Method for reducing surface defect state of perovskite thin film and perovskite battery

Abstract

The invention relates to the technical field of solar cells, in particular to a method for reducing the surface defect state of a perovskite thin film and a perovskite cell. The embodiment of the invention provides a method for reducing a surface defect state of a perovskite thin film. The method comprises the following steps: providing the perovskite thin film and a film forming solution for forming a film; covering the perovskite thin film with the film forming liquid so as to form a peelable thin film; and stripping off the strippable thin film to reduce the surface defect state of the perovskite thin film. According to the method for reducing the surface defect state of the perovskite thin film in the embodiment of the invention, the attached strippable thin film can be formed on the perovskite thin film by utilizing the flowability of the film forming liquid, and then the strippable thin film is stripped off, so that the surface defect state of the perovskite thin film can be taken away. According to the embodiment of the invention, the problem that the cleaning degree is not high because the surface of the perovskite thin film has undulation and the thin film is not attached to the undulation is solved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a method for reducing surface defect states of a perovskite film and a perovskite cell. Background Art

[0002] Perovskite materials, with their excellent defect tolerance, high light absorption coefficient, and room-temperature solution processing, are highly promising next-generation photovoltaic materials. Currently, the certified efficiency of single-junction perovskite solar cells is 26.95%, while the efficiency of perovskite / crystalline silicon tandem cells reaches as high as 34.6%. Despite significant efficiency gains, severe interfacial recombination caused by surface defects in perovskite films limits further device efficiency improvements. Reducing surface defect states in perovskite films through defect passivation or surface polishing strategies is crucial for the future development of perovskite cells. One technique involves using adhesive tape to clean the top surface of perovskite films, removing the surface defect layer without damaging the underlying crystalline regions. High-resolution TEM has demonstrated that tape treatment can effectively remove the surface defect layer of perovskite films. Another technique involves polishing the perovskite crystal surface by coating an anisole solution containing nano-Al2O3 on a rigid substrate, followed by passivation of the newly exposed highly crystalline surface. This approach can reconstruct the perovskite / electron transport layer interface and release residual lattice strain, improving charge collection and suppressing ion migration of perovskite.

[0003] However, the surface of perovskite films exhibits a certain degree of undulation due to volume shrinkage during the crystallization process, resulting in micro-wrinkles and other morphologies on the film surface. For micron-thick films, the wrinkles can reach micron levels. Furthermore, during the preparation process, perovskite films inevitably exhibit uneven thickness. For some perovskite solar cells prepared using conformal processes, such as perovskite / silicon tandem solar cells prepared using the full evaporation method, the surfaces exhibit evenly distributed pyramids. Consequently, tape or polishing particles have difficulty conformally covering the surface of perovskite films, and their ability to clean the surface of perovskite films is limited, as is their ability to reduce the density of surface defect states.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0005] The embodiments of the present application provide a method for reducing surface defect states of a perovskite film and a perovskite cell to solve or alleviate one or more of the technical problems raised above.

[0006] A first aspect of an embodiment of the present application provides a method for reducing surface defect states of a perovskite film, comprising: Providing perovskite thin films and film-forming solutions for film formation; covering the film-forming solution on the perovskite film to form a strippable film; The strippable film is peeled off to reduce surface defect states of the perovskite film.

[0007] The method for reducing surface defects in perovskite films according to embodiments of the present application utilizes the fluidity of a film-forming solution to form a conformal, peelable film on the perovskite film. The peelable film can then be removed, removing the surface defects. This embodiment of the present application solves the problem of poor cleanliness due to the uneven surface of the perovskite film and the film's poor conformity to it.

[0008] Optionally, the film-forming liquid comprises a thermoplastic polymer and a solvent, thereby enabling direct film formation through solvent volatilization.

[0009] Optionally, the mass fraction of the thermoplastic polymer in the film-forming solution is 5% to 10%, thereby enabling continuous and uniform film formation.

[0010] Optionally, the thermoplastic polymer includes at least one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), and methyl methacrylate-butyl acrylate copolymer, thereby facilitating complete peeling of the formed film.

[0011] Optionally, the solvent includes at least one of toluene, xylene, ethyl acetate, and chlorobenzene, thereby forming a uniform solution with the polymer without damaging the perovskite film.

