Solar cell and preparation method thereof, photovoltaic module, power generation device and power utilization device

Abstract

The invention provides a solar cell and a preparation method thereof, a photovoltaic module, a power generation device and a power utilization device, and the solar cell comprises a first electrode, a perovskite light absorption layer and a second electrode which are sequentially arranged in the light incidence direction. The perovskite light-absorbing layer comprises a perovskite light-absorbing material and a polymer, the polymer comprises a polar functional group, and the polymer is located on the bottom surface of the perovskite light-absorbing material. The solar cell prepared by the invention has improved photoelectric conversion efficiency.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a solar cell and its preparation method, a photovoltaic module, a power generation device, and an electrical device. Background Technology

[0002] In recent years, global energy shortages and environmental pollution have become increasingly prominent, leading to growing attention on solar cells as an ideal renewable energy source. Solar cells, also known as photovoltaic cells, are devices that directly convert light energy into electrical energy through the photoelectric effect or photochemical effect.

[0003] As a new photovoltaic technology for the future, perovskite solar cells have made remarkable progress. However, the rapid crystallization rate during the formation of perovskite thin films in related technologies leads to poor quality of the perovskite thin films, which is not conducive to the efficient operation of solar cells. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a solar cell and a method for preparing it, a photovoltaic module, a power generation device, and a power consumption device. The solar cell prepared by this application has improved photoelectric conversion efficiency.

[0005] To achieve the above objectives, the first aspect of this application provides a solar cell, comprising a first electrode, a perovskite light-absorbing layer, and a second electrode arranged sequentially along the light incident direction; the perovskite light-absorbing layer comprises a perovskite light-absorbing material and a polymer; the polymer comprises polar functional groups; the polymer is located on the bottom surface of the perovskite light-absorbing material.

[0006] In this application, the polar functional groups in the polymer can form strong interactions with the ions or polar groups in the perovskite light-absorbing material. This interaction helps the polymer adhere tightly to the bottom surface of the perovskite light-absorbing material, thereby effectively passivating defects on the bottom surface of the perovskite light-absorbing material (i.e., the perovskite light-absorbing layer). This increases the diffusion length of charge carriers and the lifetime of photogenerated charge carriers, thus improving the photoelectric conversion efficiency of the perovskite solar cell. Furthermore, the polar functional groups can enhance the bonding force between the polymer and the perovskite light-absorbing material, thereby improving the stability of the perovskite light-absorbing layer and contributing to the long-term stability of the solar cell.

[0007] In some embodiments, the polymer includes one or more polar functional groups selected from carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen groups. These polar functional groups can interact with ions or polar groups in the perovskite light-absorbing material, helping the polymer to adhere more tightly to the bottom surface and grain boundaries of the perovskite light-absorbing material, thereby more effectively passivating defects.

[0008] In some embodiments, the polymer includes a chain polymer. Due to the flexibility of its molecular chains, the chain polymer can better adapt to the complex morphology of perovskite grain boundaries and surfaces, allowing the polymer to adhere more tightly to the bottom surface and grain boundaries of the perovskite light-absorbing material. This, in turn, can more effectively passivate defects, reduce non-radiative recombination, and improve the photoelectric conversion efficiency of the solar cell.

[0009] In some embodiments, the polymer has a weight-average molecular weight of 0.2 million to 4 million. This results in a higher viscosity, allowing the polymer to form a tighter interfacial bond with the perovskite light-absorbing material, which is beneficial for maintaining the long-term passivation effect of the polymer.

[0010] In some embodiments, the polymer has a weight-average molecular weight of 100,000 to 1,000,000. This is more conducive to maintaining the long-term passivation effect of the polymer.

[0011] In some embodiments, the polymer includes one or more of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol acetoacetate methacrylate, and nitrile rubber. These polymers can stably exist on the bottom surface and at grain boundaries of the perovskite light-absorbing material, thereby more effectively passivating defects, reducing non-radiative recombination, and improving the photoelectric conversion efficiency of perovskite solar cells.

[0012] In some embodiments, the thickness of the perovskite light-absorbing layer is 0.2 μm to 2 μm. This is beneficial for improving light absorption utilization and enhancing the photoelectric conversion efficiency of solar cell devices.

[0013] In some embodiments, the thickness of the perovskite light-absorbing layer is 0.8 μm to 1.2 μm. This is more conducive to improving light absorption utilization and enhancing the photoelectric conversion efficiency of solar cell devices.

[0014] In some embodiments, the polymer accounts for 0.01% to 10% of the mass of the perovskite light-absorbing layer. This facilitates the uniform distribution of the polymer at grain boundaries and interfaces, thereby more effectively passivating defects, reducing non-radiative recombination, and without hindering carrier transport, thus improving the photoelectric conversion efficiency of the solar cell.

[0015] In some embodiments, the polymer accounts for 0.1% to 1% of the mass of the perovskite light-absorbing layer. This is more conducive to improving the photoelectric conversion efficiency of the solar cell.

[0016] In some embodiments, the average grain size of the perovskite light-absorbing material is 0.4 μm to 2 μm. This is beneficial for improving the quality of the perovskite thin film and increasing the photoelectric conversion efficiency of the solar cell device.

[0017] In some embodiments, the average grain size of the perovskite light-absorbing material is 0.9 μm to 1.5 μm. This is more conducive to improving the quality of the perovskite thin film and increasing the photoelectric conversion efficiency of the solar cell device.

[0018] In some embodiments, the perovskite light-absorbing layer comprises at least one of the compounds shown in [A][B][X]3 and [A]2[C][D][X]6, wherein A comprises at least one monovalent inorganic or organic cation, B comprises at least one divalent inorganic cation, C comprises at least one monovalent inorganic cation, D comprises at least one trivalent inorganic cation, and X comprises at least one monovalent anion.

[0019] In some embodiments, A includes CH3NH3 + CH(NH2)2 + Li + Na + K + 、Rb + Cs + One or more of them, B including Pb 2+ and / or Sn 2+ C includes Li + Na + K + 、Rb + Cs + One or more of them, X including F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - OH - CN - SeCN - One or more of them.

[0020] In some implementations, B includes Pb. 2+ and Sn 2+ .

[0021] A second aspect of this application provides a method for fabricating a solar cell, comprising the following steps: S1, forming a first electrode; S2, coating the first electrode with a perovskite precursor solution containing a polymer to form a perovskite light-absorbing layer; the perovskite light-absorbing layer comprising a perovskite light-absorbing material and the polymer, the polymer comprising polar functional groups, the polymer being located on the bottom surface of the perovskite light-absorbing material; S3, forming a second electrode on the perovskite light-absorbing layer.

[0022] In this application, a polymer is added to the perovskite precursor solution. On one hand, the polymers intertwine to form a network structure, which can inhibit solvent extraction during the crystallization of the perovskite light-absorbing material, delay the decrease in supersaturation of the perovskite wet film, and prolong the crystallization time. On the other hand, the polar functional groups in the polymer can react with cations (e.g., Sn) in the perovskite precursor solution. 2+ and / or Pb 2+ This process forms coordination interactions, which can interfere with the coordination or complexation between precursors and between precursors and solvents, delaying the crystallization process of tin and / or lead. This is beneficial for improving the crystallinity of the perovskite thin film, thereby enhancing the photoelectric conversion efficiency of solar cell devices. Furthermore, during the coating process to form the perovskite light-absorbing layer, the relatively large polymer molecules are repelled by the perovskite grains at the bottom surface of the perovskite light-absorbing layer, passivating surface defects. Therefore, this increases the diffusion length of charge carriers and the lifetime of photogenerated charge carriers, further improving the photoelectric conversion efficiency of solar cell devices.

[0023] In some embodiments, the polymer includes one or more polar functional groups selected from carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen. Polar functional groups such as carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen possess lone pairs of electrons and therefore tend to react with cations (e.g., Sn) in the perovskite precursor solution. 2+ and / or Pb 2+ This can form coordination, thereby delaying the crystallization process of lead and / or tin, which is beneficial to improving the crystallization quality of perovskite films.

