Perovskite / crystalline silicon laminated solar cell and preparation method thereof

Abstract

The invention provides a perovskite / crystalline silicon laminated solar cell and a preparation method thereof. The cell comprises a crystalline silicon bottom cell and a perovskite top cell, the perovskite top cell comprises a transparent oxide conductive layer, a hole transport layer, a perovskite active material layer, an electron transport layer and a metal electrode layer which are sequentially stacked, and the transparent oxide conductive layer is in contact with the crystalline silicon bottom cell. The perovskite active material layer comprises a perovskite active material and an additive, and the additive has a chemical structure as shown in a formula (I). Carbonyl groups in the additive can coordinate with metal cations in a perovskite active material, sulfur atoms in a thiazole structure can assist in coordination, and halogen atoms can form hydrogen bonds with organic cations in the perovskite active material, so that the passivation effect of the additive is enhanced, the defect density is remarkably reduced, and the service life of carriers is prolonged; therefore, the photoelectric conversion efficiency and the long-term stability of the perovskite / crystalline silicon solar cell can be improved. (I).

Description

Technical Field

[0001] This invention relates to the field of tandem solar cell fabrication technology, and more specifically, to a perovskite / crystalline silicon tandem solar cell and its fabrication method. Background Technology

[0002] Organic-inorganic metal halide perovskites have been extensively studied due to their superior photoelectric properties, such as high absorption coefficient, low exciton binding energy, long carrier lifetime, and tunable bandgap. Over the past decade, the photoelectric conversion efficiency (PCE) of perovskite solar cells has achieved rapid growth from 3.8% to 26%, and tandem solar cells using perovskites as top cells have also attracted considerable attention.

[0003] However, the inherent limitations of polycrystalline growth and the presence of numerous surface defects are the main challenges currently facing perovskite research. These defects reduce the efficiency of carrier extraction and transport. Simultaneously, external environmental factors such as light and humidity can adversely affect the device, accelerating degradation at defect sites and thus impacting device stability. Furthermore, residual lead iodide at the interface can become a catalytic site for perovskite decomposition. Under continuous photothermal effects, lead iodide decomposes to produce metallic lead, which becomes a non-radiative recombination center, significantly reducing the open-circuit voltage of the cell and consequently decreasing device efficiency and stability.

[0004] To overcome these technical obstacles, researchers have tried various methods, such as introducing different additives to improve the quality of perovskite films, employing special processes to reduce grain boundary defects, and designing more complex stacked structures to enhance the overall performance of devices. However, these solutions often only partially address the problems and have certain limitations in practical applications. For example, further breakthroughs are needed in areas such as additive selection and optimization, process complexity, and cost control.

[0005] Based on this, researching and developing a perovskite active material that can reduce the defect density of the perovskite active material layer and stabilize the grain boundaries is of great significance for improving the photoelectric conversion efficiency and long-term stability of tandem solar cells. Summary of the Invention

[0006] The main objective of this invention is to provide a perovskite / crystalline silicon tandem solar cell and its preparation method, in order to solve the problems of high defect density and unstable grain boundaries in the perovskite active material layer in the prior art, which lead to poor photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon tandem solar cells.

[0007] To achieve the above objectives, the present invention provides a perovskite / crystalline silicon tandem solar cell, comprising a crystalline silicon bottom cell and a perovskite top cell. The perovskite top cell comprises a transparent oxide conductive layer, a hole transport layer, a perovskite active material layer, an electron transport layer, and a metal electrode layer sequentially stacked. The transparent oxide conductive layer is in contact with the crystalline silicon bottom cell. The perovskite active material layer comprises a perovskite active material and an additive, the additive having the chemical structure shown in formula (I):

[0008] (I),

[0009] R1 and R2 are each independently selected from hydrogen, C1-C6 alkyl groups, or -L2-R5; and at least one of R1 and R2 is R4 is selected from hydrogen or C1-C6 alkyl groups; L1 and L2 are each independently selected from C6-C6 alkyl groups. 10 The arylene group or single bond; R3 and R5 are each independently selected from halogens, C1-C3 alkyl groups, or at least one halogen-substituted C1-C3 alkyl group.

[0010] Furthermore, in the additive, L1 is selected from... Or a single bond; R3 is selected from fluorine, methyl, -CF3, -CHF2, or -CH2F, and R3 is not fluorine when L1 is a single bond; preferably, R3 is selected from -CF3; R1 is selected from hydrogen, or R4 is selected from hydrogen or ethyl; R2 is selected from methyl, ethyl, or -L2-R5; R4 is selected from hydrogen or ethyl; L2 is selected from R5 is selected from fluorine.

