Preparation method of perovskite laminated cell and perovskite laminated cell

Abstract

The invention provides a preparation method of a perovskite laminated cell and the perovskite laminated cell. The preparation method comprises the following steps: providing a bottom cell; a first transparent conductive layer, a hole transport layer, a perovskite layer and a first passivation layer are sequentially formed on one side of the bottom cell in the thickness direction of the bottom cell, the preparation environment of the first passivation layer is in the air, and a solvent for preparing the first passivation layer comprises a polar solvent and a non-polar solvent; and an electron transport layer, a second transparent conductive layer and a first electrode are sequentially formed on one side, deviating from the bottom cell, of the first passivation layer, so that the problem of poor quality of the passivation layer of the perovskite laminated cell prepared in the air in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and more specifically, to a method for preparing a perovskite tandem solar cell and the perovskite tandem solar cell itself. Background Technology

[0002] Perovskite solar cells have attracted widespread attention due to their high efficiency and low cost, especially when combined with crystalline silicon cells in tandem structures to further improve efficiency and stability. The passivation process of the perovskite layer is one of the key steps in improving cell efficiency and stability; it aims to reduce defects in the perovskite film and improve its interface quality. Traditionally, the preparation of the passivation layer is usually carried out in a vacuum to avoid the influence of moisture and oxygen. However, the preparation process under vacuum conditions is not only costly but also difficult to implement in large-scale production. Therefore, researchers have attempted to prepare the passivation layer in air to simplify the process and reduce costs. However, the perovskite preparation process in air is easily affected by moisture during stable operation, especially when preparing the passivation layer. Perovskite is prone to decomposition and defect formation, resulting in low density, poor uniformity, and inadequate interface passivation.

[0003] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0004] The main objective of this application is to provide a method for preparing a perovskite tandem solar cell and a perovskite tandem solar cell, so as to solve the problem of poor quality of the passivation layer in the prior art when preparing perovskite tandem solar cells in air.

[0005] To achieve the above objectives, according to one aspect of this application, a method for fabricating a perovskite tandem solar cell is provided, comprising: providing a base cell; sequentially forming a first transparent conductive layer, a hole transport layer, a perovskite layer, and a first passivation layer along the thickness direction of the base cell on one side of the base cell, wherein the first passivation layer is prepared in air, and the solvent for preparing the first passivation layer includes a polar solvent and a non-polar solvent; and sequentially forming an electron transport layer, a second transparent conductive layer, and a first electrode on the side of the first passivation layer opposite to the base cell.

[0006] Optionally, the preparation method further includes: mixing the passivation layer material, the polar solvent, and the non-polar solvent to obtain a first passivation layer solution, wherein the solubility of the first passivation layer solution is 0.15~0.5 mg / ml; depositing the first passivation layer solution onto the side of the perovskite layer away from the bottom cell using a coating process in an air environment to form a preliminary first passivation layer; and annealing the preliminary first passivation layer to obtain the first passivation layer.

[0007] Optionally, the mass ratio of the polar solvent to the non-polar solvent is (60~90):(10~40).

[0008] Optionally, the coating process includes at least one of the following: spin coating, spray coating, and blade coating.

[0009] Optionally, the polar solvent includes at least one of the following: IPA, NBA, and isooctyl alcohol.

[0010] Optionally, the nonpolar solvent includes at least one of the following: anisole, ethyl acetate, acetic acid, anisole, and ionic liquid.

[0011] Optionally, the preparation method further includes: sputtering the material of the first transparent conductive layer onto the bottom battery using a magnetron sputtering process to form the first transparent conductive layer, wherein the power of the magnetron sputtering process is 200~600W, and a preset gas is introduced during the magnetron sputtering process, wherein the preset gas includes at least one of the following: argon and hydrogen.

[0012] Optionally, the preparation method further includes: sputtering the material of the first hole transport layer onto the first transparent conductive layer using a magnetron sputtering process to form the first hole transport layer, wherein the power of the magnetron sputtering process is 1000~2000W, and argon gas is introduced during the magnetron sputtering process; forming a second hole transport layer on the side of the first hole transport layer away from the bottom battery using an evaporation process, wherein the evaporation rate is 0.3~0.5Å / s, and the first hole transport layer and the second hole transport layer constitute the hole transport layer.

