Precursor solution, perovskite absorption layer and preparation method and application of perovskite absorption layer

Abstract

The embodiment of the invention provides a precursor solution, a perovskite absorption layer and a preparation method and application of the perovskite absorption layer. The precursor solution comprises an organic salt, a metal chloride hydrate and a solvent. The metal chloride hydrate comprises any one or a combination of at least two of neodymium chloride hexahydrate, ruthenium chloride hydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate and gadolinium chloride hexahydrate. Metal chloride hydrate is added into a precursor solution, so that water molecules in the metal chloride hydrate can be separated from the precursor solution of the perovskite solution in the preparation process of the perovskite absorption layer, a proper amount of humidity is provided for high-quality growth of perovskite, and perovskite can be immediately annealed after spin coating in a glove box is completed; according to the method, space transfer is not needed, the inert atmosphere of the glove box is not damaged, repeatability can be improved, the grain size of perovskite crystals and the quality of a perovskite absorption layer are guaranteed, and therefore the performance of the perovskite cell is further improved.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a precursor solution, a perovskite absorber layer, a method for preparing the same, and their applications. Background Technology

[0002] More and more new energy sources are replacing traditional thermal power generation. Among them, solar energy is a renewable energy source. Solar power generation is simple to install, requires little site space, and is suitable for various occasions and needs. Therefore, it is widely used in various fields.

[0003] Perovskite solar cells (PSCs) are a new generation of photovoltaic technology, and have become a research focus due to their high photoelectric conversion efficiency and low-cost solution processing.

[0004] In the process of preparing perovskite solar cells, after the perovskite thin film is prepared, it needs to be removed from the glove box and transferred to an environment with a specified humidity to allow the crystal nuclei to grow into large grains. In fact, the thin film has already begun to grow into small grains during the transfer process. Although the growth rate is slow, a large number of nucleations will limit the size of the subsequent grains. The process introduces uncertainties, reduces repeatability, and leads to a deterioration in the performance of the prepared perovskite solar cells.

[0005] Therefore, it is essential to develop a new type of perovskite solar cell.

[0006] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0007] This application provides a precursor solution, a perovskite absorber layer, a method for preparing the same, and its application, in order to solve or alleviate one or more of the technical problems mentioned above.

[0008] The first aspect of this application provides a precursor solution, the precursor solution comprising an organic salt, a metal chloride hydrate, and a solvent; The metal chloride hydrates include any one or a combination of at least two of neodymium chloride hexahydrate, ruthenium chloride hydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, and gadolinium chloride hexahydrate.

[0009] Optionally, the amount of solvent added is 1 L, and the molar amount of organic salt added is 1.4-2.5 mol.

[0010] Optionally, the amount of solvent added is 1 mL, and the amount of metal chloride hydrate added is 0.5-2 mg.

[0011] Optionally, the organic salt includes any one or a combination of at least two of formamidinium iodide, formamidinium bromide, formamidinium chloride, or methylammonium thiocyanate; The solvent includes any one or a combination of at least two of ethanol, isopropanol, or N,N-dimethylformamide.

[0012] The second aspect of this application provides a method for preparing a precursor solution, the method comprising: placing an organic salt and a metal chloride hydrate in a solvent and mixing them at 10-40°C for 30-90 min to obtain a precursor solution.

[0013] The third aspect of this application provides a method for preparing a perovskite absorber layer, the method comprising: coating an inorganic framework with the aforementioned precursor solution, reacting, annealing, and obtaining a perovskite absorber layer.

[0014] Optionally, the coating method is slot coating or scraping coating.

[0015] Optionally, the annealing includes two annealing processes, wherein the temperature of the first annealing is 60-80℃ and the time of the first annealing is 1-5 min, and the temperature of the second annealing is 90-110℃ and the time of the second annealing is 10-30 min.

[0016] Optionally, the method for preparing the inorganic framework layer includes: co-evaporating inorganic salts on the surface of a substrate to obtain the inorganic framework layer.

[0017] Optionally, the inorganic salt includes any one or a combination of at least two of lead iodide, cesium bromide, lead bromide, or cesium iodide.

[0018] The fourth aspect of this application provides a perovskite absorber layer, which is prepared by the above-described preparation method.

[0019] A fifth aspect of this application provides a solar cell, the solar cell including the perovskite absorber layer described above.

[0020] A sixth aspect of this application provides a photovoltaic module, the photovoltaic module including the solar cell described above.

