Solar cell and preparation method thereof, photovoltaic equipment, electric equipment and power generation equipment

Abstract

The invention discloses a solar cell and a preparation method thereof, photovoltaic equipment, electric equipment and power generation equipment. The solar cell comprises a first electrode, a first light absorption layer, a composite layer, a second light absorption layer and a second electrode which are sequentially stacked, the first light absorption layer is arranged between the first electrode and the composite layer, the second light absorption layer is arranged on the side, away from the first light absorption layer, of the composite layer, and the second electrode is arranged on the side, away from the composite layer, of the second light absorption layer; wherein the composite layer comprises amorphous oxides, and the amorphous oxides comprise oxides of indium, gallium and zinc. The composite layer is designed to comprise amorphous oxide, indium oxide, gallium oxide and zinc oxide which are in an amorphous state, and the amorphous state is a crystal structure lacking long-range order, so that the migration path of a carrier in the material becomes complex and discontinuous, the transverse migration of the carrier in the composite layer is reduced, and the performance of the solar cell is improved.

Description

Technical Field

[0001] This application relates to the field of solar energy technology, and in particular to solar cells and their preparation methods, photovoltaic equipment, electrical equipment, and power generation equipment. Background Technology

[0002] Solar cells have attracted widespread attention because they can directly convert sunlight into electricity without causing environmental pollution, and can be applied to a wide range of fields, including military, aerospace, industry, commerce, agriculture and communications.

[0003] Tandem solar cells are a type of solar cell. They improve photoelectric conversion efficiency by stacking multiple light-absorbing layers with different band gaps to absorb a wider range of light in the solar spectrum.

[0004] The light-absorbing layers with different band gaps are connected by composite layers, and the performance of the composite layers affects the performance of tandem solar cells. Summary of the Invention

[0005] This application provides a solar cell and its preparation method, photovoltaic equipment, electrical equipment, and power generation equipment, which improve the performance of the composite layer and thus enhance the performance of the solar cell.

[0006] To address the aforementioned technical problems, the first aspect of this application provides a solar cell, comprising: a first electrode, a first light-absorbing layer, a composite layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer is disposed between the first electrode and the composite layer, the second light-absorbing layer is disposed on the side of the composite layer opposite to the first light-absorbing layer, and the second electrode is disposed on the side of the second light-absorbing layer opposite to the composite layer. The composite layer comprises an amorphous oxide, wherein the amorphous oxide comprises oxides of indium, gallium, and zinc.

[0007] By designing a composite layer comprising amorphous oxides containing indium, gallium, and zinc, the high electron mobility of these oxides allows for faster and more efficient carrier transport within the composite layer. Furthermore, the indium, gallium, and zinc oxides are transparent conductive materials with minimal absorption of visible light, exhibiting good light transmittance, which facilitates the efficient absorption of sunlight by the second light-absorbing layer. The amorphous state of these oxides, lacking long-range ordered crystal structures, leads to complex and discontinuous carrier migration paths within the material, reducing lateral carrier migration within the composite layer and thus improving solar cell performance.

[0008] In one embodiment, the molar ratio of indium, gallium, zinc, and oxygen is 5:(0.5-2):(1-3):(4-10). This results in a composite layer with high longitudinal conductivity and good light transmittance, thereby improving the photoelectric conversion performance of the solar cell.

[0009] In one embodiment, the sheet resistance of the composite layer is 20Ω / sq-300Ω / sq.

[0010] By setting the sheet resistance of the composite layer to 20Ω / sq-300Ω / sq, the composite layer has good conductivity, which is conducive to the smooth transport of photogenerated carriers along the thickness direction of the composite layer, helps to reduce the lateral migration of carriers in the composite layer, helps to reduce leakage current, increases the fill factor, and thus helps to improve the photoelectric conversion efficiency of solar cells.

[0011] In one embodiment, the full-spectrum weighted transmittance of the composite layer is a, where a ≥ 75%.

[0012] By setting the full-spectrum weighted transmittance of the composite layer to be greater than or equal to 78%, the amount of sunlight absorbed by the composite layer is reduced, thus reducing light loss. More sunlight can pass through the composite layer to reach the second light absorption layer, activating more photogenerated carriers, which is beneficial to improving the photoelectric conversion efficiency of the solar cell.

[0013] In one embodiment, the surface roughness of the composite layer is 5nm-15nm.

[0014] By setting the surface roughness of the composite layer to 5nm-15nm, the surface of the composite layer is relatively smooth. When fabricating the first or second light-absorbing layer on one side of the composite layer, it is beneficial to improve the crystallinity of the material in the first or second light-absorbing layer. In addition, the relatively smooth surface of the composite layer reduces material agglomeration in local locations, thus reducing the problem of increased local resistance in the composite layer, reducing energy loss during transmission, and helping to maintain the consistency of resistance and longitudinal conductivity throughout the composite layer, which is beneficial to improving the performance of solar cells. The longitudinal conductivity refers to the conductivity along the thickness direction of the composite layer, reflecting its conductivity along its thickness.

[0015] In one embodiment, the thickness of the composite layer is 5nm-100nm.

[0016] By setting the thickness of the composite layer to 5nm-100nm, the transport path of charge carriers in the composite layer is shorter, which is conducive to the smooth transport of photogenerated charge carriers along the thickness direction of the composite layer, thereby improving the collection efficiency of charge carriers by the first and second electrodes and improving the photoelectric conversion efficiency of the solar cell.

[0017] In one embodiment, the solar cell further includes a first transport layer disposed between the first light-absorbing layer and the composite layer, the first transport layer having a density of 6 g / cm³. 3 -7g / cm 3 .

[0018] A first transport layer is disposed between the first light-absorbing layer and the composite layer, and the density of the first transport layer is 6 g / cm³. 3 -7g / cm 3 The first transport layer is relatively dense. The first transport layer is first prepared on one side of the first light absorption layer, and then the composite layer is prepared on the side of the first transport layer away from the first light absorption layer. This can prevent the composite layer material from penetrating into the first light absorption layer during the subsequent preparation of the composite layer, reduce the impact on the first light absorption layer, and help improve the performance of the solar cell.

[0019] In one embodiment, the first transport layer is an electron transport layer, which includes tin oxide.

[0020] By setting the first transport layer to include tin oxide, which has high conductivity, electrons generated in the first light absorption layer can be transported to the composite layer, reducing electron loss during transport. Tin oxide also has excellent photostability, which helps extend the lifespan of the solar cell. The tin oxide film is relatively dense, which can prevent the composite layer material from penetrating into the first light absorption layer during the subsequent composite layer preparation process, thus improving the performance of the solar cell.

[0021] In one embodiment, the band gap of the first light-absorbing layer is 1.6 eV-2.0 eV, and the band gap of the second light-absorbing layer is 1.1 eV-1.3 eV.

[0022] By setting the band gaps of the first and second light-absorbing layers as described above, the first light-absorbing layer absorbs short-wavelength light, and the second light-absorbing layer absorbs long-wavelength light, thus making more comprehensive use of the solar spectrum, increasing the range of light absorption and energy conversion, and improving the efficiency of solar energy conversion.

[0023] In one embodiment, the first light-absorbing layer comprises a first perovskite material; and / or, the second light-absorbing layer comprises a second perovskite material.

[0024] By setting the first light-absorbing layer to include a first perovskite material and / or the second light-absorbing layer to include a second perovskite material, one of the first perovskite material and the second perovskite material absorbs short-wavelength light, while the other absorbs long-wavelength light, thus making more comprehensive use of the solar spectrum, increasing the range of light absorption and energy conversion, and improving the solar energy conversion efficiency.

[0025] To address the aforementioned technical problems, a second aspect of this application provides a method for fabricating a solar cell, comprising: providing a first electrode; forming a first light-absorbing layer on one side of the first electrode; forming a composite layer on the side of the first light-absorbing layer opposite to the first electrode; forming a second light-absorbing layer on the side of the composite layer opposite to the first light-absorbing layer; and forming a second electrode on the side of the second light-absorbing layer opposite to the composite layer; wherein the composite layer comprises an amorphous oxide, the amorphous oxide comprising oxides of indium, gallium, and zinc; the method for fabricating the composite layer comprises: mixing a gallium source, an indium source, and a zinc source with a solvent to form a precursor solution; coating the precursor solution onto the side of the first light-absorbing layer opposite to the first electrode; and annealing to form the composite layer.

[0026] In this embodiment, the composite layer is prepared by coating a precursor solution and then annealing, i.e., by solution method. The composite layer formed by solution method has a more uniform distribution of amorphous oxides containing indium, gallium, and zinc throughout the composite layer. This significantly reduces the problem of amorphous oxide agglomeration, thus reducing the problem of increased local resistance in the composite layer, reducing energy loss during transmission, and maintaining the consistency of resistance and longitudinal conductivity throughout the composite layer. Furthermore, the indium, gallium, and zinc oxides are amorphous, lacking a long-range ordered crystal structure. This results in complex and discontinuous migration paths for charge carriers in the material, reducing lateral migration of charge carriers in the composite layer and improving the performance of the solar cell.

[0027] In one embodiment, the annealing temperature is 80°C-100°C; and / or, the annealing time is 10 min-15 min.

[0028] By controlling the annealing temperature and time, the crystal structure of the oxides containing indium, gallium, and zinc is controlled, resulting in a composite layer that includes an amorphous film containing indium, gallium, and zinc oxides. The precursor solution is annealed at 80℃-100℃ to form an amorphous film layer. Since this temperature is relatively low, when the precursor solution coated on the side of the first light-absorbing layer opposite to the first electrode is annealed in situ to form the composite layer, 80℃-100℃ is a temperature that the first light-absorbing layer can withstand, having minimal impact on it and allowing it to maintain its original properties.

