Perovskite light-emitting diode based on double-layer micro-nano grating structure and preparation method thereof

Abstract

The invention discloses a perovskite light-emitting diode based on a double-layer micro-nano grating structure and a preparation method of the perovskite light-emitting diode. The preparation method comprises the following steps: firstly, carrying out ultrasonic cleaning and drying on a substrate; then, annealing is performed after a hole transport layer is spin-coated on the substrate; spin-coating photoresist on the hole transport layer, annealing, and carrying out exposure, development, etching and photoresist removal treatment to obtain the hole transport layer with a micro-nano grating structure; then, annealing is carried out after a perovskite light active layer is spin-coated on the hole transport layer; then, the perovskite optical active layer is spin-coated with an electron transport layer and then annealed; spin-coating photoresist on the electron transport layer, annealing, and carrying out exposure, development, etching and photoresist removal treatment to obtain the electron transport layer with a micro-nano grating structure; secondly, thermally spraying silver nanowires on the electron transport layer to form a cathode; and finally, packaging the device. A double-layer micro-nano grating structure is introduced, and the size of the double-layer micro-nano grating structure is adjusted, so that the light transmission direction is changed, and the light emitting efficiency of the perovskite light emitting diode is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroluminescence, and in particular to a perovskite light-emitting diode based on a double-layer micro-nano grating structure and a preparation method thereof. Background Art

[0002] Perovskite materials are widely used in optoelectronic devices such as light-emitting diodes, solar cells, lasers, and detectors due to their excellent optoelectronic properties, such as high absorption coefficient, adjustable bandgap width, high electron mobility and hole mobility, low exciton binding energy, long carrier diffusion length, low material price, and compatibility with solution methods. Since 2014, Friend et al. first prepared perovskite light-emitting diodes by solution method at room temperature, achieving an internal quantum conversion efficiency of 3.4% and an external quantum conversion efficiency of 0.76%; since then, researchers have continuously improved efficiency through perovskite material engineering, device structure optimization, interface engineering, etc. The current maximum external quantum efficiency of perovskite diodes has exceeded 20%, but there is still a certain gap with the maximum theoretical value. Due to the refractive index mismatch between perovskite diode films, 70%-80% of the light generated by the active layer is confined between the transparent electrode and the organic carrier transport layer, reducing the light output efficiency of the light-emitting diode. Summary of the invention

[0003] The purpose of the present invention is to design a method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure in order to solve the above problems.

[0004] The present invention achieves the above-mentioned purpose through the following technical solutions: A method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure comprises the following steps: S1, ultrasonically cleaning the substrate and drying the cleaned substrate; S2, spin coating a hole transport layer on the dried substrate and then performing an annealing process; S3, after spin coating the photoresist on the hole transport layer, annealing is performed, and exposure, development, etching, and de-resist treatment are performed to obtain a hole transport layer with a micro-nano grating structure; S4, spin coating a perovskite photoactive layer on the hole transport layer of the micro-nano grating structure and then performing an annealing treatment; S5, after spin coating the electron transport layer on the perovskite photoactive layer, performing annealing treatment; S6, after spin coating the photoresist on the electron transport layer, performing annealing treatment, and performing exposure, development, etching, and desizing treatment to obtain an electron transport layer with a micro-nano grating structure; S7, thermally spraying silver nanowires on the electron transport layer of the micro-nano grating structure to form a cathode; S8, packaging devices; Wherein, the thickness of the hole transport layer is 40-80nm, the thickness of the perovskite photoactive layer is 200-500nm, the thickness of the electron transport layer is 40-80nm, and the thickness of the cathode is 50-100nm.

[0005] The present invention also proposes a perovskite light-emitting diode based on a double-layer micro-nano grating structure, wherein the perovskite light-emitting diode based on the double-layer micro-nano grating structure comprises a substrate, a hole transport layer, a perovskite photoactive layer, an electron transport layer and a cathode, and the perovskite light-emitting diode based on the double-layer micro-nano grating structure is obtained by the preparation method of the perovskite light-emitting diode based on the double-layer micro-nano grating structure as described above.

