Photovoltaic cell and method for producing a photovoltaic cell, photovoltaic module

Abstract

This application relates to photovoltaic cells and their fabrication methods, as well as photovoltaic modules. The fabrication method of the photovoltaic cell includes the following steps: providing a substrate structure, the substrate structure including a transparent conductive layer on its surface; applying a mixed solution to the transparent conductive layer to form a liquid film, the mixed solution including a nickel source, a doped metal source, and an organic reducing agent; annealing the liquid film at a temperature of 250℃~450℃ to form a hole transport layer on the surface of the transparent conductive layer. The photovoltaic cell fabrication method of this application can improve the energy level matching and contact effect between the hole transport layer and the transparent conductive layer, increase the open-circuit voltage and fill factor, thereby enabling the photovoltaic cell to have higher conversion efficiency.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to photovoltaic cells and their preparation methods, and photovoltaic modules. Background Technology

[0002] Perovskite photovoltaic cells are a type of photovoltaic cell that uses perovskite structure materials as the core light-absorbing layer. Due to their high efficiency, low cost, and ease of fabrication, they are considered one of the most industrially promising photovoltaic technologies after crystalline silicon cells. In perovskite photovoltaic cells, sunlight irradiates the perovskite layer, and its band gap causes electrons to jump from the valence band to the conduction band, generating free electrons and holes. The electron transport layer (ETL) selectively extracts electrons from the conduction band, and the hole transport layer (HTL) selectively extracts holes from the valence band, preventing electron-hole recombination.

[0003] Nickel oxide is a commonly used hole transport material in perovskite photovoltaic cells, as it can efficiently extract holes generated in the perovskite layer and exhibits good chemical stability. However, traditional preparation methods result in poor energy level matching and contact between the nickel oxide hole transport layer and the transparent conductive layer, thus affecting the conversion efficiency of the photovoltaic cell. Summary of the Invention

[0004] Therefore, it is necessary to provide photovoltaic cells, their fabrication methods, and photovoltaic modules. The photovoltaic cell fabrication method of this application can improve the energy level matching and contact effect between the hole transport layer and the transparent conductive layer, increase the open-circuit voltage and fill factor, and thus enable the photovoltaic cell to have higher conversion efficiency.

[0005] In a first aspect, this application provides a method for preparing a photovoltaic cell, comprising the following steps:

[0006] A substrate structure is provided, the substrate structure including a transparent conductive layer located on the surface;

[0007] A mixed solution is applied to the transparent conductive layer to form a liquid film, wherein the mixed solution includes a nickel source, a doped metal source, and an organic reducing agent;

[0008] The liquid film is annealed at a temperature of 250°C to 450°C to form a hole transport layer on the surface of the transparent conductive layer.

[0009] In some embodiments, the annealing process takes 20 to 60 minutes.

[0010] In some embodiments, the molar ratio of the organic reducing agent to the nickel source is (0.5~2):1.

[0011] In some embodiments, the organic reducing agent includes at least one of glycine, citric acid, urea, and ascorbic acid.

[0012] In some embodiments, the molar ratio of nickel in the nickel source to doped metal in the doped metal source is (90~99):(1~10).

[0013] In some embodiments, the nickel source includes nickel nitrate; the doped metal source includes at least two of zinc nitrate, potassium nitrate, cesium nitrate, cerium nitrate, lithium nitrate, magnesium nitrate, and chromium nitrate.

[0014] In some embodiments, the mixed solution also includes potassium chloride.

[0015] In some embodiments, the molar ratio of the potassium chloride to the total molar ratio of the nickel source and the organic reducing agent is (0.1~2):1.

[0016] In some embodiments, the material of the transparent conductive layer includes at least one of indium tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, and antimony-doped tin oxide.

[0017] In some embodiments, the substrate structure further includes a crystalline silicon bottom cell structure; the transparent conductive layer is disposed on the surface of the crystalline silicon bottom cell structure.

[0018] In some implementations, the following steps are also included:

[0019] A perovskite layer, an electron transport layer, and a top electrode are sequentially stacked on the surface of the hole transport layer away from the transparent conductive layer.

