A preparation method of a crystalline silicon-perovskite tandem cell and the crystalline silicon-perovskite tandem cell

Abstract

This application relates to the field of solar cell technology, specifically to a method for fabricating a crystalline silicon-perovskite tandem solar cell and the crystalline silicon-perovskite tandem solar cell itself. The method includes: forming a composite hole transport layer on the top surface of a transparent conductive tunneling layer of a crystalline silicon base cell by magnetron sputtering; the composite hole transport layer includes a first hole transport layer close to the transparent conductive tunneling layer and a second hole transport layer away from the transparent conductive tunneling layer; the transparent conductive tunneling layer, the first hole transport layer, and the second hole transport layer are formed in the same coating equipment; and a perovskite layer is formed on the top surface of the composite hole transport layer using inkjet printing. The method for fabricating a crystalline silicon-perovskite tandem solar cell provided by this application simplifies the process steps, reduces the complexity of the process, and ensures good performance of the cell.

Description

Technical Field

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

[0002] Perovskite / crystalline silicon tandem photovoltaic cells combine the broad-spectrum light absorption of perovskite with the stability and maturity of crystalline silicon. By combining two cells with different band gaps, the theoretical efficiency limit can be increased to over 45%, making it an important technical route for improving the photoelectric conversion efficiency of solar cells. At the same time, it is expected to achieve low-cost manufacturing on the basis of high efficiency, and is currently a hot research direction for promoting photovoltaic technology.

[0003] Currently, commonly used technologies for preparing perovskite solar cells include spin coating, coating, and deposition. The performance of perovskite solar cells largely depends on the quality of the perovskite thin film. Spin coating is simple to operate, produces uniform and continuous films with high crystallinity, but it is only suitable for small-area sample preparation, unsuitable for industrial production, and has low raw material utilization. Vacuum evaporation is used to prepare large-area perovskite solar cells, resulting in high film uniformity, improved efficiency and stability, but it requires a vacuum environment and a precision evaporation source, leading to high cost and energy consumption, which is not conducive to the industrialization of these cells. Coating produces relatively uniform films, but the process and equipment are complex. During the fabrication process, perovskite solar cells are prone to problems such as rapid degradation and efficiency decline during cell scaling due to the intrinsic instability of the material and its sensitivity to humidity, light, and thermal stress, limiting their widespread application in practical applications.

[0004] Therefore, a fabrication scheme for crystalline silicon-perovskite tandem solar cells is needed to simplify process conditions and reduce limitations in order to obtain higher-performance crystalline silicon-perovskite tandem solar cells. Summary of the Invention

[0005] In view of this, this application provides a method for preparing a crystalline silicon-perovskite tandem solar cell and a crystalline silicon-perovskite tandem solar cell, in order to solve the problem that it is difficult to balance the complexity of the process, the limitations of the conditions, and the good performance of the cell in the preparation process of the prior art.

[0006] In one aspect of this application, a method for fabricating a crystalline silicon-perovskite tandem solar cell is provided, comprising the following steps: forming a crystalline silicon solar cell as a bottom cell, forming a transparent conductive tunneling layer on the top surface of the crystalline silicon solar cell, and forming a perovskite solar cell as a top cell on the top surface of the transparent conductive tunneling layer; wherein, the step of forming the perovskite solar cell includes: forming a composite hole transport layer on the top surface of the transparent conductive tunneling layer by magnetron sputtering; the composite hole transport layer includes a first hole transport layer close to the transparent conductive tunneling layer and a second hole transport layer away from the transparent conductive tunneling layer; the doping concentration of the first hole transport layer is greater than the doping concentration of the second hole transport layer; the transmittance of the second hole transport layer to visible light is greater than the transmittance of the first hole transport layer to visible light; the hole mobility of the second hole transport layer is greater than the mobility of the first hole transport layer; the transparent conductive tunneling layer, the first hole transport layer, and the second hole transport layer are formed in the same coating equipment; and a perovskite layer is formed on the top surface of the composite hole transport layer using inkjet printing.