[0012] Optionally, the thermoplastic polymer includes methyl methacrylate-butyl acrylate copolymer, thereby making it easier to completely peel off the formed film.

[0013] Optionally, the film-forming liquid is applied to the perovskite film by blade coating, spin coating, coating, spraying, and / or dipping, thereby achieving full coverage of the perovskite film surface.

[0014] Optionally, the film-forming liquid is solidified under vacuum or heating conditions to form the peelable film, thereby accelerating the formation of the peelable film.

[0015] Optionally, the method for reducing surface defects in a perovskite film further comprises the following operation: cleaning the perovskite film with a cleaning solvent to remove residues of the film-forming solution, thereby avoiding the introduction of new impurities.

[0016] Optionally, the thickness of the strippable film is 1 μm to 100 μm, thereby being able to cover the undulations of the perovskite film.

[0017] A second aspect of the present invention provides a perovskite cell, which is prepared using the method for reducing surface defects in a perovskite film as described in the first aspect of the present invention. As a result, the perovskite film has fewer surface defects, which is beneficial for increasing the open circuit voltage of the perovskite cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0019] Figure 1 This is a flow chart for reducing surface defect states of perovskite films provided in an embodiment of the present application; Figure 2 This is a process diagram of the method for reducing surface defect states of perovskite films provided in an embodiment of the present application.

[0020] Description of reference numerals: 1-Perovskite film; 2-Peelable film. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, the sizes of layers, regions, and elements and their relative sizes may be exaggerated for clarity. The same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be understood as limiting the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0022] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it can be directly on, adjacent to, connected to, or coupled to the other element or layer, or there can be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there can be no intervening elements or layers. It should be understood that while the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or portion from another. Thus, without departing from the teachings of the present application, a first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion. Furthermore, when a second element, component, region, layer, or portion is discussed, it does not necessarily indicate that the first element, component, region, layer, or portion is present in the present application.

[0023] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly enumerating each integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0026] The following provides an explanation of the terms used in this application.

[0027] Surface defect states in perovskite films refer to localized energy states that deviate from the ideal crystal structure and form on the surface of the perovskite material. These defects significantly impact the material's optoelectronic properties. In the present application, defect states primarily refer to surface lattice defects and additional energy traps formed by the adsorption of water molecules, oxygen, or organic impurities on the surface.

[0028] The present invention provides a technical solution for reducing surface defects in perovskite films. This solution can alleviate the problem of low defect removal due to the uneven surface of the perovskite film. See below for details.

[0029] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0030] The embodiments of the present application provide a method for reducing surface defect states of perovskite films.

[0031] In an optional embodiment, if Figure 1 As shown, the method for reducing the surface defect state of the perovskite film comprises the following steps: S1. providing a perovskite film and a film-forming solution for film formation; Optionally, the perovskite film may be a perovskite light absorbing layer prepared on an electron transport layer (nip structure) or a hole transport layer (pin structure).

[0032] Furthermore, the perovskite light-absorbing layer can be prepared by spin coating, doctor blade coating, vacuum evaporation and anti-solvent assisted solution method. The perovskite light-absorbing layer prepared by the above methods has certain defect states to a greater or lesser extent. Therefore, it is necessary to adopt means to reduce the surface defect states of the perovskite film.

[0033] In an optional embodiment, the film-forming liquid includes a thermoplastic polymer and a solvent; thus, the film can be directly formed by evaporation of the solvent without chemical cross-linking and without adding a curing agent to initiate a cross-linking reaction.

[0034] Optionally, the mass fraction of the thermoplastic polymer in the film-forming solution is 5% to 10%, for example, 5%, 6%, 8%, 10%, etc. Thus, the film is formed continuously and uniformly.

[0035] Optionally, the thermoplastic polymer includes at least one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), and methyl methacrylate-butyl acrylate copolymer, thereby making it easy to completely peel off the formed film.

[0036] Optionally, the solvent includes at least one of toluene, xylene, ethyl acetate, and chlorobenzene, thereby forming a uniform solution with the polymer without damaging the perovskite film.