[0020] Secondly, this application also provides a photovoltaic cell, prepared by the photovoltaic cell preparation method described in any one of the above-mentioned methods, comprising:

[0021] A substrate structure; the substrate structure includes a transparent conductive layer located on its surface;

[0022] Hole transport layer; the hole transport layer is disposed on the surface of the transparent conductive layer, and the material of the hole transport layer includes nickel oxide doped with a doped metal source.

[0023] In some embodiments, the thickness of the transparent conductive layer is 5 nm to 30 nm.

[0024] In some embodiments, the thickness of the hole transport layer is 20 nm to 50 nm.

[0025] In some embodiments, the photovoltaic cell further includes a perovskite layer, an electron transport layer, and a top electrode, which are sequentially stacked on the surface of the hole transport layer away from the substrate structure.

[0026] In some embodiments, the substrate structure further includes a crystalline silicon bottom cell structure; the transparent conductive layer is disposed between the crystalline silicon bottom cell structure and the hole transport layer.

[0027] Thirdly, this application provides a photovoltaic module, comprising:

[0028] Cover plate;

[0029] At least one battery string, the battery string comprising a photovoltaic cell prepared by the method described in any one of the above-mentioned photovoltaic cell preparation methods, or a photovoltaic cell described in any one of the above-mentioned photovoltaic cell preparation methods;

[0030] And an encapsulation layer, which is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

[0031] In the aforementioned photovoltaic cell fabrication method, a mixed solution comprising a nickel source, a doped metal source, and an organic reducing agent is applied to a transparent conductive layer to form a liquid film, which is then annealed at 250°C to 450°C. At this annealing temperature, the organic reducing agent can be used as fuel to burn the liquid film. The combustion of the liquid film generates instantaneous high temperatures during fabrication, resulting in the in-situ generation of doped nickel oxide on the surface of the transparent conductive layer. This achieves a better doping effect of the doped metal source on the nickel oxide, and simultaneously improves the contact between the hole transport layer and the transparent conductive layer, thereby increasing the open-circuit voltage and fill factor of the photovoltaic cell. Furthermore, metal doping can alter the energy levels, making the energy levels between the hole transport layer and the transparent conductive layer more matched, thus increasing the open-circuit voltage. In other words, the photovoltaic cell fabrication method of this application can improve the energy level matching and contact effect between the hole transport layer and the transparent conductive layer, increasing the open-circuit voltage and fill factor, thereby enabling the photovoltaic cell to have higher conversion efficiency. Attached Figure Description

[0032] Figure 1 A schematic diagram of a hole transport layer formed on the surface of a transparent conductive layer;

[0033] Figure 2 In order to be in Figure 1 A schematic diagram of a perovskite layer fabricated based on the structure shown.

[0034] Figure 3 In order to be in Figure 2 A schematic diagram of an electron transport layer fabricated based on the structure shown.

[0035] Figure 4 In order to be in Figure 3 A schematic diagram of a transparent electrode fabricated based on the structure shown;

[0036] Figure 5This is a schematic diagram of the structure of a photovoltaic cell provided in one embodiment of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 10-Substrate structure; 11-Bottom electrode; 12-Crystal silicon bottom cell structure; 13-Transparent conductive layer; 20-Hole transport layer; 30-Perovskite layer; 40-Electron transport layer; 50-Transparent electrode; 60-Top electrode; 70-Protective layer. Detailed Implementation

[0039] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0040] 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 belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] In traditional perovskite photovoltaic cells, the nickel oxide hole transport layer is typically prepared by evaporating nickel oxide or spin-coating nickel oxide particles. Evaporated nickel oxide layers are prone to defects due to high-valence nickel, and the hydrophobic surface of the film is detrimental to the crystallization of the perovskite material. Spin-coated nickel oxide particles, on the other hand, tend to agglomerate, leading to poor contact between the hole transport layer and the transparent conductive layer, or between the hole transport layer and the perovskite layer. Furthermore, the energy level matching and contact between the nickel oxide hole transport layer and the transparent conductive layer prepared by these methods are poor, thus affecting the conversion efficiency of the photovoltaic cell.

[0045] Based on this, one embodiment of this application provides a method for preparing a photovoltaic cell, comprising the following steps:

[0046] A substrate structure 10 is provided, the substrate structure 10 including a transparent conductive layer 13 located on the surface;

[0047] A liquid film is formed by applying a mixed solution onto a transparent conductive layer 13. The mixed solution includes a nickel source, a doped metal source, and an organic reducing agent.