[0007] The method for fabricating a crystalline silicon-perovskite tandem solar cell provided in this application involves forming a first hole transport layer and a second hole transport layer with different transmittance and hole mobility under controlled conditions in the same coating equipment. A transparent conductive tunneling layer is also formed in the same coating equipment. The first hole transport layer has high transmittance and forms good interfacial contact with the transparent conductive tunneling layer. The second hole transport layer has better hole mobility and forms better energy level matching with the perovskite layer, reducing interfacial nonradiative recombination and minimizing energy loss to improve cell efficiency. The doping concentration of the first hole transport layer is higher than that of the second hole transport layer, resulting in a lower contact resistance with the transparent conductive tunneling layer and a higher degree of work function matching with the transparent conductive tunneling layer, thus achieving ohmic contact. The perovskite layer is prepared using inkjet printing technology to create a functional layer material with excellent crystal quality. The process is fast and can directly form patterned quantum well structures, which is beneficial for light absorption and utilization, while suppressing ion migration problems and significantly improving the stability of the perovskite material. It also allows for simultaneous printing with multiple inks, offering high flexibility. Inkjet printing is a non-contact process that can reduce the breakage rate of crystalline silicon bottom cells and is also beneficial for the fabrication and development of flexible tandem cells. The transparent conductive tunneling layer and the composite hole transport layer are formed in a single magnetron sputtering coating device under controlled conditions, eliminating the need to change equipment and simplifying the process. Since the composite hole transport layer is made of the same material, different processing conditions do not require equipment or channel changes, allowing for better utilization of equipment and simplified process steps, reducing process complexity. Therefore, the fabrication method for crystalline silicon-perovskite tandem cells provided in this application simplifies the process steps, reduces process complexity, and ensures good cell performance. Furthermore, because the transparent conductive tunneling layer is a film structure of the crystalline silicon bottom cell, the magnetron sputtering equipment used is from a crystalline silicon cell production line, and the composite hole transport layer is a structure of the perovskite top cell, using the same coating equipment as the transparent conductive tunneling layer without adding new equipment simplifies the process flow and saves costs.

[0008] In some embodiments of this application, the first hole transport layer and the second hole transport layer are formed in the same chamber using targets with different sputtering pressures, different gas ratios, and / or different doping concentrations.

[0009] In some embodiments of this application, the doping concentration of the target material used for sputtering the first hole transport layer is greater than the doping concentration of the target material used for sputtering the second hole transport layer; the coating thickness of the first hole transport layer is less than the coating thickness of the second hole transport layer.

[0010] In some embodiments of this application, the target used for sputtering the first hole transport layer is a first target, which is a Mg-doped NiO2 target; the target used for sputtering the second hole transport layer is a second target, which is a Mg-doped NiO2 target; wherein the Mg doping concentration of the first target is 3%~8%; the Mg doping concentration of the second target is 1%~5%; the coating thickness of the first hole transport layer is 5nm~20nm; and the coating thickness of the second hole transport layer is 10nm~30nm.

[0011] In some embodiments of this application, the chamber gas used for sputtering the first hole transport layer and the second hole transport layer is a mixture of O2 and Ar, wherein the O2 content of the mixture used for sputtering the first hole transport layer is... 2 / The Ar ratio is less than the O2 / Ar ratio of the mixed gas in the sputtered second hole transport layer.

[0012] In some embodiments of this application, the transmittance of the first hole transport layer to visible light is greater than or equal to 85%; the transmittance of the second hole transport layer to visible light is greater than or equal to 85%; and the hole mobility of the first hole transport layer is greater than or equal to 10. - 4 cm 2 / (V·s); the hole mobility of the second hole transport layer is greater than or equal to 10. -4 cm 2 / (V·s).

[0013] In some embodiments of this application, after sputtering to form a first hole transport layer, the first hole transport layer is treated with plasma, and then sputtered to form a second hole transport layer. After sputtering to form the second hole transport layer, the second hole transport layer is treated with plasma.

[0014] In some embodiments of this application, during the inkjet printing of the perovskite layer, various perovskite ink ratios and various inkjet conditions are used to form a composite perovskite layer. The light transmittance of the part closer to the top battery is greater than that of the part closer to the bottom battery.