[0006] The beneficial effects of the present invention are: The preparation method of the perovskite light-emitting diode based on the double-layer micro-nano grating structure first ultrasonically cleans the substrate and dries the cleaned substrate; then, spin-coats a hole transport layer on the dried substrate and performs annealing; then, spin-coats a photoresist on the hole transport layer and performs annealing, and performs exposure, development, etching, and degumming to obtain a hole transport layer of the micro-nano grating structure; then, spin-coats a perovskite photoactive layer on the hole transport layer of the micro-nano grating structure and performs annealing; then, spin-coats an electron transport layer on the perovskite photoactive layer and performs annealing; then, spin-coats a photoresist on the electron transport layer and performs annealing, and performs exposure , developing, etching, and degumming to obtain an electron transport layer of a micro-nano grating structure; then, thermally spraying silver nanowires on the electron transport layer of the micro-nano grating structure to form a cathode; finally, encapsulating the device; wherein the hole transport layer has a thickness of 40-80nm, the perovskite photoactive layer has a thickness of 200-500nm, the electron transport layer has a thickness of 40-80nm, and the cathode has a thickness of 50-100nm; it introduces a double-layer micro-nano grating structure, and adjusts the size of the micro-nano grating structure according to the mismatch degree of the refractive index between the perovskite light-emitting layer and the substrate and the wavelength of the emitted light to change the light transmission direction, thereby improving the luminescence efficiency of the perovskite light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic flow chart of a method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to the present invention; Figure 2 It is a schematic structural diagram of a perovskite light-emitting diode based on a double-layer micro-nano grating structure of the present invention; Figure 3 This is a comparison chart of the luminous brightness of Comparative Example 1 and Example 2 of the method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure of the present invention; Figure 4This is a comparison chart of the luminous brightness of Comparative Example 3 and Example 4 of the method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure of the present invention; In the figure: 1-substrate, 2-anode, 3-hole transport layer, 4-perovskite photoactive layer, 5-electron transport layer, 6-cathode. DETAILED DESCRIPTION

[0008] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0009] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0010] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0011] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0012] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0013] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0014] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0015] like Figure 1-4 As shown, the preparation method of the perovskite light-emitting diode based on the double-layer micro-nano grating structure includes the following steps: S1, ultrasonically cleaning the substrate 1, and drying the cleaned substrate 1; S2, spin coating the hole transport layer 3 on the dried substrate 1 and then performing annealing; S3, after spin coating the photoresist on the hole transport layer 3, annealing treatment is performed, and exposure, development, etching, and de-resist treatment are performed to obtain a hole transport layer 3 with a micro-nano grating structure; S4, spin coating the perovskite photoactive layer 4 on the hole transport layer 3 of the micro-nano grating structure and then performing annealing treatment; S5, after spin coating the electron transport layer 5 on the perovskite photoactive layer 4, annealing is performed; S6, after spin coating the photoresist on the electron transport layer 5, annealing treatment is performed, and exposure, development, etching, and desizing treatment are performed to obtain the electron transport layer 5 with a micro-nano grating structure; S7, thermally spraying silver nanowires on the electron transport layer 5 of the micro-nano grating structure to form a cathode 6; S8, packaging devices; The hole transport layer 3 has a thickness of 40-80 nm, the perovskite photoactive layer 4 has a thickness of 200-500 nm, the electron transport layer 5 has a thickness of 40-80 nm, and the cathode 6 has a thickness of 50-100 nm.

[0016] In one embodiment, the etching method in step S3 is: Placing the hole transport layer 3 in a reactive ion etching device; Etching was performed with oxygen for 3 minutes to obtain a hole transport layer 3 of a micro-nano grating structure with a first preset size.

[0017] In one embodiment, the hole transport layer 3 is a PEDOT:PSS hole transport layer.