[0048] The liquid film is annealed at a temperature of 250℃ to 450℃ to form a hole transport layer 20 on the surface of the transparent conductive layer 13.

[0049] In the above-described photovoltaic cell fabrication method, a mixed solution comprising a nickel source, a doped metal source, and an organic reducing agent is applied to the transparent conductive layer 13 to form a liquid film, and the liquid film is annealed at 250°C to 450°C. At the annealing temperature, the organic reducing agent can be used as fuel to burn the liquid film. The combustion of the liquid film generates instantaneous high temperatures during fabrication, generating doped nickel oxide in situ on the surface of the transparent conductive layer 13. This achieves a better doping effect of the doped metal source on the nickel oxide, and simultaneously improves the contact effect between the hole transport layer 20 and the transparent conductive layer 13, thereby increasing the open-circuit voltage and fill factor of the photovoltaic cell. Furthermore, metal doping can alter the energy levels, making the energy levels between the hole transport layer 20 and the transparent conductive layer 13 more matched, thus increasing the open-circuit voltage. In other words, the photovoltaic cell fabrication method of this application can improve the energy level matching and contact effect between the hole transport layer 20 and the transparent conductive layer 13, increase the open-circuit voltage and fill factor, and thus enable the photovoltaic cell to have a higher conversion efficiency.

[0050] For example, taking nickel nitrate as the nickel source, the liquid film will undergo the following reaction during the annealing process: Wherein, M is a doped metal element, NiO(M) is nickel oxide doped with element M, and Fuel is an organic reducing agent used as fuel, which can generate doped nickel oxide in situ on the surface of the transparent conductive layer 13 during combustion.

[0051] Understandably, the above-described annealing process involves placing the substrate structure 10, after the liquid film has formed, in an air atmosphere and heating it to 250°C~450°C using a heating device, then holding it at that temperature. During the entire annealing process, the liquid film does not burn continuously; instead, it undergoes a brief period of combustion to allow the raw materials to react, followed by crystallization and purification during the remaining annealing time. Within the temperature range described above, combustion of the liquid film and complete reaction of the raw materials are facilitated. If the annealing temperature is too low, incomplete combustion may occur. If the annealing temperature is too high, energy is wasted, which is detrimental to industrial production. Optionally, the annealing temperature can be 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, or 450°C, or the annealing temperature can fall within any two of the above temperature ranges.

[0052] In some embodiments, the annealing process takes 20 to 60 minutes.

[0053] Within the aforementioned annealing time range, it facilitates the crystallization and purification of doped nickel oxide, thereby achieving a better preparation effect of the hole transport layer 20. Optionally, the annealing time is 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min, or the annealing time can be within any two of the above-mentioned time ranges.

[0054] In some embodiments, the molar ratio of the organic reducing agent to the nickel source is (0.5~2):1.

[0055] Within the aforementioned molar ratio range of the organic reducing agent and the nickel source, it is easier for the combustion reaction of each raw material to be complete, resulting in better in-situ generation of doped nickel oxide on the surface of the transparent conductive layer 13. Optionally, the molar ratio of the organic reducing agent and the nickel source can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2:1, or the molar ratio of the organic reducing agent and the nickel source can also be within the range between any two of the above molar ratios.

[0056] In some embodiments, the organic reducing agent includes at least one of glycine, citric acid, urea, and ascorbic acid.

[0057] In some embodiments, the molar ratio of nickel in the nickel source to doped metal in the doped metal source is (90~99):(1~10).

[0058] Within the range of the molar ratio of nickel in the nickel source to the dopant metal in the doped metal source, good control of the energy level of the hole transport layer 20 is achieved, resulting in good energy level matching and contact between the hole transport layer 20 and the transparent conductive layer 13. Simultaneously, good hole transport capability of the hole transport layer 20 is also maintained, thereby achieving high conversion efficiency of the photovoltaic cell. Optionally, the molar ratio of nickel in the nickel source to the dopant metal in the doped metal source is 90:10, 91:9, 92:8, 97:3, 94:6, 95:5, 96:4, 97:3, 98:2, or 99:1. Alternatively, the molar ratio of nickel in the nickel source to the dopant metal in the doped metal source can also be within any two of the above molar ratios.

