Solvent composition, perovskite thin film and preparation method thereof, and solar cell

Abstract

The invention relates to the technical field of photovoltaic cells, in particular to a solvent composition, a perovskite thin film, a preparation method of the perovskite thin film and a solar cell. The solvent composition comprises: a main solvent, the boiling point of which is greater than 150 DEG C, the main solvent being selected from at least one of a perfluoroalkane compound and a perfluorotertiary amine compound; the boiling point of the extracting solvent is higher than 150 DEG C, and the extracting solvent is selected from at least one of aromatic ether compounds, halogenated aromatic compounds and ester compounds; the polarity of the adjusting solvent is between the polarity of the main solvent and the polarity of the extracting solvent. According to the solvent composition provided by the invention, through the synergistic effect of the main body solvent, the extraction solvent and the adjusting solvent, mild and controllable extraction is realized, the crystallization quality of the film is improved, the temperature of the solvent bath annealing treatment can reach the conversion temperature of the photoactive phase of the perovskite film or above, the phase transformation is sufficient, and the photoelectric property of a device is further improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, and in particular to solvent compositions, perovskite thin films and their preparation methods, and solar cells. Background Technology

[0002] Perovskite solar cells have attracted widespread attention due to their many advantages, such as long carrier diffusion length, high absorption coefficient, adjustable band gap, compatibility with multiple fabrication methods, and simple fabrication methods.

[0003] In the preparation of perovskite thin films for perovskite solar cells, thermal annealing is a key process. Traditional thermal annealing processes suffer from poor temperature uniformity, thermal delay, and temperature gaps, affecting the quality of the perovskite film. Immersing the wet perovskite film in a perovskite antisolvent for solvent bath annealing can improve heat transfer and promote perovskite crystallization.

[0004] In traditional techniques, solvent bath annealing often uses a single perovskite antisolvent for extraction.

[0005] For solvent bath annealing of a single component, using a highly polar solvent is beneficial for improving the extraction effect, fully extracting residual solvents in the precursor (such as DMF, DMSO, NMP, etc.), and improving the lifetime of the perovskite film under photothermal conditions. However, using highly polar solvents carries the risk of dissolving or rearranging the surface components of the perovskite, resulting in undesirable morphology and surface defects (such as incomplete crystal growth, fine grains, etc.), which are detrimental to carrier transport. In addition, most antisolvents have low boiling points (such as chlorobenzene, toluene, etc.), making it difficult for the perovskite film to reach the conversion temperature of the photoactive phase (usually 120℃~150℃), affecting the photoelectric conversion performance of the device. Summary of the Invention

[0006] Therefore, it is necessary to provide a solvent composition, a perovskite thin film and its preparation method, and a solar cell, so as to achieve mild and controllable extraction, improve the crystallinity quality of the perovskite thin film, and the solvent bath annealing temperature can reach above the conversion temperature of the photoactive phase of the perovskite thin film, so that the phase transformation is sufficient and the photoelectric performance of the device can be improved.

[0007] A first aspect of this application provides a solvent composition comprising a base solvent, an extraction solvent, and a conditioning solvent. The base solvent has a boiling point greater than 150°C and is selected from at least one of perfluoroalkane compounds and perfluorotertiary amine compounds. The extraction solvent has a boiling point greater than 150°C and is selected from at least one of aromatic ether compounds, halogenated aromatic compounds, and ester compounds. The polarity of the conditioning solvent is between that of the base solvent and the extraction solvent.

[0008] In some embodiments, the volume ratio of the main solvent, the extraction solvent and the conditioning solvent is (5~8):(0.5~2):(1~3).

[0009] Furthermore, the volume ratio of the main solvent, extraction solvent and adjustment solvent is (7~8):(1~2):(1~2).

[0010] In some embodiments, the main solvent is selected from at least one of perfluorododecane, perfluorotridecane, perfluorotetradecane, perfluoropentadecanane, perfluorohexadecane, perfluorotributylamine, perfluorotripentylamine, and perfluorotrihexylamine.

[0011] In some embodiments, the extraction solvent is selected from at least one of anisole, o-methyl anisole, m-methyl anisole, p-methyl anisole, phenethyl ether, methyl anisole, 4-methyl anisole, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, butyl butyrate, ethyl hexanoate, ethyl heptaate, ethyl octanoate, hexyl acetate, heptaate, pentyl propionate, hexyl butyrate, isobutyl isovalerate, butyl isovalerate, butyl valerate, isoamyl isovalerate, isoamyl butyrate, pentyl butyrate, isoamyl isovalerate, and methyl benzoate.

[0012] In some embodiments, the adjusting solvent is selected from at least one of octane, perfluorooctane, decadecane, perfluorotoluene, and perfluorobiphenyl.

[0013] In some embodiments, the boiling point of the main solvent is less than or equal to 250°C.

[0014] In some embodiments, the boiling point of the extraction solvent is less than or equal to 250°C.

[0015] A second aspect of this application provides a method for preparing a perovskite thin film, the method comprising the following steps: immersing a perovskite wet film in the solvent composition provided in the first aspect above, and performing solvent bath annealing treatment to form a perovskite thin film.

[0016] In some embodiments, the solvent bath annealing temperature is greater than or equal to the transition temperature of the photoactive phase of the perovskite film.

[0017] In some embodiments, the solvent bath annealing temperature is 120°C to 150°C.

[0018] In some embodiments, after solvent bath annealing, the preparation method further includes the following step: heat-treating the perovskite film formed by solvent bath annealing at a temperature lower than that of solvent bath annealing.

[0019] A third aspect of this application provides a perovskite thin film prepared using the perovskite thin film preparation method provided in the second aspect above.

[0020] A fourth aspect of this application provides a solar cell comprising the perovskite thin film provided in the third aspect above.

[0021] Compared with traditional technologies, this application has at least the following beneficial effects: The solvent composition provided in some embodiments of this application has a main solvent as the main component with low polarity, which hardly extracts the perovskite precursor solvent, providing a higher boiling point and thermal field for the solvent bath composition. Moreover, the abundant fluorine substituents on its molecule endow it with high hydrophobicity, which can isolate the perovskite from water vapor in the air during the solvent bath process, reducing the generation of high-density defect states in the perovskite caused by excessive humidity during the annealing process. This can improve the humidity tolerance of the preparation environment and reduce the operating cost of maintaining a low humidity environment. The polarity of the extraction solvent is slightly higher than that of the main solvent, and it is used to extract the perovskite precursor solvent. Adjusting the polarity of the solvent to be between that of the main solvent and the extraction solvent can regulate the extraction effect of the solvent composition on the perovskite precursor solvent in the perovskite wet film.