[0013] Optionally, the preparation method further includes: mixing lead iodide and lead bromide powders to obtain a mixed powder, and using a vapor deposition process to deposit the mixed powder and cesium bromide powder onto the side of the electron transport layer away from the bottom cell, wherein the vapor deposition rate of the mixed powder is 3~4 Å / s and the vapor deposition rate of the cesium bromide powder is 0.5~0.6 Å / s.

[0014] According to another aspect of this application, a perovskite tandem solar cell is provided, which is prepared using the aforementioned method for preparing a perovskite tandem solar cell.

[0015] Applying the technical solution of this application, a first transparent conductive layer, a hole transport layer, a perovskite layer, and a first passivation layer are sequentially formed along the thickness direction of the bottom battery on one side. The first passivation layer is prepared in air, and the solvent used to prepare the first passivation layer includes both polar and non-polar solvents. An electron transport layer, a second transparent conductive layer, and a first electrode are sequentially formed on the side of the first passivation layer facing away from the bottom battery. When preparing the first passivation layer in air, a mixture of polar and non-polar solvents is used. The polar solvent provides good solubility, while the non-polar solvent reduces the influence of the solvent on the perovskite layer, optimizing the film formation process of the passivation layer on the bottom battery. This results in a smoother interface between the first passivation layer and the perovskite layer, reducing defects and improving the passivation effect. Furthermore, by mixing these two solvents in a specific ratio, good dissolution of the passivation material is ensured while reducing side effects on the perovskite material. This facilitates the formation of a denser and more uniform passivation layer film, solving the problem of poor passivation layer quality in existing technologies for perovskite tandem solar cells prepared in air. The formed first passivation layer effectively prevents interference from moisture in the air, inhibits ion migration, passivates surface defects, and optimizes film formation quality, thereby significantly improving photoelectric conversion efficiency and battery stability. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 A schematic flowchart of a method for fabricating a perovskite tandem solar cell according to an embodiment of this application is shown.

[0018] Figure 2 A cross-sectional schematic diagram of a perovskite tandem solar cell according to an embodiment of this application is shown.

[0019] The above figures include the following reference numerals:

[0020] 10. Bottom cell; 11. Second electrode; 20. First transparent conductive layer; 30. Hole transport layer; 40. Perovskite layer; 50. First passivation layer; 60. Electron transport layer; 70. Second transparent conductive layer; 80. First electrode. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, 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.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0025] As described in the background section, the existing perovskite preparation process in air is easily affected by moisture during stable operation, especially when preparing the passivation layer. The perovskite is prone to decomposition and defects, resulting in low density, poor uniformity, and poor interface passivation. To solve the problem of poor passivation layer quality in perovskite tandem solar cells prepared in air, the embodiments of this application provide a method for preparing a perovskite tandem solar cell and a perovskite tandem solar cell.

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] Figure 1 This is a flowchart of a method for fabricating a perovskite tandem solar cell according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0028] Step S1, provide the bottom battery;

[0029] Specifically, the aforementioned base cell can be a high-efficiency and stable heterojunction solar cell (HJT), exhibiting high photoelectric conversion efficiency and good stability. If large-area tandem cells are required, a 210mm HJT solar cell can be selected as the base cell to meet the fabrication requirements of large-area, high-efficiency perovskite tandem cells. Using a high-efficiency and stable base cell as the foundation of the perovskite tandem cell ensures the initial photoelectric conversion efficiency and stability of the entire cell structure, providing a good support platform for the subsequent fabrication of the perovskite layer and other functional layers.

[0030] Step S2: A first transparent conductive layer, a hole transport layer, a perovskite layer and a first passivation layer are sequentially formed on one side of the bottom cell along the thickness direction of the bottom cell. The first passivation layer is prepared in the air, and the solvent used to prepare the first passivation layer includes polar solvents and non-polar solvents.