[0059] In some embodiments, the nickel source includes nickel nitrate; the doping metal source includes at least two of zinc nitrate, potassium nitrate, cesium nitrate, cerium nitrate, lithium nitrate, magnesium nitrate, and chromium nitrate.

[0060] It is understandable that using nickel nitrate as the nickel source and nitrates doped with metal elements as the dopant metal source can achieve a better combustion reaction effect in the liquid film. Furthermore, the dopant metal source includes at least two of zinc nitrate, potassium nitrate, cesium nitrate, cerium nitrate, lithium nitrate, magnesium nitrate, and chromium nitrate. The synergistic effect of at least two dopant elements on the energy level regulation of nickel oxide is better, facilitating better energy level matching and contact between the hole transport layer 20 and the transparent conductive layer 13.

[0061] In some embodiments, the nickel source is nickel nitrate.

[0062] In some embodiments, the doping metal source is at least two of zinc nitrate, potassium nitrate, cesium nitrate, cerium nitrate, lithium nitrate, magnesium nitrate, and chromium nitrate.

[0063] In some embodiments, the doping metal source is lithium nitrate and magnesium nitrate.

[0064] In some embodiments, the doping metal source is copper nitrate and magnesium nitrate.

[0065] In some embodiments, the doping metal source is potassium nitrate and cesium nitrate.

[0066] In some embodiments, the doping metal source is copper nitrate and potassium nitrate.

[0067] In some embodiments, the mixed solution also includes potassium chloride.

[0068] Adding potassium chloride to the mixed solution can adjust the crystallinity and morphology of the doped nickel oxide to form a hole transport layer 20 with better film-forming properties. This facilitates the preparation of a perovskite layer 30 with better crystallinity on the surface of the hole transport layer 20, thereby improving the conversion efficiency of the photovoltaic cell.

[0069] In some embodiments, the molar ratio of potassium chloride to the total molar ratio of nickel source and organic reducing agent is (0.1~2):1.

[0070] When the ratio of the molar amount of potassium chloride to the total molar amount of nickel source and organic reducing agent is too low, the effect of potassium chloride in regulating the crystallinity and morphology of doped nickel oxide is not significant. When the ratio of the molar amount of potassium chloride to the total molar amount of nickel source and organic reducing agent is too high, further increasing the amount of potassium chloride does not significantly improve the effect of regulating the crystallinity and morphology of doped nickel oxide. Optionally, the ratio of the molar amount of potassium chloride to the total molar amount of nickel source and organic reducing agent can be 0.1:1, 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, or 2:1, or the ratio can be within any two of the above ratios.

[0071] In some embodiments, the material of the transparent conductive layer 13 includes at least one of indium tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, and antimony-doped tin oxide.

[0072] In some embodiments, the substrate structure 10 further includes a crystalline silicon bottom cell structure 12; a transparent conductive layer 13 is disposed on the surface of the crystalline silicon bottom cell structure 12.

[0073] In some implementations, the following steps are also included:

[0074] A perovskite layer 30, an electron transport layer 40, and a top electrode 60 are sequentially stacked on the surface of the hole transport layer 20 away from the transparent conductive layer 13.

[0075] In some embodiments, the method for preparing a photovoltaic cell includes the following steps S10 to S50:

[0076] S10: Provide a substrate structure 10, the substrate structure 10 including a transparent conductive layer 13 located on the surface; apply a mixed solution to the transparent conductive layer 13 to form a liquid film, the mixed solution including a nickel source, a doped metal source and an organic reducing agent; anneal the liquid film at a temperature of 250℃~450℃ to form a hole transport layer 20 on the surface of the transparent conductive layer 13.

[0077] Reference Figure 1 As shown, Figure 1 This is a schematic diagram of the structure in which a hole transport layer 20 is formed on the surface of the transparent conductive layer 13.

[0078] S20: A perovskite layer 30 is prepared on the surface of the hole transport layer 20 away from the substrate structure 10.

[0079] Reference Figure 2 As shown, Figure 2 In order to be in Figure 1A schematic diagram of the perovskite layer 30 prepared based on the structure shown.

