Perovskite film, preparation method thereof and perovskite solar cell

Abstract

The invention relates to the technical field of solar cell materials, in particular to a perovskite film, a preparation method thereof and a perovskite solar cell. The preparation method of the perovskite film provided by the invention comprises the following steps: preparing a perovskite precursor solution containing a gas adsorbent; performing film forming treatment on the perovskite precursor solution to obtain an initial perovskite film; and placing the initial perovskite film in a nitrogen-containing gas for adsorption treatment to obtain the perovskite film. According to the preparation method provided by the invention, the surface defects of the perovskite film can be repaired, so that the film layer is more compact and smoother, and the obtained perovskite film has good photoelectric properties and can improve the stability of the energy conversion efficiency of the perovskite solar cell when being used in the perovskite solar cell.

Description

Technical Field

[0001] This application belongs to the technical field of solar cell materials, and particularly relates to a perovskite film, a preparation method thereof, and a perovskite solar cell. Background Art

[0002] Perovskite materials are a type of semiconductor material with uniform size and high color purity. Their elemental composition has a crystal structure similar to that of the ore CaTiO3, and they are a very promising photovoltaic material. Perovskite materials have strong light absorption ability and a wide absorption range, and have great advantages in the optoelectronic field. For example, perovskite solar cells (PSCs) using perovskite materials as the light-absorbing layer have developed rapidly. They have excellent carrier mobility, high absorption coefficient, and low-cost solution processing, etc., and have received extensive attention in the business community.

[0003] Currently, the methods for preparing large-area perovskite film crystallization generally mainly rely on chemical vapor deposition (CVD) or solution film annealing treatment. In these methods, there is a situation where the crystal particle size distribution is uneven, and there are easily large perovskite particle crystals. Therefore, in the process of forming a perovskite film through desolvation (recrystallization), the perovskite film is prone to cracking or pore formation on the film surface due to the existence of uneven particle crystals, thus affecting its performance. Summary of the Invention

[0004] The purpose of this application is to provide a perovskite film, a preparation method thereof, and a perovskite solar cell, aiming to solve the technical problem of how to improve the uniformity of the perovskite film.

[0005] To achieve the above application purpose, the technical solution adopted in this application is as follows:

[0006] In the first aspect, this application provides a preparation method of a perovskite film, including:

[0007] Preparing a perovskite precursor solution containing a gas adsorbent;

[0008] Performing film-forming treatment on the perovskite precursor solution to obtain an initial perovskite film;

[0009] Placing the initial perovskite film in a gas containing nitrogen elements for adsorption treatment to obtain a perovskite film.

[0010] In some embodiments, the gas adsorbent includes at least one of polyvinyl alcohol, polypropylene alcohol, polyethylene glycol, polyacrylic acid, polyurethane, polyhydroxyethyl methacrylate, poly(lactic-co-glycolic acid), and polydimethylsiloxane.

[0011] In some embodiments, the nitrogen-containing gas includes at least one of ammonia, methylamine, dimethylamine, trimethylamine, and ethylamine.

[0012] In some embodiments, the weight ratio of the gas adsorbent in the perovskite film is 0.1-20 wt%;

[0013] and / or, the concentration of the gas adsorbent in the perovskite precursor solution is 0.1-1 mM.

[0014] In some embodiments, the molar ratio of the gas adsorbent to the nitrogen-containing gas is 1:(3.5-5).

[0015] In some embodiments, subjecting the initial perovskite film to adsorption treatment in a nitrogen-containing gas includes: placing the initial perovskite film in a vacuum chamber, and then introducing the nitrogen-containing gas into the vacuum chamber for adsorption treatment.

[0016] In some embodiments, the film-forming treatment of the perovskite precursor solution includes: coating the perovskite precursor solution on a substrate, and then performing heat treatment under the condition of 100-150 °C.

[0017] In some embodiments, the perovskite material in the perovskite film is an organic-inorganic hybrid perovskite material with the chemical formula ABX3; wherein, A is a monovalent organic cation, B is a divalent metal cation, and X is a monovalent anion.

[0018] In a second aspect, the present application provides a perovskite film prepared by the preparation method provided in the first aspect of the present application.

[0019] In a third aspect, the present application provides a perovskite solar cell including the perovskite film provided in the second aspect of the present application.