[0022] Furthermore, the host solvent, extraction solvent, and conditioning solvent exhibit a synergistic effect. Both the host solvent and extraction solvent have boiling points greater than 150°C, collectively regulating the azeotropic point of the solvent composition. This allows the solvent bath annealing temperature to reach above the conversion temperature of the photoactive phase of the perovskite film, while preventing the solvent composition from being rapidly evaporated. The conditioning solvent not only regulates the extraction process but also buffers the polarity difference between the host solvent and extraction solvent, promoting better miscibility and preventing stratification. Thus, by coordinating solvent polarities, the host solvent, extraction solvent, and conditioning solvent control the interaction between the solvent composition and the perovskite precursor solvent, achieving a balance between extraction efficiency, boiling point, and damage to the perovskite components. Compared to a single antisolvent, the solvent composition provided in this application offers adjustable physical parameters and a wider process window.

[0023] In summary, the solvent compositions provided in some embodiments of this application achieve mild and controllable extraction through the synergistic effect of the main solvent, extraction solvent, and regulating solvent, thereby improving the crystallinity quality of perovskite films. This allows the solvent bath annealing temperature to reach above the conversion temperature of the photoactive phase of the perovskite film, ensuring a complete phase transformation and thus improving the optoelectronic performance of the device. At the same time, it reduces process costs, broadens the process window, and facilitates large-scale industrial applications. Attached Figure Description

[0024] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0025] Figure 1 This is a schematic diagram of a method for preparing a perovskite thin film according to one embodiment of this application.

[0026] Figure 2 This is a SEM image of the perovskite thin film in Example 1 of this application.

[0027] Figure 3 This is a SEM image of the perovskite thin film in Example 2 of this application.

[0028] Figure 4 This is a SEM image of the perovskite thin film in Comparative Example 1 of this application.

[0029] Figure 5 This is a SEM image of the perovskite thin film in Comparative Example 2 of this application.

[0030] Figure 6 The JV test curves are for the solar cells in Embodiment 1 and Comparative Examples 1-4 of this application.

[0031] Figure 7 The images show the XRD patterns of the perovskite films in Example 1 and Comparative Example 1 of this application. Detailed Implementation

[0032] Reference will now be made to detailed embodiments of this application, one or more of which are described below. Each example is provided for explanation and not for limitation of this application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0033] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0034] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0035] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0036] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0037] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0038] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0039] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0040] A first aspect of this application provides a solvent composition comprising a base solvent, an extraction solvent, and a conditioning solvent. The base solvent has a boiling point greater than 150°C and is selected from at least one of perfluoroalkane compounds and perfluorotertiary amine compounds. The extraction solvent has a boiling point greater than 150°C and is selected from at least one of aromatic ether compounds, halogenated aromatic compounds, and ester compounds. The polarity of the conditioning solvent is between that of the base solvent and the extraction solvent.

[0041] The solvent compositions provided in some embodiments of this application have a main solvent as the main component. This main solvent has low polarity and hardly extracts the perovskite precursor solvent, providing a high boiling point and thermal field for the solvent bath composition. Furthermore, the abundant fluorine substituents on its molecules endow it with high hydrophobicity, which can isolate the perovskite from water vapor in the air during the solvent bath process. This reduces the generation of high-density defect states in the perovskite caused by excessive humidity during annealing, thereby improving the humidity tolerance of the preparation environment and reducing the operating cost of maintaining a low-humidity environment. The polarity of the extraction solvent is slightly higher than that of the main solvent and is used to extract the perovskite precursor solvent. Adjusting the polarity of the solvent to be between that of the main solvent and the extraction solvent can regulate the extraction effect of the solvent composition on the perovskite precursor solvent in the perovskite wet film.

[0042] Furthermore, the host solvent, extraction solvent, and conditioning solvent exhibit a synergistic effect. Both the host solvent and extraction solvent have boiling points greater than 150°C, collectively regulating the azeotropic point of the solvent composition. This allows the solvent bath annealing temperature to reach above the conversion temperature of the photoactive phase of the perovskite film, while preventing the solvent composition from being rapidly evaporated. The conditioning solvent not only regulates the extraction process but also buffers the polarity difference between the host solvent and extraction solvent, promoting better miscibility and preventing stratification. Thus, by coordinating solvent polarities, the host solvent, extraction solvent, and conditioning solvent control the interaction between the solvent composition and the perovskite precursor solvent, achieving a balance between extraction efficiency, boiling point, and damage to the perovskite components. Compared to a single antisolvent, the solvent composition provided in this application offers adjustable physical parameters and a wider process window.

[0043] In summary, the solvent compositions provided in some embodiments of this application achieve mild and controllable extraction through the synergistic effect of the main solvent, extraction solvent, and regulating solvent, thereby improving the crystallinity quality of perovskite films. This allows the solvent bath annealing temperature to reach above the conversion temperature of the photoactive phase of the perovskite film, ensuring a complete phase transformation and thus improving the optoelectronic performance of the device. At the same time, it reduces process costs, broadens the process window, and facilitates large-scale industrial applications.

[0044] In some embodiments, the volume ratio of the main solvent, extraction solvent, and conditioning solvent is (5~8):(0.5~2):(1~3). Exemplarily, the volume ratio of the main solvent, extraction solvent, and conditioning solvent can be, but is not limited to, 5:2:3, 6:2:2, 6:1:3, 7:0.5:2.5, 7:1:2, 7:2:1, 8:0.5:1.5, and 8:1:1. Within the above volume ratio range, the high-boiling-point main solvent and extraction solvent constitute the majority, thereby effectively increasing the azeotropic point of the conditioning solvent composition. This allows the solvent bath annealing temperature to reach the conversion temperature of the photoactive phase of the perovskite film, while the system itself is not easily volatile. Furthermore, the main solvent, as the main component, has high hydrophobicity, which can effectively isolate the perovskite from moisture in the air during solvent bath annealing, reducing the generation of high-density defect states in the perovskite and improving the quality of the perovskite film.

[0045] Furthermore, the volume ratio of the main solvent, extraction solvent and adjustment solvent is (7~8):(1~2):(1~2).

[0046] In some embodiments, the main solvent is selected from at least one of perfluorododecane, perfluorotridecane, perfluorotetradecane, perfluoropentadecanane, perfluorohexadecane, perfluorotributylamine, perfluorotripentylamine, and perfluorotrihexylamine.

[0047] In some embodiments, the extraction solvent is selected from at least one of anisole, o-methyl anisole, m-methyl anisole, p-methyl anisole, phenethyl ether, methyl anisole, 4-methyl anisole, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, butyl butyrate, ethyl hexanoate, ethyl heptaate, ethyl octanoate, hexyl acetate, heptaate, pentyl propionate, hexyl butyrate, isobutyl isovalerate, butyl isovalerate, butyl valerate, isoamyl isovalerate, isoamyl butyrate, pentyl butyrate, isoamyl isovalerate, and methyl benzoate.