[0024] In some embodiments, the polymer comprises a chain polymer. Chain polymers possess good flexibility and can intertwine to form chain entanglements, which is more conducive to forming a network structure. This network structure can suppress solvent extraction during the crystallization process of the perovskite light-absorbing material, delay the decrease in supersaturation of the perovskite wet film, and prolong the crystallization time, thereby improving the thin film quality of the perovskite light-absorbing layer and consequently improving the photoelectric conversion efficiency of the solar cell device. In some embodiments, the polymer comprises polar functional groups.

[0025] In some embodiments, the polymer has a weight-average molecular weight of 0.2 million to 4 million. This results in a high viscosity of the polymer, which in turn leads to a high viscosity of the perovskite precursor solution. This is beneficial for increasing the thickness of the formed perovskite light-absorbing layer, improving the light absorption capacity of the perovskite layer, and thus enhancing the photoelectric conversion efficiency of the solar cell device.

[0026] In some embodiments, the polymer includes one or more of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol methacrylate, and nitrile rubber.

[0027] In some embodiments, the viscosity of the perovskite precursor solution is 1 mPa·s to 100 mPa·s. This is beneficial for increasing the thickness of the perovskite light-absorbing layer and improving its light absorption capacity.

[0028] In some embodiments, the amount of polymer added to the perovskite precursor solution is 0.1 mg / mL to 100 mg / mL. This helps to slow down the evaporation of solvent in the perovskite wet film, slow down the crystallization rate, improve the film quality of the perovskite light-absorbing layer, and thus improve the photoelectric conversion efficiency of the solar cell device.

[0029] In some embodiments, the amount of polymer added to the perovskite precursor solution is 1 mg / mL to 10 mg / mL. This is more conducive to slowing down the evaporation of solvent in the perovskite wet film, slowing down the crystallization rate, improving the film quality of the perovskite light-absorbing layer, and thus improving the photoelectric conversion efficiency of the solar cell device.

[0030] In some embodiments, the concentration of the perovskite precursor solution is 1 mg / mL to 2.4 mg / mL. This facilitates the preparation of a perovskite light-absorbing layer with a suitable thickness.

[0031] In some embodiments, the thickness of the perovskite light-absorbing layer is 0.2 μm to 2 μm. This is beneficial for improving light absorption utilization and enhancing the photoelectric conversion efficiency of solar cell devices.

[0032] A third aspect of this application provides a photovoltaic module, which includes the solar cell described in the first aspect, or a solar cell prepared according to the preparation method described in the second aspect.

[0033] The fourth aspect of this application provides a power generation device, which includes the solar cell described in the first aspect, or a solar cell prepared according to the preparation method described in the second aspect.

[0034] The fifth aspect of this application provides an electrical device, which includes the solar cell described in the first aspect, or a solar cell prepared according to the preparation method described in the second aspect. Attached Figure Description

[0035] Figure 1 A schematic diagram of the structure of a solar cell provided in one embodiment of this application;

[0036] Figure 2 A schematic flowchart illustrating a method for fabricating a solar cell according to an embodiment of this application;

[0037] Figure 3 These are scanning electron microscope (SEM) images of the perovskite light-absorbing layer in Example 1 and Comparative Example 1 of this application;

[0038] Figure 4 This is a microstructure diagram and elemental distribution diagram of the bottom surface of the perovskite light-absorbing layer in Embodiment 1 of this application.

[0039] Explanation of reference numerals in the attached figures:

[0040] Solar cell 10; first electrode 101; first transport layer 102; perovskite light-absorbing layer 103; second transport layer 104; second electrode 105. Detailed Implementation

[0041] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the solar cell and its fabrication method, photovoltaic module, power generation device, and power consumption device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0042] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0043] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0044] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0045] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means 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.

[0046] Unless otherwise specified, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0047] Unless otherwise specified, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in this application.

[0048] Currently, for perovskite solar cells, especially tandem narrow-bandgap tin-lead hybrid perovskite solar cells, the rapid crystallization rate of tin and lead makes the perovskite crystallization process difficult to control, resulting in poor perovskite film quality. Furthermore, for tandem narrow-bandgap tin-lead hybrid perovskite solar cells, a relatively thicker perovskite absorbing layer provides better light absorption. Currently, increasing the concentration of the precursor solution is often used to increase the thickness of the perovskite absorbing layer. However, increasing the thickness of the perovskite absorbing layer increases defects, reduces the lifetime of photogenerated carriers, and is detrimental to the photoelectric conversion efficiency of the solar cell.

[0049] In related technologies, passivating agents are added to passivate bulk and surface defects in perovskite thin films, thereby increasing the diffusion length of photogenerated carriers and improving the photoelectric conversion efficiency of solar cells. However, while passivating defects with passivating agents reduces their impact on carrier transport, it does not fundamentally improve the crystallinity of the perovskite thin film. Therefore, perovskite thin films prepared using these technologies still contain a large number of bulk and grain boundary defects, which is detrimental to the high-efficiency operation of solar cells.

[0050] Based on this, the embodiments of this application provide a new solar cell and its preparation method, photovoltaic module, power generation device, and power consumption device. The solar cell prepared in this application has improved photoelectric conversion efficiency.

[0051] Solar cells

[0052] A first aspect of the embodiments of this application provides a solar cell. Figure 1 A schematic diagram of the structure of a solar cell provided in one embodiment of this application is shown below. Figure 1 As shown, the solar cell 10 includes a first electrode 101, a perovskite light-absorbing layer 103, and a second electrode 105 arranged sequentially along the light incident direction; the perovskite light-absorbing layer 103 includes a perovskite light-absorbing material and a polymer, the polymer including polar functional groups, and the polymer is located on the bottom surface of the perovskite light-absorbing material.

[0053] In this application, the polar functional groups in the polymer can form strong interactions with the ions or polar groups in the perovskite light-absorbing material. This interaction helps the polymer adhere tightly to the bottom surface of the perovskite light-absorbing material, thereby effectively passivating defects on the bottom surface of the perovskite light-absorbing material (i.e., the perovskite light-absorbing layer). This increases the diffusion length of charge carriers and the lifetime of photogenerated charge carriers, thus improving the photoelectric conversion efficiency of the perovskite solar cell. Furthermore, the polar functional groups can enhance the bonding force between the polymer and the perovskite light-absorbing material, thereby improving the stability of the perovskite light-absorbing layer and contributing to the long-term stability of the solar cell.

[0054] In some embodiments, "the polymer is located on the bottom surface of the perovskite light-absorbing material" means that the polymer is located on the surface of the perovskite light-absorbing layer near the first electrode.

[0055] In some embodiments, the polymer is also located at the grain boundaries of the perovskite light-absorbing material. This allows the polymer to further passivate defects at the grain boundaries (i.e., the bulk phase), thereby further increasing the carrier diffusion length and the lifetime of photogenerated carriers, ultimately improving the photoelectric conversion efficiency of the perovskite solar cell.

[0056] In this application, the term "polar functional group" refers to a functional group whose positive and negative charge centers do not coincide, and such a functional group exhibits an affinity for polar groups.

[0057] In this application, the term "grain boundary" refers to the interface between grains with the same structure but different orientations in a polycrystalline material.

[0058] In some embodiments, the polymer includes one or more polar functional groups selected from carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen groups. These polar functional groups can interact with ions or polar groups in the perovskite light-absorbing material, facilitating tighter adhesion of the polymer to the bottom surface and grain boundaries of the perovskite light-absorbing material, thereby more effectively passivating defects. Furthermore, these functional groups can enhance the bonding force between the polymer and the perovskite light-absorbing material, thus improving the long-term stability of the solar cell.

[0059] For example, the polymer containing carboxyl groups includes one or more of polyacrylic acid, polymethacrylic acid, polymaleic acid, carboxymethyl cellulose, polyaspartic acid, polyitacic acid, polyglutamic acid, and polystyrene sulfonic acid-carboxylic acid copolymers. Optionally, the polymer containing carboxyl groups includes polyacrylic acid or carboxymethyl cellulose.