[0020] For the perovskite film preparation method provided in the first aspect of the present application, a gas adsorbent is first added to the prepared perovskite precursor solution, and then the formed initial perovskite film is subjected to adsorption treatment in a nitrogen-containing gas. Because there is a gas adsorbent in the initial perovskite film, the initial perovskite film can adsorb the nitrogen-containing gas. In this process, the perovskite crystal structure can be broken up into smaller crystal units and then recrystallized, so that the perovskite grain size can be more uniform, thereby repairing the surface defects of the perovskite film, making the film layer denser and flatter. The obtained perovskite film has good optoelectronic properties and can improve the stability of its energy conversion efficiency when used in perovskite solar cells.

[0021] The perovskite film provided in the second aspect of the present application is prepared by the preparation method provided in the first aspect of the present application. Such a perovskite film is denser, flatter, and has fewer surface defects, and thus has good optoelectronic properties.

[0022] The perovskite solar cell provided in the third aspect of the present application includes the perovskite film provided in the second aspect of the present application. Based on the advantages of this perovskite film, the perovskite solar cell of the present application has a very stable conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 is the physical appearance diagram of the perovskite film provided by the embodiments and comparative examples of the present application;

[0025] Figure 2 is the microscopic surface diagram of the perovskite film provided by the embodiments and comparative examples of the present application;

[0026] Figure 3 is the microscopic cross-sectional diagram of the perovskite solar cell provided by the embodiments and comparative examples of the present application;

[0027] Figure 4 is the energy conversion efficiency (PCE) data obtained by testing different sites of the perovskite solar cell provided by the embodiments and comparative examples of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application more clear, the following further details the present application in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] In the present application, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Wherein A and B may be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0030] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following (items)" or similar expressions refer to any combination of these items, including any combination of single (item) or plural items (items).

[0031] It should be understood that in various embodiments of the present application, the sequence numbers of the above processes do not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0032] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0033] The weight of the relevant components mentioned in the specification of the embodiments of the present application not only can refer to the specific content of each component, but also can represent the proportional relationship of the weights between the components. Therefore, as long as the content of the relevant components in the specification of the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass described in the specification of the embodiments of the present application can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0034] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX can also be referred to as the second XX. Similarly, the second XX can also be referred to as the first XX. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features.

[0035] Generally, in the film layer of the prepared perovskite film, there is a situation where the particle size distribution of perovskite crystals is uneven. The presence of larger perovskite particle crystals easily affects the denseness and flatness of the perovskite film layer, thereby affecting its performance. For example, a rough perovskite film is prone to the following defects: 1. Affecting the interfacial charge transfer of the film: Excessive surface roughness may lead to poor interfacial charge transfer, even causing leakage phenomena, reducing characteristics such as open-circuit voltage (Voc) and fill factor (FF). 2. The rough perovskite layer may affect the deposition uniformity of the electrode or encapsulation layer, increasing the risk of defects or short circuits, and thus reducing the battery performance and stability.

[0036] Based on this, in the embodiments of the present application, a gas adsorbent is first added to the prepared perovskite precursor solution, and then the initial perovskite film after film formation is placed in a nitrogen-containing gas for adsorption treatment. Through the synergistic relationship between the gas adsorbent and the nitrogen-containing gas, the crystal particles in the prepared perovskite film are made more uniform, so that the surface defects of the perovskite film can be repaired, and the film layer is made denser and flatter. The specific technical solution is as follows.

[0037] An embodiment of the present application provides a method for preparing a perovskite film. Specifically, the preparation method provided by the embodiment of the present application includes:

[0038] S01: Prepare a perovskite precursor solution containing a gas adsorbent;

[0039] S02: Perform film-forming treatment on the perovskite precursor solution to obtain an initial perovskite film;

[0040] S03: Place the initial perovskite film in a nitrogen-containing gas for adsorption treatment to obtain a perovskite film.

[0041] The nitrogen-containing gas refers to a compound in a gaseous state at normal temperature (20 - 25 °C) and normal pressure (101.325 kPa) and contains nitrogen element. For example, the nitrogen-containing gas includes ammonia (NH3), methylamine (CH3NH2), dimethylamine ((CH3)2NH), trimethylamine ((CH3)3N), ethylamine (C2H5NH2), etc.

