Preparation method of laminated cell, laminated cell and photovoltaic module

Abstract

The invention provides a preparation method of a laminated cell, the laminated cell and a photovoltaic module, and can be widely applied to the photovoltaic technical field, the preparation method of the laminated cell comprises the following steps: providing a bottom cell, and forming a composite layer on the bottom cell; a first transmission layer is formed on the composite layer, and a skeleton layer is formed on the first transmission layer through double-source evaporation; wherein a first evaporation source of the double-source evaporation comprises inorganic cesium salt, and a second evaporation source of the double-source evaporation comprises inorganic lead salt and inorganic rubidium salt; coating organic salt on the framework layer to form a perovskite layer; forming a second transmission layer and an electrode on the perovskite layer to obtain a laminated cell; wherein carriers of the first transmission layer and the second transmission layer are different. The framework layer is formed through double-source evaporation, the proportion is better controlled, through rubidium and lead, a positive effect can be generated on crystallization, stress release and the like of perovskite in the crystallization process, part of rubidium salt can be combined with PbI2 decomposed on the surface, ion migration is reduced, and the device stability is improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and more specifically, to a method for preparing a tandem battery, the tandem battery, and a photovoltaic module. Background Technology

[0002] Currently, the small size of the surface pyramid structure of the crystalline silicon substrate used in perovskite / crystalline silicon tandem solar cells weakens the excellent light-trapping properties of industrial-grade textured crystalline silicon and increases additional processing costs. Therefore, conducting research on the high-performance fabrication and stability of tandem solar cells with larger textured surfaces (greater than 2 micrometers) for industrial-grade crystalline silicon substrates has become a key issue that urgently needs to be addressed to promote their low-cost industrialization.

[0003] Achieving high-quality conformal deposition of functional layers and perovskite light-absorbing layers on industrial-grade textured silicon is a major challenge, with the preparation of the perovskite layer being particularly crucial. Currently, the evaporation-solution method is widely used to achieve high-quality conformal growth. This method belongs to a two-step preparation process, and its key lies in separately controlling the formation of the inorganic framework and the intercalation of organic ions, optimizing the crystallization process of perovskite through the combined action of physical and chemical means. Among various two-step methods, the evaporation-solution method has the greatest application potential. It retains the good uniformity and conformal properties of vapor deposition, and offers multiple options in the second step of organic salt solution coating, including spin coating and coating processes suitable for large-scale production. More importantly, various additives can be easily introduced in the solution step, resulting in significantly higher cell efficiency than other vapor deposition methods, and the solvents used are environmentally friendly and non-toxic. However, relying solely on additives in the second step is insufficient to completely control crystallization, affecting the stability of the perovskite film. Summary of the Invention

[0004] The main objective of this application is to provide a method for preparing a tandem solar cell, a tandem solar cell, and a photovoltaic module, so as to at least solve the problem of low stability of perovskite thin films in the prior art.

[0005] To achieve the above objectives, according to one aspect of this application, a method for preparing a stacked battery is provided, the method comprising:

[0006] A bottom battery is provided, and a composite layer is formed on the bottom battery;

[0007] A first transport layer is formed on the composite layer, and a framework layer is formed on the first transport layer by dual-source evaporation; wherein, the first evaporation source of the dual-source evaporation includes an inorganic cesium salt, and the second evaporation source includes an inorganic lead salt and an inorganic rubidium salt;

[0008] An organic salt is coated onto the framework layer to form a perovskite layer;

[0009] A second transport layer and an electrode are formed on the perovskite layer to obtain a tandem battery; wherein the charge carriers of the first transport layer and the second transport layer are different.

[0010] This application forms a framework layer through dual-source evaporation, allowing for better control of the ratio. By using rubidium and lead, it can have a positive effect on the crystallization and stress release of perovskite during the crystallization process. Some rubidium salts can combine with PbI2 decomposed on the surface to reduce ion migration and improve device stability.

[0011] Optionally, the step of forming a first transport layer on the composite layer, and forming a framework layer on the first transport layer by dual-source evaporation, includes:

[0012] The inorganic rubidium salt and the inorganic lead salt are mixed in a preset ratio and placed in a first container; wherein, the preset ratio includes a molar ratio of 1:100 to 10:100.

[0013] The inorganic cesium salt is placed in the second container, and the temperature is adjusted so that the evaporation rate of the first container and the second container is a preset rate to form a skeleton layer; the preset rate of the first container is 1 to 5, and the preset rate of the second container is 0.2 to 1 angstrom / s.

[0014] Optionally, coating the framework layer with an organic salt to form a perovskite layer includes:

[0015] An organic salt solution is formed, and a predetermined volume of the organic salt solution is applied to the skeleton layer; wherein the predetermined volume is 80 to 200 microliters.

[0016] The skeleton layer is spin-coated at a preset spin-coating speed and then annealed to form a perovskite layer.

[0017] Optionally, the inorganic rubidium salt includes rubidium chloride, the inorganic lead salt includes lead iodide, and the first container includes a first crucible; the step of mixing the inorganic rubidium salt and the inorganic lead salt in a preset ratio and placing them into the first container includes:

[0018] The rubidium chloride and lead iodide are mixed in a molar ratio of 1:100 and placed in the first crucible.

[0019] Optionally, forming a composite layer on the bottom battery includes:

[0020] A composite layer is formed on the bottom cell by magnetron sputtering; wherein the material of the composite layer includes at least one of indium tin oxide, indium zinc oxide, indium tungsten oxide and indium cobalt oxide, and the thickness of the composite layer is 5 to 30 nm.