[0021] The embodiments of this application employing the above-described technical solution may have the following advantages: By adding metal chloride hydrate to the precursor solution, water molecules in the metal chloride hydrate can be released from the precursor solution during the preparation of the perovskite absorber layer. This provides adequate humidity for the high-quality growth of perovskite, allowing the perovskite to be annealed immediately after spin coating in the glove box without the need for space transfer. This preserves the inert atmosphere of the glove box and eliminates the influence of other objective factors. As a result, repeatability can be improved, the grain size of the perovskite crystals can be guaranteed, and the quality of the perovskite absorber layer can be improved, thereby further enhancing the performance of the perovskite solar cell. Attached Figure Description

[0022] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0023] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of this application; Figure 2 This is a schematic diagram of another perovskite solar cell provided in the embodiments of this application.

[0024] Explanation of reference numerals in the attached figures: 20. First metal electrode layer; 30. First transparent electrode layer; 40. First electron transport layer; 50. Perovskite absorber layer; 60. First hole transport layer; 70. Second electron transport layer; 80. Substrate layer; 90. Second hole transport layer; 100. Second transparent electrode layer; 110. Second metal electrode layer; 1. Silicon substrate; 2. First passivation layer; 3. Hole transport layer (A); 4. In2O3 transparent electrode; 5. Grid-shaped silver electrode; 6. Electron transport layer (A); 7. IZO composite layer; 8. Hole transport layer (B); 9. Perovskite absorber layer; 10. Second passivation layer; 11. Third passivation layer; 12. Electron transport layer (B); 13. SnO2 buffer layer; 14. IZO transparent electrode; 15. Antireflection layer; 16. Silver grid line. Detailed Implementation

[0025] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, and elements, as well as their relative dimensions, may be exaggerated. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0026] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0027] 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.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a 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.

[0029] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0030] This application provides a technical solution for a precursor solution, a perovskite absorber layer, its preparation method, and its application. Details are provided below.

[0031] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0032] This application provides a precursor solution comprising an organic salt, a metal chloride hydrate, and a solvent. The metal chloride hydrates include any one or a combination of at least two of the following: neodymium(III) chloride hexahydrate (NdCl3·6H2O), ruthenium(III) chloride hydrate (RuCl3·xH2O), nickel(II) chloride hexahydrate (NiCl2·6H2O), cobalt chloride hexahydrate (CoCl2·6H2O), and gadolinium(III) chloride hexahydrate (GdCl3·6H2O).

[0033] In this application, by adding metal chloride hydrate to the precursor solution, water molecules in the metal chloride hydrate can be released from the perovskite solution precursor solution during the preparation of the perovskite absorber layer. This provides adequate humidity for the high-quality growth of perovskite, allowing the perovskite to be annealed immediately after spin coating in the glove box without the need for space transfer, thus preserving the inert atmosphere of the glove box and eliminating the influence of other objective factors. This improves repeatability, ensures the grain size of the perovskite crystals, improves the quality of the perovskite absorber layer, and further enhances the performance of the perovskite solar cell.

[0034] In an optional embodiment, the amount of solvent added is 1 L, and the molar amount of organic salt added is 1.4-2.5 mol (e.g., 1.4 mol, 1.6 mol, 1.8 mol, 2 mol, 2.2 mol, 2.5 mol, etc.).

[0035] In an optional embodiment, the amount of solvent added is 1 mL, and the amount of metal chloride hydrate added is 0.5-2 mg (e.g., 0.5 mg, 0.8 mg, 1 mg, 1.2 mg, 1.5 mg, 1.8 mg, 2 mg, etc.).

[0036] In this application, when the concentrations of the organic salt and the metal chloride hydrate in the solvent are within the aforementioned limits, during the reaction of the precursor solution to generate the perovskite absorber layer, water molecules in the metal chloride hydrate can detach from the perovskite solution, providing a growth environment with a relative humidity of 30-40% for perovskite growth. This ensures high-quality growth of the perovskite, guarantees the grain size of the perovskite crystals, improves the quality of the perovskite light-absorbing layer, and further enhances the performance of the perovskite solar cell.

[0037] When the concentration of organic salt in the solvent is too high, it will lead to problems such as poor film crystallization quality and solvent residue; when the concentration is too low, the bottom inorganic framework layer cannot be completely reacted, resulting in residue.