[0031] Specifically, a first transparent conductive layer (such as ITO) with a thickness of 10-20 nm is first deposited on the front side of the bottom cell (the side receiving sunlight) using deposition processes such as magnetron sputtering. Subsequently, a hole transport layer with a thickness of 40-60 nm is deposited, followed by the formation of a 500 nm thick perovskite layer. Finally, a first passivation layer is prepared in air using a mixed solution containing polar and non-polar solvents (such as a mixture of IPA and anisole) to dissolve the passivation material (such as PEAI) in an appropriate proportion. Preparing the first passivation layer in air, combined with the use of a mixed system of polar and non-polar solvents, effectively reduces the contact between the perovskite layer and moisture and oxygen in the air, preventing decomposition and performance degradation of the perovskite material. The introduction of non-polar solvents reduces the negative impact of polar solvents on the perovskite material while ensuring good dissolution and film quality of the passivation layer material.

[0032] In step S3, an electron transport layer, a second transparent conductive layer, and a first electrode are sequentially formed on the side of the first passivation layer away from the bottom cell.

[0033] Specifically, on the other side of the first passivation layer, an electron transport layer with a thickness of 10-20 nm is deposited (using a vapor deposition process, the material being TiO2). Following this, a second transparent conductive layer (such as IZO) with a thickness of approximately 15-20 nm is formed on top. Finally, a metal electrode layer (such as Ag) with a thickness of approximately 100-150 nm is deposited as the first electrode. This series of functional layer depositions and fabrications follows optimal process conditions, ensuring good contact between layers and excellent photoelectric performance. The electron transport layer and the second transparent conductive layer further optimize the carrier transport path in the perovskite tandem solar cell, reducing carrier recombination losses and improving photoelectric conversion efficiency. The introduction of the metal electrode layer provides reliable electrical contact, facilitating current collection and output.

[0034] This embodiment demonstrates that when preparing the first passivation layer in air, a mixture of polar and non-polar solvents can be used as the solvent. The polar solvent provides excellent solubility, while the non-polar solvent reduces the impact of the solvent on the perovskite layer, optimizing the film formation process of the passivation layer on the bottom cell. This results in a smoother interface between the first passivation layer and the perovskite layer, reducing defects and improving the passivation effect. Furthermore, by mixing these two solvents in a specific ratio, good dissolution of the passivation material is ensured while minimizing side effects on the perovskite material, contributing to the formation of a denser and more uniform passivation layer film. This solves the problem of poor passivation layer quality in existing technologies for perovskite tandem solar cells prepared in air. The formed first passivation layer effectively prevents interference from moisture in the air, inhibits ion migration, passivates surface defects, and optimizes film formation quality, thereby significantly improving photoelectric conversion efficiency and cell stability. Moreover, preparing the passivation layer in air is more cost-effective than preparing it under vacuum conditions and allows for large-scale production.

[0035] In the above embodiment, the bottom cell is prepared by laser non-destructive cutting of the HJT wafer into 210 half-wafers, followed by ultrasonication with deionized water and detergent for 15 minutes, and rinsing the wafer 2-3 times to remove the detergent. It is then ultrasonicated with deionized water for 15 minutes, followed by ultrasonication with IPA for 15 minutes, dried with BTU, and subjected to ultraviolet ozone radiation. Before treatment, it is first spin-coated with IPA and then washed again. The spin-coating conditions can be 1500-2000 rap / 30s, followed by ultraviolet ozone radiation treatment for 15 minutes.

[0036] In the specific implementation process, the first passivation layer in step S2 above can be obtained through the following steps:

[0037] A passivation layer material, a polar solvent, and a non-polar solvent are mixed to obtain a first passivation layer solution with a solubility of 0.15~0.5 mg / ml. The passivation layer material can be PDI, PDAI, or PEAI. The polar solvent includes at least one of the following: IPA, NBA, and isooctanol. The non-polar solvent includes at least one of the following: anisole, ethyl acetate, acetic acid, anisole, and ionic liquid. Taking PDI as the passivation layer material as an example, the solvent can be prepared using mixed solvents of IPA and anisole, IPA and ethyl acetate, or IPA, NBA, and acetic acid. The solvent ratios can be (8~9):(1~2), 8~9):(1~2), and (7~8):(1~2):(1~2), for example, 9:1, 9:1, and 8:1:1. The solubility of the obtained passivation layer is 0.15~0.5 mg / ml.

