Perovskite / crystalline silicon laminated solar cell and preparation method thereof

Abstract

The invention provides a perovskite / crystalline silicon laminated solar cell, which comprises a crystalline silicon bottom cell and a perovskite top cell which are laminated, and is characterized in that the perovskite top cell comprises a first transparent conductive layer, a hole transport layer, a perovskite active material layer, an electron transport layer, a cathode buffer layer, a second transparent conductive layer and a metal electrode layer which are laminated in sequence; the first transparent conductive layer is in contact with the crystalline silicon bottom battery; wherein the material of the perovskite active material layer is a compound of a polymer with a three-dimensional frame structure and a perovskite active material, and the polymer is selected from polyacrylate and / or polyenol ether. According to the perovskite / crystalline silicon laminated solar cell, due to the introduction of the polymer with the three-dimensional frame structure, the crystals can be orderly arranged in the specific direction, lattice distortion of perovskite is effectively inhibited, the crystal structure of the perovskite is stabilized, and the chemical stability and the photoelectric conversion efficiency of the perovskite / crystalline silicon laminated solar cell are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a perovskite / crystalline silicon tandem solar cell and a preparation method thereof. BACKGROUND

[0002] In the past decade, metal halide perovskite photovoltaics (PV) has received extensive research and commercialization interest. The power conversion efficiency (PCE) of laboratory-scale single-junction perovskite solar cells (PSCs) has exceeded 27%, approaching the efficiency record of current crystalline silicon (c-Si) solar cells. In theory, all single-junction solar cells are constrained by the theoretical efficiency limit of the Shockley-Queisser (S-Q) limit, while perovskite / crystalline silicon tandem solar cells achieve higher photoelectric conversion efficiency than single-junction solar cells by better utilizing the energy of short-wavelength photons in the solar spectrum. However, the nucleation and crystallization of the perovskite active layer in the perovskite top cell during film formation is difficult to control, resulting in inherent stress accumulation in the polycrystalline thin film, while the harmful interlayer reaction is difficult to suppress, and lattice distortion is prone to occur, resulting in poor chemical stability and electrical performance of the perovskite / crystalline silicon tandem solar cell.

[0003] On this basis, it is of great significance to research and develop a perovskite / crystalline silicon tandem solar cell with a perovskite active layer having excellent chemical stability. SUMMARY

[0004] The main purpose of the present application is to provide a perovskite / crystalline silicon tandem solar cell and a preparation method thereof, to solve the problem that the nucleation and crystallization process of the perovskite active material in the film formation process is difficult to control, resulting in inherent stress accumulation in the polycrystalline thin film, and lattice distortion is prone to occur, resulting in poor chemical stability and electrical performance of the perovskite / crystalline silicon tandem solar cell in the prior art.

[0005] In order to achieve the above-mentioned purpose, the present application provides a perovskite / crystalline silicon tandem solar cell in one aspect, comprising a crystalline silicon bottom cell and a perovskite top cell which are stacked, the perovskite top cell comprising a first transparent conductive layer, a hole transport layer, a perovskite active material layer, an electron transport layer, a cathode buffer layer, a second transparent conductive layer and a metal electrode layer which are stacked in turn, the first transparent conductive layer being in contact with the crystalline silicon bottom cell; wherein the material of the perovskite active material layer is a composite of a three-dimensional framework structure polymer and a perovskite active material, and the polymer is selected from polyacrylate and / or polyolefin ether;

[0006] The first polymerization monomer for forming polyacrylate has a structure shown in formula (I): CH2=CHCOOR (I), wherein R is selected from C1-C 15 alkyl group; the weight average molecular weight of the polyacrylate is 70-400;

[0007] The second polymerizable monomer used to form the polyenol ether has the structure shown in formula (II):

[0008] (II), wherein R1 is selected from hydrogen or halogen, and R2 is selected from C1 to C2. 15 Alkyl groups, C2-C 15 alkenyl, C6-C 18 aryl, C6-C 18 aryl-substituted C1-C 10 Alkyl groups, or at least one hydroxyl-substituted C1-C1 groups 15 Alkyl group, n is any integer from 0 to 15; R3 is selected from hydrogen, or C1 to C2. 10 Alkyl group; R4 is selected from hydrogen or C6-C6. 18 The aryl group; the weight average molecular weight of polyenol ethers is 60–2000.

[0009] Furthermore, R is selected from C4 to C6. 12 The first polymerization monomer is a straight-chain or branched alkyl group; preferably, R is selected from n-butyl, 2-ethylhexyl, or n-dodecyl; more preferably, the first polymerization monomer is selected from one or more monomers A1 to A3.

[0010] , , .

[0011] Furthermore, R1 is selected from hydrogen, fluorine, chlorine, or bromine; R2 is selected from C2-C5 straight-chain or branched alkyl groups, C2-C6 alkenyl groups, C6-C6 branched alkyl groups, and C5-C6 branched alkyl groups. 12 aryl, C6-C 12 The substituted C1-C6 alkyl group, or a C2-C8 straight-chain or branched alkyl group substituted with 1 to 3 hydroxyl groups; R3 is selected from hydrogen, or a C1-C6 straight-chain or branched alkyl group; R4 is selected from hydrogen, or a C6-C6 straight-chain or branched alkyl group. 12 The aryl group; preferably, R1 is selected from hydrogen; R2 is selected from ethyl, hydroxybutyl, R3 is selected from vinyl, allyl, benzyl, or phenyl; R4 is selected from hydrogen or phenyl; n is selected from 0 or 1; more preferably, the second polymerization monomer is selected from one or more of monomers B1 to B7:

[0012] , , , , , , .

[0013] Further, the weight percentage of the polymer in the perovskite active material layer is 10-50 wt%; preferably, the polymer is polyacrylate, and the weight percentage of the polymer in the perovskite active material layer is 25-35 wt%; or, the polymer is a mixture of polyacrylate and polyolefin ether, and the weight ratio of the two is 1: (1-3), and the weight percentage of the polymer in the perovskite active material layer is 20-40 wt%; preferably, the thickness of the perovskite active material layer is 0.5-2 μm; preferably, the perovskite active material is selected from one or more of FAPbI3, MAPbI3, CsPbI3, , , or .

[0014] Further, the perovskite top cell further comprises a functional layer disposed between the hole transport layer and the perovskite active material layer; the material of the functional layer is selected from chitosan and its derivatives; preferably, the material of the functional layer is selected from one or more of carboxymethyl chitosan, hydroxypropyl chitosan and chitosan quaternary ammonium salt; preferably, the thickness of the functional layer is 5-10 nm.

[0015] Further, the perovskite top cell further comprises an anti-reflection layer disposed on the side surface of the metal electrode layer away from the second transparent conductive layer; preferably, the material of the anti-reflection layer is selected from MgF2; preferably, the thickness of the anti-reflection layer is 50-200 nm.

