Flexible perovskite thin film and preparation method thereof, and flexible perovskite photoelectric detector

Abstract

The invention relates to the technical field of flexible photoelectric detection, in particular to a flexible perovskite thin film, a preparation method and a flexible perovskite photoelectric detector. The preparation method of the flexible perovskite thin film comprises the following steps: mixing phenethyl ammonium iodide, methyl ammonium chloride, PbI2 and PbCl2 in a solvent system to obtain a perovskite precursor solution; carrying out spin coating on the perovskite precursor solution under the protection of nitrogen, and adding an anti-solvent in the spin coating process; and then carrying out annealing treatment to obtain a flexible perovskite thin film. The anti-solvent is an SEBS (styrene-ethylene-butylene-styrene)-toluene solution. The method not only can improve the mechanical stability and flexibility of the flexible perovskite film, but also can enhance the absorption of ultraviolet visible light by the flexible perovskite film, thereby effectively improving the performance of the flexible perovskite photoelectric detector.

Description

Technical Field

[0001] The present invention relates to the field of flexible photoelectric detection technology, and in particular to a flexible perovskite film and a preparation method thereof, and a flexible perovskite photoelectric detector. Background Art

[0002] Metal halide perovskite materials have attracted widespread attention in the field of optoelectronic devices in recent years due to their unique physical and chemical properties. Compared with traditional semiconductor materials, perovskite materials exhibit advantages such as high carrier mobility, long carrier diffusion length, and high light conversion efficiency. These properties make perovskite materials an ideal choice for optoelectronic devices such as photodetectors.

[0003] Among perovskite materials, organic-inorganic hybrid quasi-two-dimensional perovskites exhibit higher stability in humidity, heat, and light environments compared to three-dimensional perovskites due to the presence of their organic spacer layers. In addition, quasi-two-dimensional perovskites also have fewer lattice defects and higher external quantum efficiency, which make them a popular research subject in the field of photodetectors. However, perovskite materials are generally rigid, resulting in poor mechanical flexibility of photodetection devices. Therefore, this characteristic of perovskite materials limits their application in flexible electronic devices such as wearable devices and foldable displays. To overcome this challenge, researchers began to explore combining perovskite materials with flexible substrates and improving the stability of perovskite photodetectors by optimizing the material composition.

[0004] During the preparation of perovskite films, adding passivators or crosslinkers is an effective method to improve film performance. However, perovskite films prepared using traditional methods often tend to increase the density of defect states, accelerating the non-radiative process of free carriers. Defects at the interface also accelerate the rate of water and oxygen intrusion into the perovskite. These problems seriously affect the performance and stability of devices based on perovskite films. Summary of the Invention

[0005] In order to solve the problem that the brittleness of perovskite prepared in the prior art leads to poor mechanical flexibility of photoelectric detection devices, the purpose of the present invention is to provide a flexible perovskite film and a preparation method and a flexible perovskite photodetector.

[0006] To achieve the above objectives, the technical solutions of the present invention are as follows.

[0007] A first aspect of the present invention provides a method for preparing a flexible perovskite film, comprising the following steps:

[0008] Phenethylammonium iodide, methylammonium chloride, PbI2 and PbCl2 are mixed in a solvent system to obtain a perovskite precursor solution; under nitrogen protection, the perovskite precursor solution is spin-coated, and an anti-solvent is added during the spin-coating process; then, the film is annealed to obtain a flexible perovskite film; the anti-solvent is a SEBS-toluene solution.

[0009] PEA is a phenylethylamine cation with the chemical formula C6H5CH2CH2NH3 + It has a benzene ring and an ethylamine group. MA is a methylamine cation, which consists of a methyl group and an amino group.

[0010] This invention primarily uses SEBS as an additive to improve the performance of perovskite photodetectors. Specifically, SEBS is dissolved in toluene and added dropwise as an antisolvent before perovskite crystallization. This additive participates in perovskite crystallization while introducing a corrugated structure onto the perovskite surface. This method not only improves the mechanical stability and flexibility of flexible perovskite films, but also enhances their absorption of ultraviolet and visible light, effectively improving the performance of flexible perovskite photodetectors.

[0011] Preferably, the concentration of SEBS in the anti-solvent is 5 mg / mL to 15 mg / mL.

[0012] Preferably, the concentration of SEBS in the anti-solvent is 10 mg / mL.

[0013] The SEBS used in this invention is a styrene-ethylene-butylene-styrene terpolymer, a thermoplastic elastomer. Its molecular structure comprises a glass-like rigidity of styrene and a rubber-like flexibility of ethylene-vinyl acetate copolymer. This structure gives SEBS excellent mechanical stability and compatibility adjustment capabilities. Furthermore, SEBS's hydrophobic properties effectively reduce the diffusion of water and oxygen molecules, providing excellent protection for perovskite materials.

[0014] Preferably, the volume ratio of the perovskite precursor solution to the antisolvent is 1:1.2.

[0015] Preferably, the annealing temperature is 100°C±1°C.

[0016] Preferably, the molar ratio of phenethylammonium iodide, methylammonium chloride, PbI2, and PbCl2 is 0.4:0.9:0.95:0.05.

[0017] Preferably, the concentration of the mixture of phenethylammonium iodide, methylammonium chloride, PbI2 and PbCl2 in the perovskite precursor solution is 1 mol / L.

[0018] Preferably, the solvent is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 9:1.

[0019] A second aspect of the present invention provides a flexible perovskite film, which is prepared using the method described in the first aspect.

[0020] The third aspect of the present invention provides a flexible perovskite photodetector, comprising a substrate and a hole transport layer, a flexible perovskite film, an electron transport layer and a buffer layer which are spin-coated sequentially on the substrate, wherein a metal electrode is evaporated on the buffer layer, and the flexible perovskite film is the flexible perovskite film according to claim 8.

[0021] Preferably, the substrate is PEN etched with indium tin oxide; the hole transport layer is a PEDOT:PSS hole transport layer; the electron transport layer is PC 61 BM electron transport layer; the buffer layer is a BCP buffer layer; and the metal electrode is a silver electrode.

[0022] Beneficial effects of the present invention:

[0023] 1. The present invention primarily uses SEBS as an additive to improve the performance of perovskite photodetectors. Specifically, SEBS is dissolved in toluene and added dropwise as an antisolvent before the perovskite begins to crystallize. This allows SEBS to participate in perovskite crystallization while introducing a wrinkled structure on the perovskite surface. This method not only improves the mechanical stability and flexibility of flexible perovskite films, but also enhances their absorption of ultraviolet and visible light, thereby effectively improving the performance of flexible perovskite photodetectors.