[0029] In one embodiment, the molar ratio of the indium source, gallium source, and zinc source is 5:(0.5-2):(1-3).

[0030] By setting the molar ratio of indium source, gallium source, and zinc source to 5:(0.5-2):(1-3), the resulting composite layer has higher longitudinal conductivity and better light transmittance, which in turn helps to improve the photoelectric conversion performance of solar cells.

[0031] In one embodiment, the concentration of the gallium source in the precursor solution is 0.06 mol / L to 0.3 mol / L; and / or, the concentration of the indium source in the precursor solution is 0.015 mol / L to 0.09 mol / L; and / or, the concentration of the zinc source in the precursor solution is 0.03 mol / L to 0.14 mol / L.

[0032] By setting the concentrations of gallium, indium, and zinc sources in the precursor solution as described above, the thickness of the formed indium gallium zinc oxide composite layer is made suitable, which reduces the longitudinal resistance of charge carriers, increases the recombination of charge carriers in the composite layer, reduces the recombination of charge carriers at the interface between the composite layer and the film layers on both sides of the composite layer, and improves the photoelectric conversion efficiency of the solar cell.

[0033] In one embodiment, the process of mixing the gallium source, indium source, zinc source and solvent to form a precursor solution further includes: mixing the gallium source, indium source, zinc source with solvent and stabilizer to form a precursor solution; wherein the concentration of stabilizer in the precursor solution is 0.2 mol / L-0.5 mol / L.

[0034] By adding a stabilizer to the precursor solution, the stability of the precursor solution is improved, reducing unwanted chemical reactions such as oxidation that may occur before annealing. In addition, the viscosity and surface tension of the precursor solution can be adjusted by the stabilizer, promoting the formation of a more uniform and flat composite layer on the side of the first light absorption layer away from the first electrode.

[0035] In one embodiment, the gallium source includes one or more of gallium nitrate, gallium chlorate, and gallium sulfate; and / or, the indium source includes one or more of indium nitrate and indium chlorate; and / or, the zinc source includes one or more of zinc nitrate, zinc chlorate, and zinc acetate; and / or, the solvent includes one or more of dimethyl ethanol, ethylene glycol methyl ether, methyl ether, toluene, diethyl ether, ethyl acetate, and chlorobenzene; and / or, the stabilizer includes one or more of monoethanolamine and monoethylene glycol.

[0036] By selecting the above-mentioned materials, which are common materials, it is beneficial to reduce costs.

[0037] In one embodiment, the step of coating the precursor solution onto the side of the first light-absorbing layer opposite to the first electrode includes: depositing tin oxide to form a first transport layer on the side of the first light-absorbing layer opposite to the first electrode using an atomic layer deposition process; and coating the precursor solution onto the side of the first transport layer opposite to the first light-absorbing layer.

[0038] By using tin oxide formed by atomic layer deposition as the first transport layer, the first transport layer is relatively dense and can prevent the precursor solution from penetrating into the first light absorption layer during the solution preparation of the composite layer. The first transport layer plays a role in protecting the first light absorption layer, which is beneficial to improving the performance of the solar cell.

[0039] A third aspect of this application provides a photovoltaic device comprising a solar cell as described in any of the preceding claims or a solar cell prepared by any of the preceding claims, having at least the same advantages as a solar cell.

[0040] The fourth aspect of this application provides an electrical device comprising a solar cell as described in any of the preceding claims or a solar cell prepared by any of the preceding claims, having at least the same advantages as a solar cell.

[0041] The fifth aspect of this application provides a power generation device comprising a solar cell as described in any one of the preceding claims or a solar cell prepared by any one of the preceding claims, having at least the same advantages as a solar cell.

[0042] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of the solar cell provided in the embodiments of this application;

[0045] Figure 2 This is an X-ray diffraction pattern of the composite layer provided in the embodiments of this application;

[0046] Figure 3 This is a schematic flowchart of the method for preparing the composite layer provided in the embodiments of this application;

[0047] Figure 4 This is a schematic diagram of the structure of the photovoltaic device provided in the embodiments of this application;

[0048] Figure 5 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application;

[0049] Figure 6 This is a schematic diagram of the power generation equipment provided in the embodiments of this application.

[0050] Label Explanation:

[0051] First electrode 11, first light absorption layer 12, first transmission layer 12a, third transmission layer 12b, composite layer 13, second light absorption layer 14, second transmission layer 14a, fourth transmission layer 14b, second electrode 15, solar cell 100, photovoltaic equipment 1000, electrical equipment 2000, power generation equipment 3000. Detailed Implementation

[0052] To make the objectives, technical solutions, and effects of this application clearer and more explicit, the embodiments of the technical solutions of this application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of this application, and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0054] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces), unless otherwise explicitly specified.

[0055] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0056] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0057] Quantities, ratios, and other numerical values ​​are presented in range format in this document. It should be understood that this range format is for convenience and brevity and should be interpreted flexibly to include not only numerical values ​​explicitly specified as range limits, but also all individual numerical values ​​or subranges covered within the range, as if each numerical value and subrange were explicitly specified.

[0058] Unless otherwise specified, all steps of this application may be performed sequentially, randomly, or in parallel, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially, or steps (a) and (b) may be performed simultaneously in parallel. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or steps (a), (c), and (b), or steps (c), (a), and (b), etc.

[0059] A tandem solar cell typically includes a first electrode, a first light-absorbing layer, a composite layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer and the second light-absorbing layer have different band gaps.

[0060] The main function of the composite layer is to recombine and annihilate the charge carriers generated by the first and second light-absorbing layers, thereby enabling the external circuit to conduct. The performance of the composite layer affects the performance of the solar cell.

[0061] Currently, one of the most commonly used composite layers in related technologies is the indium tin oxide (ITO) thin film formed by two-dimensional deposition techniques. These two-dimensional deposition techniques include physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), or reactive plasma deposition (RPD). Because ITO particles are extremely small, the resulting film is discontinuous, which effectively solves the problems of transmittance and lateral conductivity. However, due to the aggregation of ITO nanoparticles during preparation, some areas of the film beneath the ITO film lack ITO particles, while others show particle accumulation, making morphological control difficult. The absence of ITO particles in some areas exposes parts of the film, leading to incomplete carrier recombination, the appearance of a reverse electric field, and solution permeation problems during subsequent perovskite preparation. Furthermore, the accumulation of ITO particles in other areas increases resistivity, resulting in a decrease in the fill factor (FF). During the preparation of ITO nanoparticles, agglomeration occurs, resulting in an uneven film surface. This can lead to poor crystallization during the preparation of the light-absorbing layer on the composite layer.

[0062] In view of this, embodiments of this application provide a solar cell and its preparation method, a photovoltaic device, an electrical device, and a power generation device, which improve the performance of the composite layer and thus improve the performance of the solar cell.

[0063] Please see Figures 1 to 2 , Figure 1 This is a schematic diagram of the structure of the solar cell provided in the embodiments of this application. Figure 2 This is an X-ray diffraction pattern of the composite layer provided in the embodiments of this application.

[0064] The solar cell 100 includes a first electrode 11, a first light-absorbing layer 12, a composite layer 13, a second light-absorbing layer 14, and a second electrode 15. The first light-absorbing layer 12 is disposed between the first electrode 11 and the composite layer 13. The second light-absorbing layer 14 is disposed on the side of the composite layer 13 opposite to the first light-absorbing layer 12, and the second electrode 15 is disposed on the side of the second light-absorbing layer 14 opposite to the composite layer 13. The composite layer 13 comprises an amorphous oxide, which includes oxides of indium, gallium, and zinc.

[0065] Both the first light-absorbing layer 12 and the second light-absorbing layer 14 are used to absorb light and directly convert light energy into electrical energy through the photoelectric effect or photochemical effect. The first light-absorbing layer 12 includes a first light-absorbing material, and the second light-absorbing layer 14 includes a second light-absorbing material. Both the first and second light-absorbing materials have photoelectric conversion functions. They absorb photons from sunlight to generate excitation, which in turn excites electrons in the valence band to generate photogenerated holes and electron pairs. Under the action of an electric field, the holes and electrons separate. The main function of the recombination layer 13 is to recombine and annihilate the charge carriers generated by the first light-absorbing layer 12 and the second light-absorbing layer 14. One of the electrons and holes generated by the first light-absorbing layer 12 is transported to the first electrode 11, and the other electron and hole generated by the first light-absorbing layer 12 is transported to the recombination layer 12; one of the electrons and holes generated by the second light-absorbing layer 14 is transported to the second electrode 15, and the other electron and hole generated by the second light-absorbing layer 14 is transported to the recombination layer 12; the electrons generated by the first light-absorbing layer 12 and the holes generated by the second light-absorbing layer 14, or the holes generated by the first light-absorbing layer 12 and the electrons generated by the second light-absorbing layer 14, recombine and annihilate in the recombination layer 13. One of the electrons and holes collected by the first electrode 11 and the other electron and hole collected by the second electrode 15 form a loop through an external circuit, which can be used to drive the load.