[0016] Further, the crystalline silicon bottom cell is selected from a TOPCon bottom cell, an HJT bottom cell, or a BC bottom cell; preferably, the thickness of the first transparent conductive layer and the second transparent conductive layer is independently 5-30 nm, and the material thereof is independently selected from one or more of fluorine-doped tin oxide, indium tin oxide, aluminum-doped zinc oxide; preferably, the thickness of the hole transport layer is 10-20 nm, and the material thereof is selected from one or more of 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), MoO3, NiO x and Cu2O, CuI; preferably, the thickness of the electron transport layer is 5-30 nm, and the material thereof is selected from TiO2, ZnO, C 60, one or more of PCBM; preferably, the thickness of the cathode buffer layer is 2-30 nm, and the material thereof is selected from one or more of N,N'-bis(N,N-dimethylpropane-1-amine oxide)spirene-3,4,9,10-tetracarboxylic diimide, polyetherimide, poly(3-hexylthiophene-2,5-diyl), SnO2; preferably, the thickness of the metal electrode layer is 0.5-1 μm, and the material thereof is selected from one or more of Ag, Au and Cu.

[0017] To achieve the above object, another aspect of the present application further provides a preparation method of the above perovskite / crystalline silicon tandem solar cell provided by the present application, which comprises: sequentially preparing a first transparent conductive layer, a hole transport layer, a perovskite active material layer, an electron transport layer, a cathode buffer layer, a second transparent conductive layer and a metal electrode layer on the surface of a crystalline silicon bottom cell, wherein the preparation method of the perovskite active material layer comprises: step S1, mixing a first polymerized monomer and / or a second polymerized monomer with a first solvent to obtain a monomer solution; step S2, mixing a perovskite precursor with a second solvent to obtain a perovskite precursor solution; step S3, mixing the monomer solution with the perovskite precursor solution to obtain a mixed solution; step S4, under ultraviolet light irradiation, coating the mixed solution on the surface of the hole transport layer away from the first transparent conductive layer, then coating an anti-solvent, and after annealing treatment, obtaining the perovskite active material layer; wherein the first polymerized monomer and the second polymerized monomer have the same definitions as the foregoing content.

[0018] Further, in the monomer solution, the weight percentage content of the first polymerized monomer and / or the second polymerized monomer is 10-50 wt%; preferably, in the perovskite precursor solution, the weight percentage content of the perovskite precursor is 25-35 wt%; preferably, the weight ratio of the first polymerized monomer and / or the second polymerized monomer in the monomer solution to the perovskite precursor in the perovskite precursor solution is (1-3):(1-6); preferably, in step S4, the coating amount of the mixed solution is 15-20 mg / cm 2 ; preferably, the wavelength of the ultraviolet light is 300-400 nm, the irradiation time is 10-50 s, and the irradiation power is 10-40 W; preferably, the temperature of the annealing treatment is 80-150℃, and the time is 5-15 min.

[0019] Further, the preparation method further comprises: preparing a functional layer on the side surface of the hole transport layer away from the first transparent conductive layer, and the preparation method of the functional layer comprises: mixing the functional material with water to obtain a functional material dispersion, and coating the functional material dispersion on the side surface of the hole transport layer away from the first transparent conductive layer; and after drying, the functional layer is obtained; the functional material is selected from chitosan and derivatives thereof, preferably, the functional material is selected from one or more of carboxymethyl chitosan, hydroxypropyl chitosan and chitosan quaternary ammonium salt; preferably, the weight percentage content of the functional material in the functional material dispersion is 10-50 wt%.

[0020] By using the technical solution of the present application, the compound of the polymer with a three-dimensional framework structure and the perovskite active material is used as the perovskite active material layer, the polymer has a three-dimensional (3D) network structure, can provide physical restriction, restrict the free growth of the perovskite crystal, promote the ordered arrangement of the crystal along a specific direction, avoid the increase of the grain boundary and the increase of the lattice distortion caused by disordered growth, can effectively inhibit the lattice distortion of the perovskite, thereby stabilizing the crystal structure of the perovskite, and further improving the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0021] By using the first polymer monomer and / or the second polymer monomer with the specific chemical structure, the polymer with a rigid-flexible combined three-dimensional framework structure can be formed, the stress accumulation can be reduced, the lattice distortion of the perovskite can be adjusted, and thus the structural stability of the perovskite can be improved. In addition, compared with other ranges, limiting the weight average molecular weight of the polyacrylate and / or polyvinyl ether in the above range is beneficial to improving the conductivity of the perovskite active material layer, and a lower series resistance (Rs) is obtained.

[0022] By using the above technical solution provided in the present application, not only the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell can be improved, but also a feasible and stable manufacturing process is provided for the commercial production of the perovskite / crystalline silicon tandem solar cell, and the key problem in the film forming process is solved. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 A schematic diagram of the layer structure of the perovskite / crystalline silicon tandem solar cell in a preferred embodiment of the present application is shown;

[0025] Figure 2 A schematic diagram of the layer structure of the perovskite / crystalline silicon tandem solar cell in another preferred embodiment of the present application is shown;

[0026] Figure 3 A schematic diagram of the stacked structure of the perovskite / crystalline silicon tandem solar cell prepared in Example 1 of this application is shown.

[0027] The above figures include the following reference numerals:

[0028] 100, Crystalline silicon bottom cell; 200, Perovskite top cell;

[0029] 201. First transparent conductive layer; 202. Hole transport layer; 203. Perovskite active material layer; 204. Electron transport layer; 205. Cathode buffer layer; 206. Second transparent conductive layer; 207. Metal electrode layer; 208. Functional layer; 209. Anti-reflection layer. Detailed Implementation

[0030] 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.

[0031] As described in the background section, existing perovskite active layers suffer from difficulties in controlling the nucleation and crystallization of the perovskite active material during film formation. This leads to inherent stress accumulation in polycrystalline films, making them prone to lattice distortion and resulting in poor chemical stability and electrical performance of 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 stacked together. The perovskite top cell 200 includes a first transparent conductive layer 201, a hole transport layer 202, a perovskite active material layer 203, an electron transport layer 204, a cathode buffer layer 205, a second transparent conductive layer 206, and a metal electrode layer 207 stacked sequentially. The first transparent conductive layer 201 is in contact with the crystalline silicon bottom cell 100. The perovskite active material layer 203 is a composite of a three-dimensional framework polymer and a perovskite active material. The polymer is selected from polyacrylate and / or polyenol ether. The first polymeric monomer used to form the polyacrylate has the structure shown in formula (I): CH2=CHCOOR (I), where R is selected from C1 to C2. 15 The alkyl group; the weight-average molecular weight of the polyacrylate is 70–400; the second polymerizing monomer used to form the polyenol ether has the structure shown in formula (II): (II), wherein R1 is selected from hydrogen or halogen, and R2 is selected from C1 to C2. 15 Alkyl groups, C2-C 15 alkenyl, C6-C 18 aryl, C6-C 18 aryl-substituted C1-C 10Alkyl groups, or at least one hydroxyl-substituted C1-C1 groups 15 Alkyl group, n is any integer from 0 to 15; R3 is selected from hydrogen, or C1 to C2. 10 Alkyl group; R4 is selected from hydrogen or C6-C6. 18 The aryl group; the weight average molecular weight of polyenol ethers is 60–2000.