[0021] Optionally, before forming the skeleton layer on the first transport layer by dual-source evaporation, the method further includes:

[0022] A first passivation layer is formed on the first transport layer by a first spin coating process and a first annealing process; wherein the rotation speed of the first spin coating process is 3000-5000 rpm, the annealing temperature of the first annealing process is 80 to 150°C, and the first annealing time is 10 to 20 min.

[0023] Optionally, forming a first transmission layer on the composite layer includes:

[0024] A first transport layer is formed on the composite layer by one of atomic layer deposition, inkjet printing, and coating processes; wherein the material of the first transport layer includes nickel oxide and helical triphenylamine-bridged biscarbazole, and the thickness of the first transport layer is 10 to 30 nm.

[0025] Optionally, a second transport layer is formed on the perovskite layer, comprising:

[0026] A second transport layer is formed on the perovskite layer by a vapor deposition process; wherein the material of the second transport layer includes C60, the thickness is 15 to 20 nm, and the evaporation rate is 0.2 to 0.3 Å / s.

[0027] To achieve the above objectives, according to another aspect of this application, a stacked battery is provided, comprising:

[0028] The bottom cell consists of a first transport layer, a perovskite layer, a second transport layer, and electrodes stacked sequentially.

[0029] The perovskite layer is formed by a first vapor source and a second vapor source. The first vapor source includes an inorganic cesium salt, and the second vapor source includes an inorganic lead salt and an inorganic rubidium salt. The charge carriers of the first transport layer and the second transport layer are different.

[0030] According to another aspect of this application, a photovoltaic module is provided, comprising a tandem cell prepared by the above-described method for preparing tandem cells.

[0031] By applying the technical solution of this application, the framework layer is formed by dual-source evaporation, which allows for better control of the ratio. Through rubidium and lead, it can have a positive effect on the crystallization and stress release of perovskite during the crystallization process. Some rubidium salts can combine with PbI2 decomposed on the surface to reduce ion migration and improve device stability. Attached Figure Description

[0032] 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:

[0033] Figure 1A schematic diagram of a vapor deposition process for a stacked battery provided in an embodiment of the related technology is shown.

[0034] Figure 2 A schematic diagram of a vapor deposition process for a stacked battery provided in an embodiment of this application is shown.

[0035] Figure 3 A schematic flowchart of a method for fabricating a solar cell according to an embodiment of this application is shown;

[0036] Figure 4 A schematic diagram of the structure of a battery provided according to an embodiment of this application is shown.

[0037] The above figures include the following reference numerals:

[0038] 100, HJT bottom cell; 200, composite layer; 300, hole transport layer; 301, hole modification layer; 400, perovskite light-absorbing layer; 500, passivation layer; 600, electron transport layer; 700, buffer layer; 800, transparent electrode layer; 901, positive electrode; 902, back electrode; 1000, antireflection layer; 11, framework layer in related technologies; 12, evaporation source CsBr in related technologies; 13, evaporation source PbI2 in related technologies; 21, framework layer of this application; 22, evaporation source CsBr of this application; 23, evaporation source PbI2+RbCl of this application. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0041] 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 data can be interchanged where appropriate for the embodiments of this application 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.

[0042] The photovoltaic industry is a key area of ​​the new energy system and an important component of clean energy. Improving efficiency and reducing costs are the core driving forces behind the continuous progress of solar cell technology. Metal halide perovskite materials possess advantages such as tunable bandgap, strong light absorption, and low manufacturing costs. Combining them with crystalline silicon, which can absorb long-wavelength light, to construct tandem solar cells is a major direction for breaking through existing efficiency bottlenecks. In recent years, perovskite / crystalline silicon tandem cells have received widespread attention, with their efficiency reaching 35%. This significantly improves the photoelectric conversion efficiency of the cells with almost no increase in cost, demonstrating outstanding research significance and broad application prospects.

[0043] Currently, the crystalline silicon substrates used in perovskite / crystalline silicon tandem solar cells have relatively small surface pyramid structures (less than 1 micrometer), which to some extent weakens the excellent light-trapping properties of industrial-grade textured crystalline silicon and increases additional processing costs. Therefore, conducting research on the high-performance fabrication and stability of tandem solar cells with larger textured structures (greater than 2 micrometers) for industrial-grade crystalline silicon substrates has become a key issue that urgently needs to be addressed to promote their low-cost industrialization.

[0044] Achieving high-quality conformal deposition of functional layers and perovskite light-absorbing layers on industrial-grade textured silicon is a major challenge, with the preparation of the perovskite layer being particularly crucial. Currently, the evaporation-solution method is widely used to achieve high-quality conformal growth. This method is a two-step preparation process, the key being the separate control of the formation of the inorganic framework and the intercalation of organic ions, optimizing the perovskite crystallization process through the combined action of physical and chemical means. Among various two-step methods, the evaporation-solution method has the greatest application potential. It retains the good uniformity and conformal properties of vapor deposition, and offers multiple options in the second step of organic salt solution coating, including spin coating and coating processes suitable for large-scale production. More importantly, various additives can be easily introduced in the solution step, resulting in significantly higher cell efficiency than other vapor deposition methods, and the solvents used are environmentally friendly and non-toxic. However, relying solely on additives in the second step is insufficient to completely control crystallization, as the framework layer deposited in the first step remains almost unchanged. How to control the composition and state of the deposited framework layer becomes a critical issue, as it affects the subsequent perovskite reaction and is crucial for the final film growth.