[0011] Furthermore, the additive is selected from one or more of compounds 1 to 7:

[0012] ,

[0013] , ,

[0014] , ,

[0015] ,

[0016] .

[0017] Furthermore, the content of the additive is 0.1 to 4 wt% based on the weight percentage of the perovskite active material layer; and / or, the weight ratio of the perovskite active material to the additive is (80 to 99): (1 to 20).

[0018] Furthermore, the band gap of the perovskite active material ranges from 1.68 to 2.03 eV; preferably, the perovskite active material is ABX3, wherein A is selected from FA. + MA + Cs + DMA + One or more of them, B is selected from Pb 2+ Sn 2+ Mn 2+ One or more of them, X is selected from Cl - ,Br - I - F - One or more of the following; preferably, the thickness of the perovskite active material layer is 500-1000 nm.

[0019] Furthermore, the crystalline silicon bottom cell is selected from TOPCon bottom cells, HJT bottom cells, or BC bottom cells; and / or, the material of the transparent oxide conductive layer is selected from one or more of fluorine-doped tin oxide, indium tin oxide, and aluminum-doped zinc oxide; and / or, the thickness of the transparent oxide conductive layer is 10–30 nm; and / or, the material of the hole transport layer is selected from 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), MoO3, NiO x One or more of Cu2O and CuI; and / or, the hole transport layer has a thickness of 10–30 nm; and / or, the electron transport layer is made of TiO2, ZnO, C 60 One or more of PCBM and 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline; and / or, the thickness of the electron transport layer is 10 to 30 nm; and / or, the material of the metal electrode layer is selected from one or more of Ag, Au and Cu; and / or, the thickness of the metal electrode layer is 10 to 1000 nm.

[0020] Furthermore, a cathode buffer layer is disposed between the electron transport layer and the metal electrode layer; preferably, the material of the cathode buffer layer is selected from 3,3'-(1,3,8,10-tetraanthrone[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9(1H,3H,8H,10H)-diyl)bis(N,N-dimethylpropane-1-oxamine), polyethyleneimine, poly(3-hexylthiophene-2,5-diyl) and SnO x One or more of the following; preferably, the thickness of the cathode buffer layer is 15-25 nm.

[0021] Furthermore, the perovskite / crystalline silicon tandem solar cell also includes an antireflection layer; preferably, the material of the antireflection layer is selected from MgF2 and / or LiF; preferably, the thickness of the antireflection layer is 10-30 nm.

[0022] To achieve the above objectives, another aspect of the present invention provides a method for preparing the perovskite / crystalline silicon tandem solar cell provided in this application. The method includes: step S1, preparing a crystalline silicon base cell; step S2, sequentially preparing a transparent oxide conductive layer, a hole transport layer, a perovskite active material layer, an electron transport layer, and a metal electrode layer on one side surface of the crystalline silicon base cell; wherein, the method for preparing the perovskite active material layer includes: mixing a perovskite active material, an additive, and a solvent to obtain a perovskite precursor solution; coating or spray-depositing the perovskite precursor solution on the side surface of the hole transport layer away from the transparent oxide conductive layer, and then annealing the solution to obtain the perovskite active material layer.

[0023] Furthermore, in the perovskite precursor solution, the mass concentration of the additive is 0.2–2 mg / mL; preferably, the solvent is selected from DMF and / or DMSO; preferably, the annealing temperature is 90–120 °C and the time is 5–15 min.

[0024] Furthermore, the fabrication method of the perovskite / crystalline silicon tandem solar cell further includes: after the electron transport layer is fabricated, a cathode buffer layer is first fabricated on its surface, and then a metal electrode layer is fabricated; preferably, the cathode buffer layer is fabricated by magnetron sputtering; preferably, the fabrication method of the perovskite / crystalline silicon tandem solar cell further includes: depositing an antireflection layer on the side of the metal electrode layer away from the electron transport layer by vapor deposition.

[0025] Applying the technical solution of this invention, the perovskite active material layer in the perovskite top solar cell provided in this application further includes an additive with the chemical structure shown in formula (I). The carbonyl group (C=O) in this additive can act as a Lewis base and react with the metal cation (such as Pb) in the perovskite active material. 2+ In addition, the sulfur atom in the thiazole structure can assist in coordination, and the halogen atoms in the -L1-R3 and / or -L2-R5 structures can coordinate with organic cations (such as FA) in perovskite active materials. + Hydrogen bonds are formed, which synergistically passivate uncoordinated defects, further enhancing the passivation effect of the additives, significantly reducing defect density, extending carrier lifetime, and reducing nonradiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon solar cells. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 A cross-sectional structural schematic diagram of a perovskite / crystalline silicon tandem solar cell provided in a preferred embodiment of this application is shown;

[0028] Figure 2 A cross-sectional structural schematic diagram of a perovskite / crystalline silicon tandem solar cell provided in a preferred embodiment of this application is shown;

[0029] Figure 3 A cross-sectional structural schematic diagram of a perovskite / crystalline silicon tandem solar cell provided in a preferred embodiment of this application is shown.