[0032] In this application, a composite of a polymer with a three-dimensional framework structure and a perovskite active material is used as the perovskite active material layer 203. The polymer has a three-dimensional (3D) network structure, which can provide physical confinement, restrict the free growth of perovskite crystals, and promote the orderly arrangement of crystals along a specific direction. This avoids the increase in grain boundaries and lattice distortion caused by disordered growth, effectively suppressing the lattice distortion of perovskite, thereby stabilizing the crystal structure of perovskite and improving the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0033] By employing the first and / or second polymeric monomers with the specific chemical structures described above, a polymer with a rigid-flexible three-dimensional framework structure can be formed, reducing stress accumulation, regulating the lattice distortion of the perovskite, and thus improving the structural stability of the perovskite. Furthermore, compared to other ranges, limiting the weight-average molecular weight of polyacrylate and / or polyenol ether to the above range is beneficial for improving the conductivity of the perovskite active material layer 203, resulting in lower crosstalk resistance (Rs).

[0034] The technical solution provided in this application not only improves the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells, but also provides a feasible and stable manufacturing process for the commercial production of perovskite / crystalline silicon tandem solar cells, solving key problems in the film formation process.

[0035] In a preferred embodiment, in the first polymeric monomer represented by formula (I), R includes, but is not limited to, C4 to C6. 12 The R is a straight-chain or branched alkyl group. Compared to other types, using the above-mentioned R group is beneficial for improving the flexibility of polyacrylate, and for adjusting the polymer structure by adjusting the three-dimensional framework structure with the anchor point as a fulcrum, thereby adjusting local stress, reducing stress accumulation, suppressing lattice distortion of perovskite, and thus improving the structural stability of perovskite, and further improving the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells. Preferably, R includes, but is not limited to, n-butyl, 2-ethylhexyl, or n-dodecyl.

[0036] To further reduce stress accumulation in the perovskite active material layer, suppress lattice distortion of the perovskite, and further improve the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, more preferably, the first polymerization monomer includes, but is not limited to, one or more of monomers A1 to A3:

[0037] , , .

[0038] In a preferred embodiment, R1 includes, but is not limited to, hydrogen, fluorine, chlorine, or bromine; R2 includes, but is not limited to, C2-C5 straight-chain or branched alkyl groups, C2-C6 alkenyl groups, and C6-C6 alkyl groups. 12 aryl, C6-C 12 The substituted C1-C6 alkyl group, or a C2-C8 straight-chain or branched alkyl group substituted with 1 to 3 hydroxyl groups; R3 includes, but is not limited to, hydrogen, or a C1-C6 straight-chain or branched alkyl group; R4 includes, but is not limited to, hydrogen, or a C6-C6 straight-chain or branched alkyl group. 12 Aryl groups. Compared to other types, using the aforementioned R1, R2, R3, and R4 is beneficial for increasing the degree of crosslinking, improving the toughness of the network structure, and adjusting the polymer structure by using the anchor point as a fulcrum to adjust the local stress, reduce stress accumulation, suppress lattice distortion of perovskite, thereby improving the structural stability of perovskite, and further improving the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0039] To further reduce stress accumulation in the perovskite active material layer 203, suppress perovskite lattice distortion, and further improve the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, preferably, R1 includes, but is not limited to, hydrogen; R2 includes, but is not limited to, ethyl, hydroxybutyl, R3 includes, but is not limited to, vinyl, allyl, benzyl, or phenyl; R4 includes, but is not limited to, hydrogen or methyl; n includes, but is not limited to, 0 or 1.

[0040] To further reduce stress accumulation in the perovskite active material layer, suppress lattice distortion of the perovskite, and further improve the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell, more preferably, the second polymerization monomer includes, but is not limited to, one or more of monomers B1 to B7:

[0041] , , , , , , .

[0042] In a preferred embodiment, the polymer in the perovskite active material layer 203 comprises 10–50 wt% by weight. The weight percentage of the polymer in the perovskite active material layer 203 includes, but is not limited to, the above range. Limiting it to this range helps to suppress lattice distortion of the perovskite, reduce stress accumulation, and thus improve the structural stability of the perovskite, thereby enhancing the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0043] To further reduce stress accumulation in the perovskite active material layer 203 and suppress lattice distortion of the perovskite, and to regulate the directional growth of the perovskite crystal, preferably, the polymer is polyacrylate, and the weight percentage of the polymer in the perovskite active material layer 203 is 25-35 wt%; or, the polymer is a mixture of polyacrylate and polyenol ether, and the weight ratio of the two is 1:(1-3), and the weight percentage of the polymer in the perovskite active material layer 203 is 20-40 wt%.

[0044] In a preferred embodiment, the thickness of the perovskite active material layer 203 is 0.5–2 μm. The thickness of the perovskite active material layer 203 includes, but is not limited to, the above range. Limiting it to this range is beneficial for improving the light utilization efficiency of the perovskite active material layer 203, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0045] In a preferred embodiment, the perovskite active material includes, but is not limited to, FAPbI3, MAPbI3, and CsPbI3. , , or One or more of the above types. Compared with other types, using the above-mentioned types of perovskite active materials is beneficial to improving the light utilization rate of the perovskite active material layer 203, thereby improving the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0046] In a preferred embodiment, such as Figure 2 As shown, the perovskite top solar cell 200 also includes a functional layer 208, which is disposed between the hole transport layer 202 and the perovskite active material layer 203; the material of the functional layer 208 includes, but is not limited to, chitosan and its derivatives. Chitosan and its derivatives can electrostatically interact with divalent lead ions (Pb) in the perovskite precursor. 2+ It is enriched on the surface near the functional layer 208 and binds to the anion I through hydrogen bonds. - Interaction, inhibiting anion I -Excessive migration of the perovskite crystals allows the functional layer 208 to act as a template for perovskite film formation, which is beneficial for the orderly arrangement and directional growth of perovskite crystals. This helps to reduce the inherent stress accumulation of polycrystalline thin films, suppress harmful interlayer reactions, and thus improve the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells. Simultaneously, because the functional layer 208 is in contact with the perovskite active material layer 203, the introduction of polymers into the perovskite active material layer 203 allows the carboxyl groups and other functional layers to react with the divalent lead ions (Pb) in the perovskite active material. 2+ Establishes a coordination bond with formamidinium ions (FA). + When organic cations form hydrogen bonds and anchor points, they can generate local strain modulation, thereby stabilizing the crystal structure of perovskite and reducing stress accumulation.