[0048] In some embodiments, the adjusting solvent is selected from at least one of octane, perfluorooctane, decadecane, perfluorotoluene, and perfluorobiphenyl.

[0049] In some embodiments, the boiling point of the main solvent is less than or equal to 250°C.

[0050] In some embodiments, the boiling point of the extraction solvent is less than or equal to 250°C.

[0051] Therefore, there is an upper limit to the boiling points of the main solvent and the extraction solvent to prevent the viscosity of the solvent composition from being too high, and to ensure that the above components can be removed by simple heat treatment after solvent bath annealing, thereby reducing the impact of residual solvent composition on the performance of perovskite thin films.

[0052] A second aspect of this application provides a method for preparing a perovskite thin film, the method comprising the following steps: immersing a perovskite wet film in the solvent composition provided in the first aspect above, and performing solvent bath annealing treatment to form a perovskite thin film.

[0053] In some embodiments, the solvent bath annealing temperature is greater than or equal to the conversion temperature of the photoactive phase of the perovskite film. Thus, during solvent bath annealing, the non-photoactive phase of the perovskite film is transformed into an active phase with excellent photoelectric properties, resulting in solar cell devices fabricated from this perovskite film exhibiting superior photoelectric conversion performance.

[0054] In this paper, the "transition temperature of the photoactive phase in perovskite films" refers to the lowest process temperature required to transform the non-photoactive phase (such as the yellow δ-FAPbI3 phase) in a perovskite film into a photoactive phase (such as the black α-FAPbI3 phase) under solvent bath annealing conditions. Specifically, this temperature can be determined by performing X-ray diffraction (XRD) analysis on perovskite films obtained after solvent bath annealing at different temperatures. By comparing the changes in the characteristic peak intensities of the photoactive and non-photoactive phases in the perovskite films, the lowest annealing temperature required to achieve the photoactive phase transition is determined as the transition temperature of the photoactive phase in the perovskite film.

[0055] It is understandable that the photoactive phase transition temperature of perovskite thin films is typically influenced by various factors, including perovskite composition, band gap, specific fabrication process, and additives. Therefore, for those skilled in the art, the photoactive phase transition temperature defined herein is a characteristic temperature that is related to a specific system and process conditions and can be determined through objective experimental methods.

[0056] In some specific embodiments, the solvent bath annealing temperature is 120°C to 150°C. Exemplarily, the solvent bath annealing temperature can be, but is not limited to, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, and 150°C.

[0057] In some embodiments, the solvent bath annealing time is 10 min to 30 min. Exemplarily, the solvent bath annealing time can be, but is not limited to, 10 min, 15 min, 20 min, 25 min, or 30 min.

[0058] In some embodiments, after solvent bath annealing, the preparation method further includes the following step: heat-treating the perovskite film formed by solvent bath annealing at a temperature lower than that of solvent bath annealing. This heat treatment at a lower temperature removes residual solvent and allows for appropriate tempering growth of the perovskite film, which is beneficial for secondary grain growth and further reduces bulk and grain boundary defects.

[0059] In some specific implementations, such as Figure 1 As shown, the perovskite wet film is first immersed in the solvent composition and subjected to solvent bath annealing to form a perovskite thin film. After the solvent bath annealing is completed, the perovskite thin film is placed on a hot table for heat treatment to dry the residual solvent composition in the perovskite thin film.

[0060] In some specific embodiments, the heat treatment temperature is 100°C to 120°C. Exemplarily, the heat treatment temperature can be, but is not limited to, 100°C, 105°C, 110°C, 115°C, and 120°C.

[0061] In some embodiments, the perovskite wet film is obtained by coating a perovskite precursor solution onto a conductive substrate.

[0062] In this application, the conductive substrate is a conductive substrate, or a combination of a conductive substrate and a hole transport layer.

[0063] Specifically, perovskite precursor solutions can be coated onto conductive substrates using spin coating, blade coating, or slot coating methods to obtain a perovskite wet film. The coating process parameters are not particularly limited and can be adjusted according to the target thickness of the perovskite wet film. Spin coating is generally used for small-area devices due to its convenience and speed; blade coating or slot coating is generally used for large-area devices, helping to obtain a uniform and dense wet film with good process repeatability.

[0064] In some embodiments, the perovskite material components and solvents are mixed to obtain a perovskite precursor solution.

[0065] In some embodiments, the solvent for the perovskite precursor solution is selected from one or more of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), and acetonitrile.

[0066] In some embodiments, the perovskite material is denoted by the chemical formula ABX3, where A includes one or more of formamidinium cations, methylammonium cations, rubidium ions, and cesium ions, B includes lead ions and / or tin ions, and X is a chloride, bromine, or iodide halide anion, or a combination of pseudohalogens with thiocyanate or cyanate ions.

[0067] A third aspect of this application provides a perovskite thin film prepared using the perovskite thin film preparation method provided in the second aspect above.

[0068] A fourth aspect of this application provides a solar cell comprising the perovskite thin film provided in the third aspect above.

[0069] This application does not limit the specific structure of the solar cell; in one specific embodiment, the solar cell includes one of the following: perovskite single-cell cell, perovskite / perovskite tandem cell, perovskite / crystalline silicon tandem cell, perovskite / organic tandem cell, and perovskite / copper indium gallium selenide tandem cell.

[0070] In some embodiments, a method for fabricating a perovskite solar cell is provided, which includes the steps of sequentially fabricating a hole transport layer, a perovskite light-absorbing layer, a passivation layer, an electron transport layer, a buffer layer, and an electrode on a conductive substrate, wherein the perovskite light-absorbing layer can be fabricated using the steps for fabricating a perovskite thin film as described herein.

[0071] In some embodiments, the conductive substrate is selected from crystalline silicon cells, conductive glass, and flexible conductive films.

[0072] In some embodiments, the crystalline silicon solar cell includes one of the following: passivated emitter and back contact cell (PERC cell), tunnel oxide passivated contact cell (TOPCon cell), crystalline silicon heterojunction solar cell (HJT cell), and back contact cell (IBC cell).

[0073] In some embodiments, the conductive glass has a certain degree of transparency. The conductive glass typically consists of a glass substrate and a conductive oxide thin film (TCO) layer. Commonly used TCOs include, but are not limited to, the following materials: fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), and indium zinc oxide (IZO). The conductive glass is generally any conductive glass used in the art. Conductive glass is commercially available. The conductive glass needs to be cleaned before use, for example, by ultrasonic cleaning with a cleaning agent, deionized water, or ethanol.

