Intrinsic flexible electric pumping perovskite micron-scale light-emitting diode and preparation method thereof

Abstract

The invention discloses an intrinsic flexible electric pumping perovskite micron-scale light-emitting diode and a preparation method thereof, and belongs to the field of information technology and novel display. The intrinsic flexible electric pumping Micro-LED is composed of a micron-sized patterned electrode array constructed by a flexible transparent conductive substrate, a hole transport layer, a caesium lead halide perovskite quantum dot light-emitting layer loaded with an elastic ligand, an electron transport layer and a metal electrode. The perovskite quantum dot with the elastic ligand loaded on the surface and the luminescent layer of the perovskite quantum dot are realized through synthesis, and the perovskite quantum dot has the characteristics of excellent intrinsic flexibility and accurate red, green and blue luminescence. And micron-scale electrode patterning is carried out to obtain high-pixel-density luminescence. According to the method, the Micro-LED is directly obtained through the processes of electrode photoetching, solution deposition, vacuum evaporation and the like, and the method has the advantage of being short in technological process. Therefore, the Micro-LED and the preparation technology thereof have the advantages of being high in intrinsic flexibility, color purity and pixel density, short in technological process and the like, and have huge application potential in the fields of wearable electronic display equipment, intelligent equipment, augmented reality, near-eye virtual display and the like.

Description

Technical Field

[0001] This invention belongs to the field of information technology and novel light-emitting displays, specifically relating to an intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode and its fabrication method. Background Technology

[0002] With consumers' growing demand for personalized, portable, and aesthetically pleasing electronic products, flexible display technology has become a research hotspot in the field of optoelectronics. Flexible display devices, such as foldable phones and flexible smartwatches, not only require display materials to have excellent flexibility, but also need to maintain display performance such as high brightness, high contrast, and low power consumption.

[0003] Micro-LEDs, which have emerged in recent years, are used in display technology to reduce pixel pitch from millimeters to micrometers. This enables next-generation ultra-high-definition displays with features such as high brightness, high contrast, fast response time, long lifespan, low power consumption, and high integration. They can also be integrated into flexible substrates to achieve diverse applications such as curved, foldable, and transparent displays. Despite these significant advantages, Micro-LEDs currently face challenges such as high costs and low yield rates in mass transfer technology, hindering their widespread adoption and industrialization.

[0004] Furthermore, the development of intrinsically flexible Micro-LEDs faces even more challenges. Intrinsic flexibility means that the device's internal structure and performance remain stable during bending, folding, and other deformations, without relying on external supports or additional structures. Currently, most flexible display technologies still struggle to meet this requirement, especially in achieving precise structural control and stable performance at the micrometer scale. In addition, the light-emitting mechanism is also a key factor restricting its development. Using conventional LEDs or organic LEDs to micro- or nano-pattern photoluminescent materials, i.e., exciting fluorescent materials with an external light source to achieve light emission, is not strictly speaking a Micro-LED and is unlikely to reach the level of Micro-LED display technology. Electrically pumped light emission technology achieves light emission by directly injecting charges, offering higher luminous efficiency and a wider color control range, and is the true Micro-LED technology.

[0005] However, achieving intrinsically flexible Micro-LED technology with electric pumped light emission faces dual challenges in material selection and fabrication processes. On the one hand, materials with elastic deformation capabilities and cross-scale modulus adaptability need to be developed to meet the high electrical and optical performance requirements of display devices while maintaining good flexibility. On the other hand, the persistently high fabrication process cost and low yield rate have become major obstacles to its development. Metal halide semiconductor materials, which have emerged in recent years, offer advantages such as precisely tunable luminescent bandgap, high luminous efficiency, high carrier mobility, and short and low-cost solution fabrication processes. However, achieving intrinsic flexibility and micron-scale patterning of perovskite thin films remains highly challenging. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides an intrinsically flexible electrically pumped perovskite Micro-LED and its fabrication method, which features a short process flow, high external quantum efficiency, intrinsic flexibility, high pixel density, and wide emission wavelength coverage, overcoming the problems of high cost, long process flow, and low yield of Micro-LED processes.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an intrinsically flexible electrically pumped perovskite Micro-LED, the device structure of which, from bottom to top, consists of: a flexible micron-sized patterned array of transparent electrodes, a hole transport layer, perovskite quantum dots loaded with elastic ligands, an electron transport layer, and a metal electrode;

[0008] Furthermore, the flexible micron-sized patterned array transparent electrode is a micron-sized patterned array formed by photolithography on a polymer substrate such as polyethylene naphthalate, polyethylene terephthalate, thermoplastic polyurethane elastomer, or polydimethylsiloxane, using one of the following conductive films: silver nanowires, copper nanowires, graphene, carbon nanotubes, poly(3,4-ethylenedioxythiophene / polystyrene sulfonate), zinc oxide, or tin-doped indium oxide.