[0047] In a preferred embodiment, the material of the functional layer 208 includes, but is not limited to, one or more of carboxymethyl chitosan (CMC), hydroxypropyl chitosan (HPC), and chitosan quaternary ammonium salt (QAC).

[0048] The chemical structure of carboxymethyl chitosan (CMC) is as follows:

[0049] .

[0050] The chemical structure of hydroxypropyl chitosan (HPC) is as follows:

[0051] .

[0052] The chemical structure of chitosan quaternary ammonium salt (QAC) is as follows:

[0053] .

[0054] To further promote the orderly arrangement and directional growth of perovskite crystals, reduce the inherent stress accumulation of polycrystalline thin films, suppress harmful interlayer reactions, and further improve the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells, preferably, the degree of polymerization (n) of hydroxypropyl chitosan is 500–100,000; and the degree of polymerization (m) of chitosan quaternary ammonium salt is 200–50,000.

[0055] In order to further promote the orderly arrangement and directional growth of perovskite crystals, reduce the inherent stress accumulation of polycrystalline thin films, suppress harmful interlayer reactions, and further improve the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells, in a preferred embodiment, the thickness of the functional layer 208 is 5-10 nm.

[0056] In a preferred embodiment, such as Figure 3As shown, the perovskite top solar cell 200 also includes an antireflection layer 209, which is disposed on the surface of the metal electrode layer 207 away from the second transparent conductive layer 206. The antireflection layer 209 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 of the perovskite / crystalline silicon tandem solar cell. J sc (and photoelectric conversion efficiency).

[0057] To further reduce reflection loss and improve the light utilization efficiency of the perovskite active material layer 203, thereby increasing the short-circuit current density of the perovskite / crystalline silicon tandem solar cell ( J sc And photoelectric conversion efficiency, preferably, the material of the antireflective layer 209 includes, but is not limited to, MgF2.

[0058] To further reduce reflection loss and improve the light utilization efficiency of the perovskite active material layer 203, thereby increasing the short-circuit current density of the perovskite / crystalline silicon tandem solar cell ( J sc The thickness of the antireflective layer 209 is preferably 50–200 nm. The introduction of this three-dimensional framework polymer into the perovskite active material layer 203 provides physical confinement to the polymer with its three-dimensional cross-linked network structure, restricting the free growth of perovskite crystals and promoting their orderly alignment along specific directions. This avoids the increase in grain boundaries and lattice distortion caused by disordered growth, effectively suppressing lattice distortion in perovskite, thereby stabilizing the perovskite crystal structure and improving the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0059] In a preferred embodiment, the coating method in step S4 can be spin coating, blade coating, or spray deposition. Using these coating methods facilitates the improvement of the uniformity of the perovskite active material layer 203, which is beneficial for improving the crystallinity quality of the perovskite film.

[0060] In a preferred embodiment, the weight percentage of the first polymeric monomer and / or the second polymeric monomer in the monomer solution is 10–50 wt%. The weight percentage of the first polymeric monomer and / or the second polymeric monomer in the monomer solution includes, but is not limited to, the above range. Limiting it to this range helps reduce stress accumulation and suppress lattice distortion, thereby improving the structural stability of the perovskite and consequently enhancing the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0061] In a preferred embodiment, the weight percentage of the perovskite precursor in the perovskite precursor solution is 25-35 wt%. The weight percentage of the perovskite precursor in the perovskite precursor solution includes, but is not limited to, the above range. Limiting it to this range is beneficial for improving the generation rate of photogenerated electrons and holes, and for improving the light absorption and utilization rate of the prepared perovskite active material layer 203.

[0062] In a preferred embodiment, the weight ratio of the first polymerizable monomer and / or the second polymerizable monomer in the monomer solution to the perovskite precursor in the perovskite precursor solution is (1-3):(1-6). Compared to other ranges, limiting the weight ratio to the above range facilitates obtaining a perovskite active material layer 203 with a specific structure and composition, which helps reduce stress accumulation, suppress perovskite lattice distortion, and thus improve the structural stability of the perovskite, thereby improving the chemical stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0063] To obtain a perovskite active material layer 203 with a specific structure and composition, and to improve the material processing performance, preferably, in step S4, the coating amount of the mixture is 15–20 mg / cm³. 2 .

[0064] To improve the efficiency of the polymerization reaction and obtain a polymer with a more stable three-dimensional framework structure, thereby reducing stress accumulation and suppressing perovskite lattice distortion, preferably, the wavelength of the ultraviolet light is 300-400 nm, the irradiation time is 10-50 s, and the irradiation power is 10-40 W.

[0065] To improve the structural stability and crystal purity of perovskite active materials, the annealing temperature is preferably 80–150°C and the time is preferably 5–15 min.

[0066] In a preferred embodiment, the preparation method further includes: preparing a functional layer 208 on the side of the hole transport layer 202 away from the first transparent conductive layer 201. The preparation method of the functional layer 208 includes: mixing a functional material with water to obtain a functional material dispersion, coating the functional material dispersion on the side of the hole transport layer 202 away from the first transparent conductive layer 201, and drying it to obtain the functional layer 208. The functional material includes, but is not limited to, chitosan and its derivatives.

[0067] In the above preparation method, a functional material dispersion prepared by mixing chitosan and its derivatives with water is coated onto the surface of the hole transport layer 202 away from the first transparent conductive layer 201, and then dried to form the functional layer 208. The presence of the functional layer 208 enables chitosan and its derivatives to conduct divalent lead ions (Pb) in the perovskite precursor through electrostatic interactions. 2+It is enriched on the surface near the functional layer 208 and binds to halide anions (such as iodide ions) via hydrogen bonds. - The interaction between halogen anions (such as iodide ions) inhibits the interaction of halogen anions (such as iodide ions). - Excessive migration of the functional layer 208, acting as a template for perovskite film formation, facilitates the ordered arrangement and directional growth of perovskite crystals. This helps alleviate the inherent stress accumulation in polycrystalline films, suppresses harmful interlayer reactions, and ultimately improves the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells. Simultaneously, because the functional layer 208 is in contact with the perovskite active material layer 203, the introduction of polymers into the perovskite active material layer 203 allows the carboxyl groups and other functional layers to react with the divalent lead ions (Pb) in the perovskite active material. 2+ Establishes a coordination bond with formamidinium ions (FA). + When organic cations form hydrogen bonds and anchor points, they can generate local strain modulation, thereby stabilizing the crystal structure of perovskite and reducing stress accumulation.

[0068] In a preferred embodiment, the functional material dispersion can be coated by spin coating, blade coating, or spray coating. These coating methods improve the uniformity of the functional layer 208, thereby better utilizing its function, suppressing excessive migration of silver halide ions, and promoting the orderly arrangement and directional growth of perovskite crystals.