[0018] In one embodiment, the etching method in step S6 is: Placing the electron transport layer 5 in a reactive ion etching device; Etching is performed using a mixed gas of oxygen and carbon tetrafluoride for 5 minutes to obtain an electron transport layer 5 of a micro-nano grating structure of a second preset size.

[0019] In one embodiment, the electron transport layer 5 is a TPBi electron transport layer.

[0020] In one embodiment, the method of spin coating the perovskite photoactive layer 4 in step S4 is: Chlorobenzene antisolvent was drop-coated during the spin coating process to accelerate the perovskite crystallization.

[0021] In one embodiment, the substrate 1 is an ITO glass substrate.

[0022] In this embodiment, the anode 2 of the perovskite light-emitting diode based on the double-layer micro-nano grating structure is a metal or metal oxide film, and the metal oxide film can be an ITO film or a zinc oxide film or a tin oxide film, and the metal film can be a metal film such as gold, copper, and silver. The anode 2 in this embodiment is preferably an ITO film, which has strong conductivity, large work function, and good chemical stability, so as to inject holes into the electrode of the hole transport layer 3. The hole transport layer 3 can be made of an organic polymer material with good hole transport properties and good chemical stability, such as 4,4'-cyclohexylenebis[N,N-di(p-tolyl)aniline] (TAPC), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-n-butyl)phenyl)-diphenylamine)] (TFB), poly[bis(4-phenyl)(4-butylphenyl)amine] (poly-TPD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), polyethylene dioxythiophene-poly(styrene sulfonate) (PEDOT:PSS), etc. One or more combinations thereof; the hole transport material in this embodiment is preferably polyethylene dioxythiophene-poly(styrene sulfonate) (PEDOT:PSS). The perovskite photoactive layer 4 material is an organic / inorganic hybrid ABX3 type cubic crystal structure, A is an organic amine group, such as a mono- or poly-combination of CH3NH3+1(MA+1), CH(NH2)2+1, Cs+1, etc.; B is a fourth main group metal; X is a mono- or poly-halogen element. The electron transport layer 5 may use any one or a combination of multiple of 4,7-diphenyl-1,10-phenanthroline, 2-(4-diphenyl-5-4-tert-butylphenyl-1,3,4-oxadiazole, oxadiazole electron transport material 2-4-diphenyl-5-4-tert-butylphenyl-1,3,4-oxadiazole, and imidazole electron transport material 1,3,5-tri-N-phenyl-2-benzimidazole-2-benzene. The electron transport material in this embodiment is preferably 1,3,5-tri-N-phenyl-2-benzimidazole-2-benzene (TPBi). The cathode 6 may use silver nanowires as electrodes. The silver nanowires are prepared by spraying, and have a transmittance T of 85%-90% and a square resistance of about 40 ohm / sq. It has the advantages of high transmittance and high conductivity.

[0023] In this embodiment, the specific steps of the method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure are: S1: firstly use detergent, deionized water, acetone and isopropyl alcohol to ultrasonically clean the ITO glass substrate, and then dry it; S2: spin coating the hole transport layer 3PEDOT:PSS solution on the dried ITO glass substrate, and then annealing; S3: Spin-coat the photoresist AZ5214 on the cooled PEDOT:PSS substrate at a speed of 3000 rpm, and bake at 100 degrees Celsius for 10 minutes; after drying, expose it under a photolithography machine for 15 seconds; then put it into a diluted developer; put the dried sample into a reactive ion etching device, and etch it with oxygen for 3 minutes to obtain a hole transport layer 3 of a micro-nano grating structure of a first preset size; finally, expose and develop the sample again to remove the photoresist covering the surface, thereby exposing the etched PEDOT:PSS film; wherein the first preset size can be set according to the actual needs of the micro-nano grating structure of the hole transport layer 3; S4: Spin-coat the perovskite light-emitting layer on the PEDOT:PSS hole transport layer, drop-coat chlorobenzene antisolvent during the spin-coating process to accelerate the perovskite crystallization, and then anneal for 15 minutes; S5: spin coating TPBi as electron transport layer 5 on the perovskite light-emitting layer, and annealing to remove residual solvent; S6: Spin-coat the photoresist AZ5214 on the cooled TPBi substrate at a speed of 3000 rpm, and bake at 100 degrees Celsius for 10 minutes; after drying, expose it to a photolithography machine for 15 seconds, and then put it into a diluted developer; put the dried sample into a reactive ion etching device, and etch it with a mixed gas of oxygen and carbon tetrafluoride for 5 minutes to obtain an electron transport layer 5 of a micro-nano grating structure of a second preset size; finally, expose and develop the sample again to remove the photoresist covering the surface and expose the etched TPBi film; wherein the second preset size can be set according to the actual requirements of the micro-nano grating structure of the electron transport layer 5; S7: thermally spraying silver nanowires on the electron transport layer 5 as a top electrode, i.e., a cathode 6; wherein the temperature of the hot stage is set to 90 degrees Celsius; S8: Package the device.