[0074] In some embodiments, the flexible conductive film includes one of indium tin oxide (ITO) film, fluorine-doped tin oxide (FTO) film, aluminum-doped zinc oxide (AZO) film, boron-doped zinc oxide (BZO) film, and indium zinc oxide (IZO) film.

[0075] Materials suitable for hole transport layers include, but are not limited to, organic hole transport materials, inorganic hole transport materials, and self-assembled monolayer materials.

[0076] In some embodiments, hole transport materials include [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (abbreviated as 2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (abbreviated as MeO-2PACZ), (4-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid (abbreviated as Me-4PACZ), PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate), NiO x And one or more of CuSCN.

[0077] Suitable materials for the passivation layer include 2-thiophene ethylamine hydrochloride (TEACl), 1,4-phenylenediamine hydroiodide (PDADI), phenylethylamine iodide (PEAI), and 1,3-diaminopropane dihydroiodide (PDAI2). There are no particular limitations on the preparation of the passivation layer; conventional methods in the art can be used, such as blade coating or slot coating, to coat the perovskite light-absorbing layer. Process parameters can be adjusted according to the target thickness of the passivation layer.

[0078] Materials suitable for the electron transport layer include, but are not limited to, PCBM ([6,6]-phenyl-C61-isomethyl butyrate), TiO2, SnO2, ZnO, C60, and ICBA (indene-C60 diadduct). The preparation of the electron transport layer is not particularly limited, and conventional methods in the art can be used, including but not limited to one or more of spin coating, spray coating, spray pyrolysis, slot coating, and atomic layer deposition. Process parameters can be adjusted according to the target thickness of the electron transport layer.

[0079] Suitable materials for the buffer layer include, but are not limited to, BCP (2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline) or MoO x (Molybdenum oxide), etc. The preparation of the buffer layer is not particularly limited; conventional methods for preparing buffer layers in this field can be used, including but not limited to one or more of spin coating, spray coating, spray pyrolysis, slot coating, and atomic layer deposition. Process parameters can be adjusted according to the target thickness of the buffer layer.

[0080] The materials suitable for the electrodes can be selected from one or more of silver, copper, Au (gold), ITO, IZO, AZO and IWO.

[0081] The solar cells provided in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft.

[0082] Based on the same inventive concept, embodiments of this application provide a photovoltaic module, including the solar cell in any of the above embodiments.

[0083] Multiple solar cells can be arranged, and they can be electrically connected in a single unit or in multiple segments to form multiple cell strings. These cell strings can be connected in series and / or parallel. The photovoltaic module may also include an encapsulation layer and a cover plate. The encapsulation layer covers the surface of the cell strings, and the cover plate covers the surface of the encapsulation layer away from the cell strings. Specifically, in some embodiments, multiple cell strings can be electrically connected through conductive means. The encapsulation layer covers the surface of the solar cells. Exemplarily, the encapsulation layer can be an organic encapsulation film such as an ethylene-vinyl acetate copolymer film, a polyethylene octene co-elastomer film, or a polyethylene terephthalate film. The cover plate can be a glass cover plate, a plastic cover plate, or other light-transmitting cover plate.

[0084] Based on the same inventive concept, embodiments of this application provide a photovoltaic system, including the photovoltaic modules in any of the above embodiments.

[0085] It is understandable that photovoltaic (PV) systems can be applied to PV power plants, such as ground-mounted, rooftop, and floating power plants, as well as to equipment or devices that utilize solar energy for power generation, such as user-installed solar power supplies, solar streetlights, solar-powered cars, and solar-powered buildings. Of course, it is also understandable that the application scenarios of PV systems are not limited to these; that is, PV systems can be applied in all areas that require solar energy for power generation. Taking a PV power grid as an example, a PV system can include PV arrays, combiner boxes, and inverters. A PV array can be a combination of multiple PV modules; for example, multiple PV modules can form multiple PV arrays. The PV arrays are connected to combiner boxes, which collect the current generated by the PV arrays. The collected current then flows through an inverter, converting it into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0086] The present application will be further described below with reference to specific embodiments and comparative examples.

[0087] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0088] Example 1: This example provides a solvent composition, a perovskite solar cell, and a method for preparing the same.

[0089] The solvent composition comprises a main solvent, an extraction solvent, and a conditioning solvent. The preparation method is as follows: the main solvent perfluorotributylamine (PFTB), the extraction solvent phenethyl ether (PT), and the conditioning solvent perfluorotoluene (PFT) are mixed in a volume ratio of 7:1:2 and stirred until homogeneous to obtain the solvent composition. The main solvent perfluorotributylamine has a boiling point of 177℃; the extraction solvent phenethyl ether has a boiling point of 170℃; and the conditioning solvent perfluorotoluene has a polarity intermediate between the two.

[0090] Perovskite solar cells are prepared using the following steps (1)-(7).

[0091] (1) The patterned ITO conductive glass was placed in detergent, deionized water, acetone and isopropanol in sequence and sonicated for 30 min. Then it was dried with a nitrogen gun and treated in an ultraviolet ozone generator for 30 min for later use.

[0092] (2) Dissolve Me-4PACz and MeO-2PACz in ethanol to prepare a solution with a concentration of 0.4 mg / mL. Then mix the two solutions in a volume ratio of 1:1 to prepare a hole transport layer solution and sonicate for 5 minutes for later use. Dissolve 194 mg of CsI, 456 mg of FAI, 47 mg of PbCl2, 252 mg of PbBr2, 1187 mg of PbI2 and 29 mg of MACl in 2 mL of a mixed solvent of DMF and DMSO in a volume ratio of 8:1 at room temperature to prepare a perovskite precursor solution and filter for later use. Dissolve 1,3-diaminopropane dihydroiodate (PDAI2) in a mixed solvent of isopropanol (IPA) and chlorobenzene (CB) in a volume ratio of 1:1 to prepare a passivation solution with a concentration of 1 mg / mL for later use.

[0093] (3) In the glove box, the hole transport layer solution was spin-coated onto the ITO conductive substrate using a spin coater. The spin coating parameters were: 3000 rpm rotation speed, 15 s time, and 3000 rpm / s acceleration. After spin coating, the substrate was placed on a hot plate at 100℃ for annealing for 5 min, and then taken out and cooled to room temperature for later use.