[0015] In some embodiments of this application, the method for fabricating a crystalline silicon-perovskite tandem solar cell further includes: forming an electron transport layer on the perovskite layer; forming a transparent conductive window layer on the electron transport layer; and forming a metal conductive electrode on the transparent conductive window layer.

[0016] This application also provides a crystalline silicon-perovskite tandem solar cell, formed using the fabrication method provided in this application, comprising: a crystalline silicon solar cell as the bottom cell, a perovskite solar cell as the top cell, the crystalline silicon solar cell and the perovskite solar cell being connected by a transparent conductive tunneling layer; the hole transport layer of the perovskite solar cell includes a first hole transport layer formed by magnetron sputtering and a second hole transport layer formed by magnetron sputtering in the same coating equipment; and the hole transport layer and the transparent conductive tunneling layer are also formed by magnetron sputtering in the same coating equipment; the doping concentration of the first hole transport layer is greater than the doping concentration of the second hole transport layer; the transmittance of the second hole transport layer to visible light is greater than the transmittance of the first hole transport layer to visible light; the hole mobility of the second hole transport layer is greater than the mobility of the first hole transport layer; the perovskite layer of the perovskite solar cell is formed on the second hole transport layer by inkjet printing.

[0017] The crystalline silicon-perovskite tandem solar cell provided in this application is formed using the fabrication method described herein. In the same coating equipment, by controlling different conditions, a first hole transport layer and a second hole transport layer with different transmittance and hole mobility are formed. The first hole transport layer has high transmittance and forms good interfacial contact with the transparent conductive tunneling layer. The second hole transport layer has better hole mobility and forms better energy level matching with the perovskite layer, reducing interfacial non-radiative recombination and minimizing energy loss, thereby improving cell efficiency. The perovskite layer is prepared using inkjet printing technology to produce a functional layer material with excellent crystal quality. The process is fast and can directly form patterned quantum well structures, which is beneficial for light absorption and utilization, while suppressing ion migration problems and significantly improving the stability of the perovskite material. It also allows for simultaneous printing with multiple inks, offering high flexibility. Inkjet printing is a non-contact process, which can reduce the fragmentation rate of the crystalline silicon base cell and is also beneficial for the fabrication and development of flexible tandem solar cells. The transparent conductive tunneling layer and the composite hole transport layer are formed in a single magnetron sputtering coating apparatus under controlled conditions, eliminating the need to change equipment and simplifying the process. Since the composite hole transport layer is made of the same material, different processing conditions do not require equipment or channel changes, allowing for better utilization of equipment and reducing process complexity. Therefore, the method for fabricating crystalline silicon-perovskite tandem solar cells provided in this application simplifies the process, reduces complexity, and ensures good cell performance. Furthermore, because the transparent conductive tunneling layer is a film structure of the crystalline silicon bottom cell, the magnetron sputtering equipment used is from a crystalline silicon solar cell production line. The composite hole transport layer is a structure of the perovskite top cell, and the same coating equipment is used for both, eliminating the need for additional equipment and simplifying the process flow, thus saving costs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart illustrating a method for fabricating a crystalline silicon-perovskite tandem solar cell according to an embodiment of this application. Figure 2 This is a schematic diagram of the structure of a crystalline silicon-perovskite tandem solar cell prepared by a method according to an embodiment of this application. Figure 3 This is a schematic diagram of the structure of a crystalline silicon-perovskite tandem solar cell prepared by a method according to an embodiment of this application, from another angle. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Example 1 refer to Figures 1-3 This embodiment provides a method for preparing a crystalline silicon-perovskite tandem solar cell, including the following steps: A crystalline silicon solar cell 100 is formed as the bottom cell, a transparent conductive tunneling layer 200 is formed on the top surface of the crystalline silicon solar cell 100, and a perovskite solar cell is formed on the top surface of the transparent conductive tunneling layer 200 as the top cell. The steps for forming a perovskite solar cell include: forming a composite hole transport layer 300 on the top surface of the transparent conductive tunneling layer 200 by magnetron sputtering; The composite hole transport layer 300 includes a first hole transport layer 301 close to the transparent conductive tunneling layer 200 and a second hole transport layer 302 far from the transparent conductive tunneling layer 200. The doping concentration of the first hole transport layer 301 is greater than that of the second hole transport layer 302. The transmittance of the second hole transport layer 302 to visible light is greater than that of the first hole transport layer 301 to visible light; the hole mobility of the second hole transport layer 302 is greater than that of the first hole transport layer 301. The transparent conductive tunneling layer 200, the first hole transport layer 301, and the second hole transport layer 302 are formed in the same coating equipment. A perovskite layer 400 is formed on the top surface of the composite hole transport layer 300 using inkjet printing.