[0042] The gas adsorbent refers to a substance having the ability to adsorb the above nitrogen-containing gas, and specifically can be a polymer substance. It can be dissolved in the perovskite precursor solution. Generally, it contains hydroxyl or ether oxygen, and therefore has an adsorption effect on the above nitrogen-containing gas. For example, the gas adsorbent includes polyvinyl alcohol (PVA, structural formula [CH2CH(OH)] n ), polypropylene alcohol, polyethylene glycol (PEG, structural formula HO(CH2CH2O) n H), polyacrylic acid (PAA, structural formula [CH2CH(COOH)] n ), polyurethane (PU, that is, polyisocyanate, formed by the polycondensation reaction of polyol and polyisocyanate), polyhydroxyethyl methacrylate (PHEMA, that is, polyethyl methacrylate hydroxy, structural formula [CH2C(CH3)(COOCH2CH2OH)] n ), poly(lactic acid - glycolic acid) copolymer (PLGA, polymerized from lactic acid and glycolic acid), polydimethylsiloxane (PDMS, structural formula [C2H6SiO] n ), etc.

[0043] The gas adsorbent is used in combination with a nitrogen-containing gas. First, the gas adsorbent is added to the prepared perovskite precursor solution, and then the initial perovskite film formed into a film is placed in a nitrogen-containing gas for adsorption treatment. Since there is a gas adsorbent in the initial perovskite film, the initial perovskite film can adsorb the nitrogen-containing gas. In this process, the perovskite crystal structure can be broken up into smaller crystal units and then recrystallized, so that the perovskite grain size can be more uniform. Taking the nitrogen-containing gas as methylamine as an example, the reaction formula is as follows, where MA represents the gas methylamine and PVSK represents the perovskite crystal.

[0044]

[0045] There is a gas adsorbent around the perovskite crystal, which can adsorb the nitrogen-containing gas. After adsorption, the perovskite crystal structure can be broken up to form the smallest crystal units, and then rearranged and combined to form perovskite crystallization. This can repair the defects of the perovskite film, make the film layer denser and flatter. The obtained perovskite film has good optoelectronic properties and can improve the uniform stability of its energy conversion efficiency when used in perovskite solar cells.

[0046] In step S01: In the perovskite precursor solution, it is a precursor solution of an organic-inorganic hybrid perovskite material, and the chemical formula of the organic-inorganic hybrid perovskite material is ABX3; among them, A is a monovalent organic cation, B is a divalent metal cation, and X is a monovalent anion, such as a halogen.

[0047] The perovskite precursor solution is obtained by dissolving the halide of the monovalent organic cation and the halide of the divalent metal cation in a solvent. Among them, A is a monovalent organic cation, which can include CH3NH3 + (MA + ), CH(NH2)2 + (FA + ), ethylammonium (EA + ), propylammonium (PA + ), butylammonium (BA + ) and at least one of the like. B is a divalent metal cation, specifically including Pb 2+ , Sn 2+ and at least one of them; X is a monovalent anion, specifically a halide ion, including Cl - , Br - and I - and at least one of them. The halide of the monovalent organic cation and the halide of the divalent metal cation are dissolved in a solvent, and the gas adsorbent is further dissolved to obtain a perovskite precursor solution containing the gas adsorbent.

[0048] In some embodiments, the chemical formula ABX3 of the perovskite material in the perovskite film obtained by the above method may be FA1-x MA x PbI3 (where 0 ≤ x ≤ 1), or MAPb(I 1-x Br x )3 (where 0 ≤ x ≤ 1), or FA 1-x MA x Sn 1- x Pb x I3 (where 0 ≤ x ≤ 1), or FA 1-x MA x Pb(I 1-x Br x )3 (where 0 ≤ x ≤ 1). Or, it can also be (BA)2(MA) x-1 Pb x I 3x+1 (where 1 ≤ x).

[0049] In some embodiments, the gas adsorbent includes at least one of polyvinyl alcohol, polypropylene alcohol, polyethylene glycol, polyacrylic acid, polyurethane, polyhydroxyethyl methacrylate, poly(lactic-co-glycolic acid), and polydimethylsiloxane. The nitrogen-containing gas includes at least one of ammonia, methylamine, dimethylamine, trimethylamine, and ethylamine.