[0094] (4) Spin-coating the perovskite precursor solution onto the hole transport layer to form a perovskite wet film with a thickness of 500 nm. The spin-coating parameters are: rotation speed 4000 rpm, time 7s, acceleration 4000 rpm / s. After spin-coating, the substrate with the wet film is immediately transferred to a vacuum flash evaporator (VCD) for 15s (the vacuum flash evaporator evaporates the chamber vacuum from 101 kPa to below 10 Pa within 10s). After the vacuum is broken, the perovskite wet film is quickly immersed in the solvent composition and subjected to solvent bath annealing. The solvent bath annealing temperature is 120℃ and the time is 20 min.

[0095] (5) After completing the solvent bath annealing treatment, the perovskite film is placed on a hot table at 120°C for 5 min to dry the residual solvent composition and obtain the perovskite film.

[0096] Figure 2 This is a SEM image of the perovskite thin film prepared in this embodiment.

[0097] (6) Dynamic spin coating of surface passivation layer is performed on the perovskite film surface. The spin coating parameters are divided into two steps: the spin coating parameters of the first step are: rotation speed 300 rpm, time 5 s, acceleration 500 rpm / s, and the spin coating parameters of the second step are: rotation speed 3000 rpm, time 5 s, acceleration 5000 rpm / s. Between the 3rd and 5th seconds of the first spin coating process, the passivation solution is dropped onto the perovskite film surface. After the two spin coating steps are completed, the substrate is placed on a hot plate at 100℃ for annealing for 5 min.

[0098] (7) The substrate with completed surface passivation is transferred to a vacuum evaporation apparatus, and an electron transport layer C60 (thickness 20 nm, rate 0.2 Å / s), a hole blocking layer BCP (thickness 5 nm, rate 0.1 Å / s), and a metal electrode Cu (thickness 110 nm, evaporation rate of 0.2 Å / s for the first 10 nm and evaporation rate of 0.5 Å / s for the subsequent 100 nm) are deposited in sequence to obtain a perovskite solar cell.

[0099] Example 2: The preparation method of the solvent composition and perovskite solar cell in this example is basically the same as that in Example 1, except that the volume ratio of the main solvent perfluorotributylamine (PFTB), the extraction solvent phenethyl ether (PT), and the adjusting solvent perfluorotoluene (PFT) is 6:1:3.

[0100] Figure 3 This is a SEM image of the perovskite thin film prepared in this embodiment.

[0101] Example 3: The preparation method of the solvent composition and perovskite solar cell in this example is basically the same as that in Example 1, except that the volume ratio of the main solvent perfluorotributylamine (PFTB), the extraction solvent phenethyl ether (PT), and the adjusting solvent perfluorotoluene (PFT) is 5:2:3.

[0102] Example 4: The preparation method of the solvent composition and perovskite solar cell in this example is basically the same as that in Example 1, except that the volume ratio of the main solvent perfluorotributylamine (PFTB), the extraction solvent phenethyl ether (PT), and the adjusting solvent perfluorotoluene (PFT) is 8:0.5:1.5.

[0103] Example 5: The preparation method of the solvent composition and perovskite solar cell in this example is basically the same as that in Example 1, except that the main solvent is replaced with perfluorododecane, the extraction solvent is replaced with 1,2-dichlorobenzene, and the adjusting solvent is replaced with octane.

[0104] Example 6: The preparation method of the solvent composition and perovskite solar cell in this example is basically the same as that in Example 1, except that the main solvent is replaced with perfluorotrihexylamine, the extraction solvent is replaced with butyl butyrate, and the adjusting solvent is replaced with perfluorobiphenyl.

[0105] Comparative Example 1: This comparative example provides a perovskite solar cell and its fabrication method.

[0106] Perovskite solar cells are prepared using the following steps (1)-(6).

[0107] (1) The patterned ITO conductive glass was placed in detergent, deionized water, acetone and isopropanol in sequence and sonicated for 30 min. Then it was dried with a nitrogen gun and treated in an ultraviolet ozone generator for 30 min for later use.

[0108] (2) Dissolve Me-4PACz and MeO-2PACz in ethanol to prepare a solution with a concentration of 0.4 mg / mL. Then mix the two solutions in a volume ratio of 1:1 to prepare a hole transport layer solution and sonicate for 5 minutes for later use. Dissolve 194 mg of CsI, 456 mg of FAI, 47 mg of PbCl2, 252 mg of PbBr2, 1187 mg of PbI2 and 29 mg of MACl in 2 mL of a mixed solvent of DMF and DMSO in a volume ratio of 8:1 at room temperature to prepare a perovskite precursor solution and filter for later use. Dissolve 1,3-diaminopropane dihydroiodate (PDAI2) in a mixed solvent of isopropanol (IPA) and chlorobenzene (CB) in a volume ratio of 1:1 to prepare a passivation solution with a concentration of 1 mg / mL for later use.

[0109] (3) In the glove box, the hole transport layer solution was spin-coated onto the ITO conductive substrate using a spin coater. The spin coating parameters were: rotation speed 3000 rpm, time 15 s, acceleration 3000 rpm / s. After spin coating, the substrate was placed on a hot plate at 100℃ for annealing for 5 min, and then taken out and cooled to room temperature for later use.

[0110] (4) Spin-coating the perovskite precursor solution onto the hole transport layer to form a perovskite wet film with a thickness of 500 nm. The spin-coating parameters are: rotation speed 4000 rpm, time 7s, acceleration 4000 rpm / s. After spin-coating, the substrate with the wet film is immediately transferred to a vacuum flash evaporator (VCD) for 15s (the vacuum flash evaporator evaporates the chamber vacuum from 100 kPa to below 10 Pa within 10s). After breaking the vacuum, the substrate is quickly placed on a hot stage at 120 °C for annealing for 30 min to form a perovskite thin film.

[0111] Figure 4 This is a SEM image of the perovskite thin film prepared in this comparative example.

[0112] (5) Dynamic spin coating of surface passivation layer is performed on the perovskite film surface. The spin coating parameters are divided into two steps: the spin coating parameters of the first step are: rotation speed 300 rpm, time 5 s, acceleration 500 rpm / s, and the spin coating parameters of the second step are: rotation speed 3000 rpm, time 5 s, acceleration 5000 rpm / s. Between the 3rd and 5th seconds of the first spin coating process, the passivation solution is dropped onto the perovskite film surface. After the two spin coating steps are completed, the substrate is placed on a hot plate at 100℃ for annealing for 5 min.

[0113] (6) The substrate with completed surface passivation is transferred to a vacuum evaporation apparatus, and an electron transport layer C60 (thickness 20 nm, rate 0.2 Å / s), a hole blocking layer BCP (thickness 5 nm, rate 0.1 Å / s), and a metal electrode Cu (thickness 110 nm, evaporation rate of 0.2 Å / s for the first 10 nm and evaporation rate of 0.5 Å / s for the subsequent 100 nm) are deposited in sequence to obtain a perovskite solar cell.