[0024] 2. In the case of a device with a classic vertical structure, the present invention improves the performance of the flexible perovskite photodetector by adjusting the concentration of SEBS in the antisolvent. The test results show that the maximum specific detectivity of the flexible perovskite photodetector prepared by the present invention is 1.23×10 11 Jones, which is 1.68 times higher than before optimization. At the same time, the dark current is greatly reduced, and the mechanical stability of the flexible perovskite photodetector is also enhanced. This research result provides a certain reference value for future research on lightweight, cost-effective, and flexible perovskite photodetectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the flexible perovskite photodetector prepared in Example 1.

[0026] Figure 2Figure 1 shows the IPCE variation with wavelength for photodetectors based on perovskite films with different SEBS concentrations under the same test conditions, as well as the responsivity, specific detectivity, and on / off ratio of the detectors. Figure a shows the IPCE variation with wavelength for photodetectors based on perovskite films with different SEBS concentrations under the same test conditions; b shows the responsivity variation with wavelength for photodetectors based on perovskite films with different SEBS concentrations under the same test conditions; c shows the specific detectivity variation with wavelength for photodetectors based on perovskite films with different SEBS concentrations under the same test conditions; and d shows the on / off ratio variation with light intensity for photodetectors with and without 10 mg / mL of SEBS added.

[0027] Figure 3 The linear dynamic range, response time, change in normalized photocurrent with the number of bending cycles, and change in normalized photocurrent with bending radius of the photodetectors in Example 2 and Comparative Example 1 are shown. Wherein, a is the linear dynamic range of the photodetectors in Example 2 and Comparative Example 1; b is the response time of the photodetectors in Example 2 and Comparative Example 1; c is the change in normalized photocurrent with the number of bending cycles of the photodetectors in Example 2 and Comparative Example 1; and d is the change in normalized photocurrent with bending radius of the photodetectors in Example 2 and Comparative Example 1.

[0028] Figure 4 The SEM images and EDS energy spectra of the flexible perovskite films of Comparative Example 1 and Example 2 are shown.

[0029] Among them, a is the SEM image of the flexible perovskite film of comparative example 1; b is the SEM image of the flexible perovskite film of embodiment 2; c is the EDS energy spectrum of the flexible perovskite film of comparative example 1; d is the EDS energy spectrum of the flexible perovskite film of embodiment 2.

[0030] Figure 5 This is the SEM image of the flexible perovskite film prepared in Comparative Example 2.

[0031] Figure 6 2 are XRD patterns of the flexible perovskite films of Comparative Example 1 and Example 2.

[0032] Figure 7Surface AFM images, roughness images, and Young's modulus of the flexible perovskite films of Comparative Example 1 and Example 2. a is a surface AFM image of the flexible perovskite film of Comparative Example 1; b is a roughness image of the flexible perovskite film of Comparative Example 1; c is the Young's modulus of the flexible perovskite film of Comparative Example 1; d is a surface AFM image of the flexible perovskite film of Example 2; e is a roughness image of the flexible perovskite film of Example 2; and f is the Young's modulus of the flexible perovskite film of Example 2.

[0033] Figure 8 The UV-visible absorption spectra, lifetime decay diagrams, and steady-state PL spectra of the flexible perovskite films of Comparative Example 1 and Example 2 are shown. (a) The UV-visible absorption spectra of the flexible perovskite films of Comparative Example 1 and Example 2; (b) The lifetime decay diagram of the flexible perovskite films of Comparative Example 1 and Example 2; (c) The glass-side steady-state PL spectra of the flexible perovskite films of Comparative Example 1 and Example 2; and (d) The perovskite-side steady-state PL spectra of the flexible perovskite films of Comparative Example 1 and Example 2.

[0034] Figure 9 Specular reflection spectra of the flexible perovskite films of Comparative Example 1 and Example 2.

[0035] Figure 10 is the absorption edge optical band gap of the flexible perovskite film of Comparative Example 1 and Example 2.

[0036] Figure 11 FTIR spectra of the flexible perovskite films of Comparative Example 1 and Examples 1 to 3.

[0037] Description of the accompanying drawings:

[0038] 1. Substrate; 2. Hole transport layer; 3. Flexible perovskite film; 4. Electron transport layer; 5. Buffer layer; 6. Metal electrode. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0041] SEBS is a thermoplastic elastomer, a linear triblock copolymer with polystyrene as the terminal segment and ethylene-butylene copolymer obtained by hydrogenating polybutadiene as the middle elastic block. Its Chinese name is styrene-ethylene-butylene-styrene terpolymer.

[0042] The molecular structure of SEBS typically consists of two components: a rigid styrene block and an elastic ethylene-butylene copolymer block. The styrene block, designated S, exhibits glassy rigidity, while the ethylene-butylene copolymer block, designated EB, exhibits rubbery flexibility. Physical crosslinking between the S end blocks allows SEBS to exhibit a three-dimensional network structure on a macroscopic scale. This unique structure contributes to SEBS's excellent mechanical stability and elasticity. SEBS's unique structure can also be used to encapsulate perovskite nanocrystals, where its hydrophobic properties effectively reduce the diffusion of water and oxygen molecules, thereby protecting the perovskite nanocrystals. Furthermore, SEBS is chemically inert, offering not only high chemical stability to the external environment but also physical crosslinking with the perovskite material, making it highly tolerant of perovskite components. In SEBS, the styrene block exhibits a strong lipophilicity, while the ethylene-butylene copolymer block exhibits a strong hydrophilicity. This gives SEBS a unique ability to regulate compatibility, enabling its use as a compatibilizer in multiphase systems, promoting microphase separation of raw materials and enhancing the dispersion of these small phases.

[0043] The present invention dissolves SEBS in toluene and adds it dropwise as an antisolvent before the perovskite begins to crystallize. This allows SEBS to participate in the crystallization process while introducing a wrinkled structure onto the perovskite surface. Because SEBS exhibits a three-dimensional network structure and possesses strong chemical inertness, it can physically crosslink with the quasi-two-dimensional perovskite, increasing the mechanical stability and flexibility of the perovskite layer and enhancing the perovskite film's absorption of ultraviolet and visible light, effectively improving the performance of the perovskite photodetector.