[0050] In some embodiments, the weight ratio of the gas adsorbent in the perovskite film is 0.1 - 20 wt%. For example, 0.1 wt%, 1 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, etc. of the perovskite weight. By adding the gas adsorbent in the above weight ratio, the nitrogen-containing gas can be effectively adsorbed.

[0051] In some embodiments, the concentration of the gas adsorbent in the perovskite precursor solution is 0.1 - 1 mM (mmol / L). For example, the concentration of the gas adsorbent in the perovskite precursor solution can be 0.1 mM, 0.2 mM, 0.5 mM, 0.8 mM, 1 mM, etc. In this way, the gas adsorbent can be evenly dispersed.

[0052] In step S02: The perovskite precursor solution forms an initial film.

[0053] In some embodiments, the film-forming treatment of the perovskite precursor solution includes: coating the perovskite precursor solution on a substrate and then performing heat treatment under the condition of 100 - 150 °C.

[0054] In step S03: The adsorption reaction between the initial perovskite film and the nitrogen-containing gas.

[0055] In some embodiments, the molar ratio of the gas adsorbent to the nitrogen-containing gas is 1:(3.5 - 5). For example, it can be 1:3.5, 1:4, 1:4.5, 1:5, etc. Specifically, the nitrogen-containing gas can be an excess gas, so that the gas adsorbent can well assist in adsorbing the nitrogen-containing gas and promote the recrystallization of perovskite.

[0056] In some embodiments, subjecting the initial perovskite film to adsorption treatment in a nitrogen-containing gas includes: placing the initial perovskite film in a vacuum chamber, and then introducing the nitrogen-containing gas into the vacuum chamber for adsorption treatment. For example, adsorption can be carried out for 1 - 10 min. Subsequent annealing treatment can also be further carried out.

[0057] In some embodiments, the method for preparing a perovskite film includes: (1) preparing a perovskite precursor solution containing a gas adsorbent; (2) spin-coating the perovskite precursor solution on a substrate at 1000 - 2000 rpm and heat-treating it under the condition of 100 - 150 °C to obtain an initial perovskite film; (3) placing the initial perovskite film in a vacuum chamber, introducing a nitrogen-containing gas, and performing adsorption treatment to obtain a perovskite film.

[0058] The surface roughness of the perovskite film obtained by the above method will be reduced to Sa < 10 nm, which is smoother than the surface roughness (Sa > 48 nm) of the perovskite film obtained by the existing common methods. The cross-section of the perovskite film is not prone to irregular holes, and the perovskite grains are uniform, which can be greater than 450 nm. The perovskite crystal plane orientation with the crystal plane group of {110} or {100} has better crystallinity.

[0059] In the second aspect, the embodiments of the present application provide a perovskite film. Specifically, the perovskite film of the embodiments of the present application is prepared by the preparation method provided in the first aspect of the embodiments of the present application.

[0060] Based on the fact that the perovskite film of the embodiments of the present application is prepared by the preparation method provided in the first aspect of the embodiments of the present application, such a perovskite film is denser, flatter, and has fewer surface defects, and thus has good optoelectronic properties.

[0061] In the third aspect, the embodiments of the present application provide a perovskite solar cell. Specifically, the perovskite solar cell includes the perovskite film provided in the second aspect of the embodiments of the present application.

[0062] Based on the fact that the perovskite solar cell of the embodiments of the present application includes the perovskite film provided in the second aspect of the embodiments of the present application, due to the advantages of the perovskite film, the perovskite solar cell of the present application has a more stable conversion efficiency.

[0063] Specifically, in the module of the perovskite solar cell, whether it is the dead area, active area, mark area, etc., as long as the area where the above-mentioned perovskite film exists, it can present a high brightness and uniform and stable conversion efficiency effect.

[0064] Specifically, the perovskite solar cell of the embodiment of the present application includes a first electrode, a second electrode, and a perovskite layer located between the first electrode and the second electrode. An electron transport layer is provided between the perovskite layer and the first electrode, and the perovskite layer is the perovskite film obtained by the above preparation method of the embodiment of the present application.