[0038] In an air-conditioned environment, a first passivation layer solution is deposited onto the side of the perovskite layer opposite to the bottom cell using a coating process to form a preliminary first passivation layer. The coating process can include spin coating, spray coating, or blade coating. Spin coating utilizes rotational force to uniformly distribute the solution, suitable for small-area thin-film preparation on a laboratory scale, and can provide a highly uniform coating. Spray coating utilizes pressure to atomize and deposit the solution, suitable for larger-area thin-film preparation, and easily controls the coating thickness and uniformity. Blade coating is a simple, low-cost deposition method suitable for large-area coating preparation in continuous production processes. By employing a spray coating process, combined with precise spray parameter control, the first passivation layer solution can be uniformly deposited on the perovskite layer without sacrificing uniformity and density, forming a high-quality preliminary first passivation layer. Further annealing treatment forms the final passivation layer, significantly improving the photoelectric conversion efficiency and stability of the perovskite tandem solar cell. This application does not specifically limit the selection of the coating process. Taking spraying as an example, the spraying pressure is 0.3~1 Pa, and the distance between the perovskite layer and the nozzle is 15~30 cm. The spraying rate is 6~15 cm / s. After spraying, it is cleaned with IPA solution.

[0039] The first passivation layer is annealed to obtain the first passivation layer. It is then placed in an annealing apparatus for annealing at 100℃ for 5 minutes. By controlling the ratio of polar to non-polar solvents and the solubility of the solution, a high-quality first passivation layer can be successfully prepared in air. This improves the uniformity and density of the passivation layer, better isolates moisture, optimizes the film formation quality, and thus enhances the photoelectric conversion efficiency and stability.

[0040] The aforementioned polar solvents can effectively dissolve passivation layer materials such as PDI, PDAI, and PEAI. Through interactions with the passivation material molecules, the polar solvents break down the solid-state structure of the material, making it easier to disperse in the solvent and form a uniform solution, facilitating subsequent deposition or coating. However, polar solvents may have adverse effects on perovskite materials. Therefore, mixing them with non-polar solvents can balance dissolution capacity and the need to protect the perovskite, achieving efficient and stable deposition of the passivation layer. Selecting the aforementioned polar solvents is a prerequisite for ensuring the complete dissolution of the passivation layer material and is also key to achieving a uniform and dense passivation layer. By using polar solvents such as IPA, NBA, or isooctanol, a stable and uniform passivation layer solution can be formed, allowing for the fabrication of a high-quality passivation layer through deposition processes, effectively improving the photoelectric performance and environmental stability of perovskite tandem solar cells.

[0041] The introduction of the aforementioned non-polar solvent is intended to reduce the negative impact of traditional polar solvents on perovskite films, particularly the potential damage from moisture and oxygen. These non-polar solvents have low polarity and low moisture content; when mixed with the passivation layer material, they can reduce the overall polarity of the solution, minimizing damage to the perovskite layer while maintaining sufficient solubility.

[0042] To better enhance the film quality of the first passivation layer, the mass ratio of the polar solvent to the non-polar solvent is (60~90):(10~40). By adjusting the ratio of the polar and non-polar portions of the solvent, good dissolution and deposition of the passivation layer material are ensured, while the perovskite layer is protected from excessive influence by the polar solvent, thereby improving the uniformity of the passivation layer and the overall performance of the film.

[0043] The preparation of the first transparent conductive layer in step S2 above can be achieved through the following steps: The material of the first transparent conductive layer is sputtered onto the base cell using a magnetron sputtering process to form the first transparent conductive layer. The power of the magnetron sputtering process is 200~600W. During the magnetron sputtering process, a preset gas is introduced, which includes at least one of the following: argon and hydrogen. Magnetron sputtering is a highly efficient thin film deposition technique, especially suitable for the preparation of transparent conductive oxides (TCOs) such as ITO. By adjusting the sputtering power (200~600W) and the type of gas introduced (argon, hydrogen, or an argon-hydrogen mixture), the deposition rate, thin film structure, and conductivity of the first transparent conductive layer can be controlled. Argon, as an inert gas, is used to generate plasma and promote material sputtering; while the addition of hydrogen helps to reduce oxygen defects in the oxide, lower resistivity, and improve transparency.

