Perovskite crystalline silicon tandem cell with low temperature coefficient and preparation method thereof

Abstract

The application discloses a perovskite crystalline silicon laminated cell with a low temperature coefficient and a preparation method thereof. The cell comprises, from bottom to top, a crystalline silicon bottom cell, a tunneling layer and a perovskite top cell arranged in sequence. The perovskite top cell comprises a perovskite absorption layer with a nano bracket. The cell of the application can effectively inhibit the external lattice thermal expansion of the perovskite material during temperature rise, thereby reducing the temperature coefficient of the whole laminated cell device and improving the actual power generation performance of the device in a high-temperature environment. The application solves the problem that the actual power generation performance of the existing perovskite / crystalline silicon laminated cell is limited due to the high temperature coefficient.

Description

TECHNICAL FIELD

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

[0002] As a clean and unlimited energy source, solar energy has played an increasingly important role in the global energy structure due to its abundant reserves and high cost-effectiveness. Photovoltaic cells are one of the main ways to convert solar energy into electricity, and the application of materials such as monocrystalline silicon and polycrystalline silicon has reached a high level of industrialization. However, as the demand for higher photoelectric conversion efficiency and lower manufacturing costs grows, perovskite / crystalline silicon tandem technology has gradually become a hot topic in the photovoltaic field.

[0003] From a theoretical point of view, by combining perovskite materials with wide bandgaps, high absorption coefficients, and high carrier mobility with crystalline silicon materials with good stability and superior electron transport performance, a new type of heterojunction structure can be constructed, significantly improving the photoelectric conversion efficiency of solar cells. Studies have shown that this combination can achieve a photoelectric conversion efficiency of over 40%, far exceeding the performance of traditional crystalline silicon solar cells. In fact, the photoelectric conversion efficiency of perovskite / crystalline silicon tandem cells has broken through 34%, showing great commercial potential.

[0004] However, despite these advantages, perovskite / crystalline silicon tandem cells are limited in high-temperature conditions. In particular, in outdoor high-temperature environments, the output power of such cells decreases significantly due to a high temperature coefficient. Specifically, as the ambient temperature rises, the bandgap of perovskite materials increases with temperature, which, combined with the opposite trend of crystalline silicon materials, leads to a current mismatch problem, severely affecting cell efficiency. Currently, the temperature coefficient of such cells is generally between -0.3% / °C and -0.4% / °C, which makes their actual power generation in high-temperature environments significantly lower than expected, especially in hot summer weather, where daily power generation can be 5-8% lower than that of photovoltaic devices with a lower temperature coefficient. Therefore, although perovskite / crystalline silicon tandem cells have extremely high photoelectric conversion efficiency in theory, their practicality is challenged by temperature-related performance issues, especially in hot regions or seasons, where their performance advantage is difficult to fully realize.

[0005] Therefore, it is necessary to design a new cell that can effectively suppress the external lattice thermal expansion of perovskite materials during temperature rise, thereby reducing the temperature coefficient of the entire tandem cell device and improving its actual power generation performance in high-temperature environments; solve the problem of limited actual power generation performance of existing perovskite / crystalline silicon tandem cells due to a high temperature coefficient. SUMMARY

[0006] The present application aims to overcome the defects of the prior art, and provides a perovskite crystalline silicon tandem cell with a low temperature coefficient and a preparation method thereof.

[0007] To solve the above technical problems, the present application aims to provide a perovskite crystalline silicon tandem cell with a low temperature coefficient, comprising: a crystalline silicon bottom cell, a tunneling layer and a perovskite top cell arranged in sequence from bottom to top; the perovskite top cell comprises a perovskite absorption layer, and the perovskite absorption layer is provided with a nano support.

[0008] Further technical solutions are that the nano support comprises an oxide nano support.

[0009] Further technical solutions are that the oxide nano support comprises at least one of zinc oxide, aluminum oxide and silicon dioxide nano particles.

[0010] Further technical solutions are that the crystalline silicon bottom cell comprises a first metal electrode layer, a first transparent electrode layer, a P-type base doping layer, a base passivation layer, a silicon substrate, a base surface passivation layer and an N-type base doping layer arranged in sequence from bottom to top.

[0011] The present application also provides a preparation method of the perovskite crystalline silicon tandem cell with a low temperature coefficient, and the perovskite top cell comprises a hole transport layer and a perovskite absorption layer arranged on the tunneling layer.

[0012] The manufacturing method of the perovskite absorption layer comprises:

[0013] A perovskite precursor solution is prepared.

[0014] The perovskite precursor solution is uniformly coated on the surface of the hole transport layer.

[0015] After the spin coating is completed, a flash evaporation operation is performed to obtain a semi-finished perovskite wet film.

[0016] After the flash evaporation is completed, an oxide nano particle suspension is spin-coated on the semi-finished perovskite wet film, and an annealing treatment is performed.

[0017] Further technical solutions are that the oxide nano particle suspension comprises at least one of zinc oxide, aluminum oxide and silicon dioxide nano particles, and is dissolved in isopropyl alcohol.

[0018] Further technical solutions are that when the perovskite precursor solution is uniformly coated on the surface of the hole transport layer, the spin coating speed is 1000-6000 rpm, and the spin coating time is 20-120 s.

[0019] Further technical solutions are that the flash evaporation time is 10-60 s, and the flash evaporation temperature is 0-100 DEG C.

[0020] The further technical solution is as follows: when spin-coating an oxide nanoparticle suspension onto a semi-finished perovskite wet film, the spin-coating speed is 1000-6000 rpm and the spin-coating time is 20-120 s.

[0021] The further technical solution is as follows: the annealing temperature used in the annealing process is 50-150℃, and the annealing time is 5-40min.