[0060] For example, polymers containing hydroxyl groups include one or more of hydroxyl-butadiene rubber, polyvinyl alcohol, polyimide resin, polyester polyol, polyether polyol, and polylactic acid-hydroxyl group; alternatively, polymers containing hydroxyl groups include hydroxyl-butadiene rubber.

[0061] For example, the polymer containing carbonyl groups includes one or more of poly(ethylene glycol acetoacetate methacrylate), polymethyl methacrylate, polypropylene carbonate, polytrimethylene carbonate, polypropylene carbonate, and polyvinyl carbonate; alternatively, the polymer containing carbonyl groups includes poly(ethylene glycol acetoacetate methacrylate).

[0062] For example, polymers containing ether bonds include one or more of polyethylene oxide, polyaniline ether, polytetrahydrofuran, polyethylene glycol, polyethersulfone, polyphenylene ether, polyoxymethylene, and polyetheretherketone. Optionally, polymers containing ether bonds include polyethylene oxide.

[0063] For example, polymers containing cyano groups include one or more of nitrile rubber, polyacrylonitrile, polybutadiene-acrylonitrile copolymer, and cyanoacrylate polymers. Optionally, polymers containing cyano groups include nitrile rubber.

[0064] For example, the halogen-containing polymer includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, polyvinylidene chloride, polychloroprene, and poly(vinylidene fluoride hexafluoropropylene). Optionally, the halogen-containing polymer includes polytetrafluoroethylene or polyvinylidene fluoride.

[0065] In some embodiments, the polymer includes a chain polymer. Due to the flexibility of its molecular chains, the chain polymer can better adapt to the complex morphology of perovskite grain boundaries and surfaces, thereby allowing the polymer to adhere more tightly to the bottom surface and grain boundaries of the perovskite light-absorbing material. This, in turn, can more effectively passivate defects, reduce non-radiative recombination, and improve the photoelectric conversion efficiency of the solar cell.

[0066] For example, the chain polymer includes one or more of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol methacrylate, nitrile rubber, and styrene-butadiene rubber.

[0067] In this application, the term "chain polymer" refers to a high molecular weight compound in which many monomer molecules are linked by chemical bonds and the molecular chains exhibit a linear or curved shape.

[0068] In some embodiments, the weight-average molecular weight of the polymer is between 0.2 million and 4 million, optionally between 100,000 and 1 million. A weight-average molecular weight within this range results in a higher polymer viscosity, allowing the polymer to form a tighter interfacial bond with the perovskite light-absorbing material, which is beneficial for maintaining the long-term passivation effect of the polymer. Exemplarily, the weight-average molecular weight of the polymer is a value within the range of 0.2 million, 10,000, 50,000, 100,000, 500,000, 1 million, 2 million, 3 million, 4 million, or any combination thereof.

[0069] In some embodiments, the polymer includes one or more of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol acetoacetate methacrylate, and nitrile rubber. These polymers can stably exist on the bottom surface and at grain boundaries of the perovskite light-absorbing material, thereby more effectively passivating defects, reducing non-radiative recombination, and improving the photoelectric conversion efficiency of perovskite solar cells.

[0070] In some embodiments, the thickness of the perovskite light-absorbing layer is 0.2 μm to 2 μm, optionally 0.8 μm to 1.2 μm. A thickness within this range is beneficial for improving light absorption utilization and enhancing the photoelectric conversion efficiency of the solar cell device. Exemplarily, the thickness of the perovskite light-absorbing layer is a value within the range of 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, or any combination thereof.

[0071] In this application, the term "layer" refers to any substantially layered structure. A layer may have a thickness that varies along its length. Typically, the thickness of a layer is approximately constant. As used in this application, "thickness" of a layer refers to the average thickness of the layer.

[0072] In some embodiments, the polymer mass percentage in the perovskite light-absorbing layer is 0.01% to 10%, optionally 0.1% to 1%. A polymer mass percentage within this range facilitates uniform distribution of the polymer at grain boundaries and interfaces, thereby more effectively passivating defects, reducing non-radiative recombination, and without hindering carrier transport, thus improving the photoelectric conversion efficiency of the solar cell. Exemplarily, the polymer mass percentage in the perovskite light-absorbing layer is a value within the range of 0.01%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any combination thereof.

[0073] In some embodiments, the average grain size of the perovskite light-absorbing material is 0.4 μm to 2 μm, optionally 0.9 μm to 1.5 μm. An average grain size within this range reduces the number of grain boundaries, which is beneficial for reducing non-radiative recombination at grain boundaries, improving the quality of the perovskite thin film, and increasing the photoelectric conversion efficiency of the solar cell device. Exemplarily, the average grain size of the perovskite light-absorbing material is a value within the range of 0.4 μm, 0.6 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, or any combination thereof.

[0074] In this application, the position of the polymer in the perovskite absorbing layer can be reversed using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specifically, by disassembling the cell to expose the perovskite absorbing layer, and then using TOF-SIMS to characterize the perovskite absorbing layer, the spatial distribution information of polymers containing specific functional groups in the perovskite layer can be detected.

[0075] In this application, the polar functional groups in the polymer can be reversed by infrared spectroscopy using Fourier transform infrared spectroscopy (FTIR) or by Raman spectroscopy.

[0076] In this application, weight-average molecular weight (MAM) has its common meaning in the art and is the average molecular weight obtained by multiplying the mass of each molecular chain in the polymer by its mole fraction in the polymer. MAM can be determined using methods known in the art, with exemplary testing methods as follows: for example, gel permeation chromatography, such as using a Waters 2695 Isocratic HPLC gel permeation chromatograph (differential refractive index detector 2141). In some embodiments, the testing method uses a 3.0% polystyrene solution sample as a reference, selecting a matched chromatographic column (oil-based: Styragel HT5DMF7.8*300mm + Styragel HT4). A 3.0% polymer gel solution is prepared using purified N-methylpyrrolidone (NMP) solvent, and the prepared solution is allowed to stand for one day for later use. During testing, tetrahydrofuran is first drawn into a syringe for rinsing, repeated several times. Then, 5 ml of the experimental solution is drawn, air is expelled from the syringe, and the needle tip is dried. Finally, the sample solution is slowly injected into the injection port. After the reading stabilizes, the data is acquired, and the weight-average molecular weight is read.

[0077] In this application, the mass percentage of the polymer in the perovskite light-absorbing layer can be measured in the following way: Specifically, an EDS spectrometer is used to perform qualitative and quantitative analysis on all elements in the perovskite light-absorbing layer sample simultaneously. Based on the quantitative analysis results of the labeled elements corresponding to the perovskite material and the polymer, the mass percentage of the polymer in the perovskite light-absorbing layer can be calculated.

[0078] In this application, the thickness of the perovskite light-absorbing layer can be measured in the following way: specifically, the thickness of the cross-section of the perovskite light-absorbing layer is measured using a scanning electron microscope.

[0079] In this application, the grain size of the perovskite light-absorbing material can be measured in the following way: the surface morphology of the perovskite light-absorbing layer is tested using a scanning electron microscope (Hitachi, HD-2700), and the grain size of the perovskite light-absorbing material is measured based on the tested scanning electron microscope image. Then, the average grain size of the perovskite light-absorbing material is obtained by averaging.

[0080] In some embodiments, the first electrode 101 refers to the electrode that first receives incident light and is used to collect electrons / holes; the second electrode 105 refers to the electrode that last receives incident light and is used to collect holes / electrons.

[0081] In some embodiments, the first electrode 101 is a transparent electrode, which may include a transparent conductive material. This application does not particularly limit the transparent conductive material. Exemplarily, the transparent conductive material includes one or more of the following: tin oxide, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide, antimony-doped tin oxide, indium-doped tungsten oxide (IWO), indium-doped chromium oxide (ICrO), indium-doped titanium oxide (ITiO), and graphene.