[0038] When the concentration of metal chloride hydrate in the solvent is too high, the high concentration of metal ions will cause the organic salt to react too quickly, resulting in poor film quality. When the concentration is too low, there will be insufficient metal ions, which will prevent the organic salt from being fully coordinated. As a result, sufficient humidity cannot be provided during nitrogen glove box annealing, leading to poor perovskite film quality.

[0039] In an optional embodiment, the organic salt includes any one or a combination of at least two of formamidinium iodide, formamidinium bromide, formamidinium chloride, or methylammonium thiocyanate.

[0040] In an optional embodiment, the solvent includes any one or a combination of at least two of ethanol, isopropanol, or N,N-dimethylformamide.

[0041] In this application, when the organic salt is selected from the above-mentioned organic salt, the band gap gradient can be adjusted, halogen segregation can be suppressed, phase stability can be improved, and a large-grain, low-defect thin film can be obtained; when the solvent is selected from the above-mentioned solvent, it is easy to obtain a uniform, non-porous perovskite thin film.

[0042] This application provides a method for preparing a precursor solution, the method comprising: placing an organic salt and a metal chloride hydrate in a solvent and mixing at 10-40°C (exemplary temperatures are 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc.) for 30-90 min (exemplary times are 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, etc.) to obtain a precursor solution.

[0043] In this application, the preparation method of the precursor solution is simple, the raw materials are readily available, the process is mild, and it is convenient for large-scale industrial production and application.

[0044] This application provides a method for preparing a perovskite absorber layer, the method comprising: coating an inorganic framework with the aforementioned precursor solution, annealing, and obtaining a perovskite absorber layer.

[0045] In this application, the preparation method of the perovskite absorber layer is simple, the raw materials are readily available, and the process is relatively mild. It will not damage the material during the preparation process, which is convenient for large-scale industrial production and application.

[0046] In an optional embodiment, the coating method is slot coating or scraping coating.

[0047] In an optional embodiment, the annealing includes two annealing processes, wherein the temperature of the first annealing is 60-80℃ (e.g., 60℃, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, 78℃, 80℃, etc.), and the time of the first annealing is 1-5 min (e.g., 1 min, 2 min, 3 min, 4 min, 5 min, etc.), and the temperature of the second annealing is 90-110℃ (e.g., 90℃, 92℃, 95℃, 97℃, 100℃, 102℃, 105℃, 108℃, 110℃, etc.), and the time of the second annealing is 10-30 min (e.g., 10 min, 12 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, etc.).

[0048] In this application, the precursor solution is applied to the inorganic framework layer using a slot coating method or a blade coating method, and the perovskite absorber layer is formed after annealing. Different preparation methods may have some influence on the crystallization of the perovskite absorber layer; the appropriate preparation method can be selected according to actual needs.

[0049] It should be noted that both the primary and secondary annealing processes are performed within a glove box. This allows water molecules from the metal chloride hydrate in the precursor solution to detach from the perovskite solution, providing adequate humidity for high-quality perovskite growth. This enables immediate annealing after spin-coating the perovskite in the glove box, eliminating the need for space transfer, preserving the inert atmosphere of the glove box, and preventing interference from other objective factors. This ensures the grain size of the perovskite crystals, improves the quality of the perovskite light-absorbing layer, and further enhances the performance of the perovskite solar cell. Furthermore, the transfer operation is omitted during the fabrication process, further optimizing the process flow and shortening the fabrication time of the perovskite light-absorbing layer, thereby further improving the production efficiency of the perovskite solar cell.

[0050] In an optional embodiment, the method for preparing the inorganic framework layer includes: co-evaporating inorganic salts on the surface of a substrate to obtain the inorganic framework layer.

[0051] In an optional embodiment, the inorganic salt includes any one or a combination of at least two of lead iodide, cesium bromide, lead bromide, or cesium iodide.

[0052] This application does not specifically limit the material and preparation method of the inorganic framework layer. Those skilled in the art can make adjustments according to actual needs. The above preparation method is preferred, as it can achieve adjustable band gap gradient, suppress ion migration, enhance lattice toughness, and improve hygrothermal stability.