[0069] This application may employ a commonly used crystalline silicon solar cell 100 in the art. In a preferred embodiment, the crystalline silicon solar cell 100 includes, but is not limited to, TOPCon solar cells (tunneling oxide passivated contact solar cells), HJT solar cells (heterojunction solar cells), or BC solar cells (interdigitated back contact solar cells).

[0070] In a preferred embodiment, the thickness of the first transparent conductive layer 201 and the second transparent conductive layer 206 are each independently limited to, but not limited to, 5–30 nm, and their materials are each independently limited to, but not limited to, fluorine-doped tin oxide (FTO), indium tin oxide (ITO), and aluminum-doped zinc oxide (AZO). Compared to other ranges, limiting the thickness of the first transparent conductive layer 201 and the second transparent conductive layer 206 to the above range is beneficial to improving their conductivity, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell. At the same time, using the above-mentioned materials as the materials of the first transparent conductive layer 201 and the second transparent conductive layer 206 is also beneficial to improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell while reducing the fabrication difficulty.

[0071] In a preferred embodiment, the hole transport layer 202 has a thickness of 10–20 nm, and its materials include, but are 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 x The hole transport layer 202 can be one or more of Cu2O and CuI. Compared to other ranges, limiting the thickness of the hole transport layer 202 to the above range is beneficial to improving hole transport efficiency, thereby improving the photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells. Simultaneously, using the above-mentioned hole transport materials facilitates efficient hole extraction and transport, reduces recombination losses, and thus improves the open-circuit voltage and fill factor of perovskite / crystalline silicon tandem solar cells.

[0072] In a preferred embodiment, the electron transport layer 204 has a thickness of 5–30 nm, and its material includes, but is not limited to, TiO2, ZnO, and C. 60 One or more of PCBMs are used. The thickness of the electron transport layer 204 includes, but is not limited to, the range described above. Limiting it to the range is beneficial for improving electron transport efficiency, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell. Simultaneously, using the aforementioned types of electron transport materials is beneficial for improving electron transport efficiency and reducing interface defects, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0073] In a preferred embodiment, the thickness of the cathode buffer layer 205 is 2–30 nm, and its material includes, but is not limited to, one or more of N,N'-bis(N,N-dimethylpropane-1-amine oxide) alkene-3,4,9,10-tetracarboxylic acid diimide (PDINO), polyetherimide (PEIE), poly(3-hexylthiophene-2,5-diyl) (P3TMAHT), and SnO2. The thickness of the cathode buffer layer 205 is not limited to the above range, and limiting it within this range helps reduce damage to the battery film during the fabrication of the second transparent conductive layer 206. Simultaneously, using the above-mentioned cathode buffer materials helps improve electron transport efficiency, reduce interface defects, and thereby improve the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0074] In a preferred embodiment, the thickness of the metal electrode layer 207 is 0.5–1 μm, and its material includes, but is not limited to, one or more of Ag, Au, and Cu. Limiting the thickness of the metal electrode layer 207 to the above range is beneficial for improving its conductivity and suppressing secondary absorption, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell. Simultaneously, using the aforementioned types of metal electrode materials helps reduce contact resistance and facilitates more stable current output, thereby improving the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0075] The second aspect of this application also provides a method for fabricating the perovskite / crystalline silicon tandem solar cell provided in this application. The method includes: sequentially fabricating a first transparent conductive layer 201, a hole transport layer 202, a perovskite active material layer 203, an electron transport layer 204, a cathode buffer layer 205, a second transparent conductive layer 206, and a metal electrode layer 207 on the surface of a crystalline silicon base cell 100. The method for fabricating the perovskite active material layer 203 includes: step S1, mixing a first polymer monomer and / or a second polymer monomer... Step S2: Mix the perovskite precursor with the first solvent to obtain a monomer solution; Step S3: Mix the monomer solution with the perovskite precursor solution to obtain a mixed liquid; Step S4: Under ultraviolet light irradiation, coat the mixed liquid on the side of the hole transport layer 202 away from the first transparent conductive layer 201, then coat it with an anti-solvent, and after annealing, obtain the perovskite active material layer 203; wherein, the first polymerizable monomer and the second polymerizable monomer have the same definition as in the above text.

[0076] In the method for preparing the perovskite / crystalline silicon tandem solar cell provided in this application, the nucleation and crystallization process of the perovskite crystal is effectively regulated by introducing specific first and / or second polymeric monomers during the preparation of the perovskite active layer. First, monomer solutions and perovskite precursor solutions are prepared separately; then, they are mixed with the perovskite precursor solution to obtain a mixed solution; in step S3, coating is performed under ultraviolet light irradiation. During this process, the first and / or second polymeric monomers undergo in-situ polymerization to form a three-dimensional (3D) cross-linked network structure. After coating with an anti-solvent and annealing, the perovskite active material is obtained. In this process, the perovskite active material is encapsulated within the three-dimensional cross-linked network structure, thus forming a composite of a polymer with a three-dimensional framework structure and the perovskite active material. The introduction of this three-dimensional framework structure polymer plays a crucial role in the perovskite nucleation and crystallization process.

[0077] The above coating method facilitates the improvement of the uniformity of the functional layer 208, thereby better leveraging the function of the functional layer 208, suppressing the excessive migration of halide silver ions, and promoting the orderly arrangement and directional growth of perovskite crystals.

[0078] In a preferred embodiment, the functional material includes, but is not limited to, one or more of carboxymethyl chitosan (CMC), hydroxypropyl chitosan (HPC), and chitosan quaternary ammonium salt (QAC). Compared to other types, the use of the above-mentioned types of chitosan and their derivatives is beneficial for promoting the ordered arrangement and directional growth of perovskite crystals, reducing the inherent stress accumulation of polycrystalline thin films, and suppressing harmful interlayer reactions, thereby improving the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0079] To further enhance the role of functional materials and promote the orderly arrangement and directional growth of perovskite crystals, preferably, the weight percentage of functional materials in the functional material dispersion is 10-50 wt%.

[0080] In a preferred embodiment, the first transparent conductive layer 201 and the second transparent conductive layer 206 are prepared by magnetron sputtering or chemical vapor deposition (CVD). Compared with other preparation methods, the above preparation method is beneficial to improving the deposition uniformity of the first transparent conductive layer 201 and the second transparent conductive layer 206.

[0081] In a preferred embodiment, the hole transport layer 202 is prepared by vapor deposition, blade coating, spraying, or inkjet printing. Compared to other preparation methods, the above preparation method helps to avoid solution swirling during deposition, thus preventing solution overflow and waste.

[0082] In a preferred embodiment, the electron transport layer 204 is prepared by vapor deposition, blade coating, spraying, or inkjet printing. Compared to other preparation methods, the above-mentioned preparation method is beneficial to improving the uniformity and consistency of the electron transport layer 204, thereby enabling it to perform its function.