[0082] In some embodiments, the electrode material of the second electrode 105 includes one or more of transparent conductive oxides, metals and their alloys, and elemental carbon materials. Exemplarily, the transparent conductive oxide includes one or more of indium tin oxide (ITO), lanthanide-doped indium oxide, fluorine-doped tin oxide (FTO), antimony-doped tin oxide, boron-doped zinc oxide (BZO), zinc aluminum oxide (AZO), indium zinc oxide (IZO), zinc gallium oxide (GZO), and indium tungsten oxide (IWO). The metal includes one or more of Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, and Mg. Exemplarily, the metal and its alloys include one or more of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, and tungsten. Exemplarily, the elemental carbon material includes one or more of graphite, graphene, and carbon nanotubes. Exemplarily, the organic conductive material includes at least one of poly(3,4-ethylenedioxythiophene), polythiophene, and polyacetylene.

[0083] In some embodiments, the perovskite absorbing layer 103 is disposed between the first electrode 101 and the second electrode 105, and electron-hole pairs can be generated based on the excitation of incident light. This application does not impose any particular limitation on the band gap of the perovskite absorbing layer 103; a band gap commonly used in the art for perovskite absorbing layers can be used. For example, the band gap of the perovskite absorbing layer is between 1.20 eV and 2.30 eV. This application does not impose any particular limitation on the band gap measurement method. For example, the band gap measurement method may include: first, obtaining an ultraviolet absorption curve through ultraviolet absorption spectroscopy; and then calculating the band gap of the perovskite absorbing layer using the Tau equation.

[0084] In some implementations, please refer to [the documentation / reference]. Figure 1 The solar cell further includes a first transport layer 102 and a second transport layer 104; the first transport layer 102 is located between the first electrode 101 and the perovskite light-absorbing layer 103; the second transport layer 104 is located between the perovskite light-absorbing layer 103 and the second electrode 105.

[0085] In some embodiments, the first transport layer 102 is a hole transport layer and the second transport layer 104 is an electron transport layer, in which case an inverted perovskite solar cell (pin) is obtained; or, the first transport layer 102 is an electron transport layer and the second transport layer 104 is a hole transport layer, in which case a normal perovskite solar cell (nip) is obtained.

[0086] This application does not specifically limit the hole transport material used in the hole transport layer; hole transport materials commonly used in the art can be used. Exemplary examples include poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly-3-hexylthiazole (P3HT), triphenylamine with a triphenylene core (H101), 3,4-ethylenedioxythiazole-methoxytriphenylamine (EDOT-OMeTPA), and N-(4-aniline)carbamate. One or more of the following: azole-spirobisfluorene (CzPAF-SBF), poly(3,4-ethylenedioxythiazole): poly(styrene sulfonate) (PEDOT:PSS), polythiazole, nickel oxide (NiOx), molybdenum oxide (MoO3), cuprous iodide (CuI), cuprous oxide (CuO), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz).

[0087] This application does not specifically limit the electron transport material used in the electron transport layer; commonly used electron transport materials in the art can be used. For example, electron transport materials include at least one of imide compounds, quinone compounds, fullerenes and their derivatives, metal oxides, semiconductor oxides, titanates, fluorides and their derivatives, and materials obtained by doping or passivation. Exemplarily, imide compounds include at least one of phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide. Exemplarily, quinone compounds include at least one of benzoquinone, naphthoquinone, phenanthrenequinone, or anthraquinone. Exemplarily,

[0088] Fullerenes and their derivatives, including fullerene C 60 Fullerene C 70 PCBM([6,6]-phenyl-C 61 methyl butyrate), [6,6]-phenyl C 71 Methyl butyrate (PC) 71At least one of BM. Exemplarily, the metal element in the metal oxide includes at least one of Mg, Cd, Zn, In, Pb, W, Sb, Bi, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, and Cr; optionally, the metal oxide includes at least one of tin dioxide (SnO2) and zinc oxide (ZnO). Exemplarily, the semiconductor material oxide includes silicon oxide. Exemplarily, the titanate includes at least one of strontium titanate and calcium titanate. Exemplarily, the fluoride includes at least one of lithium fluoride and calcium fluoride.

[0089] In some embodiments, the solar cell 10 further includes a hole blocking layer (not shown) located on the side of the electron transport layer away from the perovskite light-absorbing layer, for blocking the transmission of holes.

[0090] In some embodiments, the hole blocking layer includes a hole blocking material. This application does not have any particular limitation on the hole blocking material, which may include at least one of SnO2 (1.5≤z≤2) and copper bath (2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline, BCP).

[0091] In some embodiments, the perovskite light-absorbing layer includes at least one of the compounds shown in [A][B][X]3 and [A]2[C][D][X]6, wherein A includes at least one monovalent inorganic or organic cation, B includes at least one divalent inorganic cation, C includes at least one monovalent inorganic cation, D includes at least one trivalent inorganic cation, and X includes at least one monovalent anion.

[0092] For example, the organic cation includes: CH(NH2)2 + (abbreviated as FA) + CH3NH3 + (abbreviated as MA) + At least one of the following. Exemplarily, the inorganic cation includes: Li + Na + K + 、Rb + Cs + Pb 2+ Sn 2+ Be 2+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ Zn 2+ 、Ge 2+ Fe 2+ Co 2+ Ni 2+At least one of the following. Exemplarily, inorganic anions include: F... - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - OH - CN - SeCN - N3 - At least one of them.

[0093] In some embodiments, A is selected from cations with larger radii; exemplarily, cations with larger radii include MA. + (CH3NH3 + ), FA + (CH(NH2)2 + ), Li + Na + K + 、Rb + Cs + At least one of them.

[0094] In some embodiments, B is selected from cations with smaller radii; exemplarily, cations with smaller radii include Pb. 2+ Sn 2+ Be 2+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ Zn 2+ 、Ge 2+ Fe 2+ Co 2+ Ni 2+ Cd 2+ Cu 2+ Mn 2+ Pd 2+ Yb 2+ Or Eu 2 + One or more of them.

[0095] In some implementations, C is selected from Li + Na + K + 、Rb + Cs + One or more.

[0096] In some implementations, D is selected from Bi.3+ Sb 3+ Cr 3+ Fe 3+ Co 3+ Ga 3+ As 3+ Ru 3+ ,Rh 3+ In 3+ Ir 3 + Au 3+ Or Al 3+ One or more of them.

[0097] In some implementations, X is selected from F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - OH - CN - SeCN - One or more.

[0098] In some implementations, B includes Pb. 2+ and / or Sn 2+ .

[0099] In some implementations, B includes Pb. 2+ and Sn 2+ .

[0100] In some embodiments, the perovskite light-absorbing layer includes FA. 0.7 MA 0.3 Sn 0.5 Pb 0.5 I3, FASnI3, FA 0.95 MA 0.05 One of PbI3, optionally, the perovskite light-absorbing layer includes FA. 0.7 MA 0.3 Sn 0.5 Pb 0.5 I3.

[0101] In some embodiments, the solar cell can be a lead-based perovskite solar cell, a tin-based perovskite solar cell, or a tin-lead hybrid perovskite solar cell, optionally a tin-lead hybrid perovskite solar cell. In the case of a tin-lead hybrid perovskite solar cell, since polymers are present on the bottom surface of the perovskite light-absorbing layer and at the grain boundaries of the perovskite light-absorbing material, the polymers can passivate defects at the grain boundaries (i.e., the bulk phase) and the bottom surface of the perovskite light-absorbing material, thereby increasing the diffusion length of charge carriers and the lifetime of photogenerated charge carriers, which in turn helps to improve the photoelectric conversion efficiency of the tin-lead hybrid perovskite solar cell.

[0102] Methods for preparing solar cells

[0103] A second aspect of this application provides a method for preparing a solar cell, used to prepare the solar cell described in the first aspect. Figure 2 A schematic flowchart illustrating the method for fabricating a solar cell according to an embodiment of this application is shown below. Figure 2 As shown, the method for fabricating a solar cell includes the following steps:

[0104] S1, forming the first electrode;

[0105] S2, a perovskite precursor solution containing a polymer is coated on the first electrode to form a perovskite light-absorbing layer; the perovskite light-absorbing layer includes a perovskite light-absorbing material and a polymer, the polymer includes polar functional groups, and the polymer is located on the bottom surface of the perovskite light-absorbing material.