[0024] The perovskite light-emitting diode is prepared by the above preparation method, which introduces a double-layer micro-nano grating structure in the conventional planar structure, namely, a hole transport layer 3 of the micro-nano grating structure and an electron transport layer 5 of the micro-nano grating structure, so as to change the light transmission direction, reduce the light capture probability, and reduce the light loss of the light emitted by the perovskite active layer during the transmission process, thereby improving the light output efficiency, and then achieving the high performance of the perovskite light-emitting diode; in addition, each film in the preparation process is prepared by a solution method, which can simplify the device preparation process, increase the device production scale, and reduce the device preparation cost. Among them, PEDOT:PSS is prepared from a mixture of four materials: 19ml Clevios PH 1000, 5 wt% ethylene glycol, 0.1 wt% 4-12 alkylbenzene sulfonic acid, and 1 wt% (3-glycidoxypropyl) trimethoxysilane.

[0025] The preparation method of the perovskite light-emitting diode based on the double-layer micro-nano grating structure of the present invention is to first ultrasonically clean the substrate 1, and dry the cleaned substrate 1; then, spin-coat the hole transport layer 3 on the dried substrate 1 and perform annealing; then, spin-coat the hole transport layer 3 with photoresist and perform annealing, and perform exposure, development, etching, and degumming to obtain the hole transport layer 3 with the micro-nano grating structure; then, spin-coat the perovskite photoactive layer 4 on the hole transport layer 3 with the micro-nano grating structure and perform annealing; then, spin-coat the electron transport layer 5 on the perovskite photoactive layer 4 and perform annealing; then, spin-coat the photoresist on the electron transport layer 5 and perform annealing, and Exposure, development, etching and degumming are performed to obtain an electron transport layer 5 of a micro-nano grating structure; then, silver nanowires are thermally sprayed on the electron transport layer 5 of the micro-nano grating structure to form a cathode 6; finally, the device is packaged; wherein the hole transport layer 3 has a thickness of 40-80nm, the perovskite photoactive layer 4 has a thickness of 200-500nm, the electron transport layer 5 has a thickness of 40-80nm, and the cathode 6 has a thickness of 50-100nm; a double-layer micro-nano grating structure is introduced, and the size of the micro-nano grating structure is adjusted according to the degree of mismatch of the refractive index between the perovskite light-emitting layer and the substrate 1 and the wavelength of the emitted light to change the light transmission direction, thereby improving the luminous efficiency of the perovskite light-emitting diode.

[0026] In order to verify that the perovskite light-emitting diode obtained by the preparation method of the perovskite light-emitting diode based on the double-layer micro-nano grating structure of the present invention has better performance, multiple embodiments and comparative examples are provided below to test the perovskite light-emitting diode based on the double-layer micro-nano grating structure obtained by the method.