[0044] The present invention adjusts the concentration of the anti-solvent to add different amounts of SEBS, which are 5 mg / mL, 10 mg / mL, and 15 mg / mL, respectively, and are symbolized by w / SEBS5, w / SEBS 10 、w / SEBS 15 In addition, the original material was used for comparison, and the device and film characterization were used to explore the effect of SEBS on the performance of the photodetector. n-1 Pb n I 3n+1 The device, constructed using the classic vertical structure of 100 nm / 100nm / PC61BM / BCP / Ag, significantly reduces dark current while maintaining photocurrent, while also enhancing the device's mechanical stability. The optimized device achieved a specific detectivity 1.68 times greater than the original device. This study proposes a method for improving perovskite photodetectors using an inorganic elastomer as an additive, which could be a valuable reference for future research into lightweight, cost-effective, and flexible perovskite photodetectors.

[0045] The technical solution of the present invention is further described below through specific embodiments.

[0046] In the following examples, the methods described are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0047] In the following examples, DMF is N,N-dimethylformamide; DMSO is dimethyl sulfoxide; PEAI is phenylethylammonium iodide; PbI2 is lead iodide; PbCl2 is lead chloride; MAI is methylammonium chloride. ITO is indium tin oxide; PEN is polyethylene 2,6-naphthyleneacetate. PEDOT:PSS is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), which is mainly used for the hole transport layer. PSS-Na is polystyrenesulfonic acid sodium salt. PC 61 BM is a fullerene derivative [6,6]-phenyl-C 61 -Methyl butyrate.

[0048] BCP, known in Chinese as bathocuproine and chemically as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, is a small organic molecule widely used in the perovskite field and is often used as a hole-blocking layer material.

[0049] Example 1

[0050] A method for preparing a flexible perovskite film comprises the following steps:

[0051] Step 1, preparation of two-dimensional perovskite precursor solution:

[0052] DMF and DMSO were mixed in a 9:1 volume ratio to create a DMF / DMSO mixed solvent. PEAI, MAI, PbI2, and PbCl2 were added to 1 mL of the DMF / DMSO mixed solvent, adjusting the molar ratio of PEAI, MAI, PbI2, and PbCl2 to 0.4:0.9:0.95:0.05, resulting in a 1.0 M two-dimensional perovskite precursor solution. A small amount of lead chloride and some methylammonium chloride were used to introduce an in-situ MACl additive via the reaction of 0.05PbCl2 + 0.1MAI = 0.05PbI2 + 0.1MACl, which improved film quality and crystallization.

[0053] Step 2, (PEA)2MA3Pb4I 13 Preparation of perovskite thin films:

[0054] The PEN / ITO substrate coated with the PEDOT:PSS hole transport layer was moved to a nitrogen glove box filled with nitrogen and placed on a heating table and heated at 100°C for 10 minutes. During the heating period, the two-dimensional perovskite precursor solution was filtered. 100 μL of the two-dimensional perovskite precursor solution was dropwise added to the fully heated PEDOT:PSS hole transport layer and spin-coated at 4000 rpm for 30 seconds. At the 6th second of spin coating, 120 μL of antisolvent was added; the antisolvent was a SEBS-toluene solution, which was used to squeeze out DMSO and accelerate the crystallization of the perovskite; the concentration of SEBS in the antisolvent was 5 mg / mL. It was then annealed at 100°C for 10 minutes to obtain (PEA)2MA3Pb4I 13 Perovskite thin films.

[0055] Example 2

[0056] A method for preparing a flexible perovskite film is carried out according to the method of Example 1, except that the concentration of the antisolvent is different. The antisolvent is a SEBS-toluene solution, which is used to squeeze out DMSO and accelerate the crystallization of the perovskite; the concentration of SEBS in the antisolvent is 10 mg / mL.

[0057] Example 3

[0058] A method for preparing a flexible perovskite film is carried out according to the method of Example 1, except that the concentration of the antisolvent is different. The antisolvent is a SEBS-toluene solution, which is used to squeeze out DMSO and accelerate the crystallization of the perovskite; the concentration of SEBS in the antisolvent is 15 mg / mL.

[0059] Comparative Example 1

[0060] A method for preparing a flexible perovskite film is carried out according to the method of Example 1, except that no anti-solvent is added. The specific method is as follows:

[0061] Step 1, preparation of two-dimensional perovskite precursor solution:

[0062] DMF and DMSO were mixed in a 9:1 volume ratio to create a DMF / DMSO mixed solvent. PEAI, MAI, PbI2, and PbCl2 were added to 1 mL of the DMF / DMSO mixed solvent, adjusting the molar ratio of PEAI, MAI, PbI2, and PbCl2 to 0.4:0.9:0.95:0.05, resulting in a 1.0 M two-dimensional perovskite precursor solution. A small amount of lead chloride and some methylammonium chloride were used to introduce an in-situ MACl additive via the reaction of 0.05PbCl2 + 0.1MAI = 0.05PbI2 + 0.1MACl, which improved film quality and crystallization.

[0063] Step 2, (PEA)2MA3Pb4I 13 Preparation of perovskite thin films:

[0064] The PEN / ITO substrate coated with the PEDOT:PSS hole transport layer was moved to a nitrogen glove box filled with nitrogen and placed on a heating table and heated at 100°C for 10 minutes. During the heating period, the two-dimensional perovskite precursor solution was filtered. 100 μL of the two-dimensional perovskite precursor solution was dropwise added to the fully heated PEDOT:PSS hole transport layer and spin-coated at 4000 rpm for 30 seconds. It was then annealed at 100°C for 10 minutes to obtain (PEA)2MA3Pb4I 13 Perovskite thin films.

[0065] Table 1 Comparison of preparation conditions for different SEBS concentrations

[0066] Example SEBS concentration <![CDATA[(PEA)2MA3Pb4I 13 Perovskite film number]]> Example 1 5mg / mL <![CDATA[w / SEBS5]]> Example 2 10 mg / mL <![CDATA[w / SEBS 10 ]]> Example 3 15 mg / mL <![CDATA[w / SEBS 15 ]]> Comparative Example 1 - Control

[0067] Note: “-” means no SEBS was added; Control means comparison.

[0068] Comparative Example 2

[0069] A method for preparing a flexible perovskite film is carried out according to the method of Example 1, except that 120 μL of anti-solvent is replaced by 120 μL of toluene as the anti-solvent.

[0070] The following examples and comparative examples are used to prepare (PEA)2MA3Pb4I 13 Perovskite thin film method for preparing flexible perovskite photodetectors.