[0022] The advantages of this invention compared to existing technologies are as follows: This invention introduces a perovskite absorber layer with a nanoscaffold into a traditional stacked structure, sequentially arranging a crystalline silicon bottom cell, a tunneling layer, and a perovskite top cell from bottom to top. This design effectively suppresses the external lattice thermal expansion of the perovskite material during temperature rise by utilizing the nanoscaffold, thereby reducing the performance fluctuations of the entire stacked cell device caused by temperature changes and lowering its temperature coefficient. In particular, the presence of the nanoscaffold not only improves the thermal stability of the perovskite layer but also enhances the actual power generation performance of the device under high-temperature environments without significantly affecting the photoelectric conversion efficiency, solving the problem of limited actual power generation performance of perovskite / crystalline silicon stacked cells in existing technologies due to their high temperature coefficient.

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of a perovskite-silicon tandem solar cell with a low temperature coefficient provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram illustrating a method for fabricating a perovskite-silicon tandem solar cell with a low temperature coefficient, provided in an embodiment of the present invention.

[0027] Figure 3 A schematic diagram illustrating the perovskite absorber layer preparation process provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram illustrating the preparation process of a perovskite absorber layer with a nanoscaffold, provided for another embodiment of the present invention;

[0029] Figure 5 A graph showing the temperature coefficient test results provided in an embodiment of the present invention;

[0030] Figure 6 A temperature coefficient test result diagram provided for another embodiment of the present invention;

[0031] Explanation of the markings in the image:

[0032] 110. First metal electrode layer; 111. First transparent electrode layer; 112. P-type substrate doped layer; 113. Substrate passivation layer; 114. Silicon substrate; 115. Substrate surface passivation layer; 116. N-type substrate doped layer; 117. Tunneling layer; 210. Hole transport layer; 211. Perovskite absorber layer; 212. Passivation layer; 213. Adhesion layer; 214. Electron transport layer; 215. Buffer layer; 216. Second transparent electrode layer; 217. Second metal electrode layer; 218. Antireflection layer. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0035] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0036] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0037] In solar photovoltaic technology, perovskite / crystalline silicon tandem solar cells, with their combination of wide-bandgap perovskite and highly stable crystalline silicon materials, can theoretically achieve photoelectric conversion efficiencies exceeding 40%, far surpassing traditional crystalline silicon solar cells. However, despite their laboratory efficiencies exceeding 34%, demonstrating significant commercial potential, these cells are limited in high-temperature conditions. Due to their high temperature coefficient, their output power decreases significantly in hot environments, with daily power generation potentially 5%-8% lower than other photovoltaic devices during hot summer days. This restricts their practicality and full realization of their performance advantages in high-temperature environments. Therefore, while perovskite / crystalline silicon tandem solar cells show great promise in improving photoelectric conversion efficiency, their temperature-related performance issues still need to be addressed to adapt to a wider range of applications.

[0038] To address this, embodiments of the present invention provide a perovskite-silicon tandem solar cell with a low temperature coefficient, which effectively suppresses the external lattice thermal expansion of the perovskite material during temperature rise, thereby reducing the temperature coefficient of the entire tandem solar cell device and improving its actual power generation performance under high temperature conditions; thus solving the problem that the actual power generation performance of existing perovskite / silicon tandem solar cells is limited due to their high temperature coefficient.

[0039] Specifically, specific structures and processes are employed to effectively suppress the external lattice thermal expansion of perovskite materials at high temperatures, thereby reducing the temperature coefficient of the entire tandem solar cell and improving its power generation performance under high-temperature conditions. Specific measures include: utilizing a perovskite absorber layer 211 with an oxide nanoscaffold; optimizing the thickness and fabrication process of each layer (such as the hole transport layer 210 and electron transport layer 214); precisely controlling the spin-coating, flash evaporation, and annealing conditions of the perovskite precursor solution; and the method for forming the passivation layer 212. These strategies work together to solve the problem of limited actual power generation performance in existing perovskite / crystalline silicon tandem solar cells due to their high temperature coefficient, enabling the tandem solar cell to maintain high photoelectric conversion efficiency even under high-temperature conditions.

[0040] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0041] Please see Figure 1 A perovskite-silicon tandem solar cell with a low temperature coefficient includes: a crystalline silicon bottom cell, a tunneling layer 117, and a perovskite top cell arranged sequentially from bottom to top; the perovskite top cell includes a perovskite absorber layer 211 with a nanoscaffold.

[0042] The crystalline silicon bottom cell includes, from bottom to top, a first metal electrode layer 110, a first transparent electrode layer 111, a P-type substrate doped layer 112, a substrate passivation layer 113, a silicon substrate 114, a substrate surface passivation layer 115, and an N-type substrate doped layer 116; the perovskite top cell includes, from bottom to top, a hole transport layer 210, a perovskite absorption layer 211, a passivation layer 212, an adhesion layer 213, an electron transport layer 214, a buffer layer 215, a second transparent electrode layer 216, a second metal electrode layer 217, and an antireflection layer 218; wherein the perovskite absorption layer 211 has a nanoscaffold.

[0043] In this embodiment, the silicon substrate 114 is a textured silicon substrate.

[0044] In this embodiment, the aforementioned nanoscaffold includes an oxide nanoscaffold. The oxide nanoscaffold includes at least one of zinc oxide, aluminum oxide, and silicon dioxide nanoparticles.

[0045] In this embodiment, the thickness of the hole transport layer 210, perovskite absorption layer 211, electron transport layer 214, second transparent electrode layer 216, second metal electrode layer 217 and antireflection layer 218 is 1 nm to 600 nm.