[0106] S3 forms a second electrode on the perovskite light-absorbing layer.

[0107] In this application, a polymer is added to the perovskite precursor solution. On one hand, the polymers intertwine to form a network structure, which can inhibit solvent extraction during the crystallization of the perovskite light-absorbing material, delay the decrease in supersaturation of the perovskite wet film, and prolong the crystallization time. On the other hand, the polar functional groups in the polymer can react with cations (e.g., Sn) in the perovskite precursor solution. 2+ and / or Pb 2+ This process forms coordination interactions, which can interfere with the coordination or complexation between precursors and between precursors and solvents, delaying the crystallization process of tin and / or lead. This is beneficial for improving the crystallinity quality of perovskite films, thereby enhancing the photoelectric conversion efficiency of solar cell devices. Furthermore, during the coating process to form a perovskite light-absorbing layer, the relatively large polymer molecules are repelled by the perovskite grains on the bottom surface of the perovskite light-absorbing material, passivating defects at the interface. Therefore, this can increase the diffusion length of charge carriers and extend the lifetime of photogenerated charge carriers, further improving the photoelectric conversion efficiency of solar cell devices.

[0108] In some embodiments, "the polymer is located on the bottom surface of the perovskite light-absorbing material" means that the polymer is located on the surface of the perovskite light-absorbing layer near the first electrode.

[0109] In some embodiments, the polymer in the perovskite light-absorbing layer formed in step S2 is also located at the grain boundaries of the perovskite light-absorbing material. This allows the polymer to further passivate defects at the grain boundaries (i.e., the bulk phase), thereby further increasing the diffusion length of charge carriers, extending the lifetime of photogenerated charge carriers, and ultimately improving the photoelectric conversion efficiency of the perovskite solar cell.

[0110] In some embodiments, the polymer includes one or more polar functional groups selected from carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen. Polar functional groups such as carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen possess lone pairs of electrons and therefore tend to react with cations (e.g., Sn) in the perovskite precursor solution. 2+ and / or Pb 2+ This can form coordination, thereby delaying the crystallization process of lead and / or tin, which is beneficial to improving the crystallization quality of perovskite films.

[0111] In some embodiments, the polymer includes a chain polymer. Chain polymers have good flexibility and can intertwine to form chain entanglements, which is more conducive to the formation of a network structure. The network structure can suppress solvent extraction during the crystallization process of the perovskite light-absorbing material, delay the decrease of supersaturation of the perovskite wet film, and prolong the crystallization time, thereby improving the film quality of the perovskite light-absorbing layer and thus improving the photoelectric conversion efficiency of the solar cell device.

[0112] For example, the chain polymer includes one or more of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol methacrylate, nitrile rubber, and styrene-butadiene rubber.

[0113] In some embodiments, the weight-average molecular weight of the polymer is 0.2 million to 4 million, optionally 100,000 to 1 million. A weight-average molecular weight within this range results in a higher polymer viscosity. Therefore, a higher viscosity of the perovskite precursor solution is beneficial for increasing the thickness of the formed perovskite light-absorbing layer, improving the light absorption capacity of the perovskite layer, and thus enhancing the photoelectric conversion efficiency of the solar cell device.

[0114] In some embodiments, the polymer includes one or more of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol acetoacetate methacrylate, and nitrile rubber. These polymers can intertwine to form a network structure, which can suppress the extraction of solvent from the perovskite wet film by antisolvents or vacuum flash evaporation during perovskite crystallization. Furthermore, the polymers can react with cations (e.g., Sn) in the perovskite precursor solution. 2+ and / or Pb 2+ The polymer forms a coordination effect, slowing down the crystallization rate of the perovskite film, improving the film quality of the perovskite light-absorbing layer, and increasing the photoelectric conversion efficiency of the solar cell device. Furthermore, the high viscosity of the polymer allows for increasing the concentration of the perovskite precursor solution, which facilitates the preparation of a thicker perovskite light-absorbing layer, thereby improving the light absorption capacity of the perovskite layer.

[0115] In some embodiments, the viscosity of the perovskite precursor solution is 1 mPa·s to 100 mPa·s; optionally, it is 1 mPa·s to 20 mPa·s. A viscosity within this range is advantageous for increasing the thickness of the perovskite light-absorbing layer and improving its light absorption capacity. Exemplarily, the viscosity of the perovskite precursor solution is a value within a range of 1 mPa·s, 10 mPa·s, 20 mPa·s, 50 mPa·s, 80 mPa·s, 100 mPa·s, or any combination thereof.

[0116] In some embodiments, the amount of polymer added to the perovskite precursor solution is 0.1 mg / mL to 100 mg / mL, optionally 1 mg / mL to 10 mg / mL. Adding polymer to the perovskite precursor solution within this range helps to slow down the evaporation of solvent in the perovskite wet film, slow down the crystallization rate, improve the film quality of the perovskite light-absorbing layer, and thus improve the photoelectric conversion efficiency of the solar cell device. Exemplarily, the amount of polymer added to the perovskite precursor solution is a value within the range of 0.1 mg / mL, 1 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, or any combination thereof.

[0117] In some embodiments, the concentration of the perovskite precursor solution is between 1 mg / mL and 2.4 mg / mL. A concentration within this range is advantageous for preparing a perovskite light-absorbing layer of suitable thickness. Exemplarily, the concentration of the perovskite precursor solution is a value within a range of 1 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2.0 mg / mL, 2.2 mg / mL, 2.4 mg / mL, or any combination thereof.

[0118] In some embodiments, the thickness of the perovskite light-absorbing layer is 0.2 μm to 2 μm, and optionally, the thickness is 0.8 μm to 1.2 μm. A thickness within this range is beneficial for improving light absorption utilization and enhancing the photoelectric conversion efficiency of the solar cell device. Exemplarily, the thickness of the perovskite light-absorbing layer is a value within the range of 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, or any combination thereof.

[0119] In some embodiments, the perovskite precursor solution further includes: halide salts, metal ions, and organic solvents.

[0120] In some embodiments, the perovskite precursor solution satisfies one or more of the following conditions:

[0121] (1) The halide salt includes one or more of iodomethylamine, bromomethylamine, iodomethylammonium, and bromomethylammonium.

[0122] (2) The metal ions include one or more of divalent tin ions and lead ions.

[0123] (3) The organic solvent includes one or more of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) and γ-butyrolactone (GBL), and optionally, the organic solvent includes N,N-dimethylformamide and dimethyl sulfoxide.

[0124] In some embodiments, the coating in step S2 includes any one of the following: sol-gel coating, spin coating, blade coating, and slot coating; optionally, the coating is spin coating.

[0125] In some implementations, step S2 includes an annealing process after coating.

[0126] In some embodiments, in step S1, the first electrode can be glass on which a transparent conductive film has been prepared. The transparent conductive film includes any one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium-doped tungsten oxide (IWO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), etc.

[0127] In some embodiments, the fabrication method further includes: forming a first transport layer between the first electrode and the perovskite light-absorbing layer, and forming a second transport layer between the perovskite light-absorbing layer and the second electrode layer.

[0128] In some implementations, the first transport layer is one of a hole transport layer and an electron transport layer, and the second transport layer is the other of the hole transport layer and the electron transport layer.

[0129] In some embodiments, a hole transport solution is coated on the surface of the first electrode and then annealed to form the first transport layer; or, an electron transport solution is vapor-deposited on the surface of the first electrode to form the first transport layer.

[0130] In some embodiments, an electron transport solution is vapor-deposited onto the surface of the perovskite light-absorbing layer to form a second transport layer, or a hole transport solution is coated onto the surface of the perovskite light-absorbing layer and then annealed to form a second transport layer.

[0131] In some embodiments, the method further includes forming a hole-blocking layer located on the side of the first or second transport layer away from the perovskite light-absorbing layer.

[0132] In some embodiments, the solar cell includes a lead-based perovskite solar cell, a tin-based perovskite solar cell, or a tin-lead hybrid perovskite solar cell, optionally a tin-lead hybrid perovskite solar cell.