[0083] In a preferred embodiment, the cathode buffer layer 205 is prepared using atomic layer deposition (ALD). Compared to other preparation methods, the above preparation method is beneficial to the deposition uniformity of the cathode buffer layer 205, thereby enabling it to perform its function.

[0084] In a preferred embodiment, the metal electrode layer 207 is prepared using screen printing or vapor deposition. Compared to other preparation methods, the above preparation method is beneficial to improving the battery preparation efficiency, thereby increasing the mass production cycle.

[0085] In a preferred embodiment, the antisolvent includes, but is not limited to, one or more of chlorobenzene, ethyl acetate, and toluene. Using the above-mentioned types of antisolvents is beneficial for the growth of perovskite active materials and helps improve the film quality of the perovskite active material layer 203.

[0086] 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.

[0087] Example 1

[0088] A method for fabricating a perovskite / crystalline silicon tandem solar cell specifically includes the following steps:

[0089] (1) Fabrication of crystalline silicon bottom cell 100:

[0090] Texturing was performed on an N-type silicon substrate. First, a pre-cleaning process was conducted using 10wt% NaOH at 78°C for 50 seconds. Then, texturing was performed on the silicon wafer using a mixed solution containing NaOH, Na₂SiO₃, and isopropanol (IPA) at 75°C for 35 minutes, resulting in a textured silicon wafer. An Ag electrode layer with a thickness of 1 μm was deposited on one side of the textured silicon wafer at a deposition rate of 350 Å / s. Finally, a plasma-enhanced chemical vapor deposition (PECVD) system (Anhui Beiyike, PECVD-III-500A-D210) was used to deposit the electrode layer on the textured silicon wafer away from the Ag electrode layer. Intrinsic amorphous silicon thin films and doped amorphous silicon thin films are sequentially deposited on one side of the substrate to form a PN junction. The chamber is preheated for 30 minutes, hydrogen gas is introduced, and the substrate is cleaned by sputtering for 10 minutes. H2, SiH4, PH3 and B2H6 are introduced into the PECVD equipment to start the deposition of amorphous silicon thin films. The treated film is placed in a double-sided heterojunction TCO magnetron sputtering deposition equipment (Hunan Hongtaiyang Optoelectronic Technology Co., Ltd., RSP-8000) to deposit an ITO thin film. The vacuum degree is 8.9 Pa, the sputtering power is 45 W, and the sputtering time is 900 minutes to obtain an HJT cell.

[0091] The stacked structure of the HJT cell is represented as: back Ag / ITO / p-polycrystalline silicon / intrinsic amorphous silicon / n-Si / intrinsic amorphous silicon / n-polycrystalline silicon / ITO;

[0092] (2) Fabrication of hole transport layer 202:

[0093] NiO with a mass concentration of 0.3 mg / mL x The aqueous solution was spin-coated onto one side of the conductive surface of the crystalline silicon bottom cell 100 prepared in step (1) at a speed of 4000 rpm for 30 s. Then, it was annealed on a hot plate at 100°C for 10 min to obtain a NiO layer with a thickness of 20 nm.x layer;

[0094] (3) Fabrication of functional layer 208:

[0095] 0.5 mg of carboxymethyl chitosan (CMC, manufacturer: Sigma-Aldrich, CAS: 83512-85-0) was dissolved in 1 mL of dimethyl sulfoxide (DMSO) to obtain a dispersion of the functional material; at 0.5 mg / cm³... 2 The coating amount is obtained by spin-coating the above functional material dispersion onto the NiO obtained in step (2). x On the side of the layer away from the crystalline silicon base cell 100, the spin coating speed is 3000 rpm, and after spin coating for 20 seconds, it is transferred to an oven at 100°C and dried for 15 minutes to obtain a CMC layer with a thickness of 5 nm.

[0096] (4) Preparation of perovskite active material layer 203:

[0097] 1 mg of butyl acrylate (monomer A1) and 2 mg of vinyl ethyl ether (monomer B1) were dispersed in a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO was 5:2) and stirred until dissolved. The solution was then diluted to a total mass percentage of 25 wt% for monomers A1 and B1 to obtain a monomer solution for later use.

[0098] The chemical structural formula of monomer A1 is as follows: The chemical structural formula of monomer B1 is: ;

[0099] PbI2, MAI, FABr and CsBr powders in a molar ratio of 5:4:5:1 were dispersed in 5 mL of a mixed solvent of DMF and DMSO (volume ratio DMF:DMSO=5:2) to obtain a perovskite precursor solution with a weight percentage of 28 wt%.

[0100] Add 100 μL of the above monomer solution to the above 1 mL perovskite precursor solution and stir for 5 h to prepare a mixture;

[0101] 20 seconds before spin coating, turn on a 365nm UV lamp (30W) to irradiate the above mixture. Spin-coat the perovskite precursor solution onto the side of the CMC layer obtained in step (3) away from the crystalline silicon bottom cell 100. First, spin-coat at 3000rpm for 20 seconds, then add 50μL of chlorobenzene (CB) and spin-coat at 5000rpm for 30 seconds. After spin-coating, stop the irradiation and transfer the wet film to a 100°C heating plate for annealing for 10 minutes to obtain a polymer (weight-average molecular weight of 300) with a three-dimensional framework structure of 500nm thickness. The composite layer; in this layer, the polymer with a three-dimensional framework structure accounts for 15 wt% by weight;

[0102] (5) Fabrication of electron transport layer 204:

[0103] The polymer with a three-dimensional framework structure obtained in step (4) and The composite layer on the side of the surface away from the crystalline silicon bottom cell 100 was deposited at a deposition rate of 300 Å / s to obtain a C60 layer with a thickness of 20 nm.

[0104] (6) Preparation of cathode buffer layer 205:

[0105] SnO2 was sputtered and deposited on the side of the C60 layer obtained in step (5) away from the crystalline silicon bottom cell 100 to obtain a SnO2 layer with a thickness of 20 nm. The vacuum degree was 4.8 Pa, the sputtering power was 35 W, the sputtering time was 60 min, and the argon flow rate was 800 sccm.

[0106] (7) Preparation of metal electrode layer 207:

[0107] On the side of the SnO2 layer obtained in step (6) away from the crystalline silicon bottom cell 100, an Ag electrode layer with a thickness of 500 nm is deposited by vapor deposition at a deposition rate of 350 Å / s.

[0108] (8) Preparation of antireflective layer 209:

[0109] On the side of the Ag electrode layer obtained in step (7) away from the crystalline silicon bottom cell 100, a MgF2 layer with a thickness of 100 nm is deposited by vapor deposition at a deposition rate of 400 Å / s.

[0110] The stacked structure of this perovskite / crystalline silicon tandem solar cell is as follows: Figure 3 As shown, its specific representation is as follows:

[0111] Back Ag / ITO / p-polycrystalline silicon / intrinsic amorphous silicon / n-Si / intrinsic amorphous silicon / n-polycrystalline silicon / ITO / NiO x / CMC / Polymers and The complex of / C60 / SnO2 / Ag / MgF2.