[0009] Furthermore, the hole transport layer is poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate, NiO x One or more of the following: poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-ALT-(4,4'-(N-(4-n-butylphenyl)-diphenylamine)], poly[bis(4-phenyl)(4-butylphenyl)amine], poly[(9,9-dioctylfluorenyl-2,7-diyl)-ALT-(9-ethylhexyl-3,6-carbazole)], poly(N-vinylcarbazole), and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine];

[0010] Furthermore, the perovskite quantum dots loaded with the elastic ligand are CsPbX3, where X is one or more of the elements Cl, Br, and I.

[0011] Furthermore, the electron transport layer is one or more of 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene, 1,3,5-tris(3-pyridyl-3-phenyl)benzene, 2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine, 3',3''',3'''''-(1,3,5-triazine-2,4,6-triyl)tris(([1,1'-biphenyl]-3-carbamate)), 4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and zinc oxide.

[0012] Furthermore, the metal electrode is one of gold, silver, lithium fluoride / aluminum, or eutectic gallium indium alloy.

[0013] The specific fabrication steps of an intrinsically flexible electrically pumped quantum dot Micro-LED are as follows:

[0014] S1. The flexible substrate loaded with conductive film is cleaned by plasma, then a photoresist film is deposited, annealed to form a layer with a thickness of 100~500 nanometers, cooled and exposed to a mask at a wavelength of 350~450 nanometers, immersed in developer, removed and annealed to obtain a flexible transparent patterned electrode.

[0015] S2. Sequentially deposit hole transport layers on flexible transparent patterned electrodes and anneal at 100~135°C for 10~40 minutes to form a thin film with a thickness of 10~60 nanometers;

[0016] S3. Deposit perovskite quantum dots and anneal at 35~75 °C for 5~10 minutes to form a thin film with a thickness of 10~40 nanometers;

[0017] S4. Vacuum evaporate the electron transport layer and anneal it at 50~90 °C for 15~20 minutes to form a thin film with a thickness of 40~100 nanometers;

[0018] S5. Vacuum evaporation is used to prepare a metal thin film top electrode with a thickness of 100~500 nanometers.

[0019] Specifically:

[0020] S1. The flexible substrate with the conductive film loaded is plasma cleaned for 1-10 minutes, then a photoresist film is deposited, and annealed at 70-110 °C for 5-15 minutes to form a layer with a thickness of 100-500 nanometers. After cooling, the substrate is exposed to a mask at a wavelength of 350-450 nanometers for 1-8 seconds, immersed in the developer for 10-50 seconds, and then annealed at 150-200 °C for 10-20 minutes.

[0021] S2. Sequentially deposit hole transport layers on flexible transparent patterned electrodes and anneal at 100~135°C for 10~40 minutes to form a thin film with a thickness of 10~60 nanometers;

[0022] S3. Deposit perovskite quantum dots and anneal at 35~75 °C for 5~10 minutes to form a thin film with a thickness of 10~40 nanometers;

[0023] S4. Vacuum evaporate the electron transport layer and anneal it at 50~90 °C for 15~20 minutes to form a thin film with a thickness of 40~100 nanometers;

[0024] S5. Vacuum evaporation is used to prepare a metal thin film top electrode with a thickness of 100~500 nanometers.

[0025] The photoresist used in step S1 is one of SU-8, AZ1500, and EOC260; the deposition process is one of spin coating, printing, and printing; and the developer is one or more of propylene glycol methyl ether acetate, xylene, butyl acetate, and cyclohexanone.

[0026] The deposition process used in steps S2 and S3 is one of spin coating, printing, and printing.

[0027] In step S3, the perovskite quantum dots are obtained by surface-loaded elastic ligands through antisolvent ligand exchange, wherein the antisolvent is any one or more of methyl acetate, ethyl acetate, and tert-butanol; and the elastic ligand is one or more of conjugated linoleic acid, lipoic acid, and ethylene glycol dimethacrylate.