[0133] photovoltaic modules

[0134] A third aspect of this application also provides a photovoltaic module. Typically, a photovoltaic module includes the aforementioned solar cell, a solder strip connecting multiple solar cells, a junction box for current transmission, and a cell encapsulation component. The solar cell is either the solar cell described in the first aspect or a solar cell prepared by the preparation method described in the second aspect.

[0135] In some embodiments, the battery encapsulation component includes photovoltaic glass, which covers the aforementioned solar cell and serves to protect it. Simultaneously, the photovoltaic glass possesses excellent light transmittance and high hardness, allowing it to withstand large diurnal temperature variations and harsh weather conditions.

[0136] In some embodiments, the battery encapsulation component includes an ethylene-vinyl acetate copolymer (EVA) film disposed between the photovoltaic glass and the solar cell for bonding the photovoltaic glass and the solar cell.

[0137] In some implementations, the battery encapsulation components include a photovoltaic backsheet, which also serves to protect the solar cells.

[0138] Optionally, the photovoltaic backsheet can be made of polyvinyl fluoride composite film or thermoplastic elastic material. The photovoltaic backsheet material has properties such as insulation, water resistance, and aging resistance.

[0139] In some implementations, the battery encapsulation component includes a solar aluminum frame, made of aluminum alloy, which features high strength and good corrosion resistance. It serves to support and protect the solar cells.

[0140] Power generation unit

[0141] A fourth aspect of the embodiments of this application also provides a power generation device, including the solar cell described in the first aspect above, or including a solar cell prepared according to the preparation method described in the second aspect above.

[0142] Electrical appliances

[0143] A fifth aspect of the embodiments of this application also provides an electrical device, including the solar cell described in the first aspect above, or including a solar cell prepared according to the preparation method described in the second aspect above.

[0144] In some embodiments, the electrical device may also be a lighting device, an energy storage device, etc., as is the case in the embodiments of this application. For example, the electrical device may be a solar water heater, a solar street light, a solar photovoltaic generator, etc.

[0145] Example

[0146] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0147] Example 1

[0148] Fabrication of hybrid tin-lead perovskite solar cells:

[0149] S1, Fabrication of the first electrode and the first transport layer:

[0150] a. Fluorine-doped tin oxide (FTO) is prepared on a glass plate as the first electrode. The first electrode is ultrasonically cleaned sequentially with acetone-alcohol-deionized water, and then dried for later use.

[0151] b. Prepare 100 μL of PEDOT:PSS solution and add it dropwise onto the first electrode dried in step a for spin coating. The spin coating speed is 3000 rpm and the spin coating time is 30 s. After spin coating, transfer it to a hot stage at 150℃ and anneal for 20 min to obtain the first transport layer, i.e., the hole transport layer. The thickness of the hole transport layer is 30 nm.

[0152] S2, Preparation of the perovskite light-absorbing layer:

[0153] c. Preparation of perovskite precursor solution: 217 mg FAI, 86 mg MAI, 415 mg PbI2, 335 mg SnI2, 23 mg SnF2 and 6 mg polymer polyacrylic acid PAA were added to 1 mL of DMF:DMSO organic solvent with a volume ratio of 3:1, and stirred at 800 rpm for 3 h on a magnetic stirrer until completely dissolved. The weight average molecular weight of the polymer was 450,000, the amount of polymer added to the perovskite precursor solution was 6 mg / mL, the viscosity of the perovskite precursor solution was 8.6 mPa·s, and the concentration of the perovskite precursor solution was 1.8 mol / L.

[0154] d. Take 100 μL of the perovskite precursor solution prepared in step c and add it dropwise onto the first transport layer prepared in step b. Perform spin coating at a speed of 1500 rpm for 10 s. Then, continue spin coating for 40 s at an acceleration of 1000 rpm / s and a spin coating speed of 4000 rpm. At approximately 30 s, drop 350 μL of ethyl acetate onto the perovskite film. Finally, anneal the spin-coated perovskite film on a hot plate at 100°C for 10 min to obtain the perovskite light-absorbing layer. The thickness of the perovskite light-absorbing layer is 1.291 μm; the polymer mass percentage in the perovskite light-absorbing layer is 0.6%.

[0155] S3, Fabrication of the second transport layer and the second electrode:

[0156] e. Evaporate C onto the perovskite light-absorbing layer prepared in step d. 60 As the second transport layer, namely the electron transport layer, the thickness of the electron transport layer is 25nm;

[0157] f. 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is deposited on the electron transport layer prepared in step e as a hole blocking layer with a thickness of 7 nm.

[0158] g. Copper is deposited on the electron transport layer prepared in step f as a second electrode, and the thickness of the second electrode is 80 nm.

[0159] By following the above steps, the perovskite light-absorbing material FA can be prepared. 0.7 MA 0.3 Sn 0.5 Pb 0.5 I3 hybrid tin-lead perovskite solar cells.

[0160] Examples 2 to 7

[0161] Mixed tin-lead perovskite solar cells were prepared using the same method as in Example 1, except that the types of polymers in the perovskite precursor solution were adjusted according to Table 1 below.

[0162] Comparative Example 1

[0163] Mixed tin-lead perovskite solar cells were prepared using the same method as in Example 1, except that the perovskite precursor solution did not contain polymers. Please refer to Table 1 below for details.

[0164] For Example 1 and Comparative Example 1, after the perovskite light-absorbing layer was prepared in step S2, the microstructure of the perovskite light-absorbing layer was tested using a scanning electron microscope (Hitachi, HD-2700). Figure 3 Scanning electron microscope (SEM) images of the perovskite light-absorbing layers in Example 1 and Comparative Example 1 are shown. It can be seen that, compared with the addition of polymer, the thickness of the perovskite light-absorbing layer with polymer increases from 669.9 nm to 1.291 μm.

[0165] The mixed tin-lead perovskite solar cell in Example 1 was disassembled to expose the bottom surface of the perovskite light-absorbing layer. The elemental composition of the bottom surface of the perovskite light-absorbing layer was analyzed using scanning electron microscopy and energy dispersive spectroscopy (EDS). Figure 4 The microstructure and elemental distribution diagram of the bottom surface of the perovskite light-absorbing layer in Example 1 are shown. Figure 4 Figure (a) shows the SEM image of the test area on the bottom surface of the perovskite light-absorbing layer. Figures (b) to (h) show the elemental distribution of C, N, O, F, Sn, I, and Pb, respectively. It can be seen that C, N, O, F, Sn, I, and Pb are uniformly distributed on the bottom surface of the perovskite light-absorbing layer. Since the O element in the perovskite light-absorbing layer only comes from the polymer polyacrylic acid, it can be determined that the polymer polyacrylic acid is located on the bottom surface of the perovskite light-absorbing layer.

[0166] The mixed tin-lead perovskite solar cell in Example 1 was disassembled to expose the perovskite light-absorbing layer. In accordance with the national standard GB / T6040-2002, the functional groups of the perovskite light-absorbing layer were tested using a Thermo Nicolet Nexus 670 attenuated total reflection Fourier transform infrared spectrometer (FTIR-ATR). The test results showed that the perovskite light-absorbing layer contains the polar functional group carboxyl.

[0167] Comparative Example 2

[0168] Mixed tin-lead perovskite solar cells were prepared using the same method as in Example 1, except that styrene-butadiene rubber (SBR) was added to the perovskite precursor solution. Please refer to Table 1 below for details.

[0169] Photovoltaic parameter testing of solar cells:

[0170] Photoelectric conversion efficiency (PCE) test

[0171] The photoelectric conversion efficiency was determined using the IV measurement method, and the specific steps are as follows:

[0172] a) Place the test fixture containing the sample cell (i.e. the mixed tin-lead perovskite solar cell prepared in Examples 1-8 and Comparative Example 1) on the sample holder, so that it is located in the measurement plane, and ensure that the sample cell is located at the center of the light spot emitted by the solar simulator (or the normal of the photovoltaic cell is parallel to the center line of the light beam emitted by the solar simulator light source).