[0030] The above figures include the following reference numerals:

[0031] 100. Crystalline silicon bottom cell; 200. Perovskite top cell; 201. Transparent oxide conductive layer; 202. Hole transport layer; 203. Perovskite active material layer; 204. Electron transport layer; 205. Metal electrode layer; 206. Cathode buffer layer; 207. Anti-reflection layer. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0033] As described in the background section, existing perovskite active material layers suffer from high defect density and unstable grain boundaries, resulting in poor photoelectric conversion efficiency and long-term stability in perovskite / crystalline silicon tandem solar cells. To address these technical problems, the first aspect of this application provides a perovskite / crystalline silicon tandem solar cell, such as... Figure 1 As shown, it includes a crystalline silicon bottom cell 100 and a perovskite top cell 200. The perovskite top cell 200 includes a transparent oxide conductive layer 201, a hole transport layer 202, a perovskite active material layer 203, an electron transport layer 204, and a metal electrode layer 205 stacked sequentially. The transparent oxide conductive layer 201 is in contact with the crystalline silicon bottom cell 100. The perovskite active material layer 203 includes a perovskite active material and an additive, which has the chemical structure shown in formula (I):

[0034] (I),

[0035] R1 and R2 are each independently selected from hydrogen, C1-C6 alkyl groups, or -L2-R5; and at least one of R1 and R2 is R4 is selected from hydrogen or C1-C6 alkyl groups; L1 and L2 are each independently selected from C6-C6 alkyl groups. 10 The arylene group or single bond; R3 and R5 are each independently selected from halogens, C1-C3 alkyl groups, or at least one halogen-substituted C1-C3 alkyl group.

[0036] It should be noted that, in this application, perovskite / crystalline silicon tandem solar cells refer to tandem solar cells with a double-layer tandem structure, wherein the crystalline silicon bottom cell 100 and the perovskite top cell 200 are connected in series.

[0037] Compared to a traditional perovskite top-mounted solar cell 200, the perovskite active material layer 203 in the perovskite top-mounted solar cell 200 provided in this application further includes an additive with the chemical structure shown in formula (I). The carbonyl group (C=O) in this additive can act as a Lewis base and react with the metal cation (such as Pb) in the perovskite active material. 2+ In addition, the sulfur atom in the thiazole structure can assist in coordination, and the halogen atoms in the -L1-R3 and / or -L2-R5 structures can coordinate with organic cations (such as FA) in perovskite active materials. + Hydrogen bonds are formed, which synergistically passivate uncoordinated defects, further enhancing the passivation effect of the additives, significantly reducing defect density, extending carrier lifetime, and reducing nonradiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon solar cells.

[0038] In a preferred embodiment, L1 in the additive includes, but is not limited to, […]. Or a single bond; R3 includes, but is not limited to, fluorine, methyl, -CF3, -CHF2, or -CH2F, and R3 is not fluorine when L1 is a single bond; R1 includes, but is not limited to, hydrogen, or R4 includes, but is not limited to, hydrogen or ethyl; R2 includes, but is not limited to, methyl, ethyl, or -L2-R5; R4 includes, but is not limited to, hydrogen or ethyl; L2 includes, but is not limited to, R5 includes, but is not limited to, fluorine. Preferably, R3 includes, but is not limited to, -CF3.

[0039] Compared to other types, the use of the above-mentioned substituents R1, R2, R3, R4, R5, L1 and L2 is beneficial to enhance the passivation effect of the additives, reduce the defect density of the perovskite active material layer 203, extend the carrier lifetime, and reduce the nonradiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon solar cells.

[0040] To further enhance the passivation effect of the additives, reduce the defect density of the perovskite active material layer 203, and further reduce the nonradiative recombination of charge carriers, thereby improving the photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon solar cells, preferably, the additives include, but are not limited to, one or more of compounds 1 to 7:

[0041] , ,

[0042] , ,

[0043] ,

[0044] ,

[0045] .

[0046] In a preferred embodiment, the additive content is 0.1–4 wt% based on the weight percentage of the perovskite active material layer 203. The additive content includes, but is not limited to, the above range. Limiting it within this range is beneficial for its passivation effect, reducing the defect density of the perovskite active material layer 203, extending carrier lifetime, and reducing non-radiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of the perovskite / crystalline silicon solar cell.