[0037] As some examples, the solute of the membrane-forming solution may be polymethyl methacrylate (PMMA), polydimethylsilane (PDMS), or methyl methacrylate-butyl acrylate copolymer, and the solvent may be toluene.

[0038] Specifically, the film-forming solution comprises, by mass, 5% to 10% polymethyl methacrylate and 90% to 95% toluene. Thus, a colorless and transparent film can be obtained after the toluene evaporates.

[0039] Preferably, the film-forming liquid includes a methyl methacrylate-butyl acrylate copolymer. Methyl methacrylate and butyl acrylate form an interpenetrating network structure through copolymerization. This structure combines the hardness of methyl methacrylate with the flexibility of butyl acrylate, resulting in a film with both strength and ease of complete peeling. In contrast, the molecular chain of polymethyl methacrylate (PMMA) is highly rigid and lacks flexible segments, making the film brittle and prone to incomplete peeling.

[0040] Furthermore, the mass ratio of methyl methacrylate to butyl acrylate can be between 0.5:1 and 1.5:1. Methyl methacrylate and butyl acrylate copolymerize to form a random copolymer, whose glass transition temperature (Tg) is directly affected by the monomer ratio. The hard monomer imparts a rigid framework to the film, while the soft monomer provides flexible segments through its long-chain alkyl groups. Within this range, the copolymer segments maintain moderate mobility at room temperature while forming a stable cross-linked network, achieving a balance between hardness and flexibility.

[0041] For example, the film-forming solution comprises, by mass, 5% to 10% methyl methacrylate-butyl acrylate copolymer and 90% to 95% of a mixed solvent of ethyl acetate and toluene. Methyl methacrylate-butyl acrylate copolymer has excellent film-forming properties. When dissolved in a mixed solvent of ethyl acetate and toluene, it forms a uniform polymer solution, making it easy to apply or spray to form a film. The resulting film has high transparency and excellent mechanical properties, and the film's hardness can be controlled by adjusting the ratio of the monomers in the copolymer.

[0042] Optionally, in the mixed solvent of ethyl acetate and toluene, the volume ratio of ethyl acetate to toluene is 3:1.

[0043] S2. Covering the perovskite film with a film-forming liquid to form a peelable film. Thus, a peelable film with a conformable surface can be obtained on the perovskite film. This is because the surface of the perovskite film is not a uniformly flat surface. Volume shrinkage during the crystallization process can lead to the formation of micro-wrinkles and other morphologies. For thick films at the micron level, the wrinkles can also reach the micron level. In addition, the perovskite film will inevitably have uneven thickness. However, when the film-forming liquid is used to cover the perovskite film, the liquid has fluidity and can fill all surfaces of the perovskite film, eliminating the problem of loose adhesion.

[0044] Optionally, the film-forming liquid may be applied to the perovskite film by blade coating, spin coating, coating, spray coating, and / or dip coating, thereby achieving full coverage of the perovskite film surface.

[0045] It is understood that the film-forming solution coated on the perovskite film can be evaporated to form a peelable film. In an optional embodiment, the solvent evaporation can be accelerated under vacuum or / and heating conditions to allow the polymer to solidify and form the peelable film. For example, annealing can be performed on a hot plate. Considering the stability of the perovskite film, annealing at 100°C is suitable.

[0046] In an optional embodiment, the thickness of the strippable film is 1 μm to 100 μm, for example, 1 μm, 10 μm, 30 μm, 50 μm, 75 μm, 100 μm, etc. Thus, the thickness of the strippable film within this range can completely cover the undulations of the perovskite film.

[0047] Preferably, the thickness of the peelable film is 5 μm to 50 μm, thereby facilitating peeling while maintaining peeling integrity.

[0048] S3. Peeling off the peelable film to reduce surface defects in the perovskite film. During the peeling process, the peelable film bonded to the perovskite film can remove surface adsorption defects. The peelable film in this embodiment of the present application is bonded to the perovskite film through physical forces (van der Waals forces and hydrogen bonds), resulting in a controllable overall peeling resistance and minimizing damage to the perovskite film during peeling.

[0049] Optionally, the peelable film can be peeled off by tearing it off.