[0027] Comparative Example 1 (as a control group of Example 2) The diode device structure from bottom to top is: ITO / PEDOT: PSS(40 nm) / CsPbBr3(300 nm) / TPBi(40 nm) / Ag nanowires(100 nm) The preparation steps are as follows: Step 1: ultrasonically clean the substrate using detergent, acetone, deionized water and isopropanol solution in sequence; Step 2: Spin-coat PEDOT:PSS (4000 rpm, 60 s) on the dried ITO glass substrate as a hole transport layer, and then anneal at 120 °C for 20 min; Step 3: Place the cooled substrate in a glove box and spin-coat the perovskite CsPbBr3 precursor at 3000 rpm for 40 seconds. During the spin-coating process, 200 μL of chlorobenzene is used as an anti-solvent to rinse the perovskite. Then, anneal the substrate at 120 degrees Celsius for 10 minutes. Step 4: Spin-coat the electron transport layer TPBi (dissolved in chlorobenzene at a concentration of 20 mg / mL) on the perovskite photoactive layer and then anneal at 120 degrees Celsius for 20 minutes; Step 5: On a hot plate at 90 degrees Celsius, spray silver nanowires with a thickness of about 100 nm; Step 6: Package the device.

[0028] The device 1 is prepared in the comparative example 1.

[0029] Example 2 The diode device structure from bottom to top is: ITO / PEDOT: PSS (micro-nano grating structure) / CsPbBr3 (300 nm) / TPBi (micro-nano grating structure) / Ag nanowire (100 nm) The preparation steps are as follows: Step 1: ultrasonically clean the substrate using detergent, acetone, deionized water and isopropanol solution in sequence; Step 2: Spin-coat PEDOT:PSS as a hole transport layer on the dried ITO glass substrate, and then anneal at 120 degrees Celsius for 20 minutes; Step 3: Spin-coat the photoresist AZ5214 on the cooled PEDOT:PSS substrate at a speed of 3000 rpm, and then bake at 100 degrees Celsius for 10 minutes; after drying, expose it to a photolithography machine for 15 seconds, and then put it into a diluted developer; then put the dried sample into a reactive ion etching device and etch it with oxygen for 3 minutes to obtain the size of the designed micro-nano grating; finally, the sample is exposed and developed again to remove the photoresist covering the surface and expose the etched PEDOT:PSS film; Step 4: Place the cooled substrate in a glove box and spin-coat the perovskite CsPbBr3 precursor at 3000 rpm for 40 seconds. During the spin-coating process, 200 μL of chlorobenzene is used as an anti-solvent to rinse the perovskite. Then, anneal the substrate at 120 degrees Celsius for 10 minutes. Step 5: Spin-coat the electron transport layer TPBi (dissolved in chlorobenzene at a concentration of 20 mg / mL) on the perovskite photoactive layer and then anneal at 120 degrees Celsius for 20 minutes; Step 6: Spin-coat the photoresist AZ5214 on the cooled TPBi substrate at a speed of 3000 rpm, and then bake at 100 degrees Celsius for 10 minutes; after drying, expose it under a photolithography machine for 15 seconds, and then put it into a diluted developer; then put the dried sample into a reactive ion etching device and etch it with a mixed gas of oxygen and carbon tetrafluoride for 5 minutes to obtain the size of the designed micro-nano grating; finally, the sample is exposed and developed again to remove the photoresist covering the surface and expose the etched TPBi film; Step 7: On a hot plate at 90 degrees Celsius, spray silver nanowires with a thickness of about 100 nm; Step 8: Package the device.

[0030] The device 2 is prepared in the above-mentioned embodiment 2.