[0053] In optional embodiments, the inorganic salt is preferably a combination of lead iodide (PbI2) and cesium bromide (CsBr). When the inorganic salt is a combination of PbI2 and CsBr, the evaporation rate of PbI2 is 0.6-1.4 Å / s (e.g., 0.6 Å / s, 0.8 Å / s, 1.0 Å / s, 1.2 Å / s, 1.4 Å / s), and the deposition thickness on the substrate is 380-420 nm (e.g., 380 nm, 390 nm, 400 nm, 410 nm, 420 nm); the evaporation rate of CsBr is 0.06-0.14 Å / s (e.g., 0.06 Å / s, 0.08 Å / s, 0.1 Å / s, 0.12 Å / s, 0.14 Å / s), and the deposition thickness on the substrate is 380-420 nm. nm (e.g., 38nm, 39nm, 40nm, 41nm, 42nm). In this way, the composition and thickness of the generated perovskite absorber layer can be precisely controlled.

[0054] This application also provides a perovskite absorber layer, which is prepared by the above method.

[0055] This application also provides a perovskite solar cell, including the perovskite absorber layer described above.

[0056] In an optional embodiment, the perovskite solar cell is a nip formal perovskite solar cell or a pin inverted perovskite solar cell.

[0057] The nip formal perovskite solar cell includes: a transparent electrode, an electron transport layer, a perovskite absorber layer, a hole transport layer, and a metal electrode stacked sequentially.

[0058] A pin-type inverted perovskite solar cell comprises: a transparent electrode, a hole transport layer, a perovskite absorber layer, an electron transport layer, and a metal electrode, which are stacked sequentially.

[0059] It should be noted that, in actual use or fabrication, other layers can be added to perovskite solar cells according to actual needs.

[0060] like Figure 1 As shown, this application provides a perovskite solar cell, comprising: 80 for the basal layer; A first metal electrode layer 20, a first transparent electrode layer 30, a first electron transport layer 40, a perovskite absorption layer 50, a first hole transport layer 60, and a second electron transport layer 70 are sequentially stacked on one side surface of the substrate layer 80, wherein the perovskite absorption layer 50 is the perovskite absorption layer described above. And a second hole transport layer 90, a second transparent electrode layer 100 and a second metal electrode layer 110 disposed on the other side surface of the substrate layer 80.

[0061] In some embodiments, n-type single crystal silicon is selected as the substrate layer 80. Before use, it is cleaned using the RCA standard process. A pyramid structure with a depth of 3-5 μm is prepared by etching the back of the silicon wafer with KOH aqueous solution. A pyramid structure with a depth of about 0.8-1.2 μm is prepared on the front side by etching the front of the wafer with a lower concentration of KOH aqueous solution.

[0062] In some embodiments, the materials of the first transparent electrode layer 30 and the second transparent electrode layer 100 are independently selected from any one or at least a combination of two of indium tin oxide, indium zinc oxide, and zinc aluminum oxide; the materials of the first metal electrode layer 20 and the second metal electrode layer 110 are independently selected from any one or at least a combination of two of silver nanowires, gold, silver, copper, and aluminum.

[0063] In some embodiments, the hole transport layer material of the first hole transport layer 60 is SAM; wherein, SAM can be [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-diphenyl9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, with a thickness of 1-2 nm; the hole transport layer material of the second hole transport layer 90 is boron-doped nanocrystalline silicon (nc-Si:H), with a thickness of 18-22 nm (e.g., 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, etc.).

[0064] In some embodiments, the material of the first electron transport layer 40 is C. 60 Or C 60 The derivatives may be any one or a combination of at least two of them, with a thickness of 8-12 nm (e.g., 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, etc.); the second electron transport layer 70 is made of phosphorus-doped nanocrystalline silicon (nc-Si:H) with a thickness of 13-17 nm (e.g., 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, etc.).

[0065] In some embodiments, a passivation layer is further provided between the perovskite absorber layer 50 and the first electron transport layer 40, and between the second electron transport layer 70 and the second hole transport layer 90.

[0066] In some embodiments, an antireflection layer is further provided on the surface of the first transparent electrode layer 30, and the antireflection layer is typically made of MgF₂. x .

[0067] In some embodiments, a specific method for forming a perovskite solar cell includes: S1. A second electron transport layer 70, a first hole transport layer 60, a perovskite absorption layer 50, a first electron transport layer 40, a first transparent electrode layer 30 and a first metal electrode layer 20 are sequentially formed on one side of the substrate layer 80 to form a stacked structure.

[0068] S2. A second hole transport layer 90, a second transparent electrode layer 100, and a second metal electrode layer 110 are sequentially formed on the other side surface of the substrate layer 80 to form a stacked structure.