[0112] Example 2

[0113] The difference from Example 1 is that in step (4), only monomer A1 is used to prepare the monomer solution.

[0114] Example 3

[0115] The difference from Example 1 is that in step (4), only monomer B1 is used to prepare the monomer solution.

[0116] Example 4

[0117] The difference from Example 1 is that in step (4), 1 mg of monomer A2 and 2 mg of monomer B2 are dispersed in a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 5:2) and stirred until dissolved. Then, the solution is diluted to a total weight percentage of 25 wt% for monomer A2 and monomer B2 to obtain a monomer solution for later use.

[0118] The chemical structural formula of monomer A2 is: The chemical structural formula of monomer B2 is: .

[0119] Example 5

[0120] The difference from Example 4 is that in step (4), only monomer A2 is used to prepare the monomer solution.

[0121] Example 6

[0122] The difference from Example 4 is that in step (4), only monomer B2 is used to prepare the monomer solution.

[0123] Example 7

[0124] The difference from Example 1 is that in step (4), 1 mg of monomer A3 and 2 mg of monomer B3 are dispersed in a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 5:2) and stirred until dissolved. Then, the solution is diluted to a total weight percentage of 25 wt% of monomer A3 and monomer B3 to obtain a monomer solution for later use.

[0125] The chemical structural formula of monomer A3 is: The chemical structural formula of monomer B3 is: .

[0126] Example 8

[0127] The difference from Example 7 is that in step (4), only monomer A3 is used to prepare the monomer solution.

[0128] Example 9

[0129] The difference from Example 7 is that in step (4), only monomer B3 is used to prepare the monomer solution.

[0130] Example 10

[0131] The difference from Example 1 is that in step (3), 0.5 mg of hydroxypropyl chitosan (HPC, CAS No.: 104673-29-2, degree of polymerization n is 682, weight average molecular weight is 120,000) was dissolved in 1 mL of dimethyl sulfoxide (DMSO) to obtain a functional material dispersion. The functional layer 208 prepared in this example is an HPC layer.

[0132] Example 11

[0133] The difference from Example 1 is that in step (3), 0.5 mg of chitosan quaternary ammonium salt (QAC, CAS No.: 70694-72-3, degree of polymerization m: 420, weight-average molecular weight: 100,000) was dissolved in 1 mL of dimethyl sulfoxide (DMSO) to obtain a functional material dispersion. The functional layer 208 prepared in this example is a QAC layer.

[0134] Example 12

[0135] The difference from Example 1 is that in step (3), the weight percentage of carboxymethyl chitosan in the functional material dispersion is 10 wt%.

[0136] Example 13

[0137] The difference from Example 1 is that in step (3), the weight percentage of carboxymethyl chitosan in the functional material dispersion is 50 wt%.

[0138] Example 14

[0139] The difference from Example 1 is that in step (3), the weight percentage of carboxymethyl chitosan in the functional material dispersion is 60 wt%.

[0140] Example 15

[0141] The difference from Example 1 is that step (3) is omitted, and the resulting perovskite / crystalline silicon tandem solar cell does not contain the functional layer 208.

[0142] Comparative Example 1

[0143] The difference from Example 1 is that: no monomer solution was prepared in step (4), no in-situ polymerization reaction was carried out during the preparation of the perovskite active material layer 203, and the material of the perovskite active material layer in the obtained perovskite / crystalline silicon tandem solar cell is... .

[0144] The photovoltaic performance of the perovskite / crystalline silicon solar cells prepared in all the embodiments and comparative examples of this application was tested under standard test conditions (AM1.5G spectrum, 1000 W / m² irradiance, 25°C). The PCE degradation rate was calculated by periodically measuring the current-voltage (JV) curves until the PCE decreased to 80% of its initial value (target TS80m), and the performance degradation time points were recorded. The test results are summarized in Table 1.

[0145] Table 1

[0146]

[0147] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0148] In the method for preparing the perovskite / crystalline silicon tandem solar cell provided in this application, the nucleation and crystallization process of the perovskite crystal is effectively regulated by introducing specific first and / or second polymeric monomers during the preparation of the perovskite active layer. First, monomer solutions and perovskite precursor solutions are prepared separately; then, they are mixed with the perovskite precursor solution to obtain a mixed solution; in step S3, coating is performed under ultraviolet light irradiation. During this process, the first and / or second polymeric monomers undergo in-situ polymerization to form a three-dimensional (3D) cross-linked network structure. After coating with an anti-solvent and annealing, the perovskite active material is obtained. In this process, the perovskite active material is encapsulated within the three-dimensional cross-linked network structure, thus forming a composite of a polymer with a three-dimensional framework structure and the perovskite active material. The introduction of this three-dimensional framework structure polymer plays a crucial role in the perovskite nucleation and crystallization process.

[0149] In this application, a composite of a polymer with a three-dimensional framework structure and a perovskite active material is used as the perovskite active material layer 203. The polymer has a three-dimensional (3D) network structure, which can provide physical confinement, restrict the free growth of perovskite crystals, and promote the orderly arrangement of crystals along a specific direction. This avoids the increase in grain boundaries and lattice distortion caused by disordered growth, effectively suppressing the lattice distortion of perovskite, thereby stabilizing the crystal structure of perovskite and improving the chemical stability and photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells.

[0150] By employing the first and / or second polymeric monomers with the specific chemical structures described above, a polymer with a rigid-flexible three-dimensional framework structure can be formed, reducing stress accumulation, regulating the lattice distortion of the perovskite, and thus improving the structural stability of the perovskite. Furthermore, compared to other ranges, limiting the weight-average molecular weight of polyacrylate and / or polyenol ether to the above range is beneficial for improving the conductivity of the perovskite active material layer 203, resulting in lower crosstalk resistance (Rs).

[0151] 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.

[0152] 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) stacked together, characterized in that, The perovskite top cell (200) includes a first transparent conductive layer (201), a hole transport layer (202), a perovskite active material layer (203), an electron transport layer (204), a cathode buffer layer (205), a second transparent conductive layer (206), and a metal electrode layer (207) stacked sequentially. The first transparent conductive layer (201) is in contact with the crystalline silicon bottom cell (100). The material of the perovskite active material layer (203) is a composite of a three-dimensional framework polymer and a perovskite active material, wherein the polymer is selected from polyacrylate and / or polyenol ether. The first polymeric monomer used to form the polyacrylate has the structure shown in formula (I): CH2=CHCOOR (I), where R is selected from C1 to C2. 15 The alkyl group; the weight-average molecular weight of the polyacrylate is 70 to 400; The second polymerizable monomer used to form the polyenol ether has the structure shown in formula (II): (II), wherein R1 is selected from hydrogen or halogen, and R2 is selected from C1 to C2. 15 Alkyl groups, C2-C 15 alkenyl, C6-C 18 aryl, C6-C 18 aryl-substituted C1-C 10 Alkyl groups, or at least one hydroxyl-substituted C1-C1 groups 15 Alkyl group, n is any integer from 0 to 15; R3 is selected from hydrogen, or C1 to C2. 10 Alkyl group; R4 is selected from hydrogen or C6-C6. 18 The aryl group; the weight average molecular weight of the polyenol ether is 60 to 2000.