[0071] Application Example 1

[0072] like Figure 1 A flexible perovskite photodetector includes a substrate 1 and a hole transport layer 2, a flexible perovskite film 3, an electron transport layer 4 and a buffer layer 5 which are spin-coated on the substrate 1 in sequence, a metal electrode 6 is evaporated on the buffer layer 5, and the flexible perovskite film 3 is the flexible perovskite film described in Example 1.

[0073] The substrate 1 is PEN / ITO with a thickness of 120 μm. The hole transport layer 2 is PEDOT:PSS with a thickness of 120 nm. The flexible perovskite film 3 is (PEA)2MA3Pb4I 13 Perovskite film, thickness is 500nm. Electron transport layer 4 is PC 61The BM layer has a thickness of 50 nm. The buffer layer 5 is made of BCP and has a thickness of several nanometers, which cannot be accurately measured. The metal electrode 6 is made of Ag and has a thickness of 80 nm.

[0074] A method for preparing a flexible perovskite photodetector comprises the following steps:

[0075] Step 1, preparation of two-dimensional perovskite precursor solution:

[0076] DMF and DMSO were mixed in a 9:1 volume ratio to create a DMF / DMSO mixed solvent. PEAI, MAI, PbI2, and PbCl2 were added to 1 mL of the DMF / DMSO mixed solvent, adjusting the molar ratio of PEAI, MAI, PbI2, and PbCl2 to 0.4:0.9:0.95:0.05, resulting in a 1.0 M two-dimensional perovskite precursor solution. A small amount of lead chloride and some methylammonium chloride were used to introduce an in-situ MACl additive via the reaction of 0.05PbCl2 + 0.1MAI = 0.05PbI2 + 0.1MACl, which improved film quality and crystallization.

[0077] Step 2, preparation of perovskite photodetector:

[0078] The substrate is polyethylene 2,6-naphthyleneacetic acid (PEA) etched with indium tin oxide (ITO), which is referred to as PEN / ITO substrate. After removing a layer of transparent plastic film from the surface, the substrate is wiped clean with a cotton swab or dust-free paper, and then plasma cleaning is performed for 180 seconds.

[0079] First, PEDOT:PSS and a 100 mg / mL aqueous PSS-Na solution were mixed in a mass ratio of 3:1 to create a PEDOT:PSS / PSS-Na mixed solution. This mixed solution was spin-coated onto a PEN / ITO substrate at a speed of 4000 rpm for 50 seconds. After spin coating, the substrate was annealed on a hot plate at 120°C for 30 minutes to form a PEDOT:PSS hole transport layer.

[0080] The PEN / ITO substrate coated with the PEDOT:PSS hole transport layer was moved to a nitrogen glove box filled with nitrogen and placed on a heating table and heated at 100°C for 10 minutes. During the heating period, the two-dimensional perovskite precursor solution was filtered. 100 μL of the two-dimensional perovskite precursor solution was dropwise added to the fully heated PEDOT:PSS hole transport layer and spin-coated at 4000 rpm for 30 seconds. At the 6th second of spin coating, 120 μL of antisolvent was added; the antisolvent was a SEBS-toluene solution, which was used to squeeze out DMSO and accelerate the crystallization of the perovskite; the concentration of SEBS in the antisolvent was 5 mg / mL. It was then annealed at 100°C for 10 minutes to obtain (PEA)2MA3Pb4I 13 Perovskite thin films.

[0081] PC 61 BM was dissolved in chlorobenzene to prepare PC at a concentration of 25 mg / mL. 61 BM chlorobenzene solution. 61 BM chlorobenzene solution was coated on (PEA)2MA3Pb4I at a rotation speed of 3000 rpm and a rotation time of 40 s. 13 On the perovskite film, annealing at room temperature for 30min to 40min, PC 61 BM electron transport layer.

[0082] Dissolve BCP in isopropanol to prepare a 0.5 mg / mL BCP isopropanol solution. Apply the BCP isopropanol solution to the PC substrate at a rotation speed of 5000 rpm for 30 seconds. 61 A BCP buffer layer is obtained on the BM electron transport layer.

[0083] The device coated with the BCP buffer layer was placed in an evaporation chamber, and an 80nm silver electrode was prepared by thermal evaporation to obtain a self-powered flexible quasi-two-dimensional perovskite photodetector, which was denoted as PEN / ITO / PEDOT:PSS / (PEA)2MA3Pb4I 13 / PC 61 BM / BCP / Ag, the specific structure is as follows Figure 1 .

[0084] Application Example 2

[0085] A flexible perovskite photodetector comprises a substrate 1 and a hole transport layer 2, a flexible perovskite film 3, an electron transport layer 4 and a buffer layer 5 which are sequentially spin-coated on the substrate 1, wherein a metal electrode 6 is evaporated on the buffer layer 5, and the flexible perovskite film 3 is the flexible perovskite film described in Example 2.

[0086] The substrate 1 is PEN / ITO with a thickness of 120 μm. The hole transport layer 2 is PEDOT:PSS with a thickness of 120 nm. The flexible perovskite film 3 is (PEA)2MA3Pb4I 13 Perovskite film, thickness is 500nm. Electron transport layer 4 is PC 61 The BM layer has a thickness of 50 nm. The buffer layer 5 is made of BCP and has a thickness of several nanometers, which cannot be accurately measured. The metal electrode 6 is made of Ag and has a thickness of 80 nm.

[0087] The flexible perovskite photodetector was prepared according to the method of Application Example 1, except that the flexible perovskite film 3 was the flexible perovskite film described in Example 2. The antisolvent was a SEBS-toluene solution, which was used to squeeze out the DMSO and accelerate the crystallization of the perovskite; the concentration of SEBS in the antisolvent was 10 mg / mL.

[0088] Application Example 3

[0089] A flexible perovskite photodetector comprises a substrate 1 and a hole transport layer 2, a flexible perovskite film 3, an electron transport layer 4 and a buffer layer 5 which are sequentially spin-coated on the substrate 1, wherein a metal electrode 6 is evaporated on the buffer layer 5, and the flexible perovskite film 3 is the flexible perovskite film described in Example 3.

[0090] The substrate 1 is PEN / ITO with a thickness of 120 μm. The hole transport layer 2 is PEDOT:PSS with a thickness of 120 nm. The flexible perovskite film 3 is (PEA)2MA3Pb4I 13 Perovskite film, thickness is 500nm. Electron transport layer 4 is PC 61 The BM layer has a thickness of 50 nm. The buffer layer 5 is made of BCP and has a thickness of several nanometers, which cannot be accurately measured. The metal electrode 6 is made of Ag and has a thickness of 80 nm.