[0022] The method for fabricating crystalline silicon-perovskite tandem solar cells provided in this application involves forming a first hole transport layer 301 and a second hole transport layer 302 with different transmittance and hole mobility under different conditions in the same coating equipment. A transparent conductive tunneling layer 200 is also formed in the same coating equipment. The first hole transport layer 301 has high transmittance and forms a good interfacial contact with the transparent conductive tunneling layer 200. The second hole transport layer 302 has a better hole mobility and forms a better energy level match with the perovskite layer, reducing nonradiative recombination at the interface and minimizing energy loss, thereby improving the cell efficiency. The doping concentration of the first hole transport layer 301 is higher than that of the second hole transport layer 302, resulting in a lower contact resistance with the transparent conductive tunneling layer 200 and a higher degree of work function matching with the transparent conductive tunneling layer 200, thus achieving ohmic contact. The perovskite layer 400 is prepared using inkjet printing technology to create a functional layer material with excellent crystal quality. The process speed is fast, and it can directly form patterned quantum well structures, which is beneficial for light absorption and utilization, while suppressing ion migration problems and significantly improving the stability of perovskite materials. It can also print with multiple inks simultaneously, offering high flexibility. Inkjet printing is a non-contact process, which can reduce the fragmentation rate of crystalline silicon bottom cells and is also beneficial for the fabrication and development of flexible tandem cells. The composite hole transport layer is formed in a magnetron sputtering coating device by controlling different conditions, without the need to change equipment, simplifying the process steps. Since the composite hole transport layer is essentially the same material, different process conditions do not require changing equipment or condition channels, allowing for better utilization of equipment to simplify process steps and reduce process complexity. Therefore, the fabrication method of the crystalline silicon-perovskite tandem solar cell provided in this application simplifies the process steps, reduces the complexity of the process, and ensures good performance of the cell. Furthermore, since the transparent conductive tunneling layer 200 is a film structure of the crystalline silicon bottom cell, the magnetron sputtering equipment used is the same as that used in crystalline silicon cell production lines. The composite hole transport layer 300 is a structure of the perovskite top cell, and the same coating equipment as the transparent conductive tunneling layer is used without the need for additional equipment, which simplifies the process and saves costs.

[0023] Furthermore, in some embodiments of this application, the first hole transport layer 301 and the second hole transport layer 302 are formed in the same chamber using targets with different sputtering pressures, different gas ratios, and / or different doping concentrations. For example, a gas isolation region is provided, forming a first region and a second region separated by an isolation gas in a chamber, and the first hole transport layer 301 and the second hole transport layer 302 are formed in the first region and the second region respectively using targets with different sputtering pressures, different gas ratios, and / or different doping concentrations.

[0024] In some embodiments of this application, the doping concentration of the target material used for sputtering the first hole transport layer 301 is greater than the doping concentration of the target material used for sputtering the second hole transport layer 302; the coating thickness of the first hole transport layer 301 is less than the coating thickness of the second hole transport layer 302.

[0025] Furthermore, in some embodiments of this application, the target material used for sputtering the first hole transport layer 301 is a first target material, which is a Mg-doped NiO2 target material; the target material used for sputtering the second hole transport layer 302 is a second target material, which is a Mg-doped NiO2 target material; wherein the Mg doping concentration of the first target material is 3%~8%; the Mg doping concentration of the second target material is 1%~5%; the coating thickness of the first hole transport layer 301 is 5nm~20nm; and the coating thickness of the second hole transport layer 302 is 10nm~30nm.

[0026] Furthermore, in some embodiments of this application, the chamber gas used for sputtering the first hole transport layer 301 and the second hole transport layer 302 is a mixture of O2 and Ar, wherein the O2 content of the mixture used for sputtering the first hole transport layer 301 is higher than that of Ar. 2 / The Ar ratio is less than the O2 / Ar ratio of the mixed gas sputtered into the second hole transport layer 302.