[0047] In a preferred embodiment, the weight ratio of perovskite active material to additive is (80-99):(1-20). This weight ratio includes, but is not limited to, the range described above. Limiting it to this range is beneficial for maximizing the passivation effect of the additive, reducing the defect density of the perovskite active material layer 203, extending carrier lifetime, and reducing non-radiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of the perovskite / crystalline silicon solar cell.

[0048] In a preferred embodiment, the band gap of the perovskite active material is in the range of 1.68–2.03 eV. The band gap range of the perovskite active material includes, but is not limited to, the range described above. Limiting it to this range is beneficial for improving light utilization, increasing the efficiency of photogenerated electrons and holes, and facilitating the extraction of electrons and holes, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0049] To further improve light utilization and increase the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells, preferably, the perovskite active material is ABX3, wherein A includes, but is not limited to, FA. + MA +Cs + DMA + One or more of the following, B including but not limited to Pb 2+ Sn 2+ Mn 2+ One or more of them, X including but not limited to Cl - ,Br - I - F - One or more of them.

[0050] To further improve light utilization and increase the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells, preferably, the thickness of the perovskite active material layer 203 is 500–1000 nm.

[0051] The perovskite / crystalline silicon tandem solar cell provided in this application does not have any particular limitation on the type of crystalline silicon base cell 100; any commonly used type with high efficiency can be used. In a preferred embodiment, the crystalline silicon base cell 100 includes, but is not limited to, TOPCon base cells (tunneling oxide passivated contact solar base cells), HJT base cells (heterojunction solar base cells), or BC base cells (interdigitated back contact solar base cells).

[0052] In a preferred embodiment, the material of the transparent oxide conductive layer 201 includes, but is not limited to, one or more of fluorine-doped tin oxide (FTO), indium tin oxide (ITO), and aluminum-doped zinc oxide (AZO). Compared to other types, using the above-mentioned materials for the transparent oxide conductive layer 201 is advantageous in maintaining high conductivity while improving transparency, and also in reducing fabrication difficulty, thereby improving the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0053] In a preferred embodiment, the thickness of the transparent oxide conductive layer 201 is 10–30 nm. The thickness of the transparent oxide conductive layer 201 includes, but is not limited to, the above range. Limiting it to this range is beneficial for improving carrier transport efficiency, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0054] In a preferred embodiment, the material of the hole transport layer 202 includes, but is not limited to, 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS), MoO3, NiO xOne or more of Cu2O and CuI. Compared to other types, the hole transport layer 202 made of the above types is beneficial to improving hole transport efficiency, thereby improving the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0055] To further improve hole transport efficiency, in a preferred embodiment, the thickness of the hole transport layer 202 is 10–30 nm.

[0056] In a preferred embodiment, the material of the electron transport layer 204 includes, but is not limited to, TiO2, ZnO, and C. 60 One or more of PCBM and 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) are used. Compared to other types, materials using the above-mentioned types of electron transport layer 204 are beneficial to improving electron transport efficiency, thereby improving the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0057] In order to further shorten the electron transport path, improve the electron transport efficiency, and thus improve the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, in a preferred embodiment, the thickness of the electron transport layer 204 is 10-30 nm.

[0058] In a preferred embodiment, the material of the metal electrode layer 205 includes, but is not limited to, one or more of Ag, Au, and Cu. Compared to other types, using the above-mentioned materials for the metal electrode layer 205 is beneficial to improving the conductivity of the metal electrode layer 205, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0059] In order to further improve the conductivity of the metal electrode layer 205 and thus improve the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, in a preferred embodiment, the thickness of the metal electrode layer 205 is 10 to 1000 nm.

[0060] like Figure 2 As shown, in a preferred embodiment, a cathode buffer layer 206 is further disposed between the electron transport layer 204 and the metal electrode layer 205. The cathode buffer layer 206 helps to reduce damage to the battery film during the fabrication of the metal electrode layer 205, and also helps to improve the stability of the perovskite / tandem solar cell.

[0061] To further reduce damage to the battery film during the fabrication of the metal electrode layer 205, preferably, the material of the cathode buffer layer 206 includes, but is not limited to, 3,3'-(1,3,8,10-tetraanthrone[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9(1H,3H,8H,10H)-diyl)bis(N,N-dimethylpropane-1-oxamine) (PDINO), polyethyleneimine (PEIE), poly(3-hexylthiophene-2,5-diyl) (P3TMAHT), and SnO. x One or more of them.

[0062] To further reduce damage to the battery film during the preparation of the metal electrode layer 205, the thickness of the cathode buffer layer 206 is preferably 15-25 nm.