[0046] In this embodiment, the thickness of the buffer layer 215 is 0 nm to 30 nm.

[0047] This embodiment addresses the limitation in actual power generation performance of existing perovskite / crystalline silicon tandem solar cells due to their high temperature coefficient. By introducing oxide nanoscaffolds during the perovskite film crystallization process, oxide nanoparticles are uniformly attached to the grain boundaries within the perovskite film, forming a support structure. This structure utilizes the low coefficient of thermal expansion of materials such as zinc oxide to effectively suppress the external lattice thermal expansion of the perovskite material at high temperatures, thereby reducing the overall temperature coefficient of the tandem solar cell and improving its power generation performance under high-temperature conditions.

[0048] By controlling the doping process, oxide nanoparticles are uniformly distributed inside the perovskite film to form a support structure.

[0049] Specifically, a substrate passivation layer 113 is formed on the back side of the silicon substrate 114; a P-type substrate doped layer 112 is formed on the surface of the substrate passivation layer 113; a first transparent electrode layer 111 is formed on the surface of the P-type substrate doped layer 112; a first metal electrode layer 110 is formed on the surface of the first transparent electrode layer 111; a substrate surface passivation layer 115 is formed on the surface of the silicon substrate 114; an N-type substrate doped layer 116 is formed on the surface of the substrate surface passivation layer 115; a tunneling layer 117 is formed on the surface of the N-type substrate doped layer 116; and holes are formed on the surface of the tunneling layer 117. The hole transport layer 210 is formed; a perovskite absorption layer 211 with a nanoscaffold is formed on the surface of the hole transport layer 210; a passivation layer 212 is formed on the perovskite absorption layer 211 with a nanoscaffold; an adhesion layer 213 is formed on the surface of the passivation layer 212; an electron transport layer 214 is formed on the surface of the adhesion layer 213; a buffer layer 215 is formed on the surface of the electron transport layer 214; a second transparent electrode layer 216 is formed on the buffer layer 215; a second metal electrode layer 217 is formed on the surface of the second transparent electrode layer 216; and an antireflection layer 218 is formed on the surface of the second metal electrode layer 217.

[0050] The first transparent electrode layer 111 is prepared by magnetron sputtering. Specifically, the silicon substrate with the prepared P-type substrate doped layer 112, substrate passivation layer 113, substrate surface passivation layer 115 and N-type substrate doped layer 116 is placed in a magnetron sputtering device with a power control between 50-200W.

[0051] The first metal electrode layer 110 is prepared by vapor deposition. Specifically, the prepared substrate sample is placed on a mask for vapor deposition, with a vacuum degree of 5 × 10⁻⁶. -5 -2×10 -4 Pa, the evaporation temperature is 500-2000℃, and the evaporation rate is 0.1-5 Å / S.

[0052] Tunneling layer 117: can be prepared by atomic layer deposition, magnetron sputtering or wet chemical methods.

[0053] Hole transport layer 210: Before preparation, it is treated with a UV-Ozone generator for 0-30 minutes. It can be prepared using spin coating or magnetron sputtering. Specific parameters for magnetron sputtering are as follows: the prepared substrate is placed in a magnetron sputtering apparatus, and the power is controlled at 30-90W. The hole transport layer 210 material includes poly(4-phenyl)(2,4,6-trimethylphenyl)amine, poly-3-hexylthiophene (P3HT), and nickel oxide (NiO). X At least one of molybdenum trioxide (MoO3), cuprous iodide (CuI), and cuprous thiocyanate (CuSCN).

[0054] The perovskite absorber layer 211 with nanoscaffolds was prepared using a solution wet method, with the specific steps as follows:

[0055] A perovskite precursor solution was prepared and uniformly coated on the surface of hole transport layer 210. The spin coating speed was 1000-6000 rpm and the spin coating time was 20-120 seconds.

[0056] After spin coating, a flash evaporation operation is performed for 10-60 seconds at a temperature of 0-100℃.

[0057] After flash evaporation, an oxide nanoparticle suspension (such as zinc oxide, aluminum oxide, or silica nanoparticles with a radius of 100-500 nm, dissolved in isopropanol (IPA)) is spin-coated onto the semi-finished perovskite wet film. The spin-coating speed is 1000-6000 rpm and the spin-coating time is 20-120 seconds.

[0058] Then, annealing is performed at a temperature of 50-150℃ for 5-40 minutes.

[0059] Specifically, the perovskite absorber layer 211 was prepared by spin-coating flash evaporation, and the specific steps are as follows:

[0060] A perovskite precursor solution was prepared and uniformly coated on the surface of hole transport layer 210. The spin coating speed was 1000-6000 rpm and the spin coating time was 20-120 seconds.

[0061] After spin coating, a flash evaporation operation is performed for 10-60 seconds at a temperature of 0-100℃.

[0062] After flash evaporation, annealing is performed at a temperature of 50-150℃ for 5-40 minutes.

[0063] After flash evaporation, an oxide nanoparticle suspension (such as zinc oxide, aluminum oxide, or silica nanoparticles with a radius of 100-500 nm, dissolved in isopropanol (IPA)) is spin-coated onto the semi-finished perovskite wet film. The spin-coating speed is 1000-6000 rpm and the spin-coating time is 20-120 seconds.

[0064] Then, annealing is performed at a temperature of 50-150℃ for 5-40 minutes.

[0065] Passivation layer 212: can be prepared by vapor deposition, spin coating or spray coating.

[0066] Evaporation method: The passivation layer material is evaporated onto the surface of the perovskite absorber layer 211, and the evaporation vacuum degree is 1×10⁻⁶. -4 -5×10 -4The vapor deposition temperature is 50-400℃, and the evaporation rate is 0.05-1 Å / s. After evaporation, annealing is performed at a temperature of 0-150℃ for 0-30 minutes.