[0069] In some embodiments, a specific method for forming a perovskite solar cell includes: S10. Single crystal silicon is selected as the substrate layer 80 with an area of ​​210 mm * 105 mm. RCA standard process cleaning is performed. KOH aqueous solution is used to etch the back of the silicon wafer to prepare a pyramid structure with a depth of 3-5 μm. A lower concentration of KOH aqueous solution is used to etch the front of the wafer to prepare a pyramid structure with a depth of about 1 μm. S20. A boron-doped nc-Si:H layer (20 nm) is deposited on the back side using PECVD process at a deposition temperature of 200℃ to form the second hole transport layer 90. S30. A phosphorus-doped nc-Si:H layer (15 nm) is deposited on the front side using PECVD process at a deposition temperature of 200℃ to form the second electron transport layer 70. S40. A second transparent electrode layer 100 (100 nm) with a sheet resistance of approximately 120 Ω / sq is deposited on the back side using magnetron sputtering; then a second metal electrode layer 110 is deposited at low temperature. S50. The first hole transport layer 60 is prepared by coating method. Its SAM is [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (Meo-4PACz), the solvent is isopropanol (IPA), the concentration is 1 mg / ml, and the thickness is 1-2 nm. S60. The perovskite absorber layer 50 is prepared using a two-step method, which is the same as the preparation method described above and will not be described in detail here. S70. The first electron transport layer 40, with a thickness of 10 nm, is prepared by thermal evaporation. S80. A first transparent electrode layer 30 with a thickness of 50 nm is prepared by magnetron sputtering; S90. The first metal electrode layer 20 with a thickness of 3 μm is prepared by screen printing through a stencil.

[0070] The following specific embodiments provide a more detailed description of this application, but should not be construed as limiting the application. Any modifications or substitutions made to the methods, steps, or conditions of this application without departing from the spirit and substance of this application are within the scope of this application.

[0071]

Example 1

[0072] This embodiment also provides a method for preparing a precursor solution, comprising: placing an organic salt and a metal chloride hydrate in a solvent and dissolving them at 25°C for 60 min to obtain a precursor solution.

[0073] This embodiment also provides a method for preparing a perovskite absorber layer, including: A1: Lead iodide and cesium bromide were co-evaporated on the substrate surface at rates of 1 Å / s and 0.1 Å / s, respectively, to form an inorganic framework layer with a thickness of 400 nm for lead iodide and 40 nm for cesium bromide. A2: The precursor solution was coated onto the inorganic framework using the slit coating method. The mixture was first annealed at 70°C for 2 min, and then annealed again at 100°C for 20 min. The mixture was then covered with a sealed quartz cap to prepare a perovskite absorption layer with a thickness of 800 nm.

[0074]

Example 2

[0075] This embodiment also provides a method for preparing a precursor solution, comprising: placing an organic salt and a metal chloride hydrate in a solvent and dissolving them at 10°C for 90 min to obtain a precursor solution.

[0076] This embodiment also provides a method for preparing a perovskite absorber layer, including: A1: Lead iodide and cesium bromide were co-evaporated on the substrate surface at rates of 0.6 Å / s and 0.06 Å / s, respectively, to form inorganic framework layers of lead iodide and cesium bromide with thicknesses of 380 nm and 38 nm, respectively. A2: The precursor solution was coated onto the inorganic framework using a slit coating method. The mixture was first annealed at 60°C for 5 min, and then annealed again at 110°C for 10 min. The mixture was then covered with a sealed quartz cap to prepare a perovskite absorption layer with a thickness of 780 nm.

[0077]

Example 3

[0078] This embodiment also provides a method for preparing a precursor solution, comprising: placing an organic salt and a metal chloride hydrate in a solvent and dissolving them at 40°C for 30 min to obtain a precursor solution.

[0079] This embodiment also provides a method for preparing a perovskite absorber layer, including: A1: Lead iodide and cesium bromide were co-evaporated on the substrate surface at rates of 1.4 Å / s and 0.14 Å / s, respectively, to form inorganic framework layers of lead iodide and cesium bromide with thicknesses of 420 nm and 42 nm, respectively. A2: The precursor solution was coated onto the inorganic framework using a blade coating method. The mixture was first annealed at 80°C for 1 min, and then annealed again at 90°C for 30 min. The mixture was then covered with a sealed quartz cap to prepare a perovskite absorption layer with a thickness of 820 nm.

[0080]

Example 4

[0081] The preparation methods of the precursor solution and the perovskite absorber layer are the same in Example 4 and Example 1.