[0066] To facilitate the transport of charge carriers generated by the first light-absorbing layer 12 and the second light-absorbing layer 14, the requirements for the recombination layer 13 are: 1) a high recombination rate, so that all charge carriers transported to the recombination layer can undergo recombination and annihilation; 2) high transmittance, which is beneficial for increasing light transmission. One of the first light-absorbing layer 12 and the second light-absorbing layer 14 has a wide bandgap, and the other has a narrow bandgap. Sunlight typically enters from the wide-bandgap light-absorbing layer side. Sunlight needs to pass through the recombination layer to reach the narrow-bandgap light-absorbing layer. The recombination layer has high transmittance, which can increase the absorption of sunlight by the narrow-bandgap light-absorbing layer. For example, the bandgap of the second light-absorbing layer 14 is smaller than that of the first light-absorbing layer 14. The band gap of the light-absorbing layer 12 and the high transmittance of the composite layer 13 are beneficial to increasing the absorption of sunlight by the second light-absorbing layer 14. The transmittance refers to the degree to which the composite layer 13 allows light to pass through, specifically the ratio of the light flux passing through the composite layer 13 to the incident light flux. 3) Low lateral conductivity is required. The lateral conductivity refers to the conductivity of the material in the two-dimensional plane. Lower lateral conductivity helps to reduce the lateral migration of photogenerated carriers in the composite layer, which is beneficial to reduce leakage current and increase the fill factor (FF). Higher lateral conductivity leads to a smaller Ponzi resistance (Rsh), thereby reducing the fill factor (FF) of the solar cell.

[0067] By designing the composite layer 13 to include an amorphous oxide containing indium, gallium, and zinc (hereinafter referred to as "indium gallium zinc oxide"), the indium gallium zinc oxide has a high electron mobility, making the transport of charge carriers in the composite layer 13 faster and more efficient. Indium gallium zinc oxide is a transparent conductive material, and it absorbs less visible light, thus having good light transmittance, which is beneficial for sunlight to pass through the composite layer and be efficiently absorbed by the first light-absorbing layer 12 or the second light-absorbing layer 14. Indium gallium zinc oxide is amorphous, and the amorphous state lacks a long-range ordered crystal structure, which makes the migration path of charge carriers in the composite layer 13 material more complex and discontinuous, reducing the lateral migration of charge carriers in the composite layer 13 and improving the performance of the solar cell.

[0068] Oxides containing indium, gallium, and zinc refer to oxides that contain all three elements: indium, gallium, and zinc.

[0069] X-ray diffraction (XRD) was performed on composite layer 13. In the XRD diffraction pattern of indium gallium zinc oxide (IGZO), the first diffraction peak was observed between 25° and 35° at a diffraction angle 2θ, with a full width at half maximum (FWHM) of α. Amorphous IGZO satisfies the condition that α ≥ 4°, meaning that IGZO does not have a sharp peak indicating crystal orientation, thus it is amorphous. The XRD testing method involved aligning one side of the thin film sample with the window aperture, ensuring the surface was flush with the sample holder. A 20 nm thin film was prepared, and testing was performed using vertical irradiation. The starting angle was 20 degrees, the ending angle was 90 degrees, the step angle was 0.02 degrees, and the measurement time was 0.5 s. The tube voltage was 40 kV, and the tube current was 30 mA. Furthermore, transmission electron microscopy (TEM) can be used to test composite layer 13 to determine whether it is amorphous. The TEM testing method is as follows: Select a microgrid of a certain diameter (e.g., 3 mm), hold the edge of the microgrid with pointed tweezers, with the film side facing up (the side that appears glossy under light, i.e., the film side), and gently place it flat on white filter paper; place the microgrid containing the sample on the sample stage, and test it with a transmission electron microscope at a certain magnification (e.g., 60,000 times) to obtain the transmission electron microscope image of the sample to be tested.

[0070] The full width at half maximum (FWHM) is a well-known concept in the art and can be measured using methods known in the field. For example, the XRD pattern of a sample can be tested according to the JIS / K0131-1996 testing standard. Based on the XRD pattern, the corresponding diffraction peaks of the target crystal can be located, and the FWHM can be determined based on the diffraction peaks. The FWHM is the width of the peak at half its height in the XRD diffraction. Specifically, it is the distance, measured in degrees, between the two points where the line drawn parallel to the base of the peak intersects the midpoint of the peak.

[0071] In one embodiment, the molar ratio of indium, gallium, zinc and oxygen is 5:(0.5-2):(1-3):(4-10). Controlling the proportion of the above elements is beneficial to the formation of a composite layer with high longitudinal conductivity and good light transmittance, which in turn helps to improve the photoelectric conversion performance of the solar cell. The molar ratio of indium, gallium, zinc, and oxygen can be 5:1:2:4, 5:0.5:1:4, 5:1.5:1:10, 5:2:1:8, 5:0.5:1.5:7, 5:0.5:2:4, 5:0.5:2.5:6, 5:0.5:3:5, 5:0.7:1:4, 5:1.2:1:10, 5:1:1.8:5.5, 5:1:2.4:8.5, etc., or 5:(0.7-1.2):(1-3):(4-7), 5:(0.7-1.2):(1.8-2.4):(7-9), etc.

[0072] In one embodiment, the sheet resistance of the composite layer 13 is 20Ω / sq-300Ω / sq.

[0073] The sheet resistance of composite layer 13 reflects the conductivity of composite layer 12. Sheet resistance is the resistance between the two ends of a unit width and unit length of film. The sheet resistance of composite layer 13 can be measured using a Hall effect meter or a four-probe sheet resistance meter. There is a negative correlation between the sheet resistance of composite layer 13 and its lateral conductivity; the sheet resistance of composite layer 13 ranges from 20 Ω / sq to 300 Ω / sq, indicating a relatively low lateral conductivity.

[0074] The sheet resistance of the composite layer 13 is 20Ω / sq-300Ω / sq. The composite layer exhibits good conductivity, which facilitates the smooth transport of photogenerated carriers along the thickness direction of the composite layer. This helps reduce lateral carrier migration within the composite layer, decreases leakage current, increases the fill factor, and ultimately improves the photoelectric conversion efficiency of the solar cell. The sheet resistance of the composite layer 13 can be 20Ω / sq, 30Ω / sq, 40Ω / sq, 50Ω / sq, 60Ω / sq, 61Ω / sq, 62Ω / sq, 63Ω / sq, 64Ω / sq, 65Ω / sq, 66Ω / sq, 67Ω / sq, 68Ω / sq, 69Ω / sq, 70Ω / sq, 71Ω / sq, 72Ω / sq, or 73Ω / sq. 74Ω / sq, 75Ω / sq, 80Ω / sq, 100Ω / sq, 200Ω / sq, 300Ω / sq, etc., or a range consisting of any two of the above values, such as 60Ω / sq-75Ω / sq, 67Ω / sq-73Ω / sq, 64Ω / sq-72Ω / sq, 70Ω / sq-300Ω / sq, 100Ω / sq-300Ω / sq, etc.

[0075] In one embodiment, the sheet resistance of the composite layer 13 is 60Ω / sq-75Ω / sq. The composite layer has good conductivity, which is conducive to the smooth transport of photogenerated carriers along the thickness direction of the composite layer. It helps to reduce the lateral migration of carriers in the composite layer, reduce leakage current, increase the fill factor, and thus improve the photoelectric conversion efficiency of the solar cell.

[0076] In one embodiment, the full-spectrum weighted transmittance of the composite layer 13 is a, where a ≥ 75%.

[0077] The full-spectrum weighted transmittance of composite layer 13 refers to the sum of the transmittance of different wavelengths of light multiplied by their corresponding weights across the entire solar spectrum. This reflects the overall transmittance performance of composite layer 13 across the entire spectral range. The full-spectrum weighted transmittance can be measured using a UV-Vis absorption spectroscopy analyzer. This analyzer includes a spectrophotometer and an integrating sphere; the spectrophotometer is used for spectral dispersion, and the integrating sphere is used for transmittance measurement.

[0078] By setting the full-spectrum weighted transmittance of the composite layer 13 as described above, the amount of sunlight absorbed by the composite layer 13 is reduced, thus reducing light loss. More sunlight can then pass through the composite layer to reach the first light-absorbing layer 12 or the second light-absorbing layer 14, activating more photogenerated carriers and improving the photoelectric conversion efficiency of the solar cell. The full-spectrum weighted transmittance of the composite layer 13 can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc., or it can be greater than or equal to 80%, or greater than or equal to 90%, etc.

[0079] In one embodiment, the surface roughness of the composite layer 13 is 5 nm to 15 nm.

[0080] The surface roughness of composite layer 13 reflects the smoothness of its surface and can indirectly reflect the degree of material aggregation in composite layer 13. The surface roughness of composite layer 13 describes the unevenness of the film surface and is usually expressed as arithmetic mean roughness (Ra). The surface roughness of composite layer 13 can be obtained by profilometer or atomic force microscope.

[0081] By controlling the surface roughness of the composite layer 13 to be 5nm-15nm, the surface of the composite layer 13 is relatively smooth. When the first light-absorbing layer 12 or the second light-absorbing layer 14 is fabricated on one side of the composite layer 13, it is beneficial to improve the crystallinity of the material of the first light-absorbing layer 12 or the second light-absorbing layer 14. In addition, the relatively smooth surface of the composite layer 13 reduces the material agglomeration at local locations, thus reducing the problem of increased local resistance in the composite layer 13, reducing energy loss during transmission, and helping to maintain the uniformity of resistance and longitudinal conductivity throughout the composite layer 13, which is beneficial to improving the performance of the solar cell. Here, longitudinal conductivity refers to the conductivity along the thickness direction of the composite layer 13, reflecting the conductivity of the composite layer 13 along its thickness direction. The surface roughness of the composite layer 13 can be 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, etc., or it can be a range of any two of the above values, such as 5nm-10nm, 6nm-12nm, etc.