[0067] Spin coating method: Prepare a passivation layer 212 dispersion and uniformly coat it onto the surface of the perovskite absorber layer 211. The concentration is 0.1-6 mg / ml. The ultrasonic time is 0-30 minutes, the spin coating speed is 1000-7000 rpm, and the spin coating time is 20-120 seconds. After spin coating, perform annealing at a temperature of 40-160℃ for 5-40 minutes.

[0068] Spraying method: The passivation layer 212 dispersion is sprayed onto the perovskite absorber layer 211 at a spraying rate of 0-100 cm / s. After spraying, annealing is performed at a temperature of 20-170℃ for 0-30 minutes.

[0069] The passivation layer 212 dispersion is obtained by dissolving the passivation layer material in a passivation layer solvent.

[0070] Adhesion layer 213: Prepared by vapor deposition, the adhesion layer 213 material is evaporated onto the surface of the hole transport layer 210 passivation layer 212, and the vapor deposition vacuum degree is 1×10⁻⁶. -4 -5×10 -4 Pa, evaporation temperature in the range of 50-400℃, evaporation rate in the range of 0.05-1 Å / S, and thickness controlled in the range of 1-5 nm.

[0071] Electron transport layer 214: can be prepared by spin coating or vapor deposition.

[0072] Spin coating method: The electron transport layer 214 dispersion is uniformly coated on the surface of the passivation layer 212 and the adhesion layer 213. The spin coating speed is 500-4000 rpm and the spin coating time is 10-80 seconds.

[0073] Evaporation method: The electron transport layer 214 material is evaporated onto the surface of the passivation layer 212 and the adhesion layer 213, and the evaporation vacuum degree is 5×10. -5 -5×10 -4 Pa, evaporation temperature is 100-400℃, evaporation rate is 0.05-1 Å / S.

[0074] Buffer layer 215: can be prepared by atomic layer deposition or vapor deposition.

[0075] Atomic layer deposition: The buffer layer 215 material is deposited onto the surface of the electron transport layer 214 using an atomic layer deposition apparatus, with a deposition vacuum of 0-1×10⁻⁶. 4 Pa, the temperature of the deposition pipe is between 50-150℃, and the temperature of the deposition chamber is between 40-150℃.

[0076] Evaporation method: The buffer layer 215 material is evaporated onto the surface of the electron transport layer 214, and the evaporation vacuum degree is 6×10⁻⁶. -5 -4×10 -4 Pa, evaporation temperature is 100-500℃, evaporation rate is 0.05-1 Å / S.

[0077] The second transparent electrode layer 216 can be prepared by magnetron sputtering or vapor deposition.

[0078] Magnetron sputtering: Transparent electrode material is sputtered onto the surface of the buffer layer 215, with the power controlled at 30-200W.

[0079] Evaporation method: The transparent electrode material is evaporated onto the surface of the buffer layer 215, and the evaporation vacuum degree is 1×10⁻⁶. -5 -5×10 -4 Pa, evaporation temperature is 1000-2000℃, evaporation rate is 0.05-3 Å / S.

[0080] The second metal electrode layer 217 is prepared by vapor deposition and is similar to the first metal electrode layer 110 except for the difference in the mask.

[0081] Antireflection layer 218: can be prepared by magnetron sputtering or vapor deposition. The vapor deposition method is similar to that of passivation layer 212, with an evaporation rate of 0-5 A / S.

[0082] In this embodiment, the hole transport layer 210 is composed of one or more of the following materials:

[0083] Poly(4-phenyl)(2,4,6-trimethylphenyl)amine; poly-3-hexylthiophene (P3HT); nickel oxide (NiO) X Molybdenum trioxide (MoO3); cuprous iodide (CuI); cuprous thiocyanate (CuSCN).

[0084] ABX3 perovskite composition:

[0085] A site: Organic cations, including but not limited to CH3NH3 + (MA+), NH2CH=NH2 + (FA+), CH3CH2NH3 + or Cs + ;

[0086] B site: Metal cations, including but not limited to Pb 2+ Sn 2+ ;

[0087] X-position: Halogen anion, including but not limited to F. - Cl- ,Br - I - ;

[0088] The passivation layer 212 material can be one or more of the following materials: propylenediamine iodine; other similar compounds, such as propylenediamine bromide (PDADBr), butylamine chloride (BACl), butylamine bromide (BABr), butylamine iodide (BAI), N,N-dimethyl-1,3-propanediamine hydrochloride (DMePDADCl), dodecylamine bromide (DDDADBr), or magnesium fluoride as an alternative material, including but not limited to lithium fluoride (LiF) and sodium fluoride (NaF); the passivation layer solvent can be selected from at least one of methanol, ethanol, and isopropanol.

[0089] Solvents for dissolving ammonium salt precursor solutions: at least one of the following solvents can be used in a ratio between 0-3:10-7: ethanol; isopropanol; methanol; dimethylformamide (DMF); G-butyrolactone (GBL); dimethyl sulfoxide (DMSO); N,N-dimethylacetamide (DMA).

[0090] Electron transport layer 214 material: at least one of the following options may be selected: zinc oxide (ZnO); tin dioxide (SnO2); titanium dioxide (TiO2); [6,6]-phenyl C61-butyrate methyl ester (PC) 61 BM); C60 (C 60 ); 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0091] Buffer layer 215 material: can be one or a combination of the following substances: zinc oxide (ZnO); tin dioxide (SnO2); titanium dioxide (TiO2).