[0045] like Figure 1 As shown, the modification of the vapor-deposited framework layer 11 by related technologies is mainly at the composition level. For example, different inorganic Cs salts and Pb salts are co-evaporated, mainly including CsI / CsBr / CsCl and PbI2 / PbBr2 / PbCl2, etc. By combining different inorganic substances, two-source, three-source, or even four-source co-evaporation can be developed. Figure 1 The related technical embodiments shown employ a two-source evaporation process, namely, the evaporation source CsBr,12 and the evaporation source PbI2,13. Of course, related technologies also utilize inorganic pre-mixing and melting techniques to reduce the number of co-evaporation sources; for example, a certain proportion of PbI2 and PbBr2 can be mechanically mixed and preheated to form a solid solution for uniform evaporation.

[0046] In general, these technologies mainly focus on adjusting conventional components (Cs, I, Br, Cl, etc.) to alter the perovskite reaction, without exploring trace elements (such as Rb). Furthermore, these component modifications do not significantly alter the overall structure of the framework layer, and the phase composition of the framework layer remains insufficiently studied. To address this issue, this invention designs a novel vapor deposition strategy capable of comprehensively modifying the framework layer and subsequent perovskite formation through component control, crystallization stress release, and phase stability.

[0047] Reference Figure 2In this invention, during the evaporation step of perovskite preparation by evaporation-solution method, a certain proportion of RbCl is incorporated into PbI2 to form the evaporation source PbI2+RbCl,23 of this application. After thorough mechanical mixing, the mixture is placed in an evaporation source, namely the evaporation source CsBr,22 of this application, and co-evaporated with another single-component source CsBr to prepare the framework layer 21 of this application.

[0048] This invention provides a novel strategy for molten salt vapor deposition of inorganic framework layers, with the following main advantages:

[0049] a) Make the framework layer more "loose". By introducing RbCl and PbI2 pre-bonded, they can form a (PbI2)2RbCl structure with a lower XRD diffraction angle than PbI2 and a larger interplanar spacing, which opens up the dense PbI2 arrangement in the framework layer, which is conducive to the penetration and reaction of the second organic salt.

[0050] b) RbCl modulates lattice stress, improves crystallization, and enhances carrier transport performance. Rb, as an element that can partially enter the A-site of the perovskite lattice, can alleviate lattice distortion stress to a certain extent, while also refining grains and making perovskite grains flat; Cl, ​​as a common additive component, can improve the carrier lifetime of thin films.

[0051] c) RbCl combines with PbI2 to improve stability. The evaporation-solution method for preparing perovskites often requires high-temperature, humidity-controlled annealing (approximately 150°C). The perovskite surface easily decomposes to form PbI2, and excessive PbI2 accumulation hinders carrier transport and leads to stability issues. RbCl can combine with the decomposed PbI2 to form a (PbI2)2RbCl structure. Compared to PbI2, it has smaller ion migration channels and is less likely to adsorb nearby fatty acids (FAs) or iodine (I), thus creating vacancies. Based on this, the stability of the final film can be improved.

[0052] In summary, this strategy can improve the framework layer and the final perovskite film in multiple ways.

[0053] 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.

[0054] Figure 3 This is a schematic flowchart of a method for preparing a stacked battery according to an embodiment of this application. The method for preparing the stacked battery includes:

[0055] Step S100: Provide a bottom battery and form a composite layer on the bottom battery;

[0056] Step S200: A first transport layer is formed on the composite layer, and a framework layer is formed on the first transport layer by dual-source evaporation; wherein, the first evaporation source of the dual-source evaporation includes an inorganic cesium salt, and the second evaporation source includes an inorganic lead salt and an inorganic rubidium salt;

[0057] Step S300: An organic salt is coated onto the framework layer to form a perovskite layer;

[0058] In step S400, a second transport layer and an electrode are formed on the perovskite layer to obtain a stacked battery; wherein the charge carriers of the first transport layer and the second transport layer are different.

[0059] This application utilizes dual-source evaporation to form the framework layer, allowing for better control of the proportions. The use of rubidium and lead positively impacts the crystallization and stress release of the perovskite during the crystallization process. Furthermore, some rubidium salts can bind with surface-decomposed PbI2, reducing ion migration and improving device stability. Figure 4 As shown, the bottom cell in this application can be a heterojunction cell, i.e., an HJT bottom cell 100, which also includes an intrinsic n-layer and an intrinsic p-layer. A composite layer 200 is formed on the first surface of the bottom cell, which can be the surface close to the intrinsic n-layer. In this application, the first transport layer can be a hole transport layer 300, and the second transport layer can be an electron transport layer 600. The first transport layer is formed on the side of the composite layer away from the bottom cell, and a hole modification layer 301 is provided. A framework layer is formed on the side of the hole transport layer away from the composite layer by dual-source evaporation, thereby preparing a perovskite layer, i.e., a perovskite light-absorbing layer 400. In some embodiments, a passivation layer 500 is formed on the side of the perovskite layer away from the hole transport layer, an electron transport layer is formed on the side of the passivation layer away from the perovskite layer, a buffer layer 700 is formed on the side of the electron transport layer away from the passivation layer, a transparent electrode layer 800 is formed on the side of the buffer layer away from the electron transport layer, a positive electrode 901 is formed on the side of the transparent electrode layer away from the buffer layer, a back electrode 902 is formed on the second surface of the bottom cell, and an antireflection layer 1000 is formed on the side of the transparent electrode layer away from the buffer layer.