[0028] The beneficial effects of this invention are as follows:

[0029] (1) Patterned photoresist arrays can localize the charge transport path within the micrometer range, avoiding carrier crosstalk between adjacent pixels, thereby enabling high pixel density electroluminescent Micro-LEDs;

[0030] (2) Transparent conductive micron-sized patterned arrays can adapt well to the stress generated by the flexible substrate during bending, twisting and stretching, and obtain Micro-LEDs with intrinsic flexibility, which can be applied to a variety of application scenarios.

[0031] (3) Perovskite quantum dots loaded with elastic ligands can undergo chemical cross-linking reaction under annealing and external light irradiation, thereby improving the resistance of the light-emitting layer to stress, obtaining intrinsic flexibility, and adapting to the application environment of flexible Micro-LED.

[0032] (4) Perovskite quantum dots have higher color purity and easier-to-tunable emission wavelength, thus better meeting the needs of near-eye virtual, outdoor enhanced display and intelligent display. Attached Figure Description

[0033] The features and advantages of embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0034] Figure 1 Here is a schematic diagram of the structure of an intrinsic flexible Micro-LED: (1) is a flexible micron-sized patterned array of transparent electrodes, (2) is a hole transport layer, (3) is a perovskite quantum dot loaded with elastic ligands, (4) is an electron transport layer, and (5) is a metal electrode.

[0035] Figure 2 These are photos of a 20-micron patterned array Micro-LED in operation: the left image is taken under an optical microscope, and the right image is taken at a working voltage of 3.0V.

[0036] Figure 3 These are the current-voltage-brightness test curves from Examples 1-5.

[0037] Figure 4 These are the test curves of the current-external quantum efficiency for Examples 1-5. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0039] Conversely, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Furthermore, to provide a better understanding of the invention, certain specific details are described in detail below. However, those skilled in the art will fully understand the invention even without these detailed descriptions.

[0040] Except for the materials specifically stated otherwise, all other materials used in this application are commercially available. Examples include photoresist, developer, chlorobenzene, methyl acetate, 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene, n-hexane, and n-octane.

[0041] Example 1

[0042] A polyethylene terephthalate substrate loaded with silver nanowires was plasma-cleaned for 5 minutes, followed by deposition of a SU-8 photoresist film. The substrate was annealed at 100 °C for 10 minutes to form a 200 nm thick layer. After cooling, it was exposed to a 400 nm wavelength for 5 seconds, immersed in propylene glycol methyl ether acetate developer for 30 seconds, and then annealed at 180 °C for 15 minutes to obtain a 100 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 120 °C for 20 minutes to form a 30 nm thick film. Then, CsPbI3 perovskite quantum dots were spin-coated and annealed at 55 °C for 8 minutes to form a 30 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 70 °C for 17 minutes to form a 70 nm thick film. Finally, a 300 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The Micro-LED exhibited a maximum external quantum efficiency of 4.59% and a maximum luminance of 1697 cd·m². -2 (See attached) Figure 3 , 4 ).

[0043] Example 2

[0044] A polyethylene terephthalate substrate loaded with silver nanowires was plasma-cleaned for 1 minute, followed by deposition of an AZ1500 photoresist film. The film was annealed at 110 °C for 5 minutes to form a 100 nm thick layer. After cooling, it was exposed to a 450 nm wavelength for 1 second, immersed in xylene developer for 50 seconds, and then annealed at 200 °C for 10 minutes to obtain an 80 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 135 °C for 10 minutes to form a 10 nm thick film. Then, CsPbI3 perovskite quantum dots were spin-coated and annealed at 35 °C for 10 minutes to form a 40 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 50 °C for 20 min to form a 40 nm thick film. Finally, a 100 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by ligand exchange with ethyl acetate as an antisolvent to load lipoic acid onto the surface. The Micro-LED exhibited a maximum external quantum efficiency of 3.49% and a maximum luminance of 4914 cd·m². -2 (See attached) Figure 3 , 4 ).