[0065] In some embodiments, the electron transport layer can be a metal oxide or a doped metal oxide. For example, the metal oxide includes at least one of TiO2, NiOx, SnO2, ZrO2, ZnO. Among them, the electron transport layer can be a single layer of metal oxide or two stacked metal oxides.

[0066] In some embodiments, the first electrode can be a transparent conductive substrate, including but not limited to the following materials: fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium-doped zinc oxide (IZO), etc. The second electrode can be a metal top electrode, such as gold, silver, copper, etc., or one or more of the conductive oxide electrodes.

[0067] The preparation method of the above perovskite solar cell includes: 1) preparing an electron transport layer on the first electrode; 2) preparing a perovskite layer on the electron transport layer, that is, the perovskite film can be prepared by the preparation method provided in the first aspect of the embodiment of the present application; 3) preparing a second electrode on the perovskite layer. By this method, a flat and dense perovskite film can be prepared on the electron transport layer.

[0068] In some embodiments, a hole transport layer can also be provided between the perovskite layer and the second electrode to further improve the hole transport performance of the perovskite solar cell. Specifically, the materials of the hole transport layer can include 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly-3-hexylthiophene (P3HT), triphenylene-based triphenylamine (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-aniline)carbazole-spirobifluorene (CzPAF-SBF), poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), etc.

[0069] The following will be described in conjunction with specific embodiments.

[0070] The following is an illustration with specific embodiments.

[0071] Embodiment 1

[0072] A perovskite solar cell and its preparation method. The structure of the perovskite solar cell sequentially includes: a first electrode (material: FTO substrate), an electron transport layer (material: TiO2), a perovskite layer (the perovskite material contained is MAPbI3), a hole transport layer (material: Spiro-OMeTAD), and a second electrode (material: gold).

[0073] The preparation method of the above perovskite solar cell includes:

[0074] Step 1: Clean the conductive FTO substrate, then sputter-deposit TiO2 on the FTO substrate, then spin-coat the TiO2 nanoparticle suspension at a speed of 4000 rpm, and then anneal at 450 °C to obtain an electron transport layer, about 200 nm.

[0075] Step 2: Prepare a perovskite precursor solution by dissolving PbI2 and MAI in a mixed solvent (DMF and DMSO mixed at a weight ratio of 4:1), where the molar ratio of PbI2 to MAI is 3:1 and the concentration of MAI is 0.25 M (mol / L); then add polyvinyl alcohol (PVA) and add it according to the weight ratio of PVA to the generated MAPbI3 of 15 wt%, and obtain a perovskite precursor solution containing PVA after uniform dispersion.

[0076] Spin-coat the above perovskite precursor solution on the electron transport layer at a speed of 2000 rpm, anneal at 130 °C for 10 min to obtain an initial perovskite film, then place the initial perovskite film in a vacuum chamber, introduce a nitrogen-containing gas methylamine for treatment for 1 min, evacuate and maintain the vacuum degree at -85 kPa for 2 min, and then anneal at 130 °C for 10 min to obtain a final perovskite film, which is the perovskite layer, about 500 nm.

[0077] Step 3: Spin-coat a chlorobenzene solution of Spiro-OMeTAD on the perovskite layer at a speed of 4000 rpm, and anneal at 100 °C to obtain a hole transport layer, about 200 nm.

[0078] Step 4: Sputter-deposit gold on the hole transport layer, about 80 nm, to obtain a second electrode.

[0079] Embodiment 2

[0080] A preparation method of a perovskite solar cell. The difference from the preparation steps of Example 1 is that polyvinyl alcohol (PVA) in the perovskite precursor solution is replaced by polyethylene glycol (PEG), and methylamine, a nitrogen-containing gas in the adsorption reaction, is replaced by ethylamine. Other steps are the same as those in Example 1.

[0081] Comparative Example 1

[0082] A preparation method of a perovskite solar cell, the difference from the preparation steps of Example 1 is that the preparation steps of the perovskite layer are as follows:

[0083] Prepare a perovskite precursor solution by dissolving PbI2 and MAI in a mixed solvent (DMF and DMSO mixed at a weight ratio of 4:1), where the molar ratio of PbI2 to MAI is 3:1 and the concentration of MAI is 0.25 M (mol / L). Spin-coat the perovskite precursor solution on the electron transport layer at a speed of 2000 rpm and anneal at 130 °C to obtain a perovskite layer, about 500 nm.