[0050] In an alternative embodiment, see Figure 2 The process flow of the method for reducing the surface defect state of the perovskite film can be to form a peelable film 2 on the perovskite film 1, and then tear off the peelable film 2, and take away the defects on the surface of the perovskite film 1 while peeling off the film 2.

[0051] In an optional embodiment, the method for reducing surface defect states of the perovskite film further includes the following steps: S4. Cleaning the perovskite film with a cleaning solvent to remove residues, thereby avoiding the introduction of residues on the surface of the perovskite film to form additional energy traps.

[0052] It is worth noting that the cleaning solvent used is a solution in which the polymer can be dissolved, so as to achieve the purpose of removing residues.

[0053] The following will conduct performance tests on the method for reducing surface defect states of perovskite films provided in the embodiments of the present application and related comparative examples.

[0054] [Example 1] The specific preparation process of perovskite cells is as follows: (1) Treat the ITO conductive substrate with UV ozone to improve the surface condition of ITO for 15 minutes; (2) Preparation of 15 nm thick NiO by magnetron sputtering x layer, using (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) to modify NiO x layer to obtain a hole transport layer; (3) MABr, CsI, FAI, PbI2 and PbBr2 were used to prepare a solution with the chemical formula of Cs 0.05 MA 0.15 FA 0.8 PbI 0.75 Br 0.25A perovskite precursor solution with a concentration of 1.7 mmol / mL; (4) Using a one-step antisolvent method with ethyl acetate as the antisolvent, a 1 μm thick perovskite light-absorbing layer was prepared on the hole transport layer; (5) A 10% mass fraction of PMMA chlorobenzene solution was spin-coated on the perovskite light-absorbing layer using a spin coating method at a rotation speed of 1000 rpm for 30 seconds. The perovskite layer was then placed in a vacuum chamber and evacuated to a vacuum pressure of 10 Pa for 30 minutes. The perovskite layer was then annealed on a hot plate at 100 °C for 5 minutes to form a conformal PMMA film with a thickness of 25 μm. (6) Peeling off the PMMA film from the perovskite light-absorbing layer by tearing and peeling to clean the surface of the perovskite light-absorbing layer; (7) Use chlorobenzene and spin coating to clean the surface of the perovskite light-absorbing layer to completely remove the residual PMMA; the spin coating speed is 5000 rpm for 30 seconds, and then it is placed on a hot plate at 100 °C for 5 minutes to anneal to remove the chlorobenzene; (8) Thermal evaporation was used to deposit 15 nm thick C 60 As the electron transport layer, a 15 nm thick SnO2 barrier layer was prepared by atomic layer deposition; (9) A 150 nm thick Ag back electrode was deposited by thermal evaporation.

[0055] [Example 2] The specific preparation process of perovskite cells is as follows: The rest is the same as Example 1, except that: A 10% PDMS toluene solution was spin-coated on the perovskite light-absorbing layer using a spin coating method at a speed of 3000 rpm for 30 seconds. The perovskite layer was then placed in a vacuum chamber and evacuated to a vacuum pressure of 10 Pa for 30 minutes. The perovskite layer was then annealed on a hot plate at 100°C for 5 minutes to form a conformal PDMS film with a thickness of 15 μm. (6) Peeling off the PDMS film from the perovskite light-absorbing layer by tearing and peeling to clean the surface of the perovskite light-absorbing layer; (7) Use toluene and spin coating to clean the surface of the perovskite light-absorbing layer to completely remove the residual PDMS; the spin coating speed is 5000 rpm and the time is 30 s. Then place it on a hot plate at 100 °C for annealing for 5 min to remove the toluene.

[0056] [Example 3] The specific preparation process of perovskite cells is as follows: The other steps were the same as those in Example 1, except that PMMA in steps (5) to (6) was replaced with methyl methacrylate-butyl acrylate (75:100) copolymer to form a 25 μm methyl methacrylate-butyl acrylate copolymer film.