[0173] b) The solar simulator from Guangyan was used for testing in accordance with the national standard IEC61215. Specifically, crystalline silicon solar cells were used to correct the light intensity to achieve a solar intensity of AM 1.5, at 1000 W / m². 2 Under irradiance conditions, a mask is installed on the sample battery to be tested, and the temperature of the sample battery is controlled by a temperature monitoring device so that the temperature of the sample battery is maintained at (30±5℃) during the measurement process.

[0174] c) Set the scan direction, voltage range, scan interval voltage, and scan interval time. Specifically, the scan interval is 0.02V, and the interval between two adjacent points is 0.3s. Measure the forward and reverse scan current-voltage characteristics of the battery sample and record the maximum power point current V. m Maximum power point voltage V m Open circuit voltage V OC and short-circuit current J SC .

[0175] Next, the photoelectric conversion efficiency is calculated using the following formula:

[0176] Photoelectric conversion efficiency PCE = P max / Pin =J SC ·V OC ·FF / P in ;

[0177] Fill factor FF = J m ×V m / V OC ×J SC ;

[0178] Among them, P max P is the maximum output power of the solar cell. in The incident light power is 1000 W / m. 2 FF is the fill factor.

[0179] Table 1 below shows the relevant parameters of the perovskite precursor solutions in Examples 1 to 7 and Comparative Examples 1 and 2. Table 2 below shows the photovoltaic parameters of the mixed tin-lead perovskite solar cells prepared in Examples 1 to 7 and Comparative Examples 1 and 2.

[0180] Table 1

[0181]

[0182] In Table 1, " / " indicates that the symbol does not exist.

[0183] Table 2

[0184]

[0185] As can be seen from Tables 1 and 2, compared with Comparative Example 1 (the perovskite light-absorbing layer does not contain polymers) and Comparative Example 2 (the polymers in the perovskite light-absorbing layer do not contain polar functional groups), Examples 1 to 7 significantly improved the photoelectric conversion efficiency of solar cell devices by introducing polymers containing polar functional groups into the perovskite light-absorbing layer.

[0186] Examples 8 to 12

[0187] Mixed tin-lead perovskite solar cells were prepared using the same method as in Example 1, except that the amount of polymer added to the perovskite precursor solution was different. Please refer to Table 3 below for details.

[0188] Table 3 below shows the relevant parameters of the perovskite precursor solutions in Examples 8 to 12, and Table 4 below shows the photovoltaic parameters of the mixed tin-lead perovskite solar cells prepared in Examples 8 to 12.

[0189] Table 3

[0190]

[0191] Table 4

[0192]

[0193] As shown in Tables 3 and 4, controlling the polymer addition amount in the perovskite precursor solution to be between 0.1 mg / mL and 100 mg / mL significantly improved the photoelectric conversion efficiency of the solar cell device. When the polymer addition amount exceeded 100 mg / mL, it was detrimental to the crystallization process of the perovskite film, increased the defects in the perovskite light-absorbing layer, and decreased the photoelectric conversion efficiency of the solar cell device.

[0194] Example 13

[0195] Fabrication of tin-based perovskite solar cells:

[0196] S1, Fabrication of the first electrode and the first transport layer:

[0197] a. Fluorine-doped tin oxide (FTO) is prepared on a glass plate as the first electrode. The first electrode is ultrasonically cleaned sequentially with acetone-alcohol-deionized water, and then dried for later use.

[0198] b. Add 1 mg MeO-4PACz to 1 mL of ethanol and stir to form an ethanol solution of MeO-4PACz. Then, drop the ethanol solution of MeO-4PACz onto the first electrode that has been dried in step a and spin-coat it. The spin-coating speed is 3000 rpm and the spin-coating time is 30 s. After spin-coating, anneal it on a hot stage at 100 °C for 10 min to obtain the first transport layer, i.e., the hole transport layer. The thickness of the hole transport layer is 5 nm.

[0199] S2, Preparation of the perovskite light-absorbing layer:

[0200] c. Preparation of perovskite precursor solution: 310 mg FAI, 671 mg SnI2, 23 mg SnF2, 14 mg phenylethyl ammonium chloride (PEACl), and 6 mg polymer polyacrylic acid were added to 1 mL of DMF:DMSO organic solvent with a volume ratio of 3:1, and stirred at 800 rpm for 12 h on a magnetic stirrer; wherein, the weight average molecular weight of the polymer is 450,000, the amount of polymer added to the perovskite precursor solution is 6 mg / mL, the viscosity of the perovskite precursor solution is 5.6 mPa·s, and the concentration of the perovskite precursor solution is 1 mol / L;

[0201] d. Take 100 μL of the perovskite precursor solution prepared in step c and drop it onto the hole transport layer prepared in step b for spin coating. The spin coating speed is 1000 rpm and the spin coating time is 10 s. Then, spin coating is continued for 40 s at an acceleration of 1000 rpm / s and a spin coating speed of 5000 rpm. At about 30 s, 400 μL of chlorobenzene is dropped on. Finally, the spin-coated perovskite film is annealed on a hot plate at 100℃ for 10 min to obtain a perovskite light-absorbing layer with a thickness of 0.65 μm. The polymer mass percentage in the perovskite light-absorbing layer is 0.6%.

[0202] S3, Fabrication of the second transport layer and the second electrode:

[0203] e. Evaporate C onto the perovskite light-absorbing layer prepared in step d. 60 As the second transport layer, namely the electron transport layer, the thickness of the electron transport layer is 25nm;

[0204] f. 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is deposited on the electron transport layer prepared in step e as a hole blocking layer with a thickness of 7 nm.

[0205] g. Copper is deposited on the electron transport layer prepared in step f as a second electrode, and the thickness of the second electrode is 80 nm.

[0206] By following the above steps, a tin-based perovskite solar cell with FASnI3 as the perovskite material can be prepared.

[0207] Comparative Example 3

[0208] Tin-based perovskite solar cells were prepared using the same method as in Example 13, except that the perovskite precursor solution did not contain polymers. Please refer to Table 5 below for details.

[0209] Comparative Example 4

[0210] Tin-based perovskite solar cells were prepared using the same method as in Example 13, except that styrene-butadiene rubber (SBR) was added to the perovskite precursor solution. Please refer to Table 5 below for details.

[0211] Table 5 below shows the relevant parameters of the tin-based perovskite precursor solutions in Examples 13 and Comparative Examples 3-4, and Table 6 below shows the photovoltaic parameters of the tin-based perovskite solar cells prepared in Examples 13 and Comparative Examples 3-4.

[0212] Table 5

[0213]

[0214] In Table 5, " / " indicates that the symbol does not exist.

[0215] Table 6

[0216]

[0217] As can be seen from Tables 5 and 6, compared with Comparative Example 3 (the perovskite light-absorbing layer does not contain polymer) and Comparative Example 4 (the added polymer does not contain polar functional groups), the introduction of a polymer with polar functional groups into the perovskite light-absorbing layer in Example 13 significantly improved the photoelectric conversion efficiency of the tin-based perovskite solar cell device.

[0218] Example 14

[0219] Fabrication of lead-based perovskite solar cells:

[0220] S1, Fabrication of the first electrode and the first transport layer:

[0221] a. Fluorine-doped tin oxide (FTO) is prepared on a glass plate as the first electrode. The first electrode is ultrasonically cleaned sequentially with acetone-alcohol-deionized water, and then dried for later use.

[0222] b. Add 1 mg of MeO-4PACz to 1 mL of ethanol and stir to form an ethanol solution of MeO-4PACz. Then, drop the ethanol solution of MeO-4PACz onto the first electrode that has been dried in step a and spin-coat it. The spin-coating speed is 3000 rpm and the spin-coating time is 30 s. After spin-coating, transfer it to a hot plate at 100 °C and anneal for 10 min to obtain the first transport layer, i.e., the hole transport layer. The thickness of the hole transport layer is 5 nm.