[0060] The tandem solar cell fabrication method of this embodiment involves forming a composite layer on a base cell, followed by depositing a framework layer on the composite layer using a dual-source evaporation technique. The second evaporation source contains a premixture of inorganic lead salt and inorganic rubidium salt. This strategy alters the crystal structure of the framework layer, promoting high-quality conformal growth of the perovskite layer on industrial-grade textured silicon. By introducing a mixture of RbCl and PbI2, a (PbI2)2RbCl structure is formed during the evaporation process. This structure has a larger interplanar spacing, making the framework layer more porous and facilitating the penetration and reaction of organic salts in the second step, thereby improving the perovskite crystallization process. Rb, as an element capable of partially entering the A-sites of the perovskite lattice, can combine with Cl to regulate lattice stress, refine grains, and improve the carrier transport performance of the perovskite film. During high-temperature annealing, RbCl can also combine with decomposed PbI2 to form a more stable compound, reducing the impact of surface decomposition products on carrier transport and improving device stability. After coating an organic salt onto the framework layer to form a perovskite layer, a second transport layer and electrodes are formed on the perovskite layer to obtain a tandem solar cell. The first and second transport layers transport different types of charge carriers, ensuring the high efficiency of the tandem solar cell. The technical solution provided by this invention solves the problem of poor deposition quality of the evaporated framework layer on textured crystalline silicon in existing technologies, while significantly improving the efficiency and stability of perovskite / crystalline silicon tandem solar cells, providing a reliable technical path for the industrial production of perovskite solar cells.

[0061] Optionally, the step of forming a first transport layer on the composite layer, and forming a framework layer on the first transport layer by dual-source evaporation, includes:

[0062] The inorganic rubidium salt and the inorganic lead salt are mixed in a preset ratio and placed in a first container; wherein, the preset ratio includes a molar ratio of 1:100 to 10:100.

[0063] The inorganic cesium salt is placed in the second container, and the temperature is adjusted so that the evaporation rate of the first container and the second container is a preset rate to form a skeleton layer; the preset rate of the first container is 1 to 5, and the preset rate of the second container is 0.2 to 1 angstrom / s.

[0064] Understandably, in the perovskite vapor deposition process, the framework layer is an incompletely reacted, porous intermediate layer composed of organohalide salts, deposited first in the two-stage vapor deposition process. The framework layer acts as a structural template, supplying reactants and controlling the reaction. Meanwhile, vapor deposition is a physical vapor deposition method where a container (which can be a crucible) containing material is heated in a high-vacuum chamber, causing it to sublimate or evaporate. This generates atomic or molecular vapor that moves to the desired deposition location on the solar cell, which in this application is the surface of the first transport layer. The vapor condenses on the lower-temperature surface of the first transport layer, forming a thin film. This application adjusts the temperatures of the first and second containers, thereby regulating their evaporation rates to form the framework layer on the surface of the first transport layer. In some embodiments, the ratio of the evaporation rate of the first container to the rate of the second container can be 5:1.

[0065] This application embodiment utilizes the pre-bonding of RbCl and PbI2 to form a (PbI2)2RbCl structure. This not only opens up the dense arrangement of PbI2, facilitating the penetration and reaction of organic salts in subsequent steps, but also refines the grains, adjusts lattice stress, and improves carrier transport performance by introducing Rb and Cl. Simultaneously, it improves film stability and reduces the negative impact of PbI2 decomposition. In subsequent organic salt coating and high-temperature annealing steps, the characteristics of this framework layer further promote the uniform growth of perovskite, thereby achieving the fabrication of high-performance perovskite-silicon tandem solar cells. Experimental results show that the cell using the RbCl and PbI2 mixed evaporation strategy outperforms the control group without RbCl, especially when the molar ratio of RbCl to PbI2 is 5:100, the open-circuit voltage, fill factor, and photoelectric conversion efficiency of the cell all reach optimal values. The implementation of this technical solution provides a new approach to improve the efficiency and stability of perovskite-silicon tandem solar cells. In other embodiments not shown, a similar effect can also be achieved by directly mixing the three inorganic salts for vapor deposition, which is also an alternative worth exploring.

[0066] Optionally, coating the framework layer with an organic salt to form a perovskite layer includes:

[0067] An organic salt solution is formed, and a predetermined volume of the organic salt solution is applied to the skeleton layer; wherein the predetermined volume is 80 to 200 microliters.

[0068] The skeleton layer is spin-coated at a preset spin-coating speed and then annealed to form a perovskite layer.

[0069] In this application, the preset spin-coating speed is 3500 rpm / 20 s to 4500 rpm / 20 s. An organic salt solution is applied to the framework layer at a preset volume and then spin-coated at the preset speed, followed by annealing, successfully preparing a high-quality perovskite layer. In this scheme, the preset volume is set to 80 to 200 microliters to ensure uniform coverage of the framework layer with the organic salt solution, promoting uniform perovskite growth. The preset spin-coating speed range of 3500 rpm / 20 s to 4500 rpm / 20 s effectively controls the thickness and density of the perovskite layer, thereby optimizing the photoelectric properties of the perovskite film. Introducing RbCl through mixed evaporation not only alters the structure of the framework layer, making it more porous and facilitating the penetration of organic salts, but also the synergistic effect of Rb and Cl alleviates stress within the perovskite lattice, improves crystal quality, enhances carrier transport efficiency, and reduces surface defects by combining with decomposed PbI2, thus enhancing device stability. The successful fabrication of the perovskite layer further promotes the improvement of the efficiency of perovskite-silicon tandem solar cells, demonstrating its application potential in the photovoltaic field. Of course, in other embodiments not mentioned in the accompanying drawings, a three-source co-evaporation method can also be used, i.e., simultaneously using CsBr, RbCl, and PbI2, to achieve similar results. However, the hybrid evaporation method provided in this embodiment offers more precise ratio control and a more economical evaporation source configuration. In subsequent large-scale production, this ability for fine control will greatly promote the commercialization of perovskite-silicon tandem solar cell technology. In other embodiments not shown in the accompanying drawings, the evaporation parameters and organic salt solution formulation can be adjusted according to specific needs to adapt to process requirements under different conditions, ensuring optimal performance of the perovskite layer.