[0045] Example 3

[0046] A polyethylene terephthalate substrate loaded with silver nanowires was plasma-cleaned for 10 minutes, followed by deposition of an EOC260 photoresist film. The film was annealed at 70°C for 15 minutes to form a 500 nm thick layer. After cooling, it was exposed to a 350 nm wavelength for 8 seconds, immersed in butyl acetate developer for 10 seconds, and then annealed at 150°C for 20 minutes to obtain a 50 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 100°C for 40 minutes to form a 60 nm thick film. Then, CsPbI3 perovskite quantum dots were spin-coated and annealed at 75°C for 5 minutes to form a 10 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 90 °C for 15 minutes to form a 100 nm thick film. Finally, a 500 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by tert-butanol antisolvent ligand exchange to obtain a surface-loaded ethylene glycol dimethacrylate. The Micro-LED exhibited a maximum external quantum efficiency of 3.01% and a maximum luminance of 2146 cd·m². -2 (See attached) Figure 3 , 4 ).

[0047] Example 4

[0048] A polyethylene terephthalate substrate loaded with silver nanowires was plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. The film was annealed at 80 °C for 9 minutes to form a 300 nm thick layer. After cooling, it was exposed to a 380 nm wavelength for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain a 20 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Then, CsPbI3 perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The Micro-LED exhibited a maximum external quantum efficiency of 4.42% and a maximum luminance of 2844 cd·m². -2 (See attached) Figure 3 , 4 ).

[0049] Example 5

[0050] A polyethylene terephthalate substrate loaded with silver nanowires was plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. The film was annealed at 80 °C for 9 minutes to form a 300 nm thick layer. After cooling, it was exposed to a mask at 380 nm wavelength for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain an 8 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Then, CsPbI3 perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The Micro-LED exhibited a maximum external quantum efficiency of 2.73% and a maximum luminance of 1058 cd·m². -2 (See attached) Figure 3 , 4).

[0051] Example 6

[0052] Polyethylene terephthalate substrates loaded with different conductive materials were plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. The film was then annealed at 80 °C for 9 minutes to form a 300 nm thick layer. After cooling, the layer was exposed at a mask wavelength of 380 nm for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain a 50 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Next, CsPbI3 perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The performance of the Micro-LED is shown in Table 1.

[0053] Table 1. Loading different conductive materials onto polyethylene terephthalate flexible substrates

[0054]

[0055] Example 7

[0056] Different flexible substrates loaded with indium tin oxide were plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. The film was then annealed at 80 °C for 9 minutes to form a 300 nm thick layer. After cooling, the substrates were exposed at a mask wavelength of 380 nm for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain a 50 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Next, CsPbI3 perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The performance of the Micro-LED is shown in Table 2.

[0057] Table 2. Tin-doped indium oxide electrodes supported on different flexible substrates

[0058]

[0059] Example 8

[0060] A polyethylene terephthalate substrate loaded with indium tin oxide (ITO) was plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. After annealing at 80 °C for 9 minutes, a 300 nm thick layer was formed. Following cooling, the layer was exposed to a 380 nm wavelength for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain a 50 μm array electrode. However, different hole transport layers were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Next, CsPbI3 perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. Then, a 1,3,5-tris(N-phenylbenzimidazol-2-yl)phenyl electron transport layer was vacuum-evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The performance of the Micro-LED is shown in Table 3.

[0061] Table 3 Different hole transport layers

[0062]

[0063] Example 9

[0064] A polyethylene terephthalate substrate loaded with indium tin oxide was plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. After annealing at 80 °C for 9 minutes, a 300 nm thick layer was formed. Following cooling, it was exposed to a 380 nm wavelength for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain a 50 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Next, CsPbI3 perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. Finally, different electron transport layers were vacuum evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The performance of the Micro-LED is shown in Table 4.

[0065] Table 4 Different electron transport layers

[0066]

[0067] Example 10

[0068] A polyethylene terephthalate substrate loaded with indium tin oxide (ITO) was plasma-cleaned for 6 minutes, followed by deposition of a SU-8 photoresist film. The substrate was annealed at 80 °C for 9 minutes to form a 300 nm thick layer. After cooling, it was exposed to a mask at 380 nm wavelength for 6 seconds, immersed in propylene glycol methyl ether acetate developer for 120 seconds, and then annealed at 160 °C for 13 minutes to obtain an 8 μm array electrode. Subsequently, a poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transport layer were spin-coated and annealed at 115 °C for 20 minutes to form a 30 nm thick film. Then, different perovskite quantum dots were spin-coated and annealed at 60 °C for 6 minutes to form a 30 nm thick film. The 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene electron transport layer was then vacuum evaporated and annealed at 70 °C for 18 minutes to form a 60 nm thick film. Finally, a 200 nm thick lithium fluoride / aluminum thin-film top electrode was prepared by vacuum evaporation. CsPbI3 quantum dots were obtained by surface-loaded conjugated linoleic acid ligands through methyl acetate antisolvent ligand exchange. The performance of the Micro-LED is shown in Table 5.