[0084] Performance test

[0085] (1) Macroscopic and microscopic detection of the perovskite film surface

[0086] Figure 1 Figs. are the physical appearance diagrams of the perovskite films provided in Example 1 and Comparative Example 1 of this application. Among them, (A) is the diagram of Comparative Example 1, and (B) is the diagram of Example 1, indicating that there are cracks on the surface of the perovskite film in Comparative Example 1, while there are basically none in Example 1. Figure 2 Figs. are the microscopic surface diagrams of the perovskite films provided in Example 1 and Comparative Example 1 of this application. Among them, (A) is the diagram of Comparative Example 1, and (B) is the diagram of Example 1, indicating that the surface of the perovskite film in Comparative Example 1 is rougher (Sa = 48.1 nm), while the perovskite film in Example 1 is smoother (Sa = 9.1 nm). Among them, the roughness is obtained by calculating the average value after testing different sites on the perovskite film surface.

[0087] (2) Perovskite solar cell detection

[0088] Figure 3 Figs. are the microscopic cross-sectional diagrams of the perovskite solar cells provided in Example 1 and Comparative Example 1 of this application. Among them, (A) is the diagram of Comparative Example 1, and (B) is the diagram of Example 1, indicating that there are some irregular holes in the cross-section of the perovskite layer of the cell in Comparative Example 1, and the surface is also uneven, while the surface of the perovskite layer of the cell in Example 1 is smooth, and there are no irregular holes in the cross-section.

[0089] Figure 4The data of the power conversion efficiency (PCE) obtained from different sites of the perovskite solar cells provided in Example 1 and Comparative Example 1 of this application. Among them, (A) is the data of Comparative Example 1, and (B) is the data of Example 1, indicating that the perovskite solar cells of the embodiments of this application are more stable. The power conversion efficiency data was obtained by designing different test sites in the corresponding 15 cm * 15 cm perovskite solar cell module for power conversion efficiency testing.

[0090] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A method for preparing a perovskite film, characterized in that: include: preparing a perovskite precursor solution containing a gas adsorbent; Performing film-forming treatment on the perovskite precursor solution to obtain an initial perovskite film; The initial perovskite film is placed in a nitrogen-containing gas for adsorption treatment to obtain a perovskite film.

2. The preparation method according to claim 1, characterized in that The gas adsorbent includes at least one of polyvinyl alcohol, polypropylene alcohol, polyethylene glycol, polyacrylic acid, polyurethane, polyhydroxyethyl methacrylate, polylactic acid-glycolic acid copolymer, and polydimethylsiloxane.

3. The preparation method according to claim 1, characterized in that: The nitrogen-containing gas includes at least one of ammonia, methylamine, dimethylamine, trimethylamine, and ethylamine.

4. The preparation method according to claim 1, characterized in that: The weight ratio of the gas adsorbent in the perovskite film is 0.1 to 20 wt %; And / or, the concentration of the gas adsorbent in the perovskite precursor solution is 0.1-1 mM.

5. The preparation method according to claim 1, characterized in that: The molar ratio of the gas adsorbent to the nitrogen-containing gas is 1:(3.5-5).

6. The preparation method according to any one of claims 1 to 5, characterized in that: Placing the initial perovskite film in a nitrogen-containing gas for adsorption treatment includes: placing the initial perovskite film in a vacuum chamber, and then introducing the nitrogen-containing gas into the vacuum chamber for adsorption treatment.

7. The preparation method according to any one of claims 1 to 5, characterized in that: The film-forming treatment of the perovskite precursor solution includes: coating the perovskite precursor solution on a substrate, and then performing a heat treatment at 100-150° C.

8. The preparation method according to any one of claims 1 to 5, characterized in that: The perovskite material in the perovskite film is an organic-inorganic hybrid perovskite, and the chemical formula of the organic-inorganic hybrid perovskite is ABX3; wherein A is a monovalent organic cation, B is a divalent metal cation, and X is a monovalent anion.

9. A perovskite film, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. A perovskite solar cell, characterized in that: Comprising the perovskite film as described in claim 9.

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