[0082]

Example 5

[0083] The preparation methods of the precursor solution and the perovskite absorber layer are the same in Example 5 and Example 1.

[0084]

Example 6

[0085] The preparation methods of the precursor solution and the perovskite absorber layer are the same in Example 6 and Example 1.

[0086]

Example 7

[0087] The preparation methods of the precursor solution and the perovskite absorber layer are the same in Example 7 and Example 1.

[0088]

Example 8

[0089] The preparation methods of the precursor solution and the perovskite absorber layer are the same in Example 8 and Example 1.

[0090] Comparative Example 1 The difference from Example 1 is that the precursor solution does not include the addition of metal chloride hydrates, while the rest of the preparation methods are the same as in Example 1.

[0091]

Application Example

[0092] The performance of the tandem perovskite solar cells finally formed in Examples 1-5 and Comparative Example 1 of this application was tested below to obtain the short-circuit current density Jsc, open-circuit voltage Voc, fill factor FF, and photoelectric conversion efficiency PCE of the corresponding cell devices. The test results are shown in Table 1. Table 1

[0093] As can be seen from Table 1 above, compared with Comparative Example 1, the open-circuit voltage, fill factor and photoelectric conversion efficiency of the solar cell of Example 1 of this application are all improved; among them, the open-circuit voltage can be 0.036V higher, the fill factor can be 1.57% higher, and the photoelectric conversion efficiency can be 1.2% higher.

[0094] This application embodiment can also provide a photovoltaic module (not shown), which includes the perovskite solar cell described above. The perovskite solar cell can be connected in series and / or in parallel with one or more other solar cells in a predetermined manner. Multiple cells can form a cell string, and adjacent cells can be connected together by string welding.

[0095] This application provides a photovoltaic system including the photovoltaic modules described in any of the above embodiments. The advantages of the aforementioned photovoltaic modules are also present in this photovoltaic system, and will not be repeated here. The application fields of the aforementioned photovoltaic system are wide, not limited to photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants, but also including various devices and apparatuses that utilize solar energy for power generation, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy for power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic modules; for example, multiple photovoltaic modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0096] It should be noted 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," and "circumferential," etc., are used 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 on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of the component itself. For example, if a device in the drawings is inverted, a device described as "above" or "on top of" other devices or structures will subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0097] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0098] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0099] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes 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 scope of patent protection of this application.

Claims

1. A precursor solution, characterized in that, The precursor solution includes an organic salt, a metal chloride hydrate, and a solvent; The metal chloride hydrates include any one or a combination of at least two of neodymium chloride hexahydrate, ruthenium chloride hydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, and gadolinium chloride hexahydrate.

2. The precursor solution according to claim 1, characterized in that, The amount of solvent added is 1 L, and the molar amount of organic salt added is 1.4-2.5 mol; The amount of solvent added is 1 mL, and the amount of metal chloride hydrate added is 0.5-2 mg.

3. The precursor solution according to claim 1, characterized in that, The organic salt includes any one or a combination of at least two of formamidin iodine, formamidin bromide, formamidin chloride, or methylammonium thiocyanate; The solvent includes any one or a combination of at least two of ethanol, isopropanol, or N,N-dimethylformamide.

4. A method for preparing a precursor solution, characterized in that, The preparation method includes: placing an organic salt and a metal chloride hydrate in a solvent and mixing them at 10-40°C for 30-90 min to obtain a precursor solution.

5. A method for preparing a perovskite absorber layer, characterized in that, The preparation method includes: The precursor solution according to any one of claims 1-3 is coated on an inorganic framework and annealed to obtain a perovskite absorber layer.

6. The preparation method according to claim 5, characterized in that, The coating method is either slot coating or scraping coating. The annealing process includes two annealing processes. The first annealing is performed at a temperature of 60-80°C for 1-5 minutes, and the second annealing is performed at a temperature of 90-110°C for 10-30 minutes.

7. The preparation method according to claim 5, characterized in that, The method for preparing the inorganic framework layer includes: co-evaporating inorganic salts on the surface of a substrate to obtain an inorganic framework layer; The inorganic salt includes any one or a combination of at least two of lead iodide, cesium bromide, lead bromide, or cesium iodide.

8. A perovskite absorber layer is prepared by the preparation method according to any one of claims 5-7.

9. A solar cell, characterized in that, The solar cell includes the perovskite absorber layer as described in claim 8.

10. A photovoltaic module, characterized in that, The photovoltaic module includes the solar cell as described in claim 9.

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