[0080] In some embodiments, the preparation of the perovskite layer 30 includes the following steps:

[0081] Provide perovskite precursor solutions;

[0082] A perovskite precursor solution is applied to the surface of the hole transport layer 20 away from the substrate structure 10 and subjected to a second annealing treatment.

[0083] In some embodiments, the temperature of the second annealing treatment is 90°C to 110°C.

[0084] Optionally, the temperature of the second annealing treatment is 90°C, 92°C, 94°C, 96°C, 98°C, 100°C, 102°C, 104°C, 106°C, 108°C, or 110°C, or the temperature of the second annealing treatment may be within the range of any two of the above temperatures.

[0085] In some embodiments, the second annealing process takes 10 to 15 minutes.

[0086] Optionally, the second annealing process can be performed for 10 min, 11 min, 12 min, 13 min, 14 min, or 15 min, or the second annealing process can be performed within any two of the above times.

[0087] S30: An electron transport layer 40 is prepared on the surface of the perovskite layer 30 away from the hole transport layer 20.

[0088] Reference Figure 3 As shown, Figure 3 In order to be in Figure 2 A schematic diagram of the electron transport layer 40 fabricated based on the structure shown.

[0089] S40: A transparent electrode 50 is fabricated on the surface of the electron transport layer 40 away from the perovskite layer 30.

[0090] Reference Figure 4 As shown, Figure 4 In order to be in Figure 3 A schematic diagram of the structure of a transparent electrode 50 fabricated based on the structure shown.

[0091] S50: A top electrode 60 is prepared on the surface of the transparent electrode 50 away from the electron transport layer 40; a protective layer 70 is prepared, which covers the surface of the top electrode 60 away from the electron transport layer 40 and exposes the transparent electrode 50 on the surface of the top electrode 60.

[0092] Reference Figure 5 As shown, Figure 5 In order to be in Figure 4 A schematic diagram of the structure for fabricating the top electrode 60 and the protective layer 70 based on the structure shown.

[0093] Another embodiment of this application provides a photovoltaic cell, prepared by the photovoltaic cell preparation method described above, comprising:

[0094] Substrate structure 10; Substrate structure 10 includes a transparent conductive layer 13 located on its surface;

[0095] Hole transport layer 20; Hole transport layer 20 is disposed on the surface of transparent conductive layer 13, and the material of hole transport layer 20 includes nickel oxide doped with a doped metal source.

[0096] In some embodiments, the thickness of the transparent conductive layer 13 is 5 nm to 30 nm.

[0097] Optionally, the thickness of the transparent conductive layer 13 is 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 28nm or 30nm, or the thickness of the transparent conductive layer 13 can be within any two of the above thicknesses.

[0098] In some embodiments, the hole transport layer 20 has a thickness of 20 nm to 50 nm.

[0099] Optionally, the thickness of the hole transport layer 20 is 20nm, 22nm, 25nm, 28nm, 30nm, 32nm, 35nm, 38nm, 40nm, 42nm, 45nm, 48nm or 50nm, or the thickness of the hole transport layer 20 may be within any two of the above thicknesses.

[0100] In some embodiments, the photovoltaic cell further includes a perovskite layer 30, an electron transport layer 40, and a top electrode 60, which are sequentially stacked on the surface of the hole transport layer 20 away from the substrate structure 10.

[0101] In some embodiments, the photovoltaic cell includes a bottom electrode 11, a crystalline silicon bottom cell structure 12, a transparent conductive layer 13, a hole transport layer 20, a perovskite layer 30, an electron transport layer 40, a transparent electrode 50, and a top electrode 60, which are stacked sequentially.

[0102] In some embodiments, the perovskite layer 30 comprises a material having the following general chemical formula: ABX3, wherein A includes FA. + MA + Cs + and Rb + At least one of them, B includes Pb 2+ Sn2+ and Sr 2+ At least one of them, X includes Cl - ,Br - and I - At least one of them.

[0103] In some embodiments, the thickness of the perovskite layer 30 is 500 nm to 1500 nm.

[0104] Optionally, the thickness of the perovskite layer 30 is 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm or 1500 nm, or the thickness of the perovskite layer 30 may be within any two of the above thicknesses.

[0105] In some embodiments, the material of the electron transport layer 40 includes at least one of SnO2, TiO2, ZnO, In2O3, and fullerenes and their derivatives.