2. The perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The R is selected from C4 to C5. 12 Straight-chain or branched alkyl groups; Preferably, R is selected from n-butyl, 2-ethylhexyl, or n-dodecyl; More preferably, the first polymerizing monomer is selected from one or more monomers A1 to A3: 、 、 。 3. The perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, R1 is selected from hydrogen, fluorine, chlorine, or bromine; R2 is selected from C2-C5 straight-chain or branched alkyl groups, C2-C6 alkenyl groups, C6-C6 branched alkyl groups, and C5-C6 branched alkyl groups. 12 aryl, C6-C 12 The substituted C1-C6 alkyl group, or a C2-C8 straight-chain or branched alkyl group substituted with 1 to 3 hydroxyl groups; R3 is selected from hydrogen, or a C1-C6 straight-chain or branched alkyl group; R4 is selected from hydrogen, or a C6-C6 straight-chain or branched alkyl group. 12 aryl; Preferably, R1 is selected from hydrogen; R2 is selected from ethyl, hydroxybutyl, ... R3 is selected from hydrogen or methyl; R4 is selected from hydrogen or phenyl; n is selected from 0 or 1; More preferably, the second polymerizing monomer is selected from one or more monomers B1 to B7: 、 、 、 、 、 、 。 4. The perovskite / crystalline silicon tandem solar cell according to any one of claims 1 to 3, characterized in that, The polymer in the perovskite active material layer (203) accounts for 10-50 wt% by weight. Preferably, the polymer is polyacrylate, and the weight percentage of the polymer in the perovskite active material layer (203) is 25-35 wt%; or, the polymer is a mixture of polyacrylate and polyvinyl ether, and the weight ratio of the two is 1:(1-3), and the weight percentage of the polymer in the perovskite active material layer (203) is 20-40 wt%. Preferably, the thickness of the perovskite active material layer (203) is 0.5–2 μm; Preferably, the perovskite active material is selected from FAPbI3, MAPbI3, CsPbI3, , , or One or more of them.

5. The perovskite / crystalline silicon tandem solar cell according to claim 4, characterized in that, The perovskite top solar cell (200) further includes a functional layer (208), which is disposed between the hole transport layer (202) and the perovskite active material layer (203); the material of the functional layer (208) is selected from chitosan and its derivatives; Preferably, the material of the functional layer (208) is selected from one or more of carboxymethyl chitosan, hydroxypropyl chitosan, and chitosan quaternary ammonium salt; Preferably, the thickness of the functional layer (208) is 5-10 nm.

6. The perovskite / crystalline silicon tandem solar cell according to any one of claims 1 to 5, characterized in that, The perovskite top solar cell (200) further includes an anti-reflection layer (209), which is disposed on the side surface of the metal electrode layer (207) away from the second transparent conductive layer (206); Preferably, the antireflective layer (209) is made of MgF2; Preferably, the thickness of the antireflective layer (209) is 50-200 nm.

7. The perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The crystalline silicon bottom cell (100) is selected from TOPCon bottom cells, HJT bottom cells, or BC bottom cells; Preferably, the thickness of the first transparent conductive layer (201) and the second transparent conductive layer (206) are each independently 5-30 nm, and their materials are each independently selected from one or more of fluorine-doped tin oxide, indium tin oxide, and aluminum-doped zinc oxide; Preferably, the hole transport layer (202) has a thickness of 10-20 nm, and its material 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 and one or more of Cu2O and CuI; Preferably, the electron transport layer (204) has a thickness of 5–30 nm, and its material is selected from TiO2, ZnO, and C. 60 One or more of the following: PCBM; Preferably, the thickness of the cathode buffer layer (205) is 2-30 nm, and its material is selected from one or more of N,N'-bis(N,N-dimethylpropane-1-amine oxide) olene-3,4,9,10-tetracarboxylic acid diimide, polyetherimide, poly(3-hexylthiophene-2,5-diyl), and SnO2. Preferably, the thickness of the metal electrode layer (207) is 0.5 to 1 μm, and its material is selected from one or more of Ag, Au and Cu.

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: sequentially preparing a first transparent conductive layer (201), a hole transport layer (202), a perovskite active material layer (203), an electron transport layer (204), a cathode buffer layer (205), a second transparent conductive layer (206), and a metal electrode layer (207) on the surface of a crystalline silicon bottom cell (100), wherein the preparation method of the perovskite active material layer (203) includes: Step S1: Mix the first polymerizable monomer and / or the second polymerizable monomer with the first solvent to obtain a monomer solution; Step S2: Mix the perovskite precursor with the second solvent to obtain a perovskite precursor solution; Step S3: Mix the monomer solution with the perovskite precursor solution to obtain a mixture; Step S4: Under ultraviolet light irradiation, the mixture is coated on the side of the hole transport layer (202) away from the first transparent conductive layer (201), and then coated with an anti-solvent. After annealing, the perovskite active material layer (203) is obtained. Wherein, the first polymeric monomer and the second polymeric monomer have the same definition as in claim 1.

9. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 8, characterized in that, In the monomer solution, the weight percentage of the first polymeric monomer and / or the second polymeric monomer is 10-50 wt%. Preferably, the perovskite precursor solution contains 25-35 wt% perovskite precursor by weight. Preferably, the weight ratio of the first polymerizable monomer and / or the second polymerizable monomer in the monomer solution to the perovskite precursor in the perovskite precursor solution is (1-3):(1-6). Preferably, in step S4, the coating amount of the mixture is 15-20 mg / cm³. 2 ; Preferably, the wavelength of the ultraviolet light is 300-400 nm, the irradiation time is 10-50 s, and the irradiation power is 10-40 W. Preferably, the annealing treatment is performed at a temperature of 80–150°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 preparation method further includes: preparing a functional layer (208) on the surface of the hole transport layer (202) away from the first transparent conductive layer (201), wherein the preparation method of the functional layer (208) includes: A functional material dispersion is obtained by mixing the functional material with water, and the functional material dispersion is coated on the surface of the hole transport layer (202) away from the first transparent conductive layer (201); after drying, the functional layer (208) is obtained; the functional material is selected from chitosan and its derivatives. Preferably, the functional material is selected from one or more of carboxymethyl chitosan, hydroxypropyl chitosan, and chitosan quaternary ammonium salt; Preferably, the functional material in the functional material dispersion contains 10 to 50 wt% of the functional material.

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