[0223] S2, Preparation of the perovskite light-absorbing layer:

[0224] c. Preparation of perovskite precursor solution: 294 mg FAI, 14 mg MAI, 830 mg PbI2, 30 mg Pb(SCN)2 and 6 mg polymer polyacrylic acid were added to 1 mL of DMF:DMSO organic solvent with a volume ratio of 3:1, and stirred at 800 rpm for 12 h on a magnetic stirrer; wherein, the weight average molecular weight of the polymer is 450,000, the amount of polymer added to the perovskite precursor solution is 6 mg / mL, the viscosity of the perovskite precursor solution is 8.6 mPa·s, and the concentration of the perovskite precursor solution is 1.5 mol / L;

[0225] d. Take 100 μL of the perovskite precursor solution prepared in step c and drop it onto the hole transport layer prepared in step b for spin coating. The spin coating speed is 1000 rpm and the spin coating time is 10 s. Then, spin coating is continued for 40 s at an acceleration of 1000 rpm / s and a spin coating speed of 5000 rpm. At about 30 s, 400 μL of chlorobenzene is dropped on. Finally, the spin-coated perovskite film is annealed on a hot plate at 100℃ for 10 min to obtain a perovskite light-absorbing layer with a thickness of 0.65 μm. The polymer mass percentage in the perovskite light-absorbing layer is 0.6%.

[0226] S3, Fabrication of the second transport layer and the second electrode:

[0227] e. Evaporate C onto the perovskite light-absorbing layer prepared in step d. 60 As the second transport layer, namely the electron transport layer, the thickness of the electron transport layer is 25nm;

[0228] f. 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is deposited on the electron transport layer prepared in step e as a hole blocking layer with a thickness of 7 nm.

[0229] g. Copper is deposited on the electron transport layer prepared in step f as a second electrode, and the thickness of the second electrode is 80 nm.

[0230] By following the above steps, the perovskite light-absorbing material FA can be prepared. 0.95 MA 0.05 PbI3 lead-based perovskite solar cells.

[0231] Comparative Example 5

[0232] Lead-based perovskite solar cells were prepared using the same method as in Example 14, except that the perovskite precursor solution did not contain polymers. Please refer to Table 7 below for details.

[0233] Comparative Example 6

[0234] Lead-based perovskite solar cells were prepared using the same method as in Example 14, except that styrene-butadiene rubber (SBR) was added to the perovskite precursor solution. Please refer to Table 7 below for details.

[0235] Table 7 below shows the relevant parameters of the lead-based perovskite precursor solutions in Examples 14 and Comparative Examples 5-6, and Table 8 below shows the photovoltaic parameters of the lead-based perovskite solar cells prepared in Examples 14 and Comparative Examples 5-6.

[0236] Table 7

[0237]

[0238] In Table 7, " / " indicates that the symbol does not exist.

[0239] Table 8

[0240]

[0241] As can be seen from Tables 7 and 8, compared with Comparative Example 5 (the perovskite light-absorbing layer does not contain polymers) and Comparative Example 6 (the polymers in the perovskite light-absorbing layer do not contain polar functional groups), the introduction of polymers with polar functional groups into the perovskite light-absorbing layer in Example 14 significantly improved the photoelectric conversion efficiency of the lead-based perovskite solar cell device.

[0242] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solar cell, characterized in that, It includes a first electrode, a perovskite light-absorbing layer, and a second electrode arranged sequentially along the light incident direction; The perovskite light-absorbing layer comprises a perovskite light-absorbing material and a polymer, wherein the polymer comprises polar functional groups; The polymer is located on the bottom surface of the perovskite light-absorbing material.

2. The solar cell according to claim 1, characterized in that, The polymer includes one or more polar functional groups selected from carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen.

3. The solar cell according to claim 1 or 2, characterized in that, The polymer includes chain polymers.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The polymer has a weight-average molecular weight of 0.2 million to 4 million.

5. The solar cell according to any one of claims 1 to 4, characterized in that, The polymer has a weight-average molecular weight of 100,000 to 1,000,000.

6. The solar cell according to any one of claims 1 to 5, characterized in that, The polymer includes one or more of the following: polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol methacrylate, and nitrile rubber.

7. The solar cell according to any one of claims 1 to 6, characterized in that, The thickness of the perovskite light-absorbing layer is 0.2 μm to 2 μm.

8. The solar cell according to any one of claims 1 to 7, characterized in that, The thickness of the perovskite light-absorbing layer is 0.8 μm to 1.2 μm.

9. The solar cell according to any one of claims 1 to 8, characterized in that, In the perovskite light-absorbing layer, the polymer accounts for 0.01% to 10% of the total mass.

10. The solar cell according to any one of claims 1 to 9, characterized in that, In the perovskite light-absorbing layer, the polymer accounts for 0.1% to 1% of the mass.

11. The solar cell according to any one of claims 1 to 10, characterized in that, The average grain size of the perovskite light-absorbing material is 0.4 μm to 2 μm.

12. The solar cell according to any one of claims 1 to 11, characterized in that, The average grain size of the perovskite light-absorbing material is 0.9 μm to 1.5 μm.

13. The solar cell according to any one of claims 1 to 12, characterized in that, The perovskite light-absorbing layer comprises at least one of the compounds shown in [A][B][X]3 and [A]2[C][D][X]6. Wherein, A includes at least one monovalent inorganic or organic cation, B includes at least one divalent inorganic cation, C includes at least one monovalent inorganic cation, D includes at least one trivalent inorganic cation, and X includes at least one monovalent anion.

14. The solar cell according to claim 13, characterized in that, A includes CH3NH3 + CH(NH2)2 + Li + Na + K + 、Rb + Cs + One or more of them, B including Pb 2+ and / or Sn 2+ C includes Li + Na + K + 、Rb + Cs + One or more of them, X including F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - OH - CN - SeCN - One or more of them.

15. The solar cell according to claim 13 or 14, characterized in that, B includes Pb 2+ and Sn 2+ .

16. A method for preparing a solar cell, characterized in that, Includes the following steps: S1, forming the first electrode; S2, A perovskite precursor solution containing a polymer is coated on the first electrode to form a perovskite light-absorbing layer; the perovskite light-absorbing layer includes a perovskite light-absorbing material and the polymer, the polymer includes polar functional groups, and the polymer is located on the bottom surface of the perovskite light-absorbing material; S3, a second electrode is formed on the perovskite light-absorbing layer.

17. The preparation method according to claim 16, characterized in that, The polymer includes one or more polar functional groups selected from carboxyl, hydroxyl, carbonyl, ether, cyano, and halogen.

18. The preparation method according to claim 16 or 17, characterized in that, The polymer includes chain polymers.

19. The preparation method according to any one of claims 16 to 18, characterized in that, The polymer has a weight-average molecular weight of 0.2 million to 4 million.

20. The preparation method according to any one of claims 16 to 19, characterized in that, The polymer includes one or more of the following: polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol methacrylate, and nitrile rubber.

21. The preparation method according to any one of claims 16 to 20, characterized in that, The viscosity of the perovskite precursor solution is 1 mPa·s to 100 mPa·s.

22. The preparation method according to any one of claims 16 to 21, characterized in that, The amount of polymer added to the perovskite precursor solution is 0.1 mg / mL to 100 mg / mL.

23. The preparation method according to any one of claims 16 to 22, characterized in that, The amount of polymer added to the perovskite precursor solution is 1 mg / mL to 10 mg / mL.

24. The preparation method according to any one of claims 16 to 23, characterized in that, The concentration of the perovskite precursor solution is 1 mg / mL to 2.4 mg / mL.

25. The preparation method according to any one of claims 16 to 24, characterized in that, The thickness of the perovskite light-absorbing layer is 0.2 μm to 2 μm.

26. A photovoltaic module, characterized in that, The photovoltaic module includes the solar cell according to any one of claims 1 to 15, or includes the solar cell prepared by the preparation method according to any one of claims 16 to 25.

27. A power generation device, characterized in that, The power generation device includes the solar cell according to any one of claims 1 to 15, or includes the solar cell prepared by the preparation method according to any one of claims 16 to 25.

28. An electrical appliance, characterized in that, The electrical device includes a solar cell according to any one of claims 1 to 15, or a solar cell prepared by the preparation method according to any one of claims 16 to 25.

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