[0114] Comparative Example 2: This comparative example provides a perovskite solar cell and its fabrication method.

[0115] Perovskite solar cells are prepared using the following steps (1)-(7).

[0116] (1) The patterned ITO conductive glass was placed in detergent, deionized water, acetone and isopropanol in sequence and sonicated for 30 min. Then it was dried with a nitrogen gun and treated in an ultraviolet ozone generator for 30 min for later use.

[0117] (2) Dissolve Me-4PACz and MeO-2PACz in ethanol to prepare a solution with a concentration of 0.4 mg / mL. Then mix the two solutions in a volume ratio of 1:1 to prepare a hole transport layer solution and sonicate for 5 minutes for later use. Dissolve 194 mg of CsI, 456 mg of FAI, 47 mg of PbCl2, 252 mg of PbBr2, 1187 mg of PbI2 and 29 mg of MACl in 2 mL of a mixed solvent of DMF and DMSO in a volume ratio of 8:1 at room temperature to prepare a perovskite precursor solution and filter for later use. Dissolve 1,3-diaminopropane dihydroiodate (PDAI2) in a mixed solvent of isopropanol (IPA) and chlorobenzene (CB) in a volume ratio of 1:1 to prepare a passivation solution with a concentration of 1 mg / mL for later use.

[0118] (3) In the glove box, the hole transport layer solution was spin-coated onto the ITO conductive substrate using a spin coater. The spin coating parameters were: rotation speed 3000 rpm, time 15 s, acceleration 3000 rpm / s. After spin coating, the substrate was placed on a hot plate at 100℃ for annealing for 5 min, and then taken out and cooled to room temperature for later use.

[0119] (4) Spin-coating the perovskite precursor solution onto the hole transport layer to form a perovskite wet film with a thickness of 500 nm. The spin-coating parameters are: rotation speed 4000 rpm, time 7s, acceleration 4000 rpm / s. After spin-coating, the substrate with the wet film is immediately transferred to a vacuum flash evaporator (VCD) for 15s (the vacuum flash evaporator evaporates the chamber vacuum from 100 kPa to below 10 Pa within 10s). After breaking the vacuum, the perovskite wet film is quickly immersed in a single-component perfluorotributylamine solvent for solvent bath annealing. The solvent bath annealing temperature is 120℃ and the time is 20 min.

[0120] (5) After completing the solvent bath annealing treatment, the perovskite film is placed on a hot table at 120°C for 5 min to dry the residual solvent and obtain the perovskite film.

[0121] Figure 5 This is a SEM image of the perovskite thin film prepared in this comparative example.

[0122] (6) Dynamic spin coating of surface passivation layer is performed on the perovskite film surface. The spin coating parameters are divided into two steps: the spin coating parameters of the first step are: rotation speed 300 rpm, time 5 s, acceleration 500 rpm / s, and the spin coating parameters of the second step are: rotation speed 3000 rpm, time 5 s, acceleration 5000 rpm / s. Between the 3rd and 5th seconds of the first spin coating process, the passivation solution is dropped onto the perovskite film surface. After the two spin coating steps are completed, the substrate is placed on a hot plate at 100℃ for annealing for 5 min.

[0123] (7) The substrate with completed surface passivation is transferred to a vacuum evaporation apparatus, and an electron transport layer C60 (thickness 20 nm, rate 0.2 Å / s), a hole blocking layer BCP (thickness 5 nm, rate 0.1 Å / s), and a metal electrode Cu (thickness 110 nm, evaporation rate of 0.2 Å / s for the first 10 nm and evaporation rate of 0.5 Å / s for the subsequent 100 nm) are deposited in sequence to obtain a perovskite solar cell.

[0124] Comparative Example 3: This comparative example provides a perovskite solar cell and its fabrication method.

[0125] Perovskite solar cells are prepared using the following steps (1)-(7).

[0126] (1) The patterned ITO conductive glass was placed in detergent, deionized water, acetone and isopropanol in sequence and sonicated for 30 min. Then it was dried with a nitrogen gun and treated in an ultraviolet ozone generator for 30 min for later use.

[0127] (2) Dissolve Me-4PACz and MeO-2PACz in ethanol to prepare a solution with a concentration of 0.4 mg / mL. Then mix the two solutions in a volume ratio of 1:1 to prepare a hole transport layer solution and sonicate for 5 minutes for later use. Dissolve 194 mg of CsI, 456 mg of FAI, 47 mg of PbCl2, 252 mg of PbBr2, 1187 mg of PbI2 and 29 mg of MACl in 2 mL of a mixed solvent of DMF and DMSO in a volume ratio of 8:1 at room temperature to prepare a perovskite precursor solution and filter for later use. Dissolve 1,3-diaminopropane dihydroiodate (PDAI2) in a mixed solvent of isopropanol (IPA) and chlorobenzene (CB) in a volume ratio of 1:1 to prepare a passivation solution with a concentration of 1 mg / mL for later use.

[0128] (3) In the glove box, the hole transport layer solution was spin-coated onto the ITO conductive substrate using a spin coater. The spin coating parameters were: rotation speed 3000 rpm, time 15 s, acceleration 3000 rpm / s. After spin coating, the substrate was placed on a hot plate at 100℃ for annealing for 5 min, and then taken out and cooled to room temperature for later use.

[0129] (4) Spin-coating the perovskite precursor solution onto the hole transport layer to form a perovskite wet film with a thickness of 500 nm. The spin-coating parameters are: rotation speed 4000 rpm, time 7s, acceleration 4000 rpm / s. After spin-coating, the substrate with the wet film is immediately transferred to a vacuum flash evaporator (VCD) for 15s (the vacuum flash evaporator evaporates the chamber vacuum from 100 kPa to below 10 Pa within 10s). After breaking the vacuum, the perovskite wet film is quickly immersed in a single-component phenylethyl ether solvent for solvent bath annealing. The solvent bath annealing temperature is 120℃ and the time is 20 min.

[0130] (5) After completing the solvent bath annealing treatment, the perovskite film is placed on a hot table at 120°C for 5 min to dry the residual solvent and obtain the perovskite film.

[0131] (6) Dynamic spin coating of surface passivation layer is performed on the perovskite film surface. The spin coating parameters are divided into two steps: the spin coating parameters of the first step are: rotation speed 300 rpm, time 5 s, acceleration 500 rpm / s, and the spin coating parameters of the second step are: rotation speed 3000 rpm, time 5 s, acceleration 5000 rpm / s. Between the 3rd and 5th seconds of the first spin coating process, the passivation solution is dropped onto the perovskite film surface. After the two spin coating steps are completed, the substrate is placed on a hot plate at 100℃ for annealing for 5 min.