[0092] Oxide nanoscaffold suspension: The following nanoparticles (radius 100-500nm) are dissolved in isopropanol (IPA): zinc oxide; aluminum oxide; silicon dioxide.

[0093] Adhesion layer 213 material: N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane.

[0094] The material of the second metal electrode layer 217 can be one or more of the following materials: silver (Ag); gold (Au); copper (Cu); aluminum (Al); carbon (C).

[0095] Antireflective layer 218 material: One or more of the following materials can be selected: magnesium fluoride; lithium fluoride (LiF); sodium fluoride (NaF); silicon oxide (SiO2).

[0096] Thickness range: The thickness of hole transport layer 210, perovskite absorption layer 211, electron transport layer 214, second transparent electrode layer 216, second metal electrode layer 217, and antireflection layer 218 is 1-600 nm.

[0097] The thickness of the buffer layer 215 is 0-30 nm.

[0098] This embodiment aims to provide a perovskite-silicon tandem solar cell with a low temperature coefficient. Its core innovation lies in introducing oxide nanoscaffolds during the perovskite thin film crystallization process. This effectively suppresses the external lattice thermal expansion of the material as the temperature rises, thereby reducing the temperature coefficient of the entire tandem solar cell device and improving its actual power generation performance under high-temperature environments.

[0099] The nanoscaffold effectively suppressed the external lattice thermal expansion of the perovskite material as the temperature rose, thereby reducing the overall temperature coefficient of the tandem solar cell.

[0100] The nanoscaffold exhibits optimal performance when the solution concentration is 1 wt%. At this concentration, the photoelectric conversion efficiency of the device can be maintained above 32%, while also exhibiting good anti-expansion effects.

[0101] In comparative examples 2 and 3, although the photoelectric conversion efficiencies of both were similar, both exceeding 32%, the nanoscaffold prepared with a concentration of 1 wt% had better expansion suppression ability than the nanoscaffold prepared with a concentration of 0.5 wt%, resulting in the device of example 3 having a lower temperature coefficient than that of example 2.

[0102] However, when the concentration was further increased to 2 wt%, although a further reduction in the temperature coefficient was expected, no additional improvement was actually observed. Instead, this high concentration led to excessively thick nanoscaffold stacking, increasing resistance, hindering efficient current transmission, and ultimately causing the photoelectric conversion efficiency to drop to 30.1%.

[0103] In summary, this embodiment, by introducing a specific concentration of oxide nanoscaffolds during the crystallization process of perovskite thin films, not only successfully reduced the temperature coefficient of the tandem solar cell, but also improved the stability and reliability of the device under high-temperature conditions while maintaining high photoelectric conversion efficiency.

[0104] The aforementioned perovskite-silicon tandem solar cell with a low temperature coefficient incorporates a perovskite absorber layer 211 with a nanoscaffold into a conventional tandem structure, with a crystalline silicon bottom cell, a tunneling layer 117, and a perovskite top cell arranged sequentially from bottom to top. This design effectively suppresses the external lattice thermal expansion of the perovskite material during temperature increases using the nanoscaffold, thereby reducing performance fluctuations caused by temperature changes and lowering its temperature coefficient. In particular, the presence of the nanoscaffold not only improves the thermal stability of the perovskite layer but also enhances the actual power generation performance of the device under high-temperature conditions without significantly affecting the photoelectric conversion efficiency, solving the problem of limited actual power generation performance in existing perovskite / crystalline silicon tandem solar cells due to their high temperature coefficient.

[0105] In one embodiment, such as Figure 2 As shown, a method for preparing the above-mentioned perovskite-silicon tandem solar cell with a low temperature coefficient is also provided, including steps S110 to S220.

[0106] S110. A silicon substrate 114 is provided, the silicon substrate 114 including a first surface and a second surface disposed opposite to each other;

[0107] S120. A substrate surface passivation layer 115 and an N-type substrate doped layer 116 are sequentially stacked on the first side of the silicon substrate 114.

[0108] S130, a substrate passivation layer 113, a P-type substrate doped layer 112, a first transparent electrode layer 111, and a first metal electrode layer 110 are sequentially stacked on the second side of the silicon substrate.

[0109] In this embodiment, the first transparent electrode layer 111 is prepared by magnetron sputtering. Specifically, the silicon substrate 114, after the preparation of the P-type substrate doped layer 112, the substrate passivation layer 113, the substrate surface passivation layer 115 and the N-type substrate doped layer 116, is placed in a magnetron sputtering device, and the power is controlled between 50-200W.

[0110] And / or, the first metal electrode layer 110 can also be deposited by vapor deposition. Specifically, the prepared substrate sample is placed on a mask for vapor deposition, and the vapor deposition vacuum degree is 5×10⁻⁶. -5 -2×10 -4 Pa, evaporation temperature is 500-2000℃, evaporation rate is 0.1-5Å / S;

[0111] S140. A tunneling layer 117 is formed on the side of the N-type substrate doped layer away from the silicon substrate;

[0112] S150, a hole transport layer 210, a perovskite absorption layer 211, a passivation layer 212, an adhesion layer 213, an electron transport layer 214, a buffer layer 215, a second transparent electrode layer 216, a second metal electrode layer 217, and an antireflection layer 218 are sequentially stacked on the side of the tunneling layer 117 away from the N-type substrate doped layer 116.

[0113] In this embodiment, the hole transport layer 210 can also be produced by magnetron sputtering, characterized in that the prepared substrate is placed in a magnetron sputtering device and the power is controlled to be 30-90W.

[0114] The perovskite absorber layer 211 has a nanoscaffold, and the method for fabricating the perovskite absorber layer 211 includes: forming the perovskite absorber layer on the side of the hole transport layer 210 away from the tunneling layer 117 by spin coating flash evaporation.