[0070] Optionally, the inorganic rubidium salt includes rubidium chloride, the inorganic lead salt includes lead iodide, and the first container includes a first crucible; the step of mixing the inorganic rubidium salt and the inorganic lead salt in a preset ratio and placing them into the first container includes:

[0071] The rubidium chloride and lead iodide are mixed in a molar ratio of 1:100 and placed in the first crucible.

[0072] Optionally, forming a composite layer on the bottom battery includes:

[0073] A composite layer is formed on the bottom cell by magnetron sputtering; wherein the material of the composite layer includes at least one of indium tin oxide, indium zinc oxide, indium tungsten oxide and indium cobalt oxide, and the thickness of the composite layer is 5 to 30 nm.

[0074] In this embodiment, a composite layer is formed on the bottom cell by magnetron sputtering. The materials used include at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), and indium cobalt oxide (ICO), ensuring that the composite layer has high mobility and transmittance, and its thickness is precisely controlled between 5 and 30 nm. The introduction of this composite layer not only optimizes charge transport in the cell structure but also effectively improves the photoelectric performance of the entire device. The use of magnetron sputtering technology ensures the uniformity and good adhesion of the composite layer, providing a solid foundation for the subsequent deposition of functional layers. In the subsequent fabrication process, the presence of the composite layer can significantly improve the charge collection and transport efficiency, thereby improving the photoelectric conversion efficiency and stability of the perovskite-silicon tandem cell. Of course, in other embodiments not shown in the accompanying drawings, the composite layer can also be prepared by other deposition techniques such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). As long as the requirements for high mobility and transmittance are met, and the thickness is controlled within a preset range, similar technical effects can be achieved. The choice of different deposition technologies can be based on specific application scenarios and cost-effectiveness considerations to achieve the best battery performance.

[0075] Optionally, before forming the skeleton layer on the first transport layer by dual-source evaporation, the method further includes:

[0076] A first passivation layer is formed on the first transport layer by a first spin coating process and a first annealing process; wherein the rotation speed of the first spin coating process is 3000-5000 rpm, the annealing temperature of the first annealing process is 80 to 150°C, and the first annealing time is 10 to 20 min.

[0077] In this embodiment, the method further includes forming a first passivation layer on the first transport layer through a first spin coating process and a first annealing process. Specifically, the rotation speed of the first spin coating process is set between 3000 and 5000 rpm, while the temperature range of the first annealing process is 80 to 150°C, and the duration is set between 10 and 20 minutes. This design allows the hole passivation layer to more effectively improve interface characteristics and enhance the contact quality between the perovskite light-absorbing layer and the underlying layer, thereby promoting carrier transport efficiency. By optimizing the rotation speed of the first spin coating process and the conditions of the first annealing process, the thickness and microstructure of the first passivation layer can be finely controlled to ensure that it provides sufficient passivation effect to reduce non-radiative recombination while maintaining good charge extraction capability without introducing additional defects or obstacles. The first passivation layer treated in this way, in conjunction with the subsequent perovskite light-absorbing layer, can significantly improve the overall performance of the battery, including open-circuit voltage, short-circuit current density, and fill factor, thereby improving photoelectric conversion efficiency. In addition, this technical solution can also enhance the stability of the battery and extend its service life, laying a solid foundation for the large-scale industrial production of perovskite-silicon tandem batteries. Of course, in other embodiments not shown in the accompanying drawings of this application, the specific parameters of the first spin coating treatment and the first annealing treatment can also be adjusted to meet the needs of different material properties and manufacturing conditions, and further expand the application scope and optimization space of the present invention.

[0078] Optionally, forming a first transmission layer on the composite layer includes:

[0079] A first transport layer is formed on the composite layer by one of atomic layer deposition, inkjet printing, and coating processes; wherein the material of the first transport layer includes nickel oxide and helical triphenylamine-bridged biscarbazole, and the thickness of the first transport layer is 10 to 30 nm.

[0080] In this embodiment, the perovskite-silicon tandem solar cell was fabricated using an improved evaporation-solution process, notably in the preparation stage of the framework layer. A novel framework structure, (PbI2)2RbCl, was formed by pre-mixing RbCl and PbI2 in a specific ratio and placing them in the same evaporation source, along with a separate CsBr source for dual-source co-evaporation. This structure not only increases the interplanar spacing, making the framework layer more porous and facilitating the penetration and reaction of organic salts within it, but the addition of Rb and Cl also helps alleviate lattice stress, refine perovskite grains, improve carrier transport performance, and combine with surface-decomposed PbI2 to reduce ion migration and enhance device stability. In subsequent processes, a first transport layer was further prepared on top of the perovskite light-absorbing layer using atomic layer deposition, inkjet printing, or coating. This layer, composed of high-mobility inorganic or organic materials such as nickel oxide or Spiro-TTB, with a thickness controlled between 10 and 30 nm, effectively promoted charge transport within the device and improved overall electrical performance. This innovative process resulted in a tandem solar cell exhibiting superior performance, specifically with significant improvements in open-circuit voltage, fill factor, and photoelectric conversion efficiency. The cell performance was optimal, particularly when the RbCl to PbI₂ ratio was 5:100. This approach not only improves the quality and stability of the perovskite thin film but also enables low-cost, large-scale production. In other unexampled cases, adjusting the RbCl content, changing the deposition conditions, and using different materials and processes to prepare the first transport layer can all influence cell performance to some extent, but further experimental verification is needed to determine the optimal conditions. The preparation parameters of the first transport layer, such as the preset rate of 1 to 5 Å / s, preset speed of 0.2 to 1 Å / s, preset volume of 80 to 200 μL, and preset spin-coating speed of 3500 rpm / 20 s to 4500 rpm / 20 s, must be strictly controlled to ensure optimal device performance and stability. In other embodiments not shown in the accompanying drawings of this application, the modification of the framework layer can also be achieved by three-source co-distillation or direct mixing of three inorganic substances, but the effectiveness and cost-effectiveness of these alternatives still need to be evaluated.