[0031] Comparative Example 3 (as a control group of Example 4) The diode device structure from bottom to top is: ITO / PEDOT:PSS(40nm) / CsPbBr2I (300 nm) / TPBi(40 nm) / Ag nanowires(100 nm) The preparation method steps are as follows: Step 1: ultrasonically clean the substrate using detergent, acetone, deionized water and isopropanol solution in sequence; Step 2: Spin-coat PEDOT:PSS (4000 rpm, 60 s) on the dried ITO glass substrate as a hole transport layer, and then anneal at 120 °C for 20 min; Step 3: Place the cooled substrate in a glove box and spin-coat the perovskite CsPbBr2I precursor at 3000 rpm for 40 seconds. During the spin-coating process, 200 μL of chlorobenzene is used as an anti-solvent to rinse the perovskite. Then, anneal the substrate at 120 degrees Celsius for 10 minutes. Step 4: Spin-coat the electron transport layer TPBi (dissolved in chlorobenzene at a concentration of 20 mg / mL) on the perovskite photoactive layer and then anneal at 120 degrees Celsius for 20 minutes; Step 5: On a hot plate at 90 degrees Celsius, spray silver nanowires with a thickness of about 100 nm; Step 6: Package the device.

[0032] The device 3 is prepared in the above comparative example 3.

[0033] Example 4 The diode device structure from bottom to top is: ITO / PEDOT:PSS (micro-nano grating structure) / CsPbBr2I (300 nm) / TPBi (micro-nano grating structure) / Ag nanowire (100 nm) The preparation method steps are as follows: Step 1: ultrasonically clean the substrate using detergent, acetone, deionized water and isopropanol solution in sequence; Step 2: Spin-coat PEDOT:PSS as a hole transport layer on the dried ITO glass substrate, and then anneal at 120 degrees Celsius for 20 minutes; Step 3: Spin-coat the photoresist AZ5214 on the cooled PEDOT:PSS substrate at a speed of 3000 rpm, and then bake at 100 degrees Celsius for 10 minutes; after drying, expose it to a photolithography machine for 15 seconds, and then put it into a diluted developer; then put the dried sample into a reactive ion etching device and etch it with oxygen for 3 minutes to obtain the size of the designed micro-nano grating; finally, the sample is exposed and developed again to remove the photoresist covering the surface and expose the etched PEDOT:PSS film; Step 4: Place the cooled substrate in a glove box and spin-coat the perovskite CsPbBr2I precursor at 3000 rpm for 40 seconds. During the spin-coating process, rinse the perovskite with 200 μL of chlorobenzene as an anti-solvent. Then anneal at 120 degrees Celsius for 10 minutes. Step 5: Spin-coat the electron transport layer TPBi (dissolved in chlorobenzene at a concentration of 20 mg / mL) on the perovskite photoactive layer and then anneal at 120 degrees Celsius for 20 minutes; Step 6: Spin-coat the photoresist AZ5214 on the cooled TPBi substrate at a speed of 3000 rpm, and then bake at 100 degrees Celsius for 10 minutes; after drying, expose it under a photolithography machine for 15 seconds, and then put it into a diluted developer; then put the dried sample into a reactive ion etching device and etch it with a mixed gas of oxygen and carbon tetrafluoride for 5 minutes to obtain the size of the designed micro-nano grating; finally, the sample is exposed and developed again to remove the photoresist covering the surface and expose the etched TPBi film; Step 7: On a hot plate at 90 degrees Celsius, spray silver nanowires with a thickness of about 100 nm; Step 8: Package the device.

[0034] The device 4 is prepared in the above-mentioned embodiment 4.

[0035] like Figure 3 As shown, the LV (Luminance-Voltage) curves of Comparative Example 1 and Example 2 were measured. Figure 4 As shown, the LV curves of Comparative Example 3 and Example 4 were measured. It can be seen from the figure that the luminous efficiency of the perovskite light-emitting diodes prepared in Example 2 and Example 4 is significantly better than that of Comparative Example 1 and Comparative Example 3.

[0036] The present invention also proposes a perovskite light-emitting diode based on a double-layer micro-nano grating structure, wherein the perovskite light-emitting diode based on the double-layer micro-nano grating structure comprises a substrate 1, a hole transport layer 3, a perovskite photoactive layer 4, an electron transport layer 5 and a cathode 6. The perovskite light-emitting diode based on the double-layer micro-nano grating structure is obtained by the preparation method of the perovskite light-emitting diode based on the double-layer micro-nano grating structure as described above.