[0115] The perovskite absorption layer is formed on the side of the hole transport layer 210 away from the tunneling layer 117 using a spin-coating flash evaporation method, including:

[0116] Preparation of perovskite precursor solution;

[0117] The perovskite precursor liquid was uniformly coated on the surface of the hole transport layer 210; the spin coating speed was 1000-6000 rpm and the spin coating time was 20-120 s.

[0118] After spin coating, a flash evaporation operation is performed to obtain a semi-finished perovskite wet film. The flash evaporation time is 10-60 seconds and the flash evaporation temperature is 0-100℃.

[0119] After flash evaporation, an oxide nanoparticle suspension is spin-coated onto the semi-finished perovskite wet film at a speed of 1000-6000 rpm for 20-120 s, followed by annealing. The annealing temperature is 50-150℃, and the annealing time is 5-40 min.

[0120] The passivation layer 212 is deposited using a vapor deposition method, specifically, by evaporating propylenediamine iodine onto the surface of the perovskite absorber layer, with a vapor deposition vacuum degree of 1×10⁻⁶. -4 -5×10 -4 The vapor deposition temperature is 50-400℃, and the evaporation rate is 0.05-1 Å / s. After evaporation, annealing is performed at a temperature of 0-150℃ for a time of 0-30 min.

[0121] And / or, the passivation layer 212 can also be applied using a spin-coating method. Specifically, a passivation layer dispersion is prepared and uniformly coated onto the surface of the perovskite absorber layer. Propylene diamine iodine is dissolved in organic solvents including but not limited to methanol, ethanol, or isopropanol, ultrasonically dissolved, and then spin-coated. The concentration of propylene diamine iodine is 0.1-6 mg / ml, the ultrasonic time is 0-30 min, the spin-coating speed is 1000-7000 rpm, and the spin-coating time is 20-120 s. After spin-coating, an annealing operation is performed at a temperature of 40-160℃ for 5-40 min.

[0122] And / or, the passivation layer 212 can also be applied by spraying, characterized in that the passivation layer dispersion is sprayed onto the perovskite absorption layer at a spraying rate of 0-100 cm / s, and after spraying, an annealing operation is performed at a temperature of 20-170℃ for a time of 0-30 min.

[0123] In this embodiment, when using the vapor deposition method, propylenediamine iodine is evaporated onto the surface of the perovskite absorber layer 211, and the vapor deposition vacuum degree is 1×10⁻⁶. -4 -5×10 -4 Pa, the evaporation temperature is between 50℃ and 400℃, and the evaporation rate is between 0.05Å / S and 1Å / S; after evaporation, annealing is performed at a temperature between 0℃ and 150℃ for a time between 0 min and 30 min.

[0124] When using spin coating, a passivation layer 212 dispersion is prepared and uniformly coated on the surface of the perovskite absorber layer 211. Propylene diamine iodine is dissolved in the solution and dissolved by ultrasonication, followed by spin coating. The concentration of propylene diamine iodine is 0.1 mg / ml to 6 mg / ml, the ultrasonication time is 0 min to 30 min, the spin coating speed is 1000 rpm to 7000 rpm, and the spin coating time is 20 s to 120 s. After spin coating, an annealing operation is performed at a temperature of 40℃ to 160℃ for 5 min to 40 min.

[0125] When using a spraying method, the passivation layer 212 dispersion is sprayed onto the perovskite absorption layer 211 at a spraying rate of 0 cm / s to 100 cm / s. After spraying, an annealing operation is performed at a temperature of 20 to 170°C for a time of 0 to 30 minutes.

[0126] The adhesion layer 213 is deposited using a vapor deposition method, specifically, the adhesion layer material is evaporated onto the surface of the passivation layer 212, and the vapor deposition vacuum degree is 1×10⁻⁶. -4 -5×10 -4 Pa, evaporation temperature in the range of 50-400℃, evaporation rate in the range of 0.05-1 Å / S, and thickness controlled in the range of 1-5 nm.

[0127] The electron transport layer 214 is coated by spin coating. Specifically, the electron transport layer dispersion is uniformly coated on the surface of the passivation layer 212 and the adhesion layer 213. The spin coating speed is 500-4000 rpm and the spin coating time is 10-80 s.

[0128] And / or, the electron transport layer 214 can also be deposited by vapor deposition. Specifically, the electron transport layer material is evaporated onto the surface of the passivation layer 212 and the adhesion layer 213, with a vapor deposition vacuum of 5 × 10⁻⁶. -5 -5×10 -4 Pa, evaporation temperature is 100-400℃, evaporation rate is 0.05-1 Å / S;

[0129] The buffer layer 215 is deposited using atomic layer deposition (ALD). Specifically, the electron transport layer buffer layer material is deposited onto the surface of the passivation layer 212 and the electron transport layer 214 using an ALD apparatus, with a deposition vacuum degree of 0-1×10⁻⁶. 4 Pa, the temperature of the deposition pipe is between 50-150℃, and the temperature of the deposition chamber is between 40-150℃.

[0130] And / or, the buffer layer 215 can also be deposited by vapor deposition. Specifically, the electron transport layer buffer layer material is evaporated onto the surface of the electron transport layer 214, and the vapor deposition vacuum degree is 6×10⁻⁶. -5 -4×10 -4 Pa, evaporation temperature is 100-500℃, evaporation rate is 0.05-1 Å / S;

[0131] The second transparent electrode layer 216 is produced by magnetron sputtering, specifically by sputtering transparent electrode material onto the surface of the buffer layer 215, with a controlled power of 30-200W.