[0081] Optionally, a second transport layer is formed on the perovskite layer, comprising:

[0082] A second transport layer is formed on the perovskite layer by a vapor deposition process; wherein the material of the second transport layer includes C60, the thickness is 15 to 20 nm, and the evaporation rate is 0.2 to 0.3 Å / s.

[0083] In this embodiment, the second transport layer is formed by covering the perovskite layer through a vapor deposition process. C60 is chosen as the material for the second transport layer, and its thickness is precisely controlled within the range of 15 to 20 nm, with the vapor deposition rate set to 0.2 to 0.3 Å / s. This design aims to optimize electron transport and enhance the performance of perovskite solar cells. C60 is widely used in the photovoltaic field due to its excellent electron transport characteristics. As an electron transport layer, it can effectively collect electrons generated in the perovskite layer, reduce carrier recombination, and improve the fill factor and photoelectric conversion efficiency of the cell. By precisely controlling the vapor deposition rate and layer thickness, it is ensured that the C60 layer is uniformly and densely deposited on the perovskite layer, avoiding defects and interface quality degradation caused by uneven layer thickness or improper vapor deposition rate, thereby ensuring effective electron transport. The precise control of the vapor deposition rate and layer thickness is also to match the properties of the perovskite layer, achieving optimal energy level docking and interface engineering, thereby improving the overall stability and efficiency of the device. In subsequent embodiments, the thickness and deposition rate of the second transport layer can be fine-tuned according to actual needs to adapt to different types of perovskite materials or cell structures, achieving optimal electron transport performance and device performance. The C60 layer formed by the deposition process not only enhances electron collection capabilities but also provides a good interface for the subsequent buffer layer, further improving the overall performance of the tandem solar cell. The optimized introduction of the second transport layer C60 signifies a deep understanding and control of the internal structure and carrier transport path of perovskite cells, laying the foundation for achieving high-efficiency and stable perovskite solar cells. In other embodiments not shown in the accompanying drawings, the deposition conditions of C60 can be flexibly adjusted to meet the performance requirements of specific application scenarios.

[0084] To achieve the above objectives, according to another aspect of this application, a stacked battery is provided, comprising:

[0085] The bottom cell consists of a first transport layer, a perovskite layer, a second transport layer, and electrodes stacked sequentially.

[0086] The perovskite layer is formed by a first vapor source and a second vapor source. The first vapor source includes an inorganic cesium salt, and the second vapor source includes an inorganic lead salt and an inorganic rubidium salt. The charge carriers of the first transport layer and the second transport layer are different.

[0087] According to another aspect of this application, a photovoltaic module is provided, comprising a tandem cell prepared by the above-described method for preparing tandem cells.

[0088] By applying the technical solution of this application, the framework layer is formed by dual-source evaporation, which allows for better control of the ratio. Through rubidium and lead, it can have a positive effect on the crystallization and stress release of perovskite during the crystallization process. Some rubidium salts can combine with PbI2 decomposed on the surface to reduce ion migration and improve device stability.

[0089] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the method for preparing the stacked battery of this application will be described in detail below with reference to specific embodiments.

[0090] The structure of perovskite-silicon tandem solar cell devices is as follows: Figure 4 As shown, from bottom to top, the layers are: HJT bottom cell 100, composite layer 200, hole transport layer 300, hole modification layer 301, perovskite light-absorbing layer 400, passivation layer 500, electron transport layer 600, buffer layer 700, transparent electrode layer 800, positive electrode 901, back electrode 902, and antireflection layer 1000.

[0091] Example 1:

[0092] Step 1: A patterned composite layer 200 is fabricated on the HJT bottom cell 100 by magnetron sputtering (PVD). The material of the composite layer can be transparent metal oxides such as ITO, IZO, IWO and ICO, which are required to have high mobility and transmittance, and a thickness of 5-30nm.

[0093] Step 2: Prepare a hole transport layer 300 on the composite layer 200. The hole transport layer can be prepared by PVD, CVD, atomic layer deposition, or inkjet printing, spraying, blade coating, slot coating, etc. The material of the hole transport layer is an inorganic material such as nickel oxide (NiOx) or an organic material such as Spiro-TTB. It is required to have high mobility and a thickness of 10-30 nm.

[0094] Step 3: Prepare a hole passivation layer on top of Step 2. The hole passivation layer material can be 2PACz or 4PACZ, with a concentration of 0.8-1 mg / mL. The hole passivation layer is a self-assembled monolayer. In this embodiment, a spin coating process is used to prepare the layer, with a rotation speed of 3000-5000 rpm, an annealing temperature of 80-120℃, and an annealing time of 10-15 min.