[0082] The composite layer 13 provided in this application has a surface roughness of 5nm-15nm, resulting in a relatively smooth surface and effectively solving the problem of ITO nanoparticle agglomeration in related technologies. In related technologies, a 3% ITO nanoparticle dispersion is used for spin coating. The spin coating process involves an acceleration of 1000 rpm / s, a speed of 4000 rpm, a spin coating time of 30s, and annealing at 100℃ for 10min, resulting in an ITO nanoparticle composite layer with a surface roughness of 30nm.

[0083] In one embodiment, the thickness of the composite layer 13 is 5 nm to 100 nm.

[0084] The thickness of composite layer 13 refers to the average distance between the surface of composite layer 13 near the first light-absorbing layer 12 and the surface of composite layer 13 near the second light-absorbing layer 14. The method for testing the thickness of composite layer 13 is as follows: obtain a cross-sectional scanning electron microscope (SEM) image of composite layer 13; specifically, randomly select multiple regions on the cross-section of composite layer 13, and measure the thickness of composite layer 13 at least five times at a magnification of 30,000x, statistically analyze the measured values ​​of different regions, and take the average value as the thickness of composite layer 13.

[0085] The thickness of the composite layer 13 can be 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, etc., or it can be a range of any two of the above values, such as 5nm-30nm, 20nm-50nm, 40nm-80nm, etc.

[0086] By setting the thickness of the composite layer 13 to 5nm-100nm, the transport path of charge carriers in the composite layer 13 is shorter, which is conducive to the smooth transport of photogenerated charge carriers along the thickness direction of the composite layer, thereby improving the collection efficiency of charge carriers by the first electrode and the second electrode and improving the photoelectric conversion efficiency of the solar cell.

[0087] In one embodiment, the thickness of the composite layer 13 is 20nm-40nm. The transport path of charge carriers in the composite layer 13 is relatively short, which is conducive to the smooth transport of photogenerated charge carriers along the thickness direction of the composite layer, thereby improving the collection efficiency of charge carriers by the first electrode and the second electrode and improving the photoelectric conversion efficiency of the solar cell.

[0088] In one implementation, such as Figure 1 As shown, the solar cell 100 further includes a first transport layer 12a, which is disposed between the first light-absorbing layer 12 and the composite layer 13. The density of the first transport layer 12a is 6 g / cm³. 3 -7g / cm 3 .

[0089] The density of the first transport layer 12a reflects its compactness. The density of the first transport layer 12a can be determined by X-ray reflectance (XRR) testing. The density of the first transport layer 12a can be 6 g / cm³. 3 6.1g / cm 3 6.2g / cm 3 6.3g / cm 3 6.4g / cm 3 6.5g / cm 3 6.6 g / cm 3 6.7g / cm 3 6.8g / cm 3 6.9g / cm 3 7g / cm 3 "etc." can also be a range consisting of any two of the above values, for example, 6.1 g / cm³. 3 -6.8g / cm 3 6.5g / cm 3 -6.9g / cm3 wait.

[0090] By setting a first transport layer 12a, carrier transport is promoted and energy level matching is adjusted, which is beneficial to improving the performance of solar cells. The first transport layer 12a is set between the first light-absorbing layer 12 and the composite layer 13, and the density of the first transport layer 12a is 6 g / cm³. 3 -7g / cm 3 The first transport layer 12a is relatively dense. The first transport layer 12a is first prepared on one side of the first light absorption layer 12, and then the composite layer 13 is prepared on the side of the first transport layer 12a away from the first light absorption layer 12. This can prevent the composite layer 13 material from penetrating into the first light absorption layer 12 during the subsequent preparation of the composite layer 13, reduce the impact on the first light absorption layer 12, and help improve the performance of the solar cell.

[0091] The first transport layer 12a can be either an electron transport layer or a hole transport layer, as long as it meets the aforementioned density requirements. When the first electrode 11 collects holes, the first transport layer 12a is an electron transport layer, which can prevent the composite layer 13 material from penetrating into the first light-absorbing layer 12 during the subsequent fabrication of the composite layer 13, while simultaneously promoting the transport of electrons generated in the first light-absorbing layer 12 to the composite layer 13. When the first electrode 11 collects electrons, the first transport layer 12a is a hole transport layer, which can prevent the composite layer 13 material from penetrating into the first light-absorbing layer 12 during the subsequent fabrication of the composite layer 13, while simultaneously promoting the transport of holes generated in the first light-absorbing layer 12 to the composite layer 13.

[0092] In one embodiment, the first transport layer 12a is an electron transport layer, which includes tin oxide.

[0093] By setting the first transport layer 12a to include tin oxide, which has high conductivity, the electrons generated by the first light absorption layer 12 can be transported to the composite layer 13, reducing the loss of electrons during the transport process. Tin oxide has excellent photostability, which is beneficial to extending the lifespan of the solar cell. The tin oxide film is relatively dense, which can prevent the composite layer 13 material from penetrating into the first light absorption layer 12 during the subsequent preparation of the composite layer 13, which is beneficial to improving the performance of the solar cell.

[0094] Optionally, an atomic layer deposition process is used to form a tin oxide film as the first transport layer 12a. The first transport layer 12a has good density, which can effectively prevent the composite layer 13 material from penetrating into the first light absorption layer 12 during the subsequent preparation of the composite layer 13, which is beneficial to improving the performance of the solar cell.

[0095] In one embodiment, the band gap of the first light absorption layer 12 is 1.6 eV-2.0 eV, and the band gap of the second light absorption layer 14 is 1.1 eV-1.3 eV.

[0096] By setting the band gaps of the first light-absorbing layer 12 and the second light-absorbing layer 14 as described above, the first light-absorbing layer 12 absorbs short-wavelength light and the second light-absorbing layer 14 absorbs long-wavelength light, making more comprehensive use of the solar spectrum, increasing the range of light absorption and energy conversion, and improving the solar light conversion efficiency.

[0097] Optionally, the first light-absorbing layer 12 includes at least one of copper indium gallium selenide, gallium arsenide, indium phosphide, and perovskite.

[0098] Optionally, the second light-absorbing layer 14 includes at least one of copper indium gallium selenide, gallium arsenide, silicon, and perovskite.

[0099] In one embodiment, the first light-absorbing layer 12 comprises a first perovskite material; and / or, the second light-absorbing layer 14 comprises a second perovskite material.

[0100] By setting the first light-absorbing layer 12 to include a first perovskite material and / or the second light-absorbing layer 14 to include a second perovskite material, one of the first perovskite material and the second perovskite material absorbs short-wavelength light, while the other absorbs long-wavelength light, thus making more comprehensive use of the solar spectrum, increasing the range of light absorption and energy conversion, and improving the solar energy conversion efficiency.

[0101] Optionally, the first perovskite material 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 inorganic or organic monovalent cation, B includes at least one inorganic divalent cation, C includes at least one inorganic monovalent cation, D includes at least one inorganic trivalent cation, and X includes at least one monovalent anion.

[0102] Optionally, the second perovskite material 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 inorganic or organic monovalent cation, B includes at least one inorganic divalent cation, C includes at least one inorganic monovalent cation, D includes at least one inorganic trivalent cation, and X includes at least one monovalent anion.

[0103] For example, organic monovalent cations include (NR1R2R3R4). + (R1R2N=CR3R4) + (R1R2N-C(R5)=NR3R4) + and (R1R2N-C(NR5R6)=NR3R4) +One or more of the following, wherein R1, R2, R3, R4, R5, and R6 are each independently selected from H, substituted or unsubstituted C1-C20 alkyl groups, or substituted or unsubstituted aryl groups. Optionally, the organic monovalent cation includes (H2N=CH-NH2). + (abbreviated as FA), CH3NH3 + (abbreviated as MA), one or more of the following: ethylamino, propylamino, butylamino, pentamino, hexamino, and imidazole.

[0104] For example, the inorganic monovalent cation includes: Li + Na + K + 、Rb + Cs + Cu + Ag + Au + or Hg + At least one of them.

[0105] For example, the inorganic divalent cation includes: 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+ At least one of them.

[0106] For example, inorganic trivalent cations include: Bi 3+ Sb 3+ Cr 3+ Fe 3+ Co 3+ Ga 3+ As 3+ Ru 3+ ,Rh 3+ In 3+ Ir 3+ Ni 3+ Au 3+ Or Al 3+ At least one of them.

[0107] For example, monovalent anions include: F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - CN - SeCN - At least one of them.

[0108] In one embodiment, the first light-absorbing layer 12 comprises a first perovskite material, and the band gap of the first light-absorbing layer 12 is 1.6 eV-2.0 eV; the second light-absorbing layer 14 comprises a second perovskite material, and the band gap of the second light-absorbing layer 14 is 1.1 eV-1.3 eV. Exemplarily, the first light-absorbing layer 12 comprises FA 0.8 Cs 0.2 PbI 1.8 Br 1.2 The second light-absorbing layer 14 includes FA 0.6 MA 0.4 Pb 0.5 Sn 0.5 I3. As another example, the first light-absorbing layer 12 includes FA. 0.8 Cs 0.2 PbI 1.8 Br 1.1 Cl 0.1 The second light-absorbing layer 14 includes Cs 0.1 FA 0.5 MA 0.4 Pb 0.5 Sn 0.5 I3.