[0037] In summary, the present invention introduces a double-layer micro-nano grating structure to adjust the light propagation path, that is, on the basis of the existing organic transmission material, the size of the micro-nano grating structure is adjusted according to the degree of refractive index mismatch between it and the upper light-emitting layer and the lower substrate and the wavelength of the emitted light, and finally a high-efficiency light-emitting diode device is realized. The method of the invention is simple, has a wide range of applications, and can avoid complex chemical synthesis; the micro-nano grating structure located on one side of the transparent electrode is to effectively guide the light generated by the active layer to be transmitted along the vertical direction of the device, and the micro-nano grating structure located on one side of the opaque electrode is to reflect the light generated by the active layer to induce the light to be output from the transparent side to avoid the light being restricted to the opaque electrode side. Compared with the single-sided grating micro-nano structure, the double-layer grating micro-nano structure has a more significant effect and can significantly improve the luminous efficiency of the device; and all its thin films are prepared by solution method, which is conducive to the commercial preparation of large-area and large-scale devices to reduce production costs and improve yield rate.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure, characterized in that: The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure comprises the following steps: S1, ultrasonically cleaning the substrate and drying the cleaned substrate; S2, spin coating a hole transport layer on the dried substrate and then performing an annealing process; S3, after spin coating the photoresist on the hole transport layer, annealing is performed, and exposure, development, etching, and de-resist treatment are performed to obtain a hole transport layer with a micro-nano grating structure; S4, spin coating a perovskite photoactive layer on the hole transport layer of the micro-nano grating structure and then performing an annealing treatment; S5, after spin coating the electron transport layer on the perovskite photoactive layer, performing annealing treatment; S6, after spin coating the photoresist on the electron transport layer, performing annealing treatment, and performing exposure, development, etching, and desizing treatment to obtain an electron transport layer with a micro-nano grating structure; S7, thermally spraying silver nanowires on the electron transport layer of the micro-nano grating structure to form a cathode; S8, packaging devices; Wherein, the thickness of the hole transport layer is 40-80nm, the thickness of the perovskite photoactive layer is 200-500nm, the thickness of the electron transport layer is 40-80nm, and the thickness of the cathode is 50-100nm.

2. The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to claim 1, characterized in that: The etching method in step S3 is: placing the hole transport layer in a reactive ion etching apparatus; Etching was performed with oxygen for 3 minutes to obtain a hole transport layer of a micro-nano grating structure of a first preset size.

3. The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to claim 2, characterized in that: The hole transport layer is a PEDOT:PSS hole transport layer.

4. The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to claim 1, characterized in that: The etching method in step S6 is: placing the electron transport layer in a reactive ion etching apparatus; Etching was performed using a mixed gas of oxygen and carbon tetrafluoride for 5 minutes to obtain an electron transport layer of a micro-nano grating structure of a second preset size.

5. The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to claim 4, characterized in that: The electron transport layer is a TPBi electron transport layer.

6. The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to claim 1, characterized in that: The method of spin coating the perovskite photoactive layer in step S4 is: Chlorobenzene antisolvent was drop-coated during the spin coating process to accelerate the perovskite crystallization.

7. The method for preparing a perovskite light-emitting diode based on a double-layer micro-nano grating structure according to claim 1, characterized in that: The substrate is an ITO glass substrate.

8. A perovskite light-emitting diode based on a double-layer micro-nano grating structure, characterized in that: The perovskite light-emitting diode based on a double-layer micro-nano grating structure includes a substrate, a hole transport layer, a perovskite photoactive layer, an electron transport layer and a cathode. The perovskite light-emitting diode based on a double-layer micro-nano grating structure is obtained by the preparation method of the perovskite light-emitting diode based on a double-layer micro-nano grating structure as described in any one of claims 1 to 7.

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