[0132] (7) The substrate with completed surface passivation is transferred to a vacuum evaporation apparatus, and an electron transport layer C60 (thickness 20 nm, rate 0.2 Å / s), a hole blocking layer BCP (thickness 5 nm, rate 0.1 Å / s), and a metal electrode Cu (thickness 110 nm, evaporation rate of 0.2 Å / s for the first 10 nm and evaporation rate of 0.5 Å / s for the subsequent 100 nm) are deposited in sequence to obtain a perovskite solar cell.

[0133] Comparative Example 4: This comparative example provides a perovskite solar cell and its fabrication method.

[0134] Perovskite solar cells are prepared using the following steps (1)-(7).

[0135] (1) The patterned ITO conductive glass was placed in detergent, deionized water, acetone and isopropanol in sequence and sonicated for 30 min. Then it was dried with a nitrogen gun and treated in an ultraviolet ozone generator for 30 min for later use.

[0136] (2) Dissolve Me-4PACz and MeO-2PACz in ethanol to prepare a solution with a concentration of 0.4 mg / mL. Then mix the two solutions in a volume ratio of 1:1 to prepare a hole transport layer solution and sonicate for 5 minutes for later use. Dissolve 194 mg of CsI, 456 mg of FAI, 47 mg of PbCl2, 252 mg of PbBr2, 1187 mg of PbI2 and 29 mg of MACl in 2 mL of a mixed solvent of DMF and DMSO in a volume ratio of 8:1 at room temperature to prepare a perovskite precursor solution and filter for later use. Dissolve 1,3-diaminopropane dihydroiodate (PDAI2) in a mixed solvent of isopropanol (IPA) and chlorobenzene (CB) in a volume ratio of 1:1 to prepare a passivation solution with a concentration of 1 mg / mL for later use.

[0137] (3) In the glove box, the hole transport layer solution was spin-coated onto the ITO conductive substrate using a spin coater. The spin coating parameters were: 3000 rpm rotation speed, 15 s time, and 3000 rpm / s acceleration. After spin coating, the substrate was placed on a hot plate at 100℃ for annealing for 5 min, and then taken out and cooled to room temperature for later use.

[0138] (4) Spin-coating the perovskite precursor solution onto the hole transport layer to form a perovskite wet film with a thickness of 200 nm. The spin-coating parameters are: rotation speed 4000 rpm, time 7s, acceleration 4000 rpm / s. After spin-coating, the substrate with the wet film is immediately transferred to a vacuum flash evaporator (VCD) for 15s (the vacuum flash evaporator evaporates the chamber vacuum from 100 kPa to below 10 Pa within 10s). After breaking the vacuum, the perovskite wet film is quickly immersed in a single-component perfluorotoluene solvent for solvent bath annealing. The solvent bath annealing temperature is 120℃ and the time is 20 min.

[0139] (5) After completing the solvent bath annealing treatment, the perovskite film is placed on a hot table at 120°C for 5 min to dry the residual solvent and obtain the perovskite film.

[0140] (6) Dynamic spin coating of surface passivation layer is performed on the perovskite film surface. The spin coating parameters are divided into two steps: the spin coating parameters of the first step are: rotation speed 300 rpm, time 5 s, acceleration 500 rpm / s, and the spin coating parameters of the second step are: rotation speed 3000 rpm, time 5 s, acceleration 5000 rpm / s. Between the 3rd and 5th seconds of the first spin coating process, the passivation solution is dropped onto the perovskite film surface. After the two spin coating steps are completed, the substrate is placed on a hot plate at 100℃ for annealing for 5 min.

[0141] (7) The substrate with completed surface passivation is transferred to a vacuum evaporation apparatus, and an electron transport layer C60 (thickness 20 nm, rate 0.2 Å / s), a hole blocking layer BCP (thickness 5 nm, rate 0.1 Å / s), and a metal electrode Cu (thickness 110 nm, evaporation rate of 0.2 Å / s for the first 10 nm and evaporation rate of 0.5 Å / s for the subsequent 100 nm) are deposited in sequence to obtain a perovskite solar cell.

[0142] Comparative Example 5: The solvent composition and the preparation method of the perovskite solar cell in this comparative example are basically the same as those in Example 1, except that the solvent composition contains only the main solvent perfluorotributylamine (PFTB) and the extraction solvent phenethyl ether (PT) in a volume ratio of 8:2.

[0143] Comparative Example 6: The solvent composition and the preparation method of the perovskite solar cell in this comparative example are basically the same as those in Example 1, except that the main solvent is replaced with perfluoronaphthalene; wherein, the boiling point of the main solvent perfluoronaphthalene is 142°C.

[0144] Comparative Example 7: The solvent composition and the preparation method of the perovskite solar cell in this comparative example are basically the same as those in Example 1, except that the extraction solvent is replaced with chlorobenzene; wherein, the boiling point of the extraction solvent chlorobenzene is 132°C.

[0145] The parameters of the solvent compositions in the above embodiments and comparative examples are summarized in Table 1 below.

[0146] Table 1: Parameters of the solvent compositions in the examples and comparative examples.

[0147] main solvent Extraction solvent Adjusting the solvent Volume ratio of main solvent, extraction solvent and adjusting solvent Example 1 perfluorotributylamine Phenylacetyl ether Perfluorotoluene 7:1:2 Example 2 perfluorotributylamine Phenylacetyl ether Perfluorotoluene 6:1:3 Example 3 perfluorotributylamine Phenylacetyl ether Perfluorotoluene 5:2:3 Example 4 perfluorotributylamine Phenylacetyl ether Perfluorotoluene 8:0.5:1.5 Example 5 Perfluorododecane 1,2-Dichlorobenzene Octane 7:1:2 Example 6 perfluorotrihexylamine Butyl butyrate Perfluorinated biphenyls 7:1:2 Comparative Example 1 / / / / Comparative Example 2 perfluorotributylamine / / / Comparative Example 3 / Phenylacetyl ether / / Comparative Example 4 / / Perfluorotoluene / Comparative Example 5 perfluorotributylamine Phenylacetyl ether / 8:2:0 Comparative Example 6 Perfluoronaphthalene Phenylacetyl ether Perfluorotoluene 7:1:2 Comparative Example 7 perfluorotributylamine chlorobenzene Perfluorotoluene 7:1:2

[0148] Performance testing: The solar cells fabricated in the above embodiments and comparative examples were placed in a solar simulator (manufacturer: Wavelabs). Under the illumination of a certain solar intensity, a bias voltage (Vp, bias voltage range of -0.1~1.3V) was applied to the device using a test source meter, and the output current of the device was tested to obtain the bias voltage-current density curve.