[0027] Furthermore, in some embodiments of this application, The first hole transport layer 301 has a transmittance of 85% or more for visible light; The second hole transport layer 302 has a transmittance of 85% or more for visible light; The hole mobility of the first hole transport layer 301 is greater than or equal to 10. -4 cm 2 / (V·s); The hole mobility of the second hole transport layer 302 is greater than or equal to 10. -4 cm 2 / (V·s).

[0028] Furthermore, in some embodiments of this application, after sputtering to form the first hole transport layer 301, the first hole transport layer 301 is treated with plasma, and then sputtered to form the second hole transport layer 302. After sputtering to form the second hole transport layer 302, the second hole transport layer 302 is treated with plasma.

[0029] Magnetron sputtering equipment typically includes a plasma treatment function. Applying plasma treatment after sputtering can improve interfacial adhesion or film wettability, thereby enhancing battery performance. Using the built-in plasma function of the sputtering equipment eliminates the need to replace the equipment, saving process steps.

[0030] Furthermore, in some embodiments of this application, during the inkjet printing of the perovskite layer 400, various perovskite ink ratios and various inkjet conditions are used to form a composite perovskite layer. The light transmittance of the part closer to the top battery is greater than that of the part closer to the bottom battery.

[0031] Furthermore, in some embodiments of this application, the method for fabricating a crystalline silicon-perovskite tandem solar cell further includes: forming an electron transport layer 500 on the perovskite layer; forming a transparent conductive window layer 600 on the electron transport layer 500; and forming a metal conductive electrode 700 on the transparent conductive window layer.

[0032] A specific implementation process is as follows: Fabrication of crystalline silicon heterojunction solar cells as bottom cells The silicon wafer raw material is cleaned and texturized, including double-sided texturing or single-sided texturing and polishing. The textured surface feature size is 0.1μm to 2μm. A composite double-sided amorphous intrinsic passivation layer and a composite microcrystalline p / n doped layer are deposited using PECVD. The intrinsic passivation layer thickness is 5nm to 7nm, and the composite microcrystalline p / n doped layer thickness is 20nm. A double-sided composite high-mobility transparent conductive film (TCO) is deposited using PVD. The main materials include indium oxide, tin oxide, and zinc oxide, and the doping elements include Sn, Ga, Al, Cr, Ti, Ce, and F. The back-side TCO thickness is 50nm to 100nm; the front-side TCO thickness is 5nm to 30nm, serving as a transparent conductive tunneling layer 200.

[0033] A hole transport layer is formed on the transparent conductive tunneling layer. A hole transport layer, such as NiO, is deposited using a PVD device on the transparent conductive tunneling layer 200. x MoO x TiOx, WO xA gas isolation zone is set between the first and second target sites in the chamber to ensure that the sputtering growth atmospheres of different material films do not contaminate each other. The hole transport layer 300 is a composite structure, obtained by adjusting different PVD coating process parameters or using targets with different material ratios. The first hole transport layer 301 uses a high-transmittance target with a coating thickness of 5nm to 20nm; the second hole transport layer 302 uses a high-mobility target. By adjusting process parameters such as PVD sputtering pressure and gas ratio, a transport layer film with high hole mobility matching the energy level of the perovskite material is obtained, with a film thickness of 10nm to 30nm. In one specific embodiment, the target material used for sputtering the first hole transport layer 301 is a first target material, which is a Mg-doped NiO2 target material; the target material used for sputtering the second hole transport layer 302 is a second target material, which is a Mg-doped NiO2 target material; wherein the Mg doping concentration of the first target material is 3%~8%; and the Mg doping concentration of the second target material is 1%~5%.

[0034] The sputtering formation process of the first hole transport layer 301 and the second hole transport layer 302 is completed in the same coating equipment as the formation process of the transparent conductive tunneling layer 200.

