating layer 4 is as follows Figure 2 As shown;

[0056] S5: preparing the electron transport layer 6, spin coating a ZnMgO solution with a concentration of 20 mg / ml on the insulating layer 4 at 4000 rpm for 30 seconds, and vacuum drying for 10 minutes;

[0057] S6: preparing a metal electrode 7, selecting Ag as the metal electrode 7, and evaporating it on the electron transport layer 6;

[0058] S7: Encapsulation;

[0059] The result is an ultra-high-resolution QLED device with a pixel size of about 1um.

[0060] The preparation method provided in the present application prepares a hole injection layer 2, a hole transport layer 3, a quantum dot light-emitting layer 5, an electron transport layer 6 and a metal electrode 7 on an anode substrate 1, and uses an electrofluid printing device to criss-cross print the insulating layer material on any one of the substrate 1, the hole injection layer 2, the hole transport layer 3, the quantum dot light-emitting layer 5, and the electron transport layer 6 to obtain an insulating layer 4. Since the printed insulating layer material cannot transport charges, the QLED device forms a uniform array pattern, thereby simply and efficiently realizing the preparation of ultra-high resolution QLED devices.

[0061] It should be noted that the types of quantum dots in the functional layers, spin coating speed, solution concentration, solvent selection, annealing temperature and annealing time used in the manufacturing process of the quantum dot light-emitting device mentioned in this embodiment are not completely fixed and can be adjusted appropriately according to actual needs.

[0062] The above description is only a partial embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the above disclosed technical content to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing an ultra-high resolution QLED device, characterized in that: The following steps are involved: S1: The substrate is ultrasonically cleaned, then dried with nitrogen and UV treated; S2: preparing a hole injection layer, making a solution of hole injection layer material and spin coating it onto the substrate, and then annealing it in air; S3: preparing a hole transport layer, preparing a solution of hole transport layer material and spin coating the solution on the hole injection layer, and then annealing the solution in a nitrogen atmosphere; S4: preparing a quantum dot light-emitting layer, dissolving the quantum dot material in n-octane to obtain a prefabricated solution, then spin-coating the prefabricated solution on the hole transport layer, and then annealing in a nitrogen atmosphere; S5: preparing an electron transport layer, preparing a solution of the electron transport layer material, spin coating it on the quantum dot light-emitting layer, and vacuum drying it; S6: Preparation of metal electrodes; S7: Encapsulation; The steps also include A0, specifically: Prepare the insulating layer. On any one of the substrate, hole injection layer, hole transport layer, quantum dot light-emitting layer, and electron transport layer, print and solidify the solution containing the insulating layer material at equal intervals horizontally and vertically in turn to form a criss-cross insulating layer grid.

2. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The ultrasonic cleaning in step S1 is specifically as follows: Ultrasonic cleaning was performed with cleaning solution, ethanol, acetone, and deionized water in sequence; Preferably, the ultrasonic cleaning time is 20min to 50min; Preferably, the substrate is made of ITO glass.

3. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The time of the UV treatment in step S1 is 15 min to 40 min.

4. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The hole injection layer material is selected from one of polymer PEDOT:PSS, molybdenum oxide, nickel oxide, and cuprous thiocyanate; Preferably, the spin coating speed in step S2 is 3500 rpm to 4500 rpm, and the spin coating time is 25 s to 35 s; Preferably, the annealing treatment in step S2 is performed for 30 min to 40 min at a temperature of 150° C. to 200° C.

5. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The hole transport layer material is selected from one or a mixture of polymer TFB, cross-linked TFB, Poly:TPD, PVK; Preferably, the concentration of TFB solution is 8-10 mg / ml; Preferably, the annealing treatment time in step S3 is 30 min to 40 min, and the temperature is 150° C. to 200° C.

6. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The quantum dot material is selected from one of cadmium-based quantum dot materials, InP quantum dot materials, rare earth quantum dot materials, and halogen perovskite quantum dot materials; The concentration of the prefabricated solution is 10 to 30 mg / ml; Preferably, the spin coating speed in step S4 is 1500 rpm to 2500 rpm, and the spin coating time is 25 s to 35 s; Preferably, the annealing treatment in step S4 is performed for 5 min to 10 min at a temperature of 100° C. to 250° C.

7. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The electron transport layer material is selected from one of ZnO nanoparticles, ZnMgO nanoparticles, ZnO or ZnMgO nanoparticles doped with PVP or PVK polymers, ZnS nanoparticles, and ZnO nanoparticles with metal cations; Preferably, the spin coating speed in step S5 is 3500 rpm to 4500 rpm, and the spin coating time is 25 s to 35 s; Preferably, the vacuum drying treatment time in step S5 is 10 min to 20 min.

8. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: In step S6, the material of the metal electrode is selected from at least one of Au, Ag, and Al; The step of preparing the metal electrode includes evaporating the material of the metal electrode to form the metal electrode.

9. The method for preparing an ultra-high resolution QLED device according to claim 1, characterized in that: The insulating layer material is selected from one of Teflon, PMMA and PVDF; Preferably, in step A0, a baking treatment is selected for curing, and the baking treatment temperature is 80° C. to 100° C. and the time is 30 min to 40 min. Preferably, the printing method is selected from electrofluidic printing.

10. An ultra-high resolution QLED device, characterized in that: It comprises an insulating layer, which is located on any one of a substrate, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer and an electron transport layer.

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