[0063] like Figure 3 As shown, in a preferred embodiment, the perovskite / crystalline silicon tandem solar cell further includes an antireflection layer 207. The antireflection layer 207 helps reduce the reflection loss of incident light at the interface, increases the light utilization rate of the perovskite active material layer 203, and thus helps improve the short-circuit current density and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0064] To further reduce reflection loss and improve the light utilization rate of the perovskite active material layer 203, thereby improving the short-circuit current density and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, preferably, the material of the antireflection layer 207 includes, but is not limited to, MgF2 and / or LiF.

[0065] To further reduce reflection loss and improve the light utilization rate of the perovskite active material layer 203, thereby improving the short-circuit current density and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, the thickness of the antireflection layer 207 is preferably 10–30 nm.

[0066] The second aspect of this application also provides a method for preparing the perovskite / crystalline silicon tandem solar cell provided in this application. The method includes: step S1, preparing a crystalline silicon base cell 100; step S2, sequentially preparing a transparent oxide conductive layer 201, a hole transport layer 202, a perovskite active material layer 203, an electron transport layer 204, and a metal electrode layer 205 on one side surface of the crystalline silicon base cell 100; wherein, the method for preparing the perovskite active material layer 203 includes: mixing a perovskite active material, an additive, and a solvent to obtain a perovskite precursor solution; coating or spraying the perovskite precursor solution onto the side surface of the hole transport layer 202 away from the transparent oxide conductive layer 201, and then annealing the solution to obtain the perovskite active material layer 203.

[0067] Compared to the preparation of the perovskite active material layer 203 using traditional perovskite precursor solutions without additives or containing other types of additives, this application adds an additive with the structure shown in formula (I) when preparing the perovskite precursor solution. The carbonyl group (C=O) in this additive can act as a Lewis base to react with the metal cations (such as Pb) in the perovskite active material. 2+ In addition, the sulfur atom in the thiazole structure can assist in coordination, and the halogen atoms in the -L1-R3 and / or -L2-R5 structures can coordinate with organic cations (such as FA) in perovskite active materials. + Hydrogen bonds are formed, which synergistically passivate uncoordinated defects, further enhancing the passivation effect of the additives, significantly reducing defect density, extending carrier lifetime, and reducing nonradiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon solar cells.

[0068] In a preferred embodiment, the mass concentration of the additive in the perovskite precursor solution is 0.2–2 mg / mL. The mass concentration of the additive includes, but is not limited to, the above range. Limiting it to this range facilitates the dispersion of the additive, thereby promoting its uniform preparation on the surface of the hole transport layer 202, and ultimately enabling it to exert its passivation effect, improving the photoelectric conversion efficiency and long-term stability of the perovskite / crystalline silicon tandem solar cell.

[0069] In a preferred embodiment, the solvent includes, but is not limited to, DMF and / or DMSO. Compared to other types, using the above-mentioned solvents is beneficial for improving the dispersibility of perovskite active materials and additives, facilitating subsequent coating or spray deposition.

[0070] In this application, the perovskite precursor solution can be deposited on the surface of the hole transport layer 202 away from the transparent oxide conductive layer 201 using spin coating, blade coating, or spray deposition methods. Compared with other preparation methods, the above preparation method is beneficial for obtaining a perovskite active material layer 203 with higher crystallinity.

[0071] In a preferred embodiment, when the perovskite precursor solution is applied to the surface of the hole transport layer 202 away from the transparent oxide conductive layer 201 using a spin coating method, the spin coating speed is 3000–6000 rpm; or, when the perovskite precursor solution is applied to the surface of the hole transport layer 202 away from the transparent oxide conductive layer 201 using a blade coating method, the coating amount is 10–20 mg / cm³. 2 When the perovskite precursor solution is deposited on the surface of the hole transport layer 202 away from the transparent oxide conductive layer 201 using the spray deposition method, the spray gun pressure is 20-100 kPa and the temperature is 20-100℃.

[0072] To improve the crystallinity of the perovskite active material layer 203, preferably, the annealing temperature is 90–120°C and the time is 5–15 min.

[0073] In a preferred embodiment, the transparent oxide conductive layer 201 is prepared using magnetron sputtering or chemical vapor deposition. Compared to other preparation methods, the above preparation method is beneficial for improving the deposition uniformity of the transparent oxide conductive layer 201.

[0074] In a preferred embodiment, the hole transport layer 202 is prepared using vapor deposition, blade coating, spray deposition, or inkjet printing. Compared to other preparation methods, the above preparation methods help avoid solution swirling during deposition, thus preventing solution overflow and waste.

[0075] In a preferred embodiment, the electron transport layer 204 is prepared using vapor deposition, blade coating, spray deposition, or inkjet printing. Compared to other preparation methods, the above-mentioned preparation methods are beneficial for improving the uniformity and consistency of the electron transport layer 204.