[0091] The flexible perovskite photodetector was prepared according to the method of Application Example 1, except that the flexible perovskite film 3 was the flexible perovskite film described in Example 3. The antisolvent was a SEBS-toluene solution, which was used to squeeze out the DMSO and accelerate the crystallization of the perovskite; the concentration of SEBS in the antisolvent was 15 mg / mL.

[0092] Comparative Application Example 1

[0093] A flexible perovskite photodetector comprises a substrate 1 and a hole transport layer 2, a flexible perovskite film 3, an electron transport layer 4 and a buffer layer 5 which are sequentially spin-coated on the substrate 1, a metal electrode 6 being evaporated on the buffer layer 5, and the flexible perovskite film 3 is the flexible perovskite film described in comparative example 1.

[0094] The substrate 1 is PEN / ITO with a thickness of 120 μm. The hole transport layer 2 is PEDOT:PSS with a thickness of 120 nm. The flexible perovskite film 3 is (PEA)2MA3Pb4I 13 Perovskite film, thickness is 500nm. Electron transport layer 4 is PC 61 The BM layer has a thickness of 50 nm. The buffer layer 5 is made of BCP and has a thickness of several nanometers, which cannot be accurately measured. The metal electrode 6 is made of Ag and has a thickness of 80 nm.

[0095] The preparation method of the flexible perovskite photodetector is carried out according to the method of Application Example 1, except that the flexible perovskite film 3 is the flexible perovskite film described in Comparative Example 1, wherein no anti-solvent is added.

[0096] The performance of the flexible perovskite photodetectors prepared in the above application examples and comparative examples is verified below.

[0097] In Examples 1 to 3, SEBS was dissolved in toluene to obtain a SEBS-toluene solution as an anti-solvent. SEBS was added in the form of an anti-solvent to enable SEBS to participate in the quasi-two-dimensional perovskite (PEA)2(MA) n-1 Pb n I 3n+1 The crystallization process of the self-powered flexible perovskite photodetector was studied and prepared based on this. For the convenience of description, it is referred to as a photodetector. The device structure of the photodetector is: PEN / ITO / PEDOT:PSS / (PEA)2MA3Pb4I 13 / PC 61 BM / BCP / Ag.

[0098] The above embodiment of the present invention adds SEBS in the form of anti-solvent to make SEBS participate in the quasi-two-dimensional perovskite (PEA)2(MA) n-1 Pb n I 3n+1 The crystallization process of the prepared photodetector can reduce the dark current and improve the specific detection rate of the photodetector; at the same time, it can also improve the mechanical stability of the photodetector; in addition, the SEBS on the surface of the perovskite can reduce the dark current, and the SEBS at the grain boundary can act as a buffer to increase the mechanical tolerance of the photodetector; it not only achieves a uniform phase distribution of the quasi-two-dimensional perovskite, but also improves the transport of carriers.

[0099] Test 1: Investigate the effect of SEBS concentration on the photoelectric conversion efficiency of the photodetector.

[0100] The concentrations of SEBS in the antisolvent were 5 mg / mL, 10 mg / mL, and 15 mg / mL, respectively. The flexible perovskite films prepared with different concentrations of antisolvents were marked with w / SEBS5, w / SEBS 10 、w / SEBS 15 The flexible perovskite film obtained in Comparative Example 1 without adding anti-solvent is recorded as Control. 10 、w / SEBS 15 Photodetectors were prepared using the flexible perovskite films of the control group and the control group, and the IPCE of the photodetectors based on perovskite films with different SEBS concentrations was tested under the same test conditions as that of the wavelength to explore the effect of SEBS concentration on the photoelectric conversion efficiency of the photodetector.

[0101] The photoelectric conversion efficiency of the photodetector at 0V bias is as follows: Figure 2 The photoelectric conversion efficiency, also known as incident photon-to-electron conversion efficiency, is also known as incident photo-to-electron conversion efficiency, or IPCE for short.

[0102] Depend on Figure 2 As shown in Figure a, the photoelectric conversion efficiency of the photodetectors from Examples 1 to 3 shows a trend of first decreasing, then increasing, and then decreasing again as the SEBS concentration in the antisolvent increases. Compared to the control device from Comparative Example 1, when the SEBS concentration in the antisolvent is 10 mg / mL, the photoelectric conversion efficiency of the resulting photodetectors increases by an average of 10% within the wavelength range of 400 nm to 650 nm.

[0103] Test 2: Investigate the effect of SEBS concentration on the photoresponsivity of the photodetector.

[0104] Photoresponsivity reflects the photodetector's ability to respond to incident light signals. It represents the ratio of the photodetector's output current to the incident light power under given lighting conditions. It can be obtained from the following formula:

[0105] Where R represents the light response; I p Represents photocurrent; I d represents dark current; S represents effective area; and P represents incident light intensity.

[0106] The responsivity of the photodetector varies with wavelength, such as Figure 2As shown in Figure b, the same trend as the change in photoelectric conversion efficiency is observed. When the SEBS concentration is 10 mg / mL, the responsivity of the obtained photodetector is enhanced, and the highest responsivity reaches 0.27 A / W at 740 nm.

[0107] Test 3: Specific detectivity of photodetectors.

[0108] The specific detectivity reflects the ability of the photodetector to detect the minimum light signal, which can be obtained by the following formula:

[0109] Where D represents the specific detectivity; R represents the photoresponsivity; I dark represents the dark current density; e represents the electron charge, which is a constant approximately equal to 1.602×10 -19 Coulomb; A represents the effective area of the photodetector.

[0110] The relationship between the specific detection rate of the photodetector and the wavelength of light, such as Figure 2 As shown in Figure c.

[0111] from Figure 2 As can be seen from Figures c and b, when the SEBS concentration is 10 mg / mL, the responsivity of the obtained photodetector is greatly improved compared to the control device, and the improvement range almost covers the entire test spectrum band.

[0112] When the SEBS concentration is 10 mg / mL, the maximum specific detectivity of the obtained photodetector reaches 12.27×10 11 Jones, compared to 7.34×10 11 Jones, an increase of 67%. The significant improvement in the specific detectivity of the photodetector obtained by using Example 2 is due to the significant reduction in the dark current of the photodetector. Among them, the dark current density of the control device is 2.93×10 -7 A / cm 2 The dark current density of the photodetector of the second embodiment of the present invention is the lowest, which is 1.73×10 -7 A / cm 2 , which greatly improves the detection rate.