[0057] [Example 4] The specific preparation process of perovskite cells is as follows: The rest is the same as Example 1, except that: (5) A 5% mass fraction of PMMA chlorobenzene solution was spin-coated on the perovskite light-absorbing layer using a spin coating method at a rotation speed of 3000 rpm for 50 s. The perovskite layer was then placed in a vacuum chamber and evacuated to a vacuum pressure of 10 Pa for 30 min. The perovskite layer was then annealed on a hot plate at 100 °C for 5 min to form a conformal PMMA film with a thickness of 5 μm. (6) Peeling off the PMMA film from the perovskite light-absorbing layer by tearing and peeling to clean the surface of the perovskite light-absorbing layer; (7) The surface of the perovskite light-absorbing layer was cleaned using chlorobenzene and spin coating to completely remove the residual PMMA; the spin coating speed was 5000 rpm for 30 s, and then the film was annealed on a hot plate at 100 °C for 5 min to remove the chlorobenzene.

[0058] [Comparative Example 1] The other steps are the same as those in Example 1, except that steps (5), (6) and (7) are replaced by: using transparent tape to stick on the perovskite light-absorbing layer, and then peeling off the transparent tape by tearing and peeling.

[0059] [Comparative Example 2] The other steps are the same as those in Example 1, except that steps (5), (6) and (7) are omitted.

[0060] The perovskite cells of Examples 1 to 4 and Comparative Examples 1 to 2 were subjected to IV testing. The specific testing method was to place the cells under a light source of 100 mW / cm 2 The results were obtained by connecting a source meter using the four-wire method under AM 1.5G simulated sunlight at 25°C. See Table 1.

[0061] Table 1:

[0062] From Table 1 above, it can be seen that the open circuit voltage of the perovskite cells of Examples 1 to 4 is V OC Compared with Comparative Examples 1 and 2, it is significantly increased. V OCIt is negatively correlated with the defect state density of the perovskite film. The lower the defect state density of the perovskite film, the better the device performance. V OC Compared with the traditional tape tearing method device V OC The gain is increased because the method of the present application can completely and conformally cover the surface of the perovskite film, and the degree of removal of surface defect states is higher.

[0063] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present application. The directional terms "inside" and "outside" refer to the inside and outside relative to the outline of the component itself. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "on top of other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here will be interpreted accordingly.

[0064] It should also be noted that references to "one embodiment," "another embodiment," "an embodiment," etc., in this application refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also fall within the scope of this application.

[0065] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0066] It should also be noted that the above are only preferred embodiments of the present application and do not limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present application.

Claims

1. A method for reducing surface defect states of a perovskite film, characterized in that: The following operations are included: Providing perovskite thin films and film-forming solutions for film formation; covering the film-forming solution on the perovskite film to form a strippable film; The strippable film is peeled off to reduce surface defect states of the perovskite film.

2. The method for reducing surface defect states of a perovskite film according to claim 1, wherein: The membrane-forming liquid comprises a thermoplastic polymer and a solvent.

3. The method for reducing surface defect states of a perovskite film according to claim 2, wherein: In the film-forming solution, the mass fraction of the thermoplastic polymer is 5% to 10%.

4. The method for reducing surface defect states of a perovskite film according to claim 2, wherein: The thermoplastic polymer comprises at least one of polydimethylsiloxane, polymethyl methacrylate, and methyl methacrylate-butyl acrylate copolymer; and / or The solvent includes at least one of toluene, xylene, ethyl acetate and chlorobenzene.

5. The method for reducing surface defect states of a perovskite film according to claim 2, wherein: The thermoplastic polymer includes methyl methacrylate-butyl acrylate copolymer.

6. The method for reducing surface defect states of a perovskite film according to claim 1, wherein: The method of covering the film-forming solution on the perovskite film includes: The film-forming liquid is covered on the perovskite film by scraping, spin coating, coating, spraying and / or dipping.

7. The method for reducing surface defect states of a perovskite film according to claim 1, wherein: The film-forming liquid is solidified under vacuum or / and heating conditions to form the peelable film.

8. The method for reducing surface defect states of a perovskite film according to claim 1, wherein: The following operations are also included: The perovskite film is cleaned with a cleaning solvent to remove residues of the film-forming solution.

9. The method for reducing surface defect states of a perovskite film according to any one of claims 1 to 8, wherein: The thickness of the peelable film is 1 μm to 100 μm.

10. A perovskite battery, characterized in that: The film is prepared by using the method for reducing surface defects of the perovskite film according to claims 1 to 9.

Images