[0044] When argon is used as the gas, it acts as an inert gas, effectively generating plasma and promoting the sputtering process, but may result in relatively high film resistance. When argon and hydrogen are used, the addition of hydrogen helps reduce oxygen defects in the oxide, thereby lowering the film resistivity and improving conductivity. Simultaneously, hydrogen also promotes film densification and improves transparency. In this case, argon and hydrogen are typically introduced into the sputtering chamber simultaneously, and the flow rate ratio needs to be optimized to achieve the best film performance. When using an argon-hydrogen mixture, the combined effect of argon and hydrogen can improve both the conductivity and transparency of the film, making it particularly suitable for preparing high-quality transparent conductive layers. The flow rate ratio of the mixture also needs to be adjusted according to the specific process. Suitable flow rates for argon, hydrogen, and argon-hydrogen are 140±20 sccm, 3.4±1 sccm, and 60±5 sccm, respectively.

[0045] The hole transport layer in step S2 above can be prepared through the following steps:

[0046] The material of the first hole transport layer is sputtered onto the first transparent conductive layer using a magnetron sputtering process to form the first hole transport layer. The power of the magnetron sputtering process is 1000~2000W, and argon gas is introduced during the magnetron sputtering process. The material of the first hole transport layer is NiOx, the flow rate of argon gas can be 400~450sccm, the deposition temperature is 160~200℃, and the thickness is 40~60nm.

[0047] A second hole transport layer is formed on the side of the first hole transport layer away from the bottom cell using a vapor deposition process. The evaporation rate is 0.3–0.5 Å / s. The first and second hole transport layers together form the hole transport layer. The second hole transport layer is a self-assembled monolayer (SAM), and the material can be 4PACD, 4PACZ, or 2PACZ. These SAM materials can serve as molecular bridging interfaces, optimizing the contact between the NiOx layer and the subsequent perovskite layer, reducing defects at the interface, and improving the overall device performance. The thickness of the deposited second hole transport layer is approximately 1–2 nm. The vapor deposition process parameters are as follows: evaporation rate 0.3–0.5 Å / s, vacuum 1–2 × 10⁻⁶. -5 The solution is annealed in air at 100°C for 5 minutes to form a molecular bridging interface, and then washed twice with IPA.

[0048] The perovskite layer in step S2 above can be prepared by the following steps:

[0049] Lead iodide and lead bromide powders are mixed to obtain a mixed powder. The mixed powder and cesium bromide powder are then deposited onto the side of the electron transport layer away from the bottom cell using a vapor deposition process. The vapor deposition rate of the mixed powder can be 3~4 Å / s, and the vapor deposition rate of the cesium bromide powder can be 0.5~0.6 Å / s.

[0050] Specifically, lead iodide and lead bromide powders are mixed in a certain ratio, such as PbI2:PbBr2 = (0.75~0.85:0.1~0.15), for example, 0.85:0.15. The mixed powder of PbI2 and PbBr2, along with CsBr, is deposited using a line source. The evaporation rates are 3~4 Å / s and 0.5~0.6 Å / s, respectively, and the thickness of the deposited film is 500 nm. The prepared structure is transferred to the next chamber, where an organic ammonium salt (containing potassium hexafluorophosphate KPF6) is deposited at an evaporation rate of 0.5~1 Å / s. The mixture is then annealed in air at 100°C for 15 min to form a perovskite layer. By precisely controlling the evaporation rate and powder ratio, the resulting perovskite layer exhibits excellent light absorption and carrier transport properties. Simultaneously, the presence of the passivation layer effectively suppresses ion migration and surface defects within the perovskite layer, further optimizing the photoelectric conversion efficiency and long-term operational stability of the perovskite tandem solar cell. This method of perovskite layer fabrication, combined with the design of the passivation layer and other functional layers, constitutes the core technical characteristic of the perovskite tandem solar cell and plays a decisive role in improving the overall performance of the cell.