[0076] In a preferred embodiment, the metal electrode layer 205 is prepared using screen printing or vapor deposition. Compared to other preparation methods, the above preparation method is advantageous in improving preparation efficiency, thereby increasing the production cycle time.

[0077] In a preferred embodiment, the fabrication method of the perovskite / crystalline silicon tandem solar cell further includes: after the electron transport layer 204 is fabricated, first fabricating a cathode buffer layer 206 on its surface, and then fabricating a metal electrode layer 205. Fabricating the cathode buffer layer 206 on the surface of the electron transport layer 204 helps to reduce damage to the cell film during the subsequent fabrication of the metal electrode layer 205, and helps to improve the stability of the perovskite / crystalline silicon tandem solar cell.

[0078] To improve the uniformity and density of the cathode buffer layer 206, it is preferable to prepare the cathode buffer layer 206 by magnetron sputtering.

[0079] The antireflection layer 207 helps reduce the reflection loss of incident light at the interface and increases the light utilization rate of the perovskite active material layer 203, thereby improving the short-circuit current density and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell. In a preferred embodiment, the fabrication method of the perovskite / crystalline silicon tandem solar cell further includes depositing the antireflection layer 207 on the surface of the metal electrode layer 205 away from the electron transport layer 204. Compared with other fabrication methods, the above-described fabrication method helps improve the deposition uniformity of the antireflection layer 207, thereby maximizing its ability to reduce the reflection loss of incident light at the interface.

[0080] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0081] Example 1

[0082] A method for fabricating a perovskite / crystalline silicon tandem solar cell, comprising:

[0083] (1) Prepare 100 crystalline silicon bottom cells:

[0084] The stacked structure of the HJT bottom cell is represented as: back Ag / ITO / p-amorphous silicon / intrinsic amorphous silicon / n-Si / intrinsic amorphous silicon / n-amorphous silicon;

[0085] (2) Preparation of transparent oxide conductive layer 201:

[0086] An ITO layer was prepared by magnetron sputtering, with a vacuum of 8 Pa, a sputtering power of 60 W, and a sputtering time of 1200 s, resulting in an ITO layer with a thickness of 15 nm.

[0087] (3) Fabrication of hole transport layer 202:

[0088] Hole transport layer 202 was prepared by spin coating. Specifically, 200 μL of NiO with a mass concentration of 5 mg / mL was applied. x The aqueous solution was spin-coated onto the surface of ITO away from the bottom of the HJT cell at a speed of 2000 rpm for 30 s, followed by annealing at 120 °C for 10 min to obtain NiO with a thickness of 20 nm. x layer;

[0089] (4) Preparation of perovskite active material layer 203:

[0090] PbI₂, FAI, and CsBr powders in a molar ratio of 5:4:5 were dispersed in 20 mL of a mixed solvent of DMF and DMSO (volume ratio DMF:DMSO = 4:1). This mixture was then combined with additive compound 1 (CAS No.: 175277-03-9) and stirred for 5 h to obtain a perovskite precursor solution; the mass concentration of compound 1 was 1 mg / mL. 150 μL of the perovskite precursor solution was spin-coated at 3000 rpm for 20 s. After spin-coating, the wet film was transferred to a hot plate at 100 °C and annealed for 10 min to obtain a film with a thickness of 600 nm. Layer (denoted as PVK layer); perovskite active material in this layer The weight ratio of compound 1 to compound 1 is 9:1;

[0091] (5) Fabrication of electron transport layer 204:

[0092] On the side of the PVK layer obtained in step (4) away from the HJT bottom cell, a BCP layer with a thickness of 20 nm was deposited by vapor deposition at a deposition rate of 300 Å / s.

[0093] (6) Preparation of cathode buffer layer 206:

[0094] SnO x Sputtering deposition was performed on the side of the BCP layer obtained in step (5) away from the PVK layer to obtain a SnO layer with a thickness of 20 nm. x The layer was prepared with a vacuum of 4.8 Pa, a sputtering power of 35 W, a sputtering time of 60 min, and an argon flow rate of 850 sccm.

[0095] (7) Preparation of metal electrode layer 205:

[0096] SnO prepared in step (6) x An Ag electrode layer with a thickness of 1000 nm was obtained by screen printing on the side of the layer away from the crystalline HJT bottom cell layer.

[0097] (8) Preparation of antireflective layer 207:

[0098] The Ag electrode layer obtained in step (8) is far from SnO. x One side surface of the layer, at 350 A MgF2 layer with a thickness of 20 nm was deposited by vapor deposition at a high deposition rate to serve as an antireflection layer 207, thus obtaining a perovskite / crystalline silicon tandem solar cell.