[0132] And / or, the second transparent electrode layer 216 can also be deposited by vapor deposition, specifically, by evaporating the transparent electrode material onto the surface of the buffer layer 215, with a vapor deposition vacuum of 1×10⁻⁶. -5 -5×10 -4 Pa, evaporation temperature is 1000-2000℃, evaporation rate is 0.05-3Å / S;

[0133] The vapor deposition method used for the second metal electrode layer 217 is similar to that of the first metal electrode layer 110, except that the mask is different.

[0134] The antireflection layer 218 is produced using a magnetron sputtering method similar to that used in the second transparent electrode layer 216;

[0135] And / or, the antireflection layer 218 is deposited using a vapor deposition method similar to that of the passivation layer 212, with an evaporation rate of 0-5 A / S;

[0136] In Example 2, asFigure 4 As shown, the perovskite absorption layer is formed on the side of the hole transport layer 210 away from the tunneling layer 117 using a spin-coating flash evaporation method, specifically including:

[0137] Using a spin-coating flash evaporation method, a perovskite precursor solution was prepared. Perovskite powder was weighed and dissolved in 1 ml of DMF and DMSO solvents at a ratio of 8:2. The mixture was magnetically stirred for 30 min. The sample was then placed on the spin-coating stage, and the spin-coating speed was set to 3500 rpm for 30 s. 120 μL of the perovskite precursor solution was applied to the sample surface. After spin-coating, the spin-coated sample was placed on a flash evaporation stage, and the flash evaporation time was set to 30 s and the flash evaporation temperature to 30 °C. After flash evaporation, a zinc oxide nanoparticle suspension with a radius of 100 nm and a concentration of 0.5 wt% was spin-coated onto the surface of the perovskite pre-crystallized film. The spin-coating speed was set to 3500 rpm for 30 s. After spin-coating, annealing was performed at 100 °C for 15 min.

[0138] In Example 3, the perovskite absorption layer is formed on the side of the hole transport layer 210 away from the tunneling layer 117 using a spin-coating flash evaporation method, specifically including:

[0139] Using a spin-coating flash evaporation method, a perovskite precursor solution was prepared. Perovskite powder was weighed and dissolved in 1 ml of DMF and DMSO solvents at a ratio of 8:2. The mixture was magnetically stirred for 30 min. The sample was then placed on the spin-coating platform, and the spin-coating speed was set to 3500 rpm for 30 s. 120 μL of the perovskite precursor solution was applied to the sample surface. After spin-coating, the spin-coated sample was placed on a flash evaporation platform, and the flash evaporation time was set to 30 s and the flash evaporation temperature to 30 °C. After flash evaporation, a zinc oxide nanoparticle suspension with a radius of 100 nm and a concentration of 1 wt% was spin-coated onto the surface of the perovskite pre-crystallized film. The spin-coating speed was set to 3500 rpm for 30 s. After spin-coating, annealing was performed at 100 °C for 15 min.

[0140] In Example 4, the perovskite absorption layer is formed on the side of the hole transport layer 210 away from the tunneling layer 117 using a spin-coating flash evaporation method, specifically including:

[0141] Using a spin-coating flash evaporation method, a perovskite precursor solution was prepared. Perovskite powder was weighed and dissolved in 1 ml of DMF and DMSO solvents at a ratio of 8:2. The mixture was magnetically stirred for 30 min. The sample was then placed on the spin-coating platform, and the spin-coating speed was set to 3500 rpm for 30 s. 120 μL of the perovskite precursor solution was applied to the sample surface. After spin-coating, the spin-coated sample was placed on a flash evaporation platform, and the flash evaporation time was set to 30 s and the flash evaporation temperature to 30 °C. After flash evaporation, a zinc oxide nanoparticle suspension with a radius of 100 nm and a concentration of 2 wt% was spin-coated onto the surface of the perovskite pre-crystallized film. The spin-coating speed was set to 3500 rpm for 30 s. After spin-coating, annealing was performed at 100 °C for 15 min.

[0142] Please see Figure 3 In Example 1, the perovskite absorber layer was prepared using a conventional method. A spin-coating flash evaporation method was employed. A perovskite precursor solution was prepared, and perovskite powder was weighed and dissolved in DMF and DMSO solvents (8:2 ratio). After magnetic stirring for 30 minutes, the sample was placed on the spin-coating stage. The spin-coating speed was set to 3500 rpm for 30 seconds, and 120 μL of the perovskite precursor solution was used to coat the sample surface. After spin-coating, the sample was placed on a flash evaporation stage. The flash evaporation time was set to 30 seconds and the flash evaporation temperature to 30°C. Annealing was then performed at 100°C for 15 minutes, resulting in a final thickness of approximately 500 nm.

[0143] By following the above steps, the external lattice thermal expansion of perovskite materials during temperature rise can be effectively suppressed, thereby reducing the temperature coefficient of the entire tandem solar cell device and improving its actual power generation performance in high-temperature environments.

[0144] Please see Figure 5 and Figure 6 A standard solar intensity calibration was performed using a solar simulator, and an IV test was conducted on an embodiment device with an area of ​​1.0 cm2 for a long period of time. The starting voltage was set to 2V, the cutoff voltage to 0V, and the range to 100 mA. The results were rounded to two decimal places. The test results are shown in Table 1.

[0145] Table 1. Test Results

[0146]

[0147] This embodiment significantly reduces the overall temperature coefficient of the tandem solar cell by introducing oxide nanoscaffolds during the crystallization process of existing perovskite thin films, and improves its actual power generation efficiency under high temperature conditions, thereby solving the problem of limited actual power generation performance caused by high temperature coefficient in the prior art.