[0051] The electron transport layer can be prepared by depositing the electron transport layer material (such as TiO2, PCBM, or C60) onto the first passivation layer using a vapor deposition method. The film thickness can be 10-20 nm. The process parameters are as follows: evaporation rate of 0.1-0.3 Å / s; vacuum level below 5 × 10⁻⁶. -4 Pa. The preparation method of the second transparent conductive layer is the same as that of the first transparent conductive layer, and will not be repeated. The first electrode can be prepared by screen printing, and the material of the first electrode can be Au, Ag, Cu, or Al.

[0052] According to another embodiment of this application, a perovskite tandem solar cell is provided, which is prepared using the perovskite tandem solar cell preparation method described above. Figure 2 As shown, the perovskite tandem solar cell, from bottom to top, includes: a bottom cell 10, a first transparent conductive layer 20, a hole transport layer 30, a perovskite layer 40, a first passivation layer 50, an electron transport layer 60, a second transparent conductive layer 70, and a first electrode 80. The bottom cell 10 includes a second electrode 11, and the hole transport layer is a composite film layer including a first hole transport layer and a self-assembled monolayer.

[0053] The photovoltaic module described above in this application will be specifically described below with reference to specific embodiments and comparative examples.

[0054] Example 1

[0055] This application proposes a method for preparing perovskite tandem solar cells, the method comprising:

[0056] Provide a base battery;

[0057] ITO was sputtered onto the bottom cell using a magnetron sputtering process to form a 10nm first transparent conductive layer. The magnetron sputtering process had a power of 200W, and 140sccm of argon gas was introduced during the magnetron sputtering process.

[0058] NiO was sputtered onto the first transparent conductive layer using magnetron sputtering at a flow rate of 450 sccm and a temperature of 160°C to form a 40 nm first hole transport layer. The magnetron sputtering process used a power of 1000 W and argon gas was introduced during the sputtering process. The material of the first hole transport layer was NiOx, the argon gas flow rate was 450 sccm, and the deposition temperature was 160°C. 4 PACD was then deposited onto the side of the first hole transport layer away from the bottom cell using an evaporation process to form a 1.5 nm second hole transport layer at an evaporation rate of 0.3 Å / s. The first and second hole transport layers together constitute the hole transport layer.

[0059] Lead iodide and lead bromide powders were mixed in a ratio of (0.85:0.15), and a mixture of PbI₂ and PbBr₂ powders and CsBr was deposited using a line source. The evaporation rates were 4 Å / s and 0.6 Å / s, respectively, and the thickness of the deposited film was 500 nm. The prepared structure was transferred to the next chamber, where an organic ammonium salt (containing potassium hexafluorophosphate KPF₆) was deposited at an evaporation rate of 1 Å / s. The mixture was then annealed in air at 100 °C for 15 min to form a perovskite layer.

[0060] A passivation layer material, PDI, was mixed with a solvent (IPA and anisole in a 9:1 ratio) to form a solution for preparing the passivation layer. The solution had a solubility of 0.2 mg / ml, and the mass ratio of polar solvent to non-polar solvent was 6:1. The passivation layer solution was sprayed onto the perovskite layer using a spraying process. The spraying pressure was 0.5 Pa, the nozzle distance from the perovskite layer was 20 cm, and the spraying rate was 6 cm / s. After spraying, the layer was cleaned with an IPA solution and then annealed in an annealing apparatus at 100°C for 5 min to form the first passivation layer.

[0061] TiO2, the material for the electron transport layer, was deposited onto the first passivation layer using a vapor deposition method. The film thickness was 10 nm, the evaporation rate was 0.1 Å / s, and the vacuum degree was 4. 10 -4 Pa forms an electron transport layer.

[0062] ITO was sputtered onto the electron transport layer using magnetron sputtering to form a 10nm second transparent conductive layer. The magnetron sputtering process had a power of 200W, and 140sccm of argon gas was introduced during the magnetron sputtering process.

[0063] The first electrode was prepared using a screen printing process. The material of the first electrode was Ag, and the thickness was 10 nm.

[0064] Example 2

[0065] The difference from Example 1 is that the mass ratio of polar solvent to non-polar solvent is 75:24.

[0066] Example 3

[0067] The difference from Example 1 is that the mass ratio of polar solvent to non-polar solvent is 86:35.