[0113] Test 4: On / Off ratio of the photodetector.

[0114] The on / off ratio is the ratio of the device's photocurrent to its dark current under the same bias voltage. Figure 2 As shown in Figure d, it can be seen that with the increase of light intensity, the on-off ratio of the photodetector tends to increase. However, the on-off ratio of the photodetector of Example 2 of the present invention is significantly improved compared with the control device; at 100mW / cm2 Under the light intensity, the on-off ratio of the photodetector of the second embodiment of the present invention is 3.38×10 5 , which is 6 times that of the control device.

[0115] Test 5: Linear dynamic range and response time of the photodetector.

[0116] The full name of linear dynamic range is Linear Dynamic Range, or LDR for short. LDR is an indicator that characterizes the linear relationship between light intensity and photocurrent. It is calculated as follows:

[0117] Wherein, LDR represents linear dynamic range; J Ligth represents the photocurrent density; J dark represents the dark current density.

[0118] At a light intensity of 0.28 mW·cm -2 ~1946mW·cm -2 In the range of light intensity, the photodetector LDR under 0V bias, such as Figure 3 As shown in Figure a, the actual measured value of the LDR of the photodetector of Example 2 of the present invention is 68.6dB, while the theoretical LDR value calculated by dark current can reach 108.5dB, which are 1.125 times and 1.148 times that of the control device respectively.

[0119] Response time is also an important indicator of the detector, such as Figure 3 As shown in Figure b, the rise time and fall time are calculated from the time when the photocurrent rises from 10% to 90% and falls from 90% to 10%, respectively. The rise time and fall time of the control device were measured to be 2.3ms and 2.1ms respectively; while the rise time and fall time of the photodetector of Example 2 of the present invention were 2.0ms and 1.6ms respectively, and the response speed was also increased. It can be seen that Example 2 of the present invention can significantly enhance the quasi-two-dimensional perovskite (PEA)2(MA) by adding the elastomer SEBS during the crystallization of the perovskite n-1 Pb n I 3n+1 Various parameters and performance of basic photoelectric detectors.

[0120] Test 6: Photodetector stability.

[0121] In practical applications, the stability of photodetectors is extremely important. Especially for flexible photodetectors, their mechanical stability determines their bendability and foldability during application. The block copolymer SEBS incorporated into the embodiments and application examples of the present invention exhibits excellent mechanical flexibility and good interfacial compatibility. While enhancing the photoelectric properties of the perovskite material, it can also improve the mechanical performance of the photodetector, particularly under external stress conditions such as extreme bending and stretching.

[0122] When the bending curvature radius is 9.5 mm, the normalized photocurrent change curves of the photodetectors of Example 2 and Comparative Example 1 after repeated bending for 10,000 times are as follows: Figure 3 As shown in Figure c.

[0123] Depend on Figure 3 As shown in Figure c, the responsivity of the control device using Comparative Example 1 gradually decreases with the number of bends, reaching 76% of its initial value by 10,000 bends. However, the responsivity of the photodetector using Example 2 remained essentially unchanged from its initial value after 6,000 bends. This is because the presence of SEBS at the perovskite grain boundaries acts as a buffer during the bending process, preventing performance degradation caused by crystal compression. After 10,000 bends, the photodetector using Example 2 still maintained 93% of its initial responsivity, demonstrating that the addition of SEBS significantly improves the mechanical stability of the photodetector.

[0124] In addition, the change of device responsivity at different bending curvature radii was also studied. The photodetector was bent 500 times at various curvature radii such as 11.7mm, 9.5mm, 8.1mm, 7.2mm, 6.5mm and 6.0mm, and the attenuation of the normalized responsivity was measured. Figure 3 As shown in Figure d.

[0125] Depend on Figure 3 As can be seen in Figure d, the responsivity of the control device using Comparative Example 1 rapidly decays as the curvature radius decreases. At a curvature radius of 6 mm, the performance of the control device is only 83.6% of its initial value. However, under the same conditions at 6 mm, the performance of the photodetector using Example 2 still maintains 97.9% of its initial value. This clearly demonstrates that the introduction of SEBS significantly improves the photodetector's bending resistance.

[0126] Test 7: SEM image, EDS spectrum and XRD pattern of flexible perovskite film.

[0127] In order to reveal the optimization principle of the present invention, the perovskite layer in the control device of comparative example 1 and the photodetector of embodiment 2 were investigated separately. In order to investigate the crystallization of perovskite after adding SEBS, the flexible perovskite films of comparative example 1 and embodiment 2 were characterized by SEM morphology. The results are shown in the figure. Figure 4 As shown in Figures a and b.

[0128] Depend on Figure 4 As can be seen in Figures a and b, the surface of the flexible perovskite film of the control device exhibits a relatively flat and dense grain distribution, while the surface of the flexible perovskite film with SEBS added in Example 2 forms a very obvious wrinkled structure. The wrinkled structure on the surface of the flexible perovskite film prepared using an antisolvent is due to the rapid crystallization of the surface perovskite by the addition of the antisolvent, which generates compressive stress between the grains.

[0129] In order to verify whether the wrinkled structure is caused by the addition of anti-solvent, the flexible perovskite film prepared in Comparative Example 2 was used as a control sample, that is, only 120 μL of toluene was added as anti-solvent, and the SEM morphology of the control film of Comparative Example 2 was analyzed. Figure 5 It can be seen that the addition of antisolvent can form a wrinkle structure on the perovskite surface. However, the wrinkle structure of the entire surface of the flexible perovskite film prepared by adding SEBS in Example 2 is more dense, showing an extremely compact texture.

[0130] pass Figure 4 From the EDS spectra of Figures c and d, it can be found that compared with the control film of Comparative Example 1, the w / SEBS film of Example 2 10 The proportion of carbon in the sample increased significantly, which proves that the surface of the flexible perovskite film prepared by adding SEBS in Example 2 is covered with a layer of SEBS film. This is because SEBS exists in the grain boundaries. When the surface perovskite grains squeeze each other, the SEBS in the grain boundaries will be squeezed out, thereby forming a thin layer of SEBS with a wrinkled structure on the surface. Such a structure has two advantages: first, the wrinkled structure can cause multiple scattering of light, thereby increasing the light absorption of the perovskite film; second, the formation of the SEBS thin insulating layer will greatly reduce the dark current. Under light illumination, the accumulation of carriers will form a tunneling effect without affecting the transmission of the photocurrent. The formation of this structure explains the reason for the increase in photocurrent and the reduction in dark current of the photodetector device of Example 2 of the present invention.