[0148] Oxide nanoscaffolds were introduced during the crystallization process of perovskite thin films. By precisely controlling the doping process, oxide nanoparticles were uniformly attached to the grain boundaries inside the perovskite film, forming a support structure. This nanoscaffold, composed of materials with low thermal expansion coefficients such as zinc oxide, effectively suppresses the external lattice thermal expansion of the perovskite material when the temperature rises, thereby reducing the temperature coefficient of the entire tandem solar cell device. This not only improves the stability of the battery under high-temperature conditions but also enhances its photoelectric conversion efficiency.

[0149] Example 1: Although this example demonstrates a photoelectric conversion efficiency as high as 32.5%, its temperature coefficient is relatively high at -0.41% / ℃. This result indicates that even at high efficiency, a high temperature coefficient still limits its performance in practical applications.

[0150] Examples 2 through 4: The tandem solar cells prepared using these methods exhibit significantly reduced temperature coefficients. This is because the introduced zinc oxide nanoscaffold effectively suppresses the lattice thermal expansion of the perovskite material under temperature changes. Therefore, these examples not only maintain high photoelectric conversion efficiency but also demonstrate better stability and higher power generation performance at high temperatures.

[0151] Furthermore, this embodiment also optimized the solution concentration during the nanoscaffold preparation process. The study found that when the solution concentration was 1 wt%, the prepared nanoscaffold exhibited the best performance in suppressing expansion and improving photoelectric conversion efficiency. For example:

[0152] Comparison between Example 2 and Example 3: The photoelectric conversion efficiency of both devices can reach more than 32%, but the nanoscaffold prepared with a 1 wt% concentration solution showed better anti-expansion performance compared with the 0.5 wt% concentration, resulting in a lower temperature coefficient in Example 3.

[0153] Example 4 (2wt% concentration): Although attempts were made to further reduce the temperature coefficient, no significant improvement was actually observed. On the contrary, the excessively high concentration (2wt%) led to an increase in resistance, affecting current transmission and causing the photoelectric conversion efficiency to drop to 30.1%.

[0154] In summary, this embodiment successfully achieved a low temperature coefficient for perovskite / crystalline silicon tandem solar cells by introducing a specifically designed oxide nanoscaffold and optimizing its fabrication parameters, while ensuring high photoelectric conversion efficiency. This method not only broadens the application range of perovskite solar cells but also provides strong technical support for their commercialization.

[0155] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A perovskite-silicon tandem solar cell with a low temperature coefficient, characterized in that, include: The perovskite top cell, the crystalline silicon bottom cell, the tunneling layer, and the perovskite top cell are arranged sequentially from bottom to top; the perovskite top cell includes a perovskite absorber layer with a nanoscaffold. The nanoscaffold includes an oxide nanoscaffold; The oxide nanoscaffold includes at least one of zinc oxide, aluminum oxide, and silicon dioxide nanoparticles; The perovskite top solar cell includes a hole transport layer and a perovskite absorber layer disposed on the tunneling layer. The method for fabricating the perovskite absorber layer includes: Preparation of perovskite precursor solution; The perovskite precursor solution is uniformly coated on the surface of the hole transport layer. After spin coating, flash evaporation is performed to obtain a semi-finished perovskite wet film; After flash evaporation, an oxide nanoparticle suspension is spin-coated onto the semi-finished perovskite wet film and then annealed. Oxide nanoparticles are uniformly attached to the grain boundaries inside the perovskite film, forming oxide nanoscaffolds to suppress the thermal expansion of the external lattice of the perovskite material at high temperatures.

2. The perovskite-silicon tandem solar cell with a low temperature coefficient according to claim 1, characterized in that, The crystalline silicon base cell includes, from bottom to top, a first metal electrode layer, a first transparent electrode layer, a P-type substrate doped layer, a substrate passivation layer, a silicon substrate, a substrate surface passivation layer, and an N-type substrate doped layer.

3. A method for fabricating a perovskite-silicon tandem solar cell with a low temperature coefficient as described in any one of claims 1 to 2, characterized in that, The perovskite top solar cell includes a hole transport layer and a perovskite absorber layer disposed on the tunneling layer. The method for fabricating the perovskite absorber layer includes: Preparation of perovskite precursor solution; The perovskite precursor solution is uniformly coated on the surface of the hole transport layer. After spin coating, flash evaporation is performed to obtain a semi-finished perovskite wet film; After flash evaporation, an oxide nanoparticle suspension is spin-coated onto the semi-finished perovskite wet film and then annealed.

4. The method for preparing a perovskite-silicon tandem solar cell with a low temperature coefficient according to claim 3, characterized in that, The oxide nanoparticle suspension includes at least one zinc oxide, aluminum oxide, or silicon dioxide nanoparticle, dissolved in isopropanol.

5. The method for preparing a perovskite-silicon tandem solar cell with a low temperature coefficient according to claim 3, characterized in that, When uniformly coating the perovskite precursor liquid onto the surface of the hole transport layer, the spin coating speed is 1000-6000 rpm and the spin coating time is 20-120 s.

6. The method for preparing a perovskite-silicon tandem solar cell with a low temperature coefficient according to claim 5, characterized in that, The flash evaporation time used in the flash evaporation operation is 10-60 seconds, and the flash evaporation temperature is 0-100℃.

7. The method for preparing a perovskite-silicon tandem solar cell with a low temperature coefficient according to claim 3, characterized in that, When spin-coating an oxide nanoparticle suspension onto a semi-finished perovskite wet film, the spin-coating speed is 1000-6000 rpm and the spin-coating time is 20-120 s.

8. The method for preparing a perovskite-silicon tandem solar cell with a low temperature coefficient according to claim 3, characterized in that, The annealing process is performed at a temperature of 50-150℃ for a time of 5-40 minutes.

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