[0099] like Figure 3 As shown, the stacked structure of this perovskite / silicon tandem solar cell is represented as follows:

[0100] .

[0101] Example 2

[0102] The difference from Example 1 is that the mass concentration of compound 1 in the perovskite precursor solution is 0.2 mg / mL. The remaining steps are the same as in Example 1.

[0103] Example 3

[0104] The difference from Example 1 is that the mass concentration of compound 1 in the perovskite precursor solution is 2 mg / mL. The remaining steps are the same as in Example 1.

[0105] Example 4

[0106] The difference from Example 1 is that the mass concentration of compound 1 in the perovskite precursor solution is 0.1 mg / mL. The remaining steps are the same as in Example 1.

[0107] Example 5

[0108] The difference from Example 1 is that the mass concentration of compound 1 in the perovskite precursor solution is 2.5 mg / mL. The remaining steps are the same as in Example 1.

[0109] Example 6

[0110] The difference from Example 1 is that in step (4), the annealing temperature is 90°C and the time is 15 min. The remaining steps are the same as in Example 1.

[0111] Example 7

[0112] The difference from Example 1 is that in step (4), the annealing temperature is 120°C and the time is 5 minutes. The remaining steps are the same as in Example 1.

[0113] Example 8

[0114] The difference from Example 1 is that in step (4), the annealing temperature is 150°C. The remaining steps are the same as in Example 1.

[0115] Example 9

[0116] The difference from Example 1 is that in step (4), an equal amount of compound 2 (CAS No.: 175204-88-3) is used as an additive to replace compound 1. The remaining steps are the same as in Example 1.

[0117] The chemical structure of compound 2 is as follows:

[0118] .

[0119] Example 10

[0120] The difference from Example 1 is that in step (4), an equal amount of compound 3 (CAS No.: 1263286-63-0) is used as an additive to replace compound 1. The remaining steps are the same as in Example 1.

[0121] The chemical structure of compound 3 is as follows:

[0122] .

[0123] Example 11

[0124] The difference from Example 1 is that in step (4), an equal amount of compound 4 (CAS No.: 347173-47-1) is used as an additive to replace compound 1. The remaining steps are the same as in Example 1.

[0125] The chemical structure of compound 4 is as follows:

[0126] .

[0127] Comparative Example 1

[0128] The difference from Example 1 is that in step (4), additive compound 1 was not introduced into the perovskite precursor solution. The remaining steps are the same as in Example 1.

[0129] The perovskite solar cells prepared in all the above embodiments and comparative examples of this application were placed at 100mW / cm². 2 Under illumination, its photovoltaic performance was tested, and the test results are summarized in Table 1.

[0130] Table 1

[0131]

[0132] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0133] Compared to the preparation of the perovskite active material layer 203 using traditional perovskite precursor solutions without additives or containing other types of additives, this application adds an additive with the structure shown in formula (I) when preparing the perovskite precursor solution. The carbonyl group (C=O) in this additive can act as a Lewis base to react with the metal cations (such as Pb) in the perovskite active material. 2+ In addition, the sulfur atom in the thiazole structure can assist in coordination, and the halogen atoms in the -L1-R3 and / or -L2-R5 structures can coordinate with organic cations (such as FA) in perovskite active materials. + Hydrogen bonds are formed, which synergistically passivate uncoordinated defects, further enhancing the passivation effect of the additives, significantly reducing defect density, extending carrier lifetime, and reducing nonradiative recombination of carriers, thereby improving the photoelectric conversion efficiency and long-term stability of perovskite / crystalline silicon solar cells.

[0134] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0135] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A perovskite / crystalline silicon tandem solar cell, comprising a crystalline silicon bottom cell (100) and a perovskite top cell (200), characterized in that, The perovskite top solar cell (200) comprises a transparent oxide conductive layer (201), a hole transport layer (202), a perovskite active material layer (203), an electron transport layer (204), and a metal electrode layer (205) stacked sequentially. The transparent oxide conductive layer (201) is in contact with the crystalline silicon bottom solar cell (100). The perovskite active material layer (203) comprises a perovskite active material and an additive, the additive having the chemical structure shown in formula (I): （I）， R1 and R2 are each independently selected from hydrogen, C1-C6 alkyl groups, , or -L2-R5; and at least one of R1 and R2 is R4 is selected from hydrogen or C1-C6 alkyl groups; L1 and L2 are each independently selected from C6 to C6. 10 aryl groups, or single bonds; R3 and R5 are each independently selected from halogens, C1-C3 alkyl groups, or at least one halogen-substituted C1-C3 alkyl group.