[0109] In one embodiment, the first light-absorbing layer 12 includes a first perovskite material, the first perovskite material including FA. 0.8 Cs 0.2 PbI 1.8 Br 1.1 Cl 0.1 The second light-absorbing layer 12 comprises crystalline silicon.

[0110] In one implementation, such as Figure 1As shown, the solar cell 100 further includes a second transport layer 14a, a third transport layer 12b, and / or a fourth transport layer 14b. The second transport layer 14a is disposed between the composite layer 13 and the second light-absorbing layer 14, the third transport layer 12b is disposed between the first light-absorbing layer 12 and the first electrode 11, and the fourth transport layer 14b is disposed between the second light-absorbing layer 14 and the second electrode 15. The transport properties of the second transport layer 14a and the third transport layer 12b are consistent, and the transport properties of the fourth transport layer 14b are consistent with those of the first transport layer 12a. By setting the second transport layer 14a, the third transport layer 12b, and the fourth transport layer 14b, it is beneficial to improve the carrier transport efficiency, adjust the energy level matching between the film layers, and thus improve the performance of the solar cell.

[0111] Optionally, the third transport layer 12b is a hole transport layer, the first transport layer 12a is an electron transport layer, the second transport layer 14a is a hole transport layer, and the fourth transport layer 14b is an electron transport layer.

[0112] Optionally, the third transport layer 12b is an electron transport layer, the first transport layer 12a is a hole transport layer, the second transport layer 14a is an electron transport layer, and the fourth transport layer 14b is a hole transport layer.

[0113] Optionally, the electron transport layer material is at least one of the following materials and their derivatives, or materials obtained by doping or passivation. Electron transport materials include, but are not limited to, at least one of imide compounds, quinone compounds, fullerenes and their derivatives, metal oxides, semiconductor oxides, titanates, and fluorides. Imide compounds include at least one of phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide. Quinone compounds include at least one of benzoquinone, naphthoquinone, phenanthrenequinone, or anthraquinone. Fullerenes and their derivatives include methyl [6,6]-phenyl-C61-butyrate (PC... 61 BM), [6,6]-phenyl-C71-butyrate methyl ester (PC) 71 The metal oxide includes at least one of BM, fullerene C60 (C60), and fullerene C70 (C70). 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; for example, zinc oxide (ZnO) and tin dioxide (SnO2). The semiconductor material oxide includes silicon oxide. The titanate includes at least one of strontium titanate and calcium titanate. The fluoride includes at least one of lithium fluoride and calcium fluoride.

[0114] Optionally, the hole transport layer is made of at least one of the following materials and their derivatives, or materials obtained by doping or passivation. The hole transport layer includes, but is not limited to, 2,2',7,7'-tetra(N,N-p-methoxyaniline)-9,9'-spirodifluorene (Spiro-OMeTAD), methoxytriphenylamine-fluoroformamidinium, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, poly3-hexylthiophene (P3HT), and triphenylene-based core triphenylene. Amine (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-aniline)carbazole-spirobisfluorene (CzPAF-SBF), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), polythiophene, phosphate monomers, carbazole monomers (such as [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphate (MeO-4PACz)), sulfonic acid monomers, triphenylamine monomers, aromatic monomers, nickel oxide (NiO) x At least one of molybdenum oxide (MoO3), cuprous iodide (CuI), cuprous oxide (CuO), and cuprous thiocyanate.

[0115] In one specific embodiment, tin oxide is deposited on the surface of the first light-absorbing layer 12 to form a first transport layer 12a (i.e., an electron transport layer), and then a composite layer 13, a second transport layer 14a, a second light-absorbing layer 14, a fourth transport layer 14b, and a second electrode 15 are sequentially formed on the surface of the first transport layer 12a away from the surface of the first light-absorbing layer 12; wherein, the second transport layer 14a is a hole transport layer and the fourth transport layer 14b is an electron transport layer.

[0116] In one embodiment, the material of the first electrode 11 includes one or more of organic conductive materials, inorganic conductive materials, or organic-inorganic mixed conductive materials. Optionally, the material of the first electrode 11 includes one or more of transparent conductive metal oxides, carbon, metals, and their alloys. Optionally, the material of the first electrode 11 includes at least one 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), indium tungsten oxide (IWO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, Mg, Mo, W, and their alloys, graphite, graphene, and carbon nanotubes. Optionally, the material of the first electrode 11 includes at least one of Ag, Cu, C, Au, Al, ITO, AZO, BZO, and IZO. Optionally, the material of the first electrode 11 is at least one of Cu, Ag, and Au. When the first electrode 11 is used as the light-incident side, transparent inorganic conductive oxide materials such as ITO, AZO, BZO, IZO, and FTO are usually selected.

[0117] In one embodiment, the material of the second electrode 15 includes one or more of organic conductive materials, inorganic conductive materials, or organic-inorganic mixed conductive materials. Optionally, the material of the second electrode 15 includes one or more of transparent conductive metal oxides, carbon, metals, and their alloys. Optionally, the material of the second electrode 15 includes at least one 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), indium tungsten oxide (IWO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, Mg, Mo, W, and their alloys, graphite, graphene, and carbon nanotubes. Optionally, the material of the second electrode 15 includes at least one of Ag, Cu, C, Au, Al, ITO, AZO, BZO, and IZO. Optionally, the material of the second electrode 15 is at least one of Cu, Ag, and Au. When the second electrode 15 is used as the light-incident side, transparent inorganic conductive oxide materials such as ITO, AZO, BZO, IZO, and FTO are usually selected.

[0118] In one embodiment, at least one of the first electrode 11 and the second electrode 15 is a transparent electrode for allowing incident light to enter. Furthermore, the first electrode 11 is a transparent electrode, typically made of a transparent inorganic conductive oxide material, such as ITO, AZO, BZO, IZO, FTO, etc.

[0119] In some embodiments, the solar cell further includes a hole-blocking layer disposed between the fourth transport layer 14b and the second electrode 15, wherein the fourth transport layer 14b is an electron transport layer. The hole-blocking layer improves both electron extraction and hole blocking performance. The hole-blocking layer comprises a hole-blocking material. This application does not particularly limit the hole-blocking material; exemplaryly, the hole-blocking material may include SnO2, ZnO, or CeO. x One or more of copper bath (BCP, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). This application does not impose a particular limitation on the thickness of the hole blocking layer; a thickness conventionally used in the art for hole blocking layers may be employed. For example, the thickness of the hole blocking layer can be from 0.5 nm to 20 nm.

[0120] In some embodiments, the solar cell further includes a passivation layer disposed on at least one surface of the first light-absorbing layer 12 and / or the second light-absorbing layer 14, thereby helping to reduce defects at the interface and further improve the performance of the solar cell. The passivation layer may include passivating agents conventionally used in the art for passivating light-absorbing layers, such as small organic molecules, organic salts, inorganic salts, polymers, etc. Small organic molecule passivating agents include, but are not limited to, phenylethylamine, ethylenediamine, pyridine, butanethiol, 2,5-thiophene dicarboxylic acid, etc. Organic salt passivating materials include, but are not limited to, piperazine iodine, phenylethylamine hydroiodate, dodecyl hydroiodate, guanidine bromide, thiophene ethylamine hydroiodate, ethylenediamine hydroiodate, and oleylamine iodine. Inorganic salt passivating materials include, but are not limited to, zinc chloride, potassium chloride, and gallium chloride. Polymer passivating materials include, but are not limited to, polymethyl methacrylate, polyethylene oxide, polyacrylonitrile, and polyvinyl alcohol.

[0121] In one embodiment, the solar cell further includes a substrate layer disposed on the side of the first electrode 11 away from the first light-absorbing layer 12 for supporting the solar cell. The substrate layer may be, but is not limited to, a glass substrate or a flexible substrate. In some embodiments, the material of the flexible substrate layer may be, for example (but not limited to), an organic polymer material, and further, may be a mixture of one or more of the following materials in different proportions: including but not limited to polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), etc.

[0122] The method for preparing the solar cell provided in this application can be used to prepare the solar cell provided in the above embodiments.

[0123] The method for fabricating a solar cell provided in this application specifically includes: providing a first electrode 11; forming a first light-absorbing layer 12 on one side of the first electrode 11; forming a composite layer 13 on the side of the first light-absorbing layer 12 away from the first electrode 11; forming a second light-absorbing layer 14 on the side of the composite layer 13 away from the first light-absorbing layer 12; and forming a second electrode 15 on the side of the second light-absorbing layer 14 away from the composite layer 13; wherein, the composite layer 13 includes an amorphous oxide, and the amorphous oxide includes oxides of indium, gallium, and zinc. The method for fabricating the composite layer 13 includes: step S01: mixing a gallium source, an indium source, and a zinc source with a solvent to form a precursor solution; step S02: coating the precursor solution onto the side of the first light-absorbing layer 12 away from the first electrode 11, and annealing to form the composite layer 13 (e.g., ...). Figure 3 As shown, Figure 3 This is a schematic flowchart of the composite layer preparation method provided in the embodiments of this application.

[0124] By designing the composite layer 13 to include amorphous indium gallium zinc oxide (IGZO), which has a high electron mobility, the transport of charge carriers in the composite layer 13 becomes faster and more efficient. IGZO is a transparent conductive material with low absorption of visible light, exhibiting good light transmittance, which facilitates the efficient absorption of sunlight by the first light-absorbing layer 12 or the second light-absorbing layer 14 as it passes through the composite layer. Furthermore, the amorphous state of IGZO, lacking a long-range ordered crystal structure, leads to complex and discontinuous migration paths of charge carriers within the material, reducing lateral migration of charge carriers in the composite layer and thus improving the performance of the solar cell.