[0131] In addition, XRD was performed on the flexible perovskite films of Comparative Example 1 and Example 2 to analyze the crystallization. Figure 6As shown, the main diffraction peaks of the control film of Comparative Example 1 are both at ~14° and ~28°, corresponding to the (110) and (220) planes of the 3D perovskite component (large n value) or the (111) and (202) planes of the small n value perovskite component, respectively. However, for the flexible perovskite film with SEBS added in Example 2, its XRD intensity is significantly reduced, with only a weak diffraction peak detected at ~28°. This is because the SEBS wrinkle structure on the surface greatly affects the XRD diffraction signal, making it difficult to use the XRD pattern to analyze the crystallization of the sample.

[0132] Test 8: Surface AFM image, roughness image, and Young's modulus of flexible perovskite films.

[0133] The surface AFM images of the flexible perovskite films of Comparative Example 1 and Example 2 were analyzed using AFM to show the surface structure of the perovskite, such as Figure 7 As shown in Figures a, b, d and e.

[0134] Depend on Figure 7 As can be seen from Figures a and b, the surface of the flexible perovskite film of Comparative Example 1 is relatively smooth, with a roughness of 14.2 nm. Figure 7 As can be seen from Figures d and e, the surface of the flexible perovskite film with SEBS added in Example 2 can be clearly observed to form a wrinkle structure, with a roughness of 77.3nm, which is consistent with the results of SEM. In addition, SEBS elastomer has good mechanical ductility and can effectively increase the mechanical stability of the photodetector device, as shown in Figure d. Figure 3 As shown in Figures c and d.

[0135] The Young's modulus of the control film of Comparative Example 1 and the flexible perovskite film with SEBS added in Example 2 were tested using the force curve mode of AFM. The results are as follows: Figure 7 As shown in Figures c and f.

[0136] like Figure 7 In Figures c and f, the red curve represents the probe's gradual approach to the film. At approximately 23 nm on the x-axis, the curve suddenly drops, indicating that the probe is approaching the sample and is bending downward due to attractive forces. As the probe continues to descend, reaching approximately 20 nm on the x-axis, the attractive and repulsive forces balance, and the probe no longer bends. Beyond this point, repulsive forces cause the probe to bend upward until it reaches 0 nm on the x-axis, at which point the absolute bending value of the probe is 20 nm. Since the bending of the probe is linearly related to the applied force, the calculated force at 0 nm is approximately 32 nN.

[0137] The blue curve represents the reverse release process. Positive values above 0 nN indicate repulsive forces, while negative values below 0 nN indicate attractive forces. For the flexible perovskite film with SEBS added in Example 2, the absolute bending value of the probe was 118 nm, and the calculated force at 0 nm was approximately 33 nN.

[0138] The Derjaguin-Muller-Toporov model, or DMT model for short, is used to fit force curves. The elastic modulus can be determined by fitting the force curve using the DMT model. For the control film of Comparative Example 1, the calculated Young's modulus is 1.4 GPa, which is comparable to previously reported results. However, the Young's modulus of the flexible perovskite film in Example 2 with the addition of SEBS is reduced to 38.8 MPa, nearly two orders of magnitude lower than that of the control film of Comparative Example 1. This further confirms that the addition of SEBS can significantly improve the mechanical resistance of flexible perovskite films.

[0139] Test 9: UV-Vis absorption spectrum, lifetime decay diagram, and steady-state PL spectrum of the flexible perovskite film. PL stands for photoluminescence.

[0140] In order to explore the effect of SEBS on the optical properties of perovskite materials, a series of absorption and luminescence characteristics were investigated. Figure 8 Figure a shows the UV-visible absorption spectra of the flexible perovskite films of Comparative Example 1 and Example 2 in the 350nm-850nm band. For the control film of Comparative Example 1, the absorption peaks observed at 565nm, 600nm, 637nm, and 750nm correspond to perovskite components with n=2, 3, 4, and ∞, respectively. This indicates that the quasi-two-dimensional perovskite film of the control film of Comparative Example 1 is a mixed phase containing components with different n values. In other words, although the solution for the prepared film was prepared according to n=4, the actual film contained perovskite components with multiple n values.

[0141] In Example 2, SEBS was added to (PEA)2(MA) n-1 Pb n I 3n+1 The film also shows peaks corresponding to those of the control film of Comparative Example 1, indicating that the flexible perovskite film of Example 2 is also a mixed phase. However, the exciton absorption peak of the n=3 perovskite component is significantly enhanced, and the absorption peak of the three-dimensional perovskite corresponding to n=∞ is significantly weakened. This indicates that the addition of SEBS antisolvent affects the crystallization process of the quasi-two-dimensional perovskite, increasing the n=3 component and reducing the three-dimensional component. This is because SEBS, added in the form of an antisolvent, undergoes physical cross-linking during the nucleation and crystallization process of the perovskite, forming a network structure, which reduces the diffusion rate of MA ions to the upper surface, thereby inhibiting the initial growth of the three-dimensional perovskite.

[0142] In addition, the absorption of the flexible perovskite film with SEBS added in Example 2 is enhanced in the 400nm to 700nm spectral range, which is basically consistent with the IPCE and responsivity improvement spectrum range of the corresponding device, indicating that the enhanced light absorption of the flexible perovskite film is the main reason for the improvement of the photocurrent of the photodetector. Figure 2 As can be seen from the SEM results, the surface of the flexible perovskite film with the addition of SEBS antisolvent forms a wrinkled structure, which can enhance the scattering of light and reduce the reflection of the material to the incident light. Figure 9 , thereby enhancing the light absorption of the film.

[0143] In order to study the phase distribution of perovskite films, steady-state PL spectroscopy analysis was performed on these films. The normalized PL spectra obtained by measuring the front and back surfaces of the flexible perovskite films at grazing incidence are shown in Figure 2. Figure 8 The front side is defined as the direction of light excitation and PL detection on the surface of the flexible perovskite film, while the back side is defined as the direction of the substrate.