[0068] Example 4

[0069] The difference from Example 1 is that the mass ratio of polar solvent to non-polar solvent is 9:4.

[0070] Example 5

[0071] The difference from Example 1 is that the passivation layer material PDI is mixed with a solvent (IPA and ethyl acetate are mixed in a 9:1 ratio) to form a solution for preparing the passivation layer.

[0072] Example 6

[0073] The difference from Example 1 is that the passivation layer material PDI is mixed with a solvent (IPA, NBA and acetic acid are mixed in a ratio of 8:1:1) to form a solution for preparing the passivation layer.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that only a polar solvent was used to form the solution for preparing the passivation layer.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that only a non-polar solvent was used to form the solution for preparing the passivation layer.

[0078] The perovskite tandem solar cells obtained by the preparation methods of Examples 1-6 and Comparative Examples 1-2 were tested, and the specific test data are as follows:

[0079]

[0080] As can be seen from the above experimental data, the first passivation layer of the perovskite tandem solar cell prepared by mixing polar solvents and non-polar solvents with passivation materials in this application can improve the density of the first passivation layer, improve the quality of the film layer, and thus improve the photoelectric conversion efficiency of the perovskite tandem solar cell. It can also reduce the cost of preparing the passivation layer under vacuum conditions.

[0081] 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.

[0082] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a perovskite tandem solar cell, characterized in that, include: Provide a base battery; A first transparent conductive layer, a hole transport layer, a perovskite layer, and a first passivation layer are sequentially formed along the thickness direction of the bottom battery on one side. The first passivation layer is prepared in air, and the solvent used to prepare the first passivation layer includes both polar and non-polar solvents. An electron transport layer, a second transparent conductive layer, and a first electrode are sequentially formed on the side of the first passivation layer opposite to the bottom battery.

2. The preparation method according to claim 1, characterized in that, The preparation method further includes: The passivation layer material, the polar solvent, and the non-polar solvent are mixed to obtain a first passivation layer solution, the solubility of which is 0.15~0.5 mg / ml. In an air environment, the first passivation layer solution is deposited onto the side of the perovskite layer away from the bottom cell using a coating process to form a preliminary first passivation layer; The prepared first passivation layer is annealed to obtain the first passivation layer.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the polar solvent to the non-polar solvent is (60~90):(10~40).

4. The preparation method according to claim 3, characterized in that, The coating process includes at least one of the following: spin coating, spray coating, and blade coating.

5. The preparation method according to claim 1, characterized in that, The polar solvent includes at least one of the following: IPA, NBA, and isooctyl alcohol.

6. The preparation method according to claim 1, characterized in that, The nonpolar solvent includes at least one of the following: anisole, ethyl acetate, acetic acid, anisole, and ionic liquid.

7. The preparation method according to claim 1, characterized in that, The preparation method further includes: The material of the first transparent conductive layer is sputtered onto the bottom battery using a magnetron sputtering process to form the first transparent conductive layer. The power of the magnetron sputtering process is 200~600W. A preset gas is introduced during the magnetron sputtering process. The preset gas includes at least one of the following: argon and hydrogen.

8. The preparation method according to claim 1, characterized in that, The preparation method further includes: The material of the first hole transport layer is sputtered onto the first transparent conductive layer using a magnetron sputtering process to form the first hole transport layer. The power of the magnetron sputtering process is 1000~2000W, and argon gas is introduced during the magnetron sputtering process. A second hole transport layer is formed on the side of the first hole transport layer away from the bottom cell using a vapor deposition process with an evaporation rate of 0.3~0.5 Å / s. The first hole transport layer and the second hole transport layer constitute the hole transport layer.

9. The preparation method according to claim 1, characterized in that, The preparation method further includes: Lead iodide and lead bromide powders are mixed to obtain a mixed powder, and the mixed powder and cesium bromide powder are deposited onto the side of the electron transport layer away from the bottom cell using a vapor deposition process. The vapor deposition rate of the mixed powder is 3~4 Å / s, and the vapor deposition rate of the cesium bromide powder is 0.5~0.6 Å / s.

10. A perovskite tandem solar cell, characterized in that, The perovskite tandem solar cell was prepared using the method described in any one of claims 1 to 9.

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