[0125] Before annealing, gallium, source, and zinc exist in ionic form and have not formed indium gallium zinc oxide. After annealing, gallium, source, and zinc in the precursor solution are transformed into indium gallium zinc oxide in situ. In other words, composite layer 13 is prepared in situ.

[0126] The method of forming a film layer by coating with a solution is called the solution method. In this embodiment, the composite layer 13 is prepared by coating with a precursor solution and then annealing, i.e., the composite layer 13 is formed by the solution method. The composite layer 13 formed by the solution method has a more uniform distribution of indium gallium zinc oxide throughout the composite layer 13, which helps to significantly reduce the problem of indium gallium zinc oxide agglomeration, thereby reducing the problem of increased local resistance in the composite layer 13, reducing energy loss during transmission, and helping to maintain the consistency of resistance and longitudinal conductivity throughout the composite layer 13, which is beneficial to improving the performance of the solar cell.

[0127] In one embodiment, in step S02, the annealing temperature is 80°C-100°C; and / or, the annealing time is 10 min-15 min.

[0128] By controlling the annealing temperature and time, the crystal structure and crystal sufficiency of indium gallium zinc oxide are controlled, so that the composite layer 13 is a film layer including amorphous indium gallium zinc oxide. The precursor solution is annealed at 80℃-100℃ to form an amorphous film layer. The temperature is relatively low. When the precursor solution coated on the side of the first light absorption layer 12 away from the first electrode 11 is annealed in situ to form the composite layer 13, 80℃-100℃ is a temperature that the first light absorption layer 12 can withstand. The impact on the first light absorption layer 12 is small, and the first light absorption layer 12 can still maintain its original performance.

[0129] The annealing temperature can be 80℃, 82℃, 84℃, 86℃, 90℃, 92℃, 94℃, 96℃, 100℃, etc., or a range consisting of any two of the above values, such as 86℃-96℃, 82℃-90℃, etc. The annealing time can be 10min, 11min, 12min, 13min, 14min, 15min, etc., or a range consisting of any two of the above values, such as 10min-13min, 11min-14min, etc.

[0130] In one embodiment, in step S01, the molar ratio between the indium source, gallium source, and zinc source is 5:(0.5-2):(1-3).

[0131] The molar ratio between the indium source, gallium source, and zinc source can be 5:1:2, 5:0.5:1, 5:1.5:1, 5:2:1, 5:0.5:1.5, 5:0.5:2, 5:0.5:2.5, 5:0.5:3, 5:0.7:1, 5:1.2:1, 5:1:1.8, 5:1:2.4, etc., or 5:(0.7-1.2):(1-3), 5:(0.7-1.2):(1.8-2.4), etc.

[0132] By controlling the molar ratio between the indium source, gallium source, and zinc source, the resulting composite layer 13 can have higher longitudinal conductivity and better light transmittance, which in turn helps to improve the photoelectric conversion performance of the solar cell.

[0133] In one embodiment, in step S01, the concentration of the gallium source in the precursor solution is 0.06 mol / L-0.3 mol / L; and / or, the concentration of the indium source in the precursor solution is 0.015 mol / L-0.09 mol / L; and / or, the concentration of the zinc source in the precursor solution is 0.03 mol / L-0.14 mol / L.

[0134] By setting the concentrations of gallium source, indium source, and zinc source in the precursor solution as described above, the thickness of the formed indium gallium zinc oxide composite layer 13 is made suitable, which reduces the longitudinal resistance of charge carriers, increases the recombination of charge carriers in the composite layer, reduces the recombination of charge carriers at the interface between the composite layer and the film layers on both sides of the composite layer, and improves the photoelectric conversion efficiency of the solar cell.

[0135] The concentration of the gallium source in the precursor solution can be 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L, 0.20 mol / L, 0.22 mol / L, 0.24 mol / L, 0.26 mol / L, 0.28 mol / L, 0.3 mol / L, etc., or it can be a range of any two of the above values, such as 0.16 mol / L-0.26 mol / L, 0.1 mol / L-0.3 mol / L, etc. The concentration of the indium source in the precursor solution can be 0.015 mol / L, 0.02 mol / L, 0.025 mol / L, 0.03 mol / L, 0.035 mol / L, 0.04 mol / L, 0.045 mol / L, 0.05 mol / L, 0.055 mol / L, 0.06 mol / L, 0.065 mol / L, 0.07 mol / L, 0.075 mol / L, 0.08 mol / L, 0.085 mol / L, 0.09 mol / L, etc., or it can be a range of any two of the above values, such as 0.03 mol / L-0.075 mol / L, 0.05 mol / L-0.09 mol / L, etc. The concentration of the zinc source in the precursor solution can be 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, 0.11 mol / L, 0.12 mol / L, 0.13 mol / L, 0.14 mol / L, etc., or it can be a range of any two of the above values, such as 0.05 mol / L-0.12 mol / L, 0.07 mol / L-0.14 mol / L, etc.

[0136] In one embodiment, step S01, in which the gallium source, indium source, zinc source and solvent are mixed to form a precursor solution, further includes: mixing the gallium source, indium source, zinc source with solvent and stabilizer to form a precursor solution; wherein the concentration of stabilizer in the precursor solution is 0.2 mol / L-0.5 mol / L.

[0137] By adding stabilizers to the precursor solution and controlling the concentration of stabilizers, the stability of the precursor solution can be improved, reducing unwanted chemical reactions such as oxidation and polymerization that occur in the precursor solution before annealing. In addition, the viscosity and surface tension of the precursor solution can be adjusted by stabilizers, which can promote the formation of a more uniform and flat composite layer 13 on the side of the first light absorption layer 12 away from the first electrode 11. The concentration of the stabilizer in the precursor solution can be 0.2 mol / L, 0.23 mol / L, 0.25 mol / L, 0.28 mol / L, 0.3 mol / L, 0.32 mol / L, 0.35 mol / L, 0.39 mol / L, 0.4 mol / L, 0.42 mol / L, 0.45 mol / L, 0.47 mol / L, 0.49 mol / L, 0.5 mol / L, etc., or it can be a range of any two of the above values, such as 0.4 mol / L-0.5 mol / L, 0.28 mol / L-0.47 mol / L, etc.

[0138] In one embodiment, in step S01, the gallium source includes one or more of gallium chlorate, gallium nitrate, and gallium sulfate; and / or, the indium source includes one or more of indium nitrate and indium chlorate; and / or, the zinc source includes one or more of zinc nitrate, zinc chlorate, and zinc acetate; and / or, the solvent includes one or more of dimethyl ethanol, ethylene glycol methyl ether, methyl ether, toluene, diethyl ether, ethyl acetate, and chlorobenzene; and / or, the stabilizer includes one or more of monoethanolamine and monoethylene glycol.

[0139] By selecting the aforementioned materials, which are common materials, costs can be reduced. It is understood that the aforementioned metal source may also include hydrates of the aforementioned metal salts, such as gallium chlorate hydrate, gallium nitrate hydrate, zinc nitrate hydrate, indium chlorate hydrate, zinc nitrate hydrate, zinc acetate dihydrate, etc., without limitation.

[0140] Optionally, the gallium source includes hydrated gallium nitrate; the indium source includes hydrated indium nitrate; and the zinc source includes hydrated zinc nitrate.

[0141] In one embodiment, step S02, the step of coating the precursor solution on the side of the first light absorption layer 12 away from the first electrode 11, includes: depositing tin oxide to form a first transport layer 12a using an atomic layer deposition process on the side of the first light absorption layer 12 away from the first electrode 11; and coating the first transport layer 12a on the side away from the first light absorption layer 12 with the precursor solution.

[0142] Tin oxide formed by atomic layer deposition is used as the first transport layer 12a. The first transport layer 12a is relatively dense and can prevent the precursor solution from penetrating into the first light absorption layer 12 during the preparation of the composite layer 13 by solution method. The first transport layer 12a plays a role in protecting the first light absorption layer 12, which is beneficial to improving the performance of the solar cell.

[0143] In one embodiment, during step S01, the gallium source, indium source, and zinc source are dissolved in a solvent and then stirred at 20°C-60°C. The solution is then transferred to a dust-free, sealed environment and allowed to stand for a certain period of time. After filtration, a homogeneous, colorless, and transparent solution is obtained, i.e., the precursor solution. The purpose of transferring the solution to a dust-free, sealed environment is to reduce the influence of dust on the precursor solution. The state of the homogeneous, colorless, and transparent solution is similar to that of water.

[0144] By stirring at 20℃-60℃, the solubility of gallium, indium, and zinc sources can be increased, and the dissolution time required can be reduced. For example, a precursor solution with an indium:gallium:zinc molar ratio of 5:1:2, an indium concentration of 0.1875 mol / L, a gallium concentration of 0.0375 mol / L, and a zinc concentration of 0.075 mol / L was prepared and stirred at 60℃ for 2 hours.

[0145] In one embodiment, step S02, coating the precursor solution onto the side of the first light-absorbing layer 12 opposite to the first electrode 11, specifically includes: spin-coating the precursor solution at a first rotation speed for a first time, and then increasing the rotation speed to a second rotation speed for a second time.

[0146] The first speed can be 300rpm-1000rpm, and the first time can be 9s-12s. The second speed can be 3000rpm-8000rpm, and the second time can be 38s-43s.