[0095] Step 4: The perovskite layer serves as the light-absorbing layer, with a film thickness ranging from 500-1000 nm. The two-step process involves first preparing a framework layer through vacuum thermal evaporation, and then coating the framework layer with an organic salt via a solution method to react and form the perovskite. The first step primarily involves evaporation, while the second step is completed using methods such as spin coating, blade coating, and slot coating. In this embodiment, the area is 2.5 x 2.5 cm. 2On the bottom cell, a dual-source evaporation method was used. 2.6 mg of RbCl and 1000 mg of PbI₂ (molar ratio 1:100) were thoroughly mechanically mixed and added to a crucible. In another crucible, 500 mg of CsBr was added. The evaporation rates were controlled by temperature adjustment to 4 Å / s and 0.8 Å / s (preset rates), depositing a 600 nm framework layer. The second step involved spin-coating an organic salt solution with the following formulation: 40 mg formamidinium hydroiodate (FAI), 12 mg methylamine bromide (MABr), and 12 mg methylamine chloride (MACl), dissolved in 1 mL of anhydrous ethanol. After complete dissolution, 100 μL (preset volume) was dropped onto the framework layer and dynamically spin-coated at 4000 rpm / 20 s (preset spin-coating speed). After cation coating, the layer was annealed on a 150°C hot plate for 15 min to complete perovskite grain growth.

[0096] Step 5: A passivation layer is prepared on the perovskite light-absorbing layer by solution method. The passivation molecules are EDAI2, etc. The spin coating rate is 3000 rpm and the annealing time is 10 mins.

[0097] Step 6: On the film layer described in Step 5, an electron transport layer 600 is deposited by vapor deposition; the electron transport layer material is C60, the thickness is 15-20 nm, and the evaporation rate is 0.2-0.3 Å / s;

[0098] Step 7: Prepare a buffer layer 700 on the electron transport layer by atomic deposition (ALD); the buffer layer material is tin dioxide (SnO2), and the film thickness is 20-30 nm;

[0099] Step 8: On the film layer of step 7, a patterned transparent electrode 800 is fabricated by magnetron sputtering (PVD); the transparent electrode material can be ITO or IZO, and the thickness is 80-120 nm.

[0100] Step 9-1: Deposit a positive electrode 901 on the transparent electrode; the positive electrode is a patterned metal electrode, and the material can be silver (Ag), copper (Cu), or aluminum (Al), with a thickness of 150-300 nm and an evaporation rate of 2-4 Å / s;

[0101] Step 9-2: After completing the above steps, deposit the back electrode 902 on the back of the HJT bottom cell; the back electrode is similar to the positive electrode, and the material can be silver (Ag), copper (Cu), or aluminum (Al), with a thickness of 150-300nm and an evaporation rate of 2-4Å / s.

[0102] Step 10: Prepare an antireflection layer on the positive electrode described in step 9-1. The antireflection layer is also prepared by vapor deposition. The material can be MgF2 or LiF, the thickness is 100-120 nm, the evaporation rate is 0.5-2 Å / s, and the refractive index n value is about 1.4.

[0103] Example 2:

[0104] The remaining process steps are the same as in Example 1, only requiring adjustment in step 4. Specifically:

[0105] Step 4: In this embodiment, the area is 2.5 x 2.5 cm. 2 On the bottom cell, a dual-source evaporation method was used. 13.1 mg of RbCl and 1000 mg of PbI2 (molar ratio 5:100) were thoroughly mechanically mixed and added to a crucible. Another crucible contained 500 mg of CsBr. The evaporation rates were controlled by temperature adjustment to 4 Å / s and 0.8 Å / s, respectively, to deposit a 600 nm framework layer. Subsequent organic salt formulations and spin-coating methods were the same as in Example 1.

[0106] Example 3:

[0107] The remaining process steps are the same as in Example 1, only requiring adjustment in step 4. Specifically:

[0108] Step 4: In this embodiment, the area is 2.5 x 2.5 cm. 2 On the bottom cell, a dual-source evaporation method was used. 26.2 mg of RbCl and 1000 mg of PbI2 (molar ratio 10:100) were thoroughly mechanically mixed and added to a crucible. Another crucible contained 500 mg of CsBr. The evaporation rates were controlled by temperature adjustment to 4 Å / s and 0.8 Å / s, respectively, to deposit a 600 nm framework layer. Subsequent organic salt formulations and spin-coating methods were the same as in Example 1.

[0109] Comparative Examples 1 and 2:

[0110] The remaining process steps are the same as in Example 1, only requiring adjustment in step 4. Specifically:

[0111] Step 4: In an area of ​​2.5 x 2.5 cm 2 On the bottom cell, a dual-source evaporation method was used. One crucible contained 1g of PbI2, and the other crucible contained 500mg of CsBr. By controlling the temperature separately, the evaporation rates were 4 Å / s and 0.8 Å / s, respectively, to prepare a 600nm framework layer. The second step was spin-coating with an organic salt solution, the formulation of which was: 40mg formamidinium hydroiodate (FAI), 12mg methylamine bromide (MABr), and 12mg methylamine chloride (MACl), dissolved in 1mL of anhydrous ethanol. After complete dissolution, 100 μL was dropped onto the framework layer and dynamically spin-coated at 4000rpm / 20s. Subsequently, the layer was placed on a 150℃ hot plate and annealed for 15min to complete perovskite grain growth.

[0112] The battery performance parameters are shown in Table 1 below.

[0113] Table 1

[0114]

[0115] Performance comparisons show that the introduction of RbCl significantly improves the open-circuit voltage and flyback distance (FF), but excessive RbCl content leads to lattice distortion, resulting in decreased performance and instability of the perovskite composition. In the examples, the optimal performance was achieved when the RbCl to PbI2 ratio was 5:100, yielding the highest open-circuit voltage and performance. It should be noted that the parameters involved in the preparation processes in the above examples and comparative examples are illustrative and not intended to limit the scope of this application.