[0035] Perovskite layers were fabricated on composite hole transport layers using inkjet printing technology. The perovskite material has an ABX3 structure, where A is a positively charged organic, inorganic, or organic-inorganic mixture, such as one or more of methylamine, formamidinium, and Cs; B is a small-molecule cationic material, such as one or a combination of lead (Pb) and tin (Sn); and X is a halogen material, such as one or a combination of Cl, Br, and I. The thickness ranges from 300 nm to 1200 nm. The optical band gap and band structure of the perovskite can be altered by adjusting the proportions of components A, B, or X.

[0036] Inkjet printing systems include: Sample transfer platform: It carries and transfers battery cells, and has planar movement and lifting functions. It can be heated to 250℃.

[0037] Printhead: Prints ink onto the substrate either on the entire surface or in a specific pattern. By selecting the printhead resolution and adjusting the pulse voltage and frequency, the printing accuracy and film thickness can be controlled.

[0038] Ink supply system: Provides a stable source of material for the printing process and has heating and heat preservation functions.

[0039] Control system: It can control the movement and temperature of the stage, detect positioning, and control the movement and temperature of the print head.

[0040] Ink made from perovskite material is loaded into the ink supply system, and the solar cell intermediate to be printed is conveyed to a stage with a certain temperature. The printhead moves above the silicon wafer, is optically positioned, and ink droplets are ejected under the drive of an electrical signal, forming a perovskite thin film on the composite hole transport layer 300 of the intermediate. By adjusting parameters such as pulse voltage and frequency, a film layer with a specific pattern and thickness can be obtained. The silicon wafer is then conveyed to a curing oven for heat curing or light curing at a curing temperature of 100-200°C, forming a uniform perovskite photoelectric conversion layer (i.e., perovskite layer 400) with excellent crystallinity. By installing multiple printheads, adjusting printing parameters, and using perovskite inks with different component ratios, multiple components can be printed simultaneously or composite films can be formed, achieving electrical optimization of interfacial contact performance and optical formation of a composite structure with gradient band gap and gradient refractive index, thus facilitating higher cell conversion efficiency.

[0041] In this embodiment, a first ink and a second ink containing perovskite are respectively loaded into the ink supply system. First, the first ink is printed on the hole transport layer and cured at 80°C for 2 minutes to form a first perovskite layer with an absorption bandwidth of 1.5 eV. Then, the second ink is printed on the first perovskite layer and cured at 100°C for 2 minutes to form a second perovskite layer with an absorption bandwidth of 2.5 eV and a total thickness of 500 nm to 600 nm.

[0042] Fabrication of electron transport layer 500 and passivation layer Electron transport layer materials include C 60 SnO x TiO x The thickness ranges from 5 nm to 50 nm, and the fabrication process can include ALD, vapor deposition, coating, etc. 60 It is a highly efficient electron transport material that promotes electron migration from the perovskite layer to the electrode, reducing non-radiative recombination losses; SnO x As an electron transport layer 500 or a buffer layer, by adjusting SnO x The concentration of oxygen vacancies in the layer can reduce the band shift between the conduction band and the perovskite layer, reduce carrier recombination losses, optimize the interface, and improve charge collection and transport efficiency.

[0043] Fabrication of transparent conductive window layer A transparent conductive window layer 600 is fabricated using magnetron sputtering or RPD processes. Materials include indium oxide-based, zinc oxide-based, and tin oxide-based materials, with doping elements including Sn, Ga, Al, Cr, Ti, Ce, and F. The thickness ranges from 30 nm to 100 nm.

[0044] Preparation of metal conductive electrodes Metal conductive electrodes 700 are fabricated using screen printing, electroplating, or PVD processes. Electrode materials include metals or alloys such as Ag, AgCu, Cu, CuSn, and Sn. The grid lines fabricated using screen printing and electroplating have a width of 5μm to 40μm and a height of 5μm to 20μm; the metal thin films deposited using electroplating, evaporation, or magnetron sputtering processes have a thickness of 50nm to 200nm.