[0147] By first spin coating at a low speed and then increasing the speed, a more uniform film layer can be formed.

[0148] In one specific embodiment, gallium nitrate hydrate as the gallium source, indium nitrate hydrate as the indium source, and zinc acetate dihydrate as the zinc source are dissolved in dimethyl ethanol. Ethanolamine is then added as a stabilizer to prepare a solution with an indium:gallium:zinc molar ratio of 5:1:2, resulting in an indium concentration of 0.1875 mol / L, a gallium concentration of 0.0375 mol / L, and a zinc concentration of 0.075 mol / L. The solution is then stirred at 60°C for 2 hours in a brown wide-mouth bottle with a magnetic stir bar. Afterward, it is transferred to a dust-free, sealed environment and allowed to stand for 24 hours, followed by filtration to obtain a homogeneous, colorless, and transparent solution, forming the precursor solution. After the ALD tin oxide preparation is completed, the precursor solution is spin-coated onto the tin oxide surface. The spin-coating process involves first rotating at a low speed of 350 rpm for 9-12 seconds, then increasing the speed to 4000 rpm for 40 seconds. Finally, it is placed on a hot plate and annealed at 100°C for 10 minutes to form a composite layer 13.

[0149] The method for preparing the composite layer provided in this application embodiment can prepare a precursor solution at a low temperature (20℃-60℃) and anneal it at 80℃-100℃ to form an amorphous indium gallium zinc oxide film. The resulting composite layer 13 has high light transmittance, low lateral conductivity, and a relatively smooth surface, which is beneficial to improving the performance of solar cells.

[0150] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of the photovoltaic device provided in the embodiments of this application.

[0151] This application also provides a photovoltaic device 1000, which includes the solar cell 100 provided in the above embodiments of this application and has at least the same advantages as the solar cell 100, thereby improving the performance of the photovoltaic device. The photovoltaic device can be applied to building rooftops, etc.

[0152] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application.

[0153] This application also provides an electrical device 2000, which is a common device including the solar cell 100 provided in the above embodiments of this application. It has at least the same advantages as the solar cell 100 and can improve the performance of the electrical device.

[0154] The solar cell 100 powers the aforementioned electrical device 2000; alternatively, the solar cell 100 can serve as an energy storage unit for the electrical device 2000. For example, the electrical device 2000 can be a lighting element, a display element, or an automobile, etc. The electrical device 2000 can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among these, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0155] Please see Figure 6 , Figure 6 This is a schematic diagram of the power generation equipment provided in the embodiments of this application.

[0156] This application also provides a power generation device 3000, which is a common device including the solar cell 100 provided in the above embodiments of this application. The power generation device 3000 has at least the same advantages as the solar cell 100, and can improve the power generation performance of the power generation device. The solar cell 100 serves as the energy source for the power generation device 3000, enabling the power generation device to output electrical energy. As an example, the power generation device can be applied to fields such as building power supply, wearable device power supply, smartphone power supply, and vehicle battery power supply.

[0157] To make the technical problems, technical solutions, and beneficial effects solved by the embodiments of this application clearer, the following will provide a more detailed description in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0158] Example 1:

[0159] (1) Preparation of the first electrode:

[0160] The first electrode is disposed on a glass substrate and is made of indium tin oxide (ITO). The glass substrate with the first electrode is cleaned sequentially with acetone-alcohol-deionized water and then dried for later use.

[0161] (2) Preparation of the third transport layer:

[0162] [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid (MeO-4PACz) was added to an ethanol solvent and stirred. The ethanol solution of MeO-4PACz was then spin-coated onto the first electrode at a speed of 4000 rpm for 30 s. The electrode was then transferred to a hot plate and annealed at 100 °C for 10 min to form a 2 nm third transport layer.

[0163] (3) Preparation of the first light-absorbing layer:

[0164] 3 mg of FAI, 59 mg of FABr, 46 mg of CsI, 25 mg of CsBr, 428 mg of PbI2 and 209 mg of PbBr2 were added to 1 mL of a mixture of DMF and DMSO (DMF to DMSO volume ratio of 3:1). The mixture was stirred at 600 rpm for 8 h on a magnetic stirrer and then filtered to obtain a perovskite precursor solution. 100 μL of the above perovskite precursor solution was spin-coated onto the third transport layer (first spin-coating at 2000 rpm and 200 rpm / s for 10 s; then spin-coating at 4000 rpm and 1000 rpm / s for 25 s). Then 200 μL of chlorobenzene was added dropwise onto the spin-coated perovskite precursor solution. The perovskite precursor solution was then spin-coated again (spin-coating at 4000 rpm for 15 s). The solution was then transferred to a hot plate and annealed at 100 °C for 15 min to form a 400 nm first light-absorbing layer.

[0165] (4) Preparation of the first transport layer:

[0166] First, 25 nm C60 is deposited using an evaporation device, and then a 20 nm SnO2 layer is prepared on the first light absorption layer using an atomic layer deposition (ALD) device to form the first transport layer.

[0167] (5) Preparation of composite layer:

[0168] Precursor solution preparation: Gallium nitrate hydrate as the gallium source, indium nitrate hydrate as the indium source, and zinc acetate dihydrate as the zinc source were dissolved in dimethyl ethanol. Ethanolamine was then added as a stabilizer to prepare a solution with indium:gallium:zinc molar ratio of 5:1:2, resulting in indium concentrations of 0.1875 mol / L, gallium concentrations of 0.0375 mol / L, and zinc concentrations of 0.075 mol / L. The molar ratio of ethanolamine to metal ions (indium, gallium, zinc) was 1:1. The solution was then stirred at 60°C for 2 hours in a brown wide-mouth bottle with a magnetic stir bar. Afterward, it was transferred to a dust-free, sealed environment and allowed to stand for 24 hours. The mixture was then filtered to obtain a homogeneous, colorless, and transparent solution, which was the precursor solution.

[0169] Spin coating of precursor solution: The precursor solution is spin coated on the surface of the first transport layer. The spin coating process is to first rotate at a low speed of 350 rpm for 10 seconds, then increase the speed to 4000 rpm for 40 seconds, and then place it on a hot plate and anneal at 100°C for 10 minutes to form a composite layer.

[0170] (6) Fabrication of the second transport layer:

[0171] Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was spin-coated onto the above composite layer at a spin speed of 4000 rpm for 30 s. The coating was then transferred to a hot plate and annealed at 150 °C for 10 min to form a 20 nm second transport layer.

[0172] (7) Preparation of the second light-absorbing layer:

[0173] 2 mg of CH(NH2)2I, 85 mg of CH3NH2I, 4 mg of PbI2, 335 mg of SnI2, and 0.5 mg of MeO-4PACz were added to 1 mL of a mixture of DMF and DMSO (DMF to DMSO volume ratio 3:1). The mixture was stirred at 600 rpm for 2 h on a magnetic stirrer, filtered, and a perovskite precursor solution was obtained. 100 μL of the above perovskite precursor solution was spin-coated onto the second transport layer. The perovskite precursor solution was first spin-coated at 1000 rpm and 200 rpm / s for 10 s; then at 3000 rpm and 1000 rpm / s for 20 s. 350 μL of ethyl acetate was then added to the spin-coated perovskite precursor solution. The perovskite precursor solution was then spin-coated again (at 4000 rpm and 20 s). The solution was then transferred to a hot plate and annealed at 100 °C for 10 min to form a 1 μm second light-absorbing layer.

[0174] (8) Preparation of the fourth transport layer:

[0175] A 25 nm layer of C60 is deposited on the second light absorption layer, followed by a 10 nm layer of 1,10-o-phenanthroline derivative (BCP) to form the fourth transport layer.

[0176] (9) Preparation of the second electrode:

[0177] A 100nm layer of metallic copper (Cu) is deposited on the aforementioned fourth transport layer to form the second electrode.

[0178] After the above steps, a solar cell is obtained.

[0179] It should be noted that the XRD pattern of the composite layer in Example 1 is shown in [reference needed]. Figure 2 .

[0180] The difference between Example 2, Example 3 and Example 1 is that the annealing temperature and annealing time are different.

[0181] The differences between Examples 4 and 5 and Example 1 are: the molar ratio of indium source, gallium source, and zinc source, and the concentrations of indium source, gallium source, and zinc source are different.

[0182] The difference between Examples 6 and 7 and Example 1 is that the materials of the first light absorption layer and the second light absorption layer are different.

[0183] The difference between Comparative Example 1 and Example 1 is that the preparation of the composite layer in step (5) is different. Specifically, ITO is used as the composite layer. Specifically, at a radio frequency power of 100W and a temperature of 100℃, a 25nm thick ITO composite layer is formed by physical vapor deposition (PVD).

[0184] The relevant parameter testing process for the embodiments and comparative examples of this application is as follows:

[0185] I. Thin-film sheet resistors.

[0186] The Hall effect tester uses four probes to strike the thin film for testing, and the values ​​displayed on the monitor are then read. Specifically:

[0187] 1. Turn on the computer and turn on the power switch on the back of the Hall effect meter, and preheat for 10 minutes.

[0188] 2. Clamp the sample onto the sample plate with four probes, making sure the center of the sample is on the "+" side. Insert the sample plate into the sample slot, and then place the sample slot on the test chamber, with the side of the slot marked "N" corresponding to the side of the test chamber marked "N".