[0106] In some embodiments, the thickness of the electron transport layer 40 is 10 nm to 30 nm.

[0107] Optionally, the thickness of the electron transport layer 40 is 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 22nm, 24nm, 26nm, 28nm or 30nm, or the thickness of the electron transport layer 40 may be within any two of the above thicknesses.

[0108] In some embodiments, the material of the transparent electrode 50 includes at least one of indium tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, and antimony-doped tin oxide.

[0109] In some embodiments, the thickness of the transparent electrode 50 is 30 nm to 100 nm.

[0110] Optionally, the thickness of the transparent electrode 50 is 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, or the thickness of the transparent electrode 50 may be within any two of the above thicknesses.

[0111] In some embodiments, the photovoltaic cell also includes a protective layer 70 that covers the surface of the top electrode 60 away from the electron transport layer 40, and a transparent electrode 50 exposed on the surface of the top electrode 60.

[0112] In some embodiments, the material of the protective layer 70 includes at least one of metal fluorides.

[0113] In some embodiments, the material of the protective layer 70 includes magnesium fluoride.

[0114] In some embodiments, the thickness of the protective layer 70 is 50 nm to 200 nm.

[0115] Optionally, the thickness of the protective layer 70 is 50nm, 80nm, 100nm, 120nm, 150nm, 180nm or 200nm, or the thickness of the protective layer 70 may be within any two of the above thicknesses.

[0116] In some embodiments, the substrate structure 10 further includes a crystalline silicon bottom cell structure 12; a transparent conductive layer 13 is disposed between the crystalline silicon bottom cell structure 12 and the hole transport layer 20.

[0117] This application provides a photovoltaic module, including:

[0118] Cover plate;

[0119] At least one battery string, the battery string including a photovoltaic cell prepared by the photovoltaic cell preparation method described above in this application, or a photovoltaic cell described above in this application;

[0120] And the encapsulation layer, which is located between the cover plate and the battery string, with the cover plate connected to the battery string through the encapsulation layer.

[0121] The following are the specific implementation methods:

[0122] Example 1

[0123] Methods for preparing photovoltaic cells:

[0124] (1) A crystalline silicon bottom cell structure 12 is provided, and an ITO transparent conductive layer 13 with a thickness of 20 nm is prepared by sputtering on the surface of the crystalline silicon bottom cell structure 12.

[0125] (2) Weigh 10 mmol nickel nitrate, 0.1 mol lithium nitrate and 0.1 mmol cesium nitrate and dissolve them in 10 ml deionized water. Then add 10 mmol citric acid and stir for 30 min. Take an appropriate amount of solution and drop it evenly onto the transparent conductive layer 13. Spin coat it at 5000 rpm for 30 s to form a liquid film. Then anneal it at 350℃ for 40 min to prepare the hole transport layer 20.

[0126] (3) Prepare a perovskite precursor solution with a molar concentration of 1.5 mol / L. Drop the perovskite precursor solution onto the hole transport layer 20, spin-coat at 3500 rpm for 40 s, and anneal at 100 °C for 12 min to prepare a perovskite precursor solution with the chemical formula Cs. 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I0.77 Br 0.23 )3 perovskite layer 30;

[0127] (4) A C layer with a thickness of 20 nm is deposited on the surface of the perovskite layer 30. 60 Electron transport layer 40;

[0128] (5) Sputter a 60 nm ITO transparent electrode 50 onto the surface of the electron transport layer 40;

[0129] (6) A silver top electrode 60 is deposited on the surface of the transparent electrode 50 by vapor deposition;

[0130] (7) Prepare a 100 nm magnesium fluoride protective layer 70, the protective layer 70 covers the surface of the top electrode 60 away from the electron transport layer 40, and the transparent electrode 50 is exposed on the surface of the top electrode 60.

[0131] Example 2

[0132] The preparation method of the photovoltaic cell in Example 2 is basically the same as that in Example 1, except that in step (2), 5 mmol of citric acid and 10 mmol of glycine are used to replace 10 mmol of citric acid.

[0133] Example 3

[0134] The preparation method of the photovoltaic cell in Example 3 is basically the same as that in Example 1, except that in step (2), 5 mmol KCl is added to the deionized water.

[0135] Example 4

[0136] The preparation method of the photovoltaic cell in Example 4 is basically the same as that in Example 2, except that in step (2), 5 mmol KCl is added to the deionized water.