[0116] The key to this invention is replacing the traditional single Pb deposition with a mixture of RbCl and PbI2. I2 Evaporation deposition allows for precise control of the content of RbCl in the framework layer, forming a (PbI2)2RbCl structure. During high-temperature annealing, this structure can transform into a photoactive perovskite phase. Fine control of the RbCl content enables Rb and Cl to have a positive effect on the crystallization and stress release of the perovskite during the crystallization process. Furthermore, some RbCl can combine with surface-decomposed PbI2 to reduce ion migration and improve device stability.

[0117] The core of this method lies in introducing RbCl into the inorganic framework layer during the vapor deposition process. This can be achieved through three-source co-evaporation (CsBr, RbCl, and PbI2), but this invention uses a mixture of RbCl and PbI2 for vapor deposition, which allows for better control of the ratio and reduces the number of evaporation sources, thus saving costs. Furthermore, the same effect can be achieved by directly mixing the three inorganic substances using a single evaporation source.

[0118] It should be noted that the above are merely illustrative examples and do not specifically limit the methods, steps, or execution logic provided in this application.

[0119] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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.

[0120] Furthermore, where the terms "first" and "second" appear, these terms are 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 with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0121] 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 based on the specific circumstances.

[0122] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0123] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0124] 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.

[0125] 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 patent application. 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.

[0126] The above description is merely a preferred embodiment of this application and is 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 stacked battery, characterized in that, The method for preparing the tandem battery includes: A bottom battery is provided, and a composite layer is formed on the bottom battery; A first transport layer is formed on the composite layer, and a framework layer is formed on the first transport layer by dual-source evaporation; wherein, the first evaporation source of the dual-source evaporation includes an inorganic cesium salt, and the second evaporation source includes an inorganic lead salt and an inorganic rubidium salt; An organic salt is coated onto the framework layer to form a perovskite layer; A second transport layer and an electrode are formed on the perovskite layer to obtain a tandem battery; wherein the charge carriers of the first transport layer and the second transport layer are different.

2. The method for preparing a tandem battery according to claim 1, characterized in that, The process of forming a first transport layer on the composite layer, and forming a framework layer on the first transport layer by dual-source evaporation, includes: The inorganic rubidium salt and the inorganic lead salt are mixed in a preset ratio and placed in a first container; wherein, the preset ratio includes a molar ratio of 1:100 to 10:

100. The inorganic cesium salt is placed in the second container, and the temperature is adjusted so that the evaporation rate of the first container and the second container is a preset rate to form a skeleton layer; the preset rate of the first container is 1 to 5, and the preset rate of the second container is 0.2 to 1 angstrom / s.

3. The method for preparing a stacked battery according to claim 1, characterized in that, The process of coating the framework layer with an organic salt to form a perovskite layer includes: An organic salt solution is formed, and a predetermined volume of the organic salt solution is applied to the skeleton layer; wherein the predetermined volume is 80 to 200 microliters. The skeleton layer is spin-coated at a preset spin-coating speed and then annealed to form a perovskite layer.

4. The method for preparing a stacked battery according to claim 2, characterized in that, The inorganic rubidium salt includes rubidium chloride, and the inorganic lead salt includes lead iodide. The first container includes a first crucible. The step of mixing the inorganic rubidium salt and the inorganic lead salt in a preset ratio and placing them into the first container includes: The rubidium chloride and lead iodide are mixed in a molar ratio of 1:100 and placed in the first crucible.

5. The method for preparing a stacked battery according to claim 1, characterized in that, The formation of the composite layer on the bottom battery includes: A composite layer is formed on the bottom cell by magnetron sputtering; wherein the material of the composite layer includes at least one of indium tin oxide, indium zinc oxide, indium tungsten oxide and indium cobalt oxide, and the thickness of the composite layer is 5 to 30 nm.

6. The method for preparing a tandem battery according to claim 1, characterized in that, Before forming the skeleton layer on the first transport layer by dual-source evaporation, the method further includes: A first passivation layer is formed on the first transport layer by a first spin coating process and a first annealing process; wherein the rotation speed of the first spin coating process is 3000-5000 rpm, the annealing temperature of the first annealing process is 80 to 150°C, and the duration of the first annealing is 10 to 20 minutes.

7. The method for preparing a cascaded battery according to claim 1, characterized in that, The formation of a first transmission layer on the composite layer includes: A first transport layer is formed on the composite layer by one of atomic layer deposition, inkjet printing, and coating processes; wherein the material of the first transport layer includes nickel oxide and helical triphenylamine-bridged biscarbazole, and the thickness of the first transport layer is 10 to 30 nm.

8. The method for preparing a tandem battery according to claim 1, characterized in that, A second transport layer is formed on the perovskite layer, comprising: A second transport layer is formed on the perovskite layer by a vapor deposition process; wherein the material of the second transport layer includes C60, the thickness of the second transport layer is 15 to 20 nm, and the evaporation rate of the vapor deposition is 0.2 to 0.3 Å / s.

9. A stacked battery, characterized in that, The stacked battery is prepared by the method for preparing a stacked battery as described in any one of claims 1 to 8; the stacked battery comprises a bottom cell, a first transport layer, a perovskite layer, a second transport layer, and an electrode stacked sequentially. The perovskite layer is formed by a plurality of vapor sources, including inorganic cesium salts, inorganic lead salts, and inorganic rubidium salts; the charge carriers of the first transport layer and the second transport layer are different.

10. A photovoltaic module, characterized in that, The photovoltaic module includes a tandem cell prepared by the method described in any one of claims 1 to 8.

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