[0189] 3. Open the test program and enter the test parameters: "DATE" (test date), "USER NAME" (user name), "SAMPLE NAME" (sample name and number), "TEMP" (room temperature), "I" (current range 2mA), "Delay" (delay time from input current to measurement, 0.1s), "D" (sample thickness), and "B" (magnetic field strength 0.55T). Click "Go to I / V curve" to confirm ohmic contact or view the "IV, IR" values. First, enter the initial, final, and step values ​​for the input curve. Click "MEASUREMENT" to start the measurement.

[0190] 4. When the program prompts "Insert magnetS", insert the magnet into the test chamber from the end marked "N", and then click "OK".

[0191] 5. When the program prompts "InsertmagnetS->N", remove the magnet and insert it from the other end of the test chamber, then click "OK" to confirm.

[0192] 6. After the measurement is complete, "Remove Magnet" will appear. Remove the magnet and click "OK".

[0193] 7. After the test is complete, click "Save" to save the test data.

[0194] II. Light transmittance.

[0195] The test was conducted using a UV-Vis absorption spectrometer. The UV-Vis absorption spectrometer includes a spectrophotometer and an integrating sphere. The spectrophotometer is used for spectral dispersion, and the integrating sphere is used for light transmittance measurement. Specifically:

[0196] 1. Powering on and preheating:

[0197] Turn on the instrument and allow it to warm up for 20 to 30 minutes to ensure the light source is stable.

[0198] 2. Instrument calibration:

[0199] Calibrate without placing a sample, setting the instrument to read the absorbance without a sample, typically set to zero absorbance or 100% transmittance.

[0200] 3. Prepare samples:

[0201] Place the sample above the integrating sphere.

[0202] 4. Measure the transmittance of the sample:

[0203] The wavelength range is set from 300nm to 1200nm, with a step size of 5nm.

[0204] III. Surface roughness.

[0205] The atomic force microscopy (AFM) method involves the following steps: An instrument with a flexible microcantilever, fixed at one end and equipped with a needle tip at the other, is used to detect the sample surface morphology. When the needle tip contacts the sample surface and moves relative to it, the interaction force (attractive or repulsive force) between the needle tip and the sample, related to the distance, causes deformation of the microcantilever. This deformation serves as a direct measure of the interaction force between the sample and the needle tip. A Z-axis feedback system continuously adjusts the sample's Z-axis position via piezoelectric ceramic based on changes in the detector voltage to maintain a constant interaction force between the needle tip and the sample. By measuring the change in the detector voltage relative to the sample scanning position, the surface roughness of the sample can be obtained.

[0206] Calculation of arithmetic mean surface roughness (Ra):

[0207]

[0208] In the formula:

[0209] Z i —The height of point i;

[0210] N – The total number of data points on the entire surface.

[0211] IV. Photovoltaic conversion efficiency of solar cells.

[0212] Using Keithley 2400SMU, AM 1.5G solar irradiation at 100 mW / cm 2 Under the light source, the battery performance was tested, and the photoelectric conversion efficiency was calculated as follows:

[0213] PCE = P out / P opt

[0214] =V oc ×J sc ×(V mpp ×J mpp ) / (V oc ×J sc )

[0215] =V oc ×J sc ×FF / P opt

[0216] Where P out P opt V mpp J mpp V oc and J sc These are the battery's operating output power, incident light power, battery's maximum power point voltage, battery's maximum power point current, open-circuit voltage, and short-circuit current, respectively.

[0217] V. Stability Testing.

[0218] Perovskite solar cells were placed in an environment with a temperature of 85°C and a relative humidity of 85%, and the change in their photoelectric conversion efficiency (PCE) with aging time was tracked. The time required for their PCE to decay to 80% of the initial efficiency was recorded.

[0219] VI. Testing the thickness of the composite layer.

[0220] Obtain cross-sectional scanning electron microscope (SEM) images of composite layer 13; specifically, randomly select multiple regions on the cross-section of composite layer 13, and measure the thickness of composite layer 13 at least five times at a magnification of 30,000x. Statistically analyze the measurement values ​​of different regions, and take the average value as the thickness of composite layer 13.

[0221]

[0222]

[0223]

[0224] As shown in Table 1, the composite layer 13 provided in this application, compared with Comparative Example 1, is beneficial to improving the photoelectric conversion efficiency and stability of the solar cell. Comparing Examples 1 to 5 with Comparative Example 1, the sheet resistance of Comparative Example 1 is greater than that of Examples 1 to 5. However, the longitudinal carrier transport of the composite layer 13 in Examples 1 to 5 is better than that of the composite layer in Comparative Example 1, and the photoelectric conversion efficiency of the solar cells in Examples 1 to 5 is better than that of the solar cell in Comparative Example 1.

[0225] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A solar cell, characterized in that, include: The system comprises a first electrode, a first light-absorbing layer, a composite layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer is disposed between the first electrode and the composite layer. The second light-absorbing layer is disposed on the side of the composite layer opposite to the first light-absorbing layer. The second electrode is disposed on the side of the second light-absorbing layer opposite to the composite layer. The composite layer includes amorphous oxides, which include oxides of indium, gallium, and zinc.

2. The solar cell according to claim 1, characterized in that, The molar ratio of indium, gallium, zinc and oxygen is 5:(0.5-2):(1-3):(4-10).

3. The solar cell according to claim 1 or 2, characterized in that, The sheet resistance of the composite layer is 20Ω / sq-300Ω / sq.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The full-spectrum weighted transmittance of the composite layer is a, where a ≥ 75%.

5. The solar cell according to any one of claims 1 to 4, characterized in that, The surface roughness of the composite layer is 5nm-15nm.

6. The solar cell according to any one of claims 1 to 5, characterized in that, The thickness of the composite layer is 5nm-100nm.

7. The solar cell according to any one of claims 1 to 6, characterized in that, The solar cell further includes a first transport layer disposed between the first light-absorbing layer and the composite layer, the first transport layer having a density of 6 g / cm³. 3 -7g / cm 3 .

8. The solar cell according to claim 7, characterized in that, The first transport layer is an electron transport layer, which includes tin oxide.

9. The solar cell according to any one of claims 1 to 8, characterized in that, The band gap of the first light absorption layer is 1.6eV-2.0eV, and the band gap of the second light absorption layer is 1.1eV-1.3eV.

10. The solar cell according to any one of claims 1 to 9, characterized in that, The first light-absorbing layer comprises a first perovskite material; and / or, the second light-absorbing layer comprises a second perovskite material.

11. A method for preparing a solar cell, characterized in that, include: Provide a first electrode; A first light-absorbing layer is formed on one side of the first electrode, a composite layer is formed on the side of the first light-absorbing layer opposite to the first electrode, a second light-absorbing layer is formed on the side of the composite layer opposite to the first light-absorbing layer, and a second electrode is formed on the side of the second light-absorbing layer opposite to the composite layer. The composite layer comprises an amorphous oxide, wherein the amorphous oxide includes oxides of indium, gallium, and zinc; the method for preparing the composite layer includes: A precursor solution is formed by mixing gallium source, indium source, zinc source and solvent; The precursor solution is coated on the side of the first light-absorbing layer opposite to the first electrode, and then annealed to form the composite layer.

12. The method for preparing a solar cell according to claim 11, characterized in that, The annealing temperature is 80℃-100℃; and / or the annealing time is 10min-15min.

13. The method for preparing a solar cell according to claim 11 or 12, characterized in that, The molar ratio of the indium source, the gallium source, and the zinc source is 5:(0.5-2):(1-3).

14. The method for preparing a solar cell according to any one of claims 11 to 13, characterized in that, The concentration of the gallium source in the precursor solution is 0.06 mol / L to 0.3 mol / L; and / or, The concentration of the indium source in the precursor solution is 0.015 mol / L to 0.09 mol / L; and / or, The concentration of the zinc source in the precursor solution is 0.03 mol / L to 0.14 mol / L.

15. The method for preparing a solar cell according to any one of claims 11 to 14, characterized in that, The step of mixing gallium source, indium source, zinc source and solvent to form precursor solution further includes: The gallium source, the indium source, the zinc source, the solvent, and the stabilizer are mixed to form the precursor solution; The concentration of the stabilizer in the precursor solution is 0.2 mol / L to 0.5 mol / L.

16. The method for preparing a solar cell according to claim 15, characterized in that, The gallium source includes one or more of gallium nitrate, gallium chlorate, gallium nitrate, and gallium sulfate; and / or, The indium source includes one or more of indium nitrate and indium chlorate; and / or, The zinc source includes one or more of zinc nitrate, zinc chlorate, and zinc acetate; and / or, The solvent includes one or more of dimethyl ethanol, ethylene glycol methyl ether, methyl ether, toluene, diethyl ether, ethyl acetate, and chlorobenzene; and / or, The stabilizer includes one or more of monoethanolamine and monoethylene glycol.

17. The method for preparing a solar cell according to any one of claims 11 to 16, characterized in that, The step of coating the precursor solution onto the side of the first light-absorbing layer opposite to the first electrode includes: A first transport layer is formed by depositing tin oxide on the side of the first light absorption layer opposite to the first electrode using an atomic layer deposition process. The precursor solution is coated on the side of the first transport layer opposite to the first light absorption layer.

18. A photovoltaic device, characterized in that, The solar cell includes the solar cell according to any one of claims 1 to 10 or the solar cell prepared by any one of claims 11 to 17.

19. An electrical appliance, characterized in that, The solar cell includes the solar cell according to any one of claims 1 to 10 or the solar cell prepared by any one of claims 11 to 17.

20. A power generation device, characterized in that, The solar cell includes the solar cell according to any one of claims 1 to 10 or the solar cell prepared by any one of claims 11 to 17.

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