[0045] Example 2 This embodiment provides a crystalline silicon-perovskite tandem solar cell, formed using the fabrication method for crystalline silicon-perovskite tandem solar cells provided in this application, with reference to... Figure 2 and Figure 3 ,include: The crystalline silicon solar cell 100 serves as the bottom cell, and the perovskite solar cell serves as the top cell. The crystalline silicon solar cell 100 and the perovskite solar cell are connected by a transparent conductive tunneling layer 200. The hole transport layer of the perovskite solar cell includes a first hole transport layer 301 formed by magnetron sputtering and a second hole transport layer 302 formed by magnetron sputtering in the same coating equipment; and the hole transport layer and the transparent conductive tunneling layer 200 are also formed by magnetron sputtering in the same coating equipment. The doping concentration of the first hole transport layer 301 is greater than that of the second hole transport layer 302. The transmittance of the first hole transport layer 301 to visible light is greater than that of the second hole transport layer 302 to visible light. The hole mobility of the second hole transport layer 302 is greater than that of the first hole transport layer 301. The perovskite layer of the perovskite solar cell is formed on the second hole transport layer 302 by inkjet printing.

[0046] The crystalline silicon-perovskite tandem solar cell provided in this application is formed using the fabrication method described herein. In the same coating equipment, by controlling different conditions, a first hole transport layer 301 and a second hole transport layer 302 with different transmittance and hole mobility are formed. The first hole transport layer 301 has high transmittance and forms good interfacial contact with the transparent conductive tunneling layer. The second hole transport layer 302 has better hole mobility and forms better energy level matching with the perovskite layer, reducing interfacial non-radiative recombination and minimizing energy loss, thereby improving cell efficiency. The perovskite layer is prepared using inkjet printing technology to produce a functional layer material with excellent crystal quality. The process is fast and can directly form patterned quantum well structures, which is beneficial for light absorption and utilization, while suppressing ion migration problems and significantly improving the stability of the perovskite material. It also allows for simultaneous printing with multiple inks, offering high flexibility. Inkjet printing is a non-contact process, which can reduce the fragmentation rate of the crystalline silicon base cell and is also beneficial for the fabrication and development of flexible tandem solar cells. The transparent conductive tunneling layer 200 and the composite hole transport layer are formed in a single magnetron sputtering coating apparatus under controlled conditions, eliminating the need to change equipment and simplifying the process. Since the composite hole transport layer is made of the same material, different processing conditions do not require equipment or channel changes, allowing for better utilization of equipment and reducing process complexity. Therefore, the method for fabricating crystalline silicon-perovskite tandem solar cells provided in this application simplifies the process, reduces complexity, and ensures good cell performance. Furthermore, because the transparent conductive tunneling layer 200 is a film structure of the crystalline silicon bottom cell, the magnetron sputtering equipment used is from a crystalline silicon solar cell production line. The composite hole transport layer is a structure of the perovskite top cell, and the same coating equipment is used for both, eliminating the need for additional equipment, which simplifies the process and saves costs.

[0047] In a specific embodiment: The textured surface feature size of crystalline silicon solar cells is 0.8 μm to 1.0 μm. The intrinsic passivation layer thickness is 5nm~7nm; The thickness of the composite microcrystalline p / n doped layer is 20 nm; The thickness of the transparent conductive layer on the back is 95nm; The front transparent conductive layer is 15nm thick and serves as a transparent conductive tunneling layer. The first hole transport layer 301 has a thickness of 15nm, and the target material used is a NiO2 target with a Mg doping concentration of 1%~5%. The second hole transport layer is 302 degrees thick and 10 nm thick. The target material used is a NiO2 target with a Mg doping concentration of 3%~8%. The perovskite layer 400 includes a first perovskite layer formed using a first ink and a second perovskite layer formed using a second ink; the first perovskite layer has an absorption bandwidth of 1.5 eV, and the second perovskite layer has an absorption bandwidth of 2.5 eV; the total thickness is 500 nm to 600 nm.

[0048] Electron transport layer 500 is a C60 electron transport layer with a thickness of 15nm; The thickness of the transparent conductive window layer 600 is 100 nm; The grid line electrode, i.e. the metal conductive electrode 700, is an Ag electrode with a width of 20 μm and a height of 12 μm.