[0144] Under positive excitation, after adding SEBS, the emission peak corresponding to the wavelength of the three-dimensional component position with n=∞ is blue-shifted from 762nm of the control film of Comparative Example 1 to 731nm, and there is no other emission peak. This 731nm emission peak corresponds to the perovskite component with mixed phase n=3, as shown in Figure 8 As shown in the UV-visible absorption spectrum results in Figure a, in the perovskite film with SEBS added in Example 2, the n=3 component increases, while the three-dimensional component decreases significantly, which is consistent with the PL results. The PL peak of the n=3 component observed on the front side indicates that it is mainly distributed on the perovskite surface.

[0145] In addition, in order to verify whether this blue shift is caused by the band gap and defects, the optical band gap of the three-dimensional component of the perovskite was obtained using the Tauc plot based on the perovskite UV-visible absorption spectrum, as shown in Figure 2. Figure 10 , the optical band gap of the optimized material in Example 2 is not significantly different from that of the original material in Comparative Example 1, which indicates that the blue shift of the PL peak position is not caused by the change of the band gap.

[0146] In order to verify whether SEBS has a defect passivation effect, the infrared Fourier reflectance spectra of the control film of Comparative Example 1 and the flexible perovskite films added with different SEBS amounts in Examples 1 to 3 were compared. Figure 11 , it was observed that the intensity and peak position of each curve were basically consistent, indicating that the addition of SEBS did not interact with the perovskite, which is consistent with the chemical inertness of SEBS itself. ,It can be seen that after the addition of SEBS in Example 2, the perovskite defect state density did not change.

[0147] Therefore, the significant blue shift in the PL peak position from the front side demonstrates that the n=3 perovskite composition dominates the optimized perovskite film of Example 2. When excited from the back side, the emission peak of the control film of Comparative Example 1 is primarily concentrated at the peak of the low-n perovskite phase. This is consistent with the common gradient-phase quasi-two-dimensional perovskite structure, where the three-dimensional phase first grows at the interface with air, and then the n value of the perovskite gradually decreases as it grows toward the substrate. The back side PL peak of the film of Example 2 with SEBS added is at 764nm, corresponding to the emission peak of the n=∞ component. This indicates that the three-dimensional component of the perovskite film with SEBS added is instead concentrated at the bottom of the film, close to the substrate, exhibiting a phase distribution opposite to that of the control film of Comparative Example 1. This phase distribution avoids the charge transport inhibition effect caused by the low-n perovskite component on the lower surface.

[0148] from Figure 8 This is also confirmed by the TRPL results in Figure b. Both the control film in Comparative Example 1 and the perovskite film in Example 2 were deposited on PEDOT:PSS films. The perovskite film in Example 2 exhibits a shorter PL lifetime than the control film in Comparative Example 1, indicating more efficient charge transport. TRPL stands for Time-Resolved Photoluminescence.

[0149] In summary, the embodiment of the present invention introduces SEBS into the quasi-two-dimensional perovskite system (PEA)2(MA) by means of an anti-solvent. n-1 Pb n I 3n+1 , achieving a comprehensive improvement in the performance of the self-powered flexible perovskite photodetector. The optimized device of the embodiment of the present invention has an average 10% improvement in responsivity at 420nm to 615nm compared to the control device of Comparative Example 1. In the embodiment of the present invention, the introduction of SEBS significantly reduces the dark current of the device, from 1.17×10 -8 A is reduced to 6×10 -9 A.

[0150] The specific detectivity of the optimized device of the embodiment of the present invention is greatly improved in the range of 400nm to 750nm, and the maximum specific detectivity at 740nm is 1.23×10 11 Jones, which is 1.68 times that before optimization. In addition, the addition of SEBS also greatly improves the mechanical stability of the device.

[0151] Further research in the examples of the present invention has shown that the surface of the perovskite film prepared using this method forms a corrugated structure, with the SEBS being partially squeezed onto the surface during crystal formation, while some remains at the grain boundaries. This corrugated structure increases the film's light absorption, while the SEBS on the perovskite surface reduces dark current, and the SEBS at the grain boundaries acts as a buffer to increase the device's mechanical resistance.

[0152] Furthermore, the introduction of SEBS achieves a uniform phase distribution of the quasi-two-dimensional perovskite, enhancing carrier transport. This embodiment of the present invention provides a method for using an elastomer as an additive to enhance the photoelectric performance and stability of detectors. This approach is expected to provide new insights into the design and application of flexible perovskite photodetectors, promoting their widespread adoption in wearable devices, flexible displays, and smart sensors.

[0153] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a flexible perovskite film, characterized in that: The following steps are involved: Phenethylammonium iodide, methylammonium chloride, PbI2 and PbCl2 are mixed in a solvent system to obtain a perovskite precursor solution; Under nitrogen protection, the perovskite precursor solution is spin-coated, and an anti-solvent is added during the spin-coating process; then, the film is annealed to obtain a flexible perovskite film; the anti-solvent is a SEBS-toluene solution.

2. The method for preparing a flexible perovskite film according to claim 1, wherein: The concentration of SEBS in the anti-solvent is 5 mg / mL to 15 mg / mL.

3. The method for preparing a flexible perovskite film according to claim 2, wherein: The concentration of SEBS in the anti-solvent is 10 mg / mL.

4. The method for preparing a flexible perovskite film according to claim 1, wherein: The annealing temperature is 100℃±1℃.

5. The method for preparing a flexible perovskite film according to claim 1, wherein: The molar ratio of phenethylammonium iodide, methylammonium chloride, PbI2, and PbCl2 is 0.4:0.9:0.95:0.

05.

6. The method for preparing a flexible perovskite film according to claim 1, wherein: The concentration of the mixture of phenethylammonium iodide, methylammonium chloride, PbI2 and PbCl2 in the perovskite precursor solution is 1 mol / L.

7. The method for preparing a flexible perovskite film according to claim 1, wherein: The solvent is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 9:

1.

8. A flexible perovskite film, characterized in that: The method is prepared by any one of claims 1 to 7.

9. A flexible perovskite photodetector comprising a substrate and a hole transport layer, a flexible perovskite film, an electron transport layer, and a buffer layer, which are sequentially spin-coated on the substrate, wherein a metal electrode is evaporated on the buffer layer, characterized in that: The flexible perovskite film is the flexible perovskite film according to claim 8.

10. The flexible perovskite photodetector according to claim 9, characterized in that: The substrate is PEN etched with indium tin oxide; the hole transport layer is a PEDOT:PSS hole transport layer; the electron transport layer is PC 61 BM electron transport layer; the buffer layer is a BCP buffer layer; and the metal electrode is a silver electrode.

Images