[0149] Open-circuit voltage (Voc): The terminal voltage of the solar cell when no load is connected, i.e., when the current density in the bias-current density curve is 0 mA·cm. -2 The bias voltage value at that time.

[0150] Short-circuit current density (Jsc): The output current per unit area of ​​the solar cell when it is short-circuited, i.e., the current density when the bias voltage is 0V in the bias voltage-current density curve.

[0151] Fill factor (FF): FF = max(Vp × Jsc), where Vp is the bias voltage and Jsc is the short-circuit current density.

[0152] Photovoltaic cell efficiency (PCE): PCE = Voc × Jsc × FF.

[0153] The test results are shown in Table 2.

[0154] Table 2: Photovoltaic performance test results of solar cells in the examples and comparative examples.

[0155] Voc(V) <![CDATA[Jsc(mA·cm -2 )]]> FF (%) PCE (%) Example 1 1.287 21.52 86.12 23.86 Example 2 1.291 20.77 85.28 22.86 Example 3 1.282 20.31 85.46 22.24 Example 4 1.290 20.77 84.42 22.61 Example 5 1.273 20.47 84.75 22.09 Example 6 1.273 20.13 84.88 21.75 Comparative Example 1 1.269 20.40 82.86 21.45 Comparative Example 2 1.252 20.05 83.26 20.91 Comparative Example 3 1.246 19.89 82.99 20.57 Comparative Example 4 1.259 20.13 83.15 21.08 Comparative Example 5 1.256 20.33 82.65 21.11 Comparative Example 6 1.261 20.19 83.28 21.20 Comparative Example 7 1.255 20.44 83.47 21.40

[0156] As shown in Table 2, Figures 2 to 6 As shown in the comparison examples 1-6 and 1-7, the solvent composition provided in this application improves the crystallinity of the perovskite film, enabling the perovskite film to complete the conversion of the photoactive phase, thereby improving the photoelectric performance of the solar cell.

[0157] Comparing Examples 1-6 and Comparative Example 1, it can be seen that solvent bath annealing, compared with traditional hot-stage annealing, can improve heat transfer uniformity, thereby obtaining perovskite films with fewer defects and more uniform quality, and thus improving the photoelectric performance of solar cells.

[0158] Comparing Examples 1-6 and Comparative Examples 2-4, it can be seen that the three-component synergistic system of main solvent, extraction solvent and regulating solvent can synergistically regulate the crystallization process of perovskite film, improve the crystallization quality of perovskite film, and enable perovskite film to complete the conversion of photoactive phase, thereby improving the photoelectric performance of solar cell.

[0159] Comparing Examples 1-6 and Comparative Example 5, it can be seen that when no regulating solvent is contained, the extraction effect of the solvent composition on the perovskite precursor solvent in the perovskite wet film cannot be regulated, resulting in an excessively fast extraction rate, which affects the crystal quality of the perovskite film and thus affects the photoelectric performance of the solar cell.

[0160] Comparative Examples 1-6 and 6-7 show that when the boiling point of the main solvent or extraction solvent does not meet the requirements, the azeotropic point of the solvent composition cannot reach the transformation temperature of the photoactive phase of the perovskite film, resulting in insufficient phase transformation of the perovskite film, which in turn affects the photoelectric performance of the solar cell.

[0161] like Figures 2 to 5 As shown, compared with the perovskite films of Comparative Examples 1 and 2, the perovskite films of Examples 1 and 2 have fewer surface defects, smoother surfaces, and higher perovskite film quality.

[0162] like Figure 7 As shown, the characteristic peak intensity of the perovskite film in Example 1 is higher than that in Comparative Example 1, indicating that its perovskite film has better crystallinity and higher perovskite film quality.

[0163] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0164] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A solvent composition, characterized in that, For solvent bath annealing to form perovskite thin films, the solvent composition comprises: The main solvent has a boiling point greater than 150°C and is selected from at least one of perfluoroalkane compounds and perfluorotertiary amine compounds. An extraction solvent having a boiling point greater than 150°C, wherein the extraction solvent is selected from at least one of aromatic ether compounds, halogenated aromatic compounds, and ester compounds; and The adjusting solvent has a polarity between that of the bulk solvent and the extraction solvent. The solvent bath annealing temperature is greater than or equal to the transition temperature of the photoactive phase of the perovskite film.

2. The solvent composition according to claim 1, characterized in that, The volume ratio of the main solvent, the extraction solvent and the adjustment solvent is (5~8):(0.5~2):(1~3).

3. The solvent composition according to claim 2, characterized in that, The volume ratio of the main solvent, the extraction solvent and the adjustment solvent is (7~8):(1~2):(1~2).

4. The solvent composition according to any one of claims 1 to 3, characterized in that, At least one of the following conditions must be met: (1) The main solvent is selected from at least one of perfluorododecane, perfluorotridecane, perfluorotetradecane, perfluoropentadecanane, perfluorohexadecane, perfluorotributylamine, perfluorotripentylamine and perfluorotrihexylamine; (2) The extraction solvent is selected from at least one of anisole, o-methyl anisole, m-methyl anisole, p-methyl anisole, phenethyl ether, methyl anisole, 4-methyl anisole, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, butyl butyrate, ethyl hexanoate, ethyl heptaate, ethyl octanoate, hexyl acetate, heptaate, pentyl propionate, hexyl butyrate, isobutyl isovalerate, butyl isovalerate, butyl valerate, isoamyl isovalerate, isoamyl butyrate, isoamyl butyrate, isoamyl butyrate, isoamyl butyrate, and methyl benzoate. (3) The adjusting solvent is selected from at least one of octane, perfluorooctane, decadecane, perfluorotoluene, and perfluorobiphenyl; (4) The boiling point of the main solvent is less than or equal to 250°C; (5) The boiling point of the extraction solvent is less than or equal to 250°C.

5. A method for preparing a perovskite thin film, characterized in that, Includes the following steps: The perovskite wet film is immersed in the solvent composition as described in any one of claims 1 to 4 and subjected to solvent bath annealing to form a perovskite thin film.

6. The method for preparing perovskite thin films according to claim 5, characterized in that, The solvent bath annealing temperature is 120℃~150℃.

7. The method for preparing perovskite thin films according to claim 5 or 6, characterized in that, After the solvent bath annealing treatment, the following steps are also included: The perovskite film formed by the solvent bath annealing is subjected to heat treatment at a temperature lower than that of the solvent bath annealing.

8. A perovskite thin film, characterized in that, The perovskite thin film was prepared using the method described in any one of claims 5 to 7.

9. A solar cell, characterized in that, Including the perovskite thin film as described in claim 8.

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