[0069] Table 5 Different quantum dot layers

[0070]

[0071] While several embodiments of the present invention have been provided herein, those skilled in the art should understand that modifications can be made to these embodiments without departing from the spirit of the invention. The above embodiments are merely exemplary and should not be construed as limiting the scope of the invention.

Claims

1. A method for fabricating intrinsically flexible electrically pumped perovskite micron-scale light-emitting diodes, characterized in that: The specific preparation steps are as follows: S1. The flexible substrate loaded with conductive film is cleaned by plasma, then a photoresist film is deposited, annealed to form a layer with a thickness of 100~500 nanometers, cooled and exposed to a mask at a wavelength of 350~450 nanometers, immersed in developer, removed and annealed to obtain a flexible transparent patterned electrode. S2. Sequentially deposit hole transport layers on flexible transparent patterned electrodes and anneal at 100~135°C for 10~40 minutes to form a thin film with a thickness of 10~60 nanometers; S3. Deposit perovskite quantum dots and anneal at 35~75 °C for 5~10 minutes to form a thin film with a thickness of 10~40 nanometers; S4. Vacuum evaporate the electron transport layer and anneal it at 50~90 °C for 15~20 minutes to form a thin film with a thickness of 40~100 nanometers; S5. Vacuum evaporation is used to prepare a metal thin film top electrode with a thickness of 100~500 nanometers.

2. The method for fabricating an intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 1, characterized in that: In step S1, the photoresist used is one of SU-8, AZ1500, and EOC260; the deposition process is one of spin coating, printing, and printing; and the developer is one or more of propylene glycol methyl ether acetate, xylene, butyl acetate, and cyclohexanone.

3. The method for fabricating an intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 1, characterized in that: The deposition process used in steps S2 and S3 is one of spin coating, printing, and printing. In step S3, the perovskite quantum dots are obtained by surface-loaded elastic ligands through antisolvent ligand exchange, wherein the antisolvent is any one or more of methyl acetate, ethyl acetate, and tert-butanol; and the elastic ligand is one or more of conjugated linoleic acid, lipoic acid, and ethylene glycol dimethacrylate.

4. An intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode, characterized in that, The light-emitting diode is fabricated using the preparation method described in any one of claims 1-3. The structure of the light-emitting diode, from bottom to top, consists of a flexible micron-sized patterned array of transparent electrodes, a hole transport layer, perovskite quantum dots loaded with elastic ligands, an electron transport layer, and a metal electrode.

5. The intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 4, characterized in that: The flexible substrate in the flexible micron-sized patterned array transparent electrode is polyethylene naphthalate, polyethylene terephthalate, thermoplastic polyurethane elastomer, or polydimethylsiloxane polymer. The conductive film is one or more of the following: silver nanowires, copper nanowires, graphene, carbon nanotubes, poly(3,4-ethylenedioxythiophene / polystyrene sulfonate), zinc oxide, or tin-doped indium oxide.

6. The intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 4, characterized in that: The hole transport layer is made of poly(3,4-ethylenedioxythiophene / polystyrene sulfonate), NiO x One or more of the following: poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-ALT-(4,4'-(N-(4-n-butylphenyl)-diphenylamine)], poly[bis(4-phenyl)(4-butylphenyl)amine], poly[(9,9-dioctylfluorenyl-2,7-diyl)-ALT-(9-ethylhexyl-3,6-carbazole)], poly(N-vinylcarbazole), and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine].

7. The intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 4, characterized in that: The perovskite quantum dots loaded with the elastic ligands are CsPbX3, where X is one or more of the elements Cl, Br, and I.

8. The intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 4, characterized in that: The electron transport layer is made of one or more of the following materials: 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene, 1,3,5-tris(3-pyridyl-3-phenyl)benzene, 2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine, 3',3''',3'''''-(1,3,5-triazine-2,4,6-triyl)tris(([1,1'-biphenyl]-3-carbamate)), 4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and zinc oxide.

9. The intrinsically flexible electrically pumped perovskite micron-scale light-emitting diode according to claim 4, characterized in that: The metal electrode is one of gold, silver, lithium fluoride / aluminum, or eutectic gallium indium alloy.

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