[0049] The solutions of this application have been disclosed above through embodiments. Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A method for fabricating a crystalline silicon-perovskite tandem solar cell, characterized in that, Includes the following steps: A crystalline silicon solar cell is formed as the bottom cell, a transparent conductive tunneling layer is formed on the top surface of the crystalline silicon solar cell, and a perovskite solar cell is formed on the top surface of the transparent conductive tunneling layer as the top cell. The steps involved in forming a perovskite solar cell include: A composite hole transport layer is formed on the top surface of the transparent conductive tunneling layer by magnetron sputtering; the composite hole transport layer includes a first hole transport layer close to the transparent conductive tunneling layer and a second hole transport layer away from the transparent conductive tunneling layer. The doping concentration of the first hole transport layer is greater than the doping concentration of the second hole transport layer; The transmittance of the second hole transport layer to visible light is greater than that of the first hole transport layer to visible light. The hole mobility of the second hole transport layer is greater than that of the first hole transport layer; The transparent conductive tunneling layer is formed in the same coating equipment as the first hole transport layer and the second hole transport layer; A perovskite layer is formed on the top surface of the composite hole transport layer using inkjet printing.

2. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 1, characterized in that, The first hole transport layer and the second hole transport layer are formed in the same chamber using targets with different sputtering pressures, different gas ratios, and / or different doping concentrations.

3. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 2, characterized in that, The doping concentration of the target material used for sputtering the first hole transport layer is greater than the doping concentration of the target material used for sputtering the second hole transport layer; The coating thickness of the first hole transport layer is less than that of the second hole transport layer.

4. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 3, characterized in that, The target material used for sputtering the first hole transport layer is a first target material, which is a Mg-doped NiO2 target material; The target used for sputtering the second hole transport layer is a second target, which is a Mg-doped NiO2 target; The Mg doping concentration of the first target is 3% to 8%; the Mg doping concentration of the second target is 1% to 5%. The coating thickness of the first hole transport layer is 5nm~20nm; The coating thickness of the second hole transport layer is 10nm~30nm.

5. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 1, characterized in that, The chamber gas used for sputtering the first hole transport layer and the second hole transport layer is a mixture of O2 and Ar, wherein the O2 / Ar ratio of the mixture used for sputtering the first hole transport layer is less than the O2 / Ar ratio of the mixture used for sputtering the second hole transport layer.

6. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 1, characterized in that, The first hole transport layer has a transmittance of visible light greater than or equal to 85%; The second hole transport layer has a transmittance of 85% or more for visible light; The hole mobility of the first hole transport layer is greater than or equal to 10. -4 cm 2 / (V·s); The hole mobility of the second hole transport layer is greater than or equal to 10. -4 cm 2 / (V·s).

7. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 2, characterized in that, After sputtering to form the first hole transport layer, the first hole transport layer is treated with plasma, and then sputtered to form the second hole transport layer. After the second hole transport layer is formed by sputtering, the second hole transport layer is treated with plasma.

8. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 2, characterized in that, During the inkjet printing of the perovskite layer, various perovskite ink ratios and various inkjet conditions are used to form a composite perovskite layer. The light transmittance of the portion closer to the top battery is greater than that of the portion closer to the bottom battery.

9. The method for preparing a crystalline silicon-perovskite tandem solar cell according to claim 2, characterized in that, Also includes: An electron transport layer is formed on the perovskite layer; A transparent conductive window layer is formed on the electron transport layer; Metal conductive electrodes are formed on the transparent conductive window layer.

10. A crystalline silicon-perovskite tandem solar cell, characterized in that, Formed using the fabrication method of any one of claims 1-9, comprising: A crystalline silicon solar cell serves as the bottom cell, and a perovskite solar cell serves as the top cell. The crystalline silicon solar cell and the perovskite solar cell are connected by a transparent conductive tunneling layer. The hole transport layer of the perovskite solar cell includes a first hole transport layer formed by magnetron sputtering and a second hole transport layer formed by magnetron sputtering in the same coating equipment; and the hole transport layer and the transparent conductive tunneling layer are also formed by magnetron sputtering in the same coating equipment. The doping concentration of the first hole transport layer is greater than the doping concentration of the second hole transport layer; The transmittance of the second hole transport layer to visible light is greater than that of the first hole transport layer to visible light. The hole mobility of the second hole transport layer is greater than that of the first hole transport layer; The perovskite layer of the perovskite solar cell is formed on the second hole transport layer by inkjet printing.

Images