[0137] Comparative Example 1

[0138] The preparation method of the photovoltaic cell in Comparative Example 1 is basically the same as that in Example 1, except that: in step (2), a 10nm nickel oxide hole transport layer is prepared by magnetron sputtering.

[0139] The photovoltaic cells prepared in Examples 1 to 4 and Comparative Example 1 were tested, and the test results are shown below:

[0140]

[0141] The photovoltaic cell fabrication method of this application can improve the energy level matching and contact effect between the hole transport layer 20 and the transparent conductive layer 13, thereby increasing the open-circuit voltage and fill factor, and thus enabling the photovoltaic cell to have a higher conversion efficiency. Furthermore, the addition of potassium chloride to the mixed solution can adjust the crystallinity and morphology of the doped nickel oxide to form a hole transport layer 20 with better film-forming properties, facilitating the fabrication of a perovskite layer 30 with better crystallinity on the surface of the hole transport layer 20, thereby improving the conversion efficiency of the photovoltaic cell.

[0142] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method of producing a photovoltaic cell, characterized by, Includes the following steps: A substrate structure is provided, the substrate structure including a transparent conductive layer located on the surface; A mixed solution is applied to the transparent conductive layer to form a liquid film. The mixed solution includes a nickel source, a doped metal source, and an organic reducing agent. The nickel source includes nickel nitrate. The doped metal source is lithium nitrate and magnesium nitrate, or, the doped metal source is copper nitrate and magnesium nitrate, or, the doped metal source is potassium nitrate and cesium nitrate, or, the doped metal source is copper nitrate and potassium nitrate. The molar ratio of the organic reducing agent to the nickel source is (0.5~2):

1. The molar ratio of nickel element in the nickel source to doped metal element in the doped metal source is (90~99):(1~10). The liquid film is annealed at a temperature of 275°C to 450°C, and the organic reducing agent is used as fuel to burn the liquid film, forming a hole transport layer on the surface of the transparent conductive layer.

2. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The annealing process takes 20 to 60 minutes.

3. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The organic reducing agent includes at least one of glycine, citric acid, urea, and ascorbic acid.

4. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The mixed solution also includes potassium chloride.

5. The method for preparing a photovoltaic cell according to claim 4, characterized in that, The ratio of the molar amount of potassium chloride to the total molar amount of the nickel source and the organic reducing agent is (0.1~2):

1.

6. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The material of the transparent conductive layer includes at least one of indium tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, and antimony-doped tin oxide.

7. The method for preparing a photovoltaic cell according to any one of claims 1 to 6, characterized in that, The substrate structure further includes a crystalline silicon bottom cell structure; the transparent conductive layer is disposed on the surface of the crystalline silicon bottom cell structure.

8. The method for preparing a photovoltaic cell according to any one of claims 1 to 6, characterized in that, It also includes the following steps: A perovskite layer, an electron transport layer, and a top electrode are sequentially stacked on the surface of the hole transport layer away from the transparent conductive layer.

9. A photovoltaic cell, characterized in that, The photovoltaic cell is prepared by the method described in any one of claims 1 to 8, comprising: A substrate structure; the substrate structure includes a transparent conductive layer located on its surface; Hole transport layer; the hole transport layer is disposed on the surface of the transparent conductive layer, and the material of the hole transport layer includes nickel oxide doped with a doped metal source.

10. The photovoltaic cell according to claim 9, characterized in that, The thickness of the transparent conductive layer is 5nm~30nm; and / or, The thickness of the hole transport layer is 20nm~50nm.

11. The photovoltaic cell according to any one of claims 9 to 10, characterized in that, The photovoltaic cell further includes a perovskite layer, an electron transport layer, and a top electrode, sequentially stacked on the surface of the hole transport layer away from the substrate structure; and / or, The substrate structure further includes a crystalline silicon bottom cell structure; the transparent conductive layer is disposed between the crystalline silicon bottom cell structure and the hole transport layer.

12. A photovoltaic module, characterized in that, include: Cover plate; At least one battery string, the battery string comprising a photovoltaic cell prepared by the method of any one of claims 1 to 8, or a photovoltaic cell prepared by any one of claims 9 to 11; And an encapsulation layer, which is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

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