2. The perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, In the additive, L1 is selected from... Or a single bond; R3 is selected from fluorine, methyl, -CF3, -CHF2, or -CH2F, and when L1 is a single bond, R3 is not fluorine; preferably, R3 is selected from -CF3; R1 is selected from hydrogen, or R4 is selected from hydrogen or ethyl. R2 is selected from methyl, ethyl, and... or -L2-R5; wherein R4 is selected from hydrogen or ethyl; L2 is selected from The R5 is selected from fluorine. Preferably, the additive is selected from one or more of compounds 1 to 7: 、 、 、 、 、 、 。 3. The perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The content of the additive is 0.1 to 4 wt% based on the weight percentage of the perovskite active material layer (203); and / or the weight ratio of the perovskite active material to the additive is (80 to 99): (1 to 20).

4. The perovskite / crystalline silicon tandem solar cell according to any one of claims 1 to 3, characterized in that, The band gap of the perovskite active material ranges from 1.68 to 2.03 eV; Preferably, the perovskite active material is ABX3, wherein A is selected from FA. + MA + Cs + DMA + One or more of them, B is selected from Pb 2+ Sn 2+ Mn 2+ One or more of them, X is selected from Cl - ,Br - I - F - One or more of the following; Preferably, the thickness of the perovskite active material layer (203) is 500-1000 nm.

5. The perovskite / crystalline silicon tandem solar cell according to claim 4, characterized in that, The crystalline silicon base cell (100) is selected from TOPCon base cells, HJT base cells, or BC base cells; and / or, The material of the transparent oxide conductive layer (201) is selected from one or more of fluorine-doped tin oxide, indium tin oxide, and aluminum-doped zinc oxide; and / or, The thickness of the transparent oxide conductive layer (201) is 10–30 nm; and / or, The hole transport layer (202) is made of a material selected from 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), MoO3, NiO x One or more of Cu₂O and CuI; and / or, The hole transport layer (202) has a thickness of 10–30 nm; and / or, The electron transport layer (204) is made of TiO2, ZnO, or C. 60 One or more of PCBM and 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline; and / or, The thickness of the electron transport layer (204) is 10–30 nm; and / or, The material of the metal electrode layer (205) is selected from one or more of Ag, Au, and Cu; and / or, The thickness of the metal electrode layer (205) is 10 to 1000 nm.

6. The perovskite / crystalline silicon tandem solar cell according to claim 5, characterized in that, A cathode buffer layer (206) is also provided between the electron transport layer (204) and the metal electrode layer (205). Preferably, the cathode buffer layer (206) is made of a material selected from 3,3'-(1,3,8,10-tetraanthrone[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9(1H,3H,8H,10H)-diyl)bis(N,N-dimethylpropane-1-oxamine), polyethyleneimine, poly(3-hexylthiophene-2,5-diyl) and SnO. x One or more of the following; Preferably, the thickness of the cathode buffer layer (206) is 15-25 nm.

7. The perovskite / crystalline silicon tandem solar cell according to claim 5 or 6, characterized in that, The perovskite / crystalline silicon tandem solar cell also includes an anti-reflection layer (207). Preferably, the material of the antireflective layer (207) is selected from MgF2 and / or LiF; Preferably, the thickness of the antireflective layer (207) is 10–30 nm.

8. A method for preparing a perovskite / crystalline silicon tandem solar cell according to any one of claims 1 to 7, characterized in that, The preparation method includes: Step S1, prepare crystalline silicon bottom cell (100). Step S2, a transparent oxide conductive layer (201), a hole transport layer (202), a perovskite active material layer (203), an electron transport layer (204), and a metal electrode layer (205) are sequentially prepared on one side surface of the crystalline silicon bottom cell (100); wherein, the method for preparing the perovskite active material layer (203) includes: The perovskite active material, additives and solvents are mixed to obtain a perovskite precursor solution; The perovskite precursor solution is coated or spray-deposited on the side of the hole transport layer (202) away from the transparent oxide conductive layer (201), and then annealed to obtain the perovskite active material layer (203).

9. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 8, characterized in that, In the perovskite precursor solution, the mass concentration of the additive is 0.2–2 mg / mL; Preferably, the solvent is selected from DMF and / or DMSO; Preferably, the annealing treatment is performed at a temperature of 90–120°C for 5–15 minutes.

10. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 8 or 9, characterized in that, The method for preparing the perovskite / crystalline silicon tandem solar cell further includes: after the electron transport layer (204) is prepared, a cathode buffer layer (206) is first prepared on its surface, and then the metal electrode layer (205) is prepared. Preferably, the cathode buffer layer (206) is prepared by magnetron sputtering. Preferably, the method for fabricating the perovskite / crystalline silicon tandem solar cell further includes: depositing an antireflection layer (207) on the side of the metal electrode layer (205) away from the electron transport layer (204).

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