Preparation method of perovskite light absorption layer and solar cell

Abstract

The invention relates to a preparation method of a perovskite light absorption layer and a solar cell. The preparation method comprises the following steps: providing a crystalline silicon imprint template, wherein the crystalline silicon imprint template is provided with a first suede; coating a perovskite precursor solution on a substrate to form a perovskite wet film; the first suede surface is pressed into the perovskite wet film; and annealing treatment is carried out, so that the perovskite wet film is dried and crystallized to form a perovskite light absorption layer, and a second suede is formed on one side, in contact with the first suede, of the perovskite light absorption layer. According to the preparation method, the crystalline silicon imprint template is pressed into the perovskite wet film, annealing treatment is carried out, the suede is re-etched to the surface of the perovskite light absorption layer, and a good anti-reflection effect is achieved. The textured structure of the crystalline silicon imprinting template can be used as a supporting point for perovskite crystal nucleation, perovskite is induced to longitudinally grow from bottom to top through a confinement effect, and a perovskite light absorption layer with large-size grains and low defect density is formed.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a method for preparing a perovskite light-absorbing layer and a solar cell. Background Art

[0002] Perovskite materials offer numerous significant advantages. Their absorption coefficient is over 10 times that of traditional crystalline silicon materials. They also possess a tunable bandgap, adaptable to varying spectral ranges, and can be prepared via a low-cost solution method. In terms of theoretical efficiency, single-junction perovskite cells can reach 33%. Using a stacked structure, this efficiency can exceed 45%, making them considered a key material for breaking through the bottleneck in the development of crystalline silicon materials.

[0003] In the optical design of perovskite solar cells, methods for reducing reflectivity primarily include applying antireflective coatings to the cell surface and constructing nanostructures on the surface of the perovskite light-absorbing layer. However, the reflectivity of conventional antireflective coatings (such as MgF2 coatings) remains high within specific wavelength ranges, reaching, for example, 15% at 400nm. Conventional processes for constructing nanostructures on the surface of perovskite light-absorbing layers also have limitations: these processes rely on complex etching or nanoimprinting processes, which can easily damage the perovskite film and increase defect density. Conventional nanoimprinting templates require complex techniques such as nanolithography, resulting in high production costs and difficulty adapting to commercial applications. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for preparing a perovskite light-absorbing layer and a solar cell to solve the problem that traditional nanoimprint templates need to be prepared through complex technologies such as nanolithography and have high production costs.

[0005] The first aspect of the present invention is to provide a method for preparing a perovskite light-absorbing layer, the scheme is as follows:

[0006] A method for preparing a perovskite light-absorbing layer comprises the following steps:

[0007] Providing a crystalline silicon imprint template, wherein the crystalline silicon imprint template has a first velvet surface;

[0008] coating a perovskite precursor solution on a substrate to form a perovskite wet film;

[0009] pressing the first velvet surface into the perovskite wet film;

[0010] Annealing treatment is performed to dry and crystallize the perovskite wet film to form a perovskite light absorption layer, and a side of the perovskite light absorption layer in contact with the first textured surface forms a second textured surface.

[0011] In one embodiment, before the first velvet surface is pressed into the perovskite wet film, the solvent content of the perovskite wet film is controlled to be 1% to 5%.

[0012] In one embodiment, the roughness of the first suede surface is 200 nm to 600 nm.

[0013] In one embodiment, the pressure applied by the first velvet surface is 20 kPa to 80 kPa.

[0014] In one embodiment, when the first velvet surface is pressed into the perovskite wet film, the pressure is first maintained at 15 kPa to 20 kPa for 3 to 5 minutes, and then increased to 50 kPa to 60 kPa and maintained for 10 to 20 minutes.

[0015] In one embodiment, the annealing treatment is performed at a temperature of 70°C to 150°C.

[0016] In one embodiment, the annealing process includes:

[0017] In the first stage, the heating temperature is 50℃~70℃ and the holding time is 3min~5min;

[0018] In the second stage, the heating temperature is 100℃~120℃ and the holding time is 10min~15min;

[0019] In the third stage, the heating temperature is 150℃~180℃ and the insulation time is 3min~5min.

[0020] In one embodiment, the method for preparing the crystalline silicon imprint template comprises the following steps:

[0021] Provide silicon wafers;

[0022] A texturing process is performed on one side of the silicon wafer to form the first textured surface.

[0023] The second aspect of the present invention is to provide a solar cell, the scheme is as follows:

[0024] A solar cell comprises a first electrode layer, a perovskite light absorbing layer and a second electrode layer stacked in sequence, wherein the perovskite light absorbing layer is prepared by the preparation method described in any of the above embodiments, and the second velvet surface of the perovskite light absorbing layer faces the second electrode layer.

[0025] In one embodiment, a first carrier transport layer is further provided between the first electrode layer and the perovskite light absorbing layer.

[0026] In one embodiment, at least one of a passivation layer and a second carrier transport layer is further provided between the perovskite light absorption layer and the second electrode layer; when the passivation layer and the second carrier transport layer are both provided between the perovskite light absorption layer and the second electrode layer, the passivation layer is located between the perovskite light absorption layer and the second carrier transport layer.

[0027] Compared with traditional technologies, the above-mentioned method for preparing the perovskite light-absorbing layer has the following beneficial effects:

[0028] The above-mentioned perovskite light-absorbing layer preparation method uses a crystalline silicon imprint template to press into the perovskite wet film and then perform an annealing process to replicate the textured surface of the perovskite light-absorbing layer, achieving a good anti-reflection effect. The textured structure of the crystalline silicon imprint template can serve as a support point for the nucleation of perovskite crystals, inducing the vertical growth of perovskite from bottom to top through the confinement effect, forming a perovskite light-absorbing layer with large grains and low defect density.

[0029] By using a crystalline silicon imprint template, there is no need to use complex technologies such as nanolithography. The roughness of the crystalline silicon velvet surface is easy to adjust. Its production process is mature and the cost is low. It is also compatible with large-area deposition processes such as scraping and slit coating, which is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 1 is a schematic flow chart of a method for preparing a perovskite light-absorbing layer according to an embodiment;

[0031] Figure 2 Schematic diagram of pressing the first velvet surface of the crystalline silicon imprint template into the perovskite wet film;

[0032] Figure 3 FIG. 1 is a schematic structural diagram of a solar cell according to an embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 10. Crystalline silicon imprint template; 11. First velvet surface; 21. Substrate; 22. Perovskite wet film; 100. Solar cell; 110. First electrode layer; 120. Perovskite light absorption layer; 121. Second velvet surface; 130. Second electrode layer; 140. First carrier transport layer; 150. Passivation layer; 160. Second carrier transport layer; 170. Hole blocking layer. DETAILED DESCRIPTION

[0035] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0039] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0040] like Figure 1 and Figure 2As shown, the method for preparing a perovskite light absorbing layer according to one embodiment of the present invention includes the following steps:

[0041] Step S1 : providing a crystalline silicon imprint template 10 , wherein the crystalline silicon imprint template 10 has a first textured surface 11 .

[0042] Step S2 : coating a perovskite precursor solution on the substrate 21 to form a perovskite wet film 22 .

[0043] Step S3 , pressing the first velvet surface 11 into the perovskite wet film 22 .

[0044] In step S4 , an annealing treatment is performed to dry and crystallize the perovskite wet film 22 to form a perovskite light absorbing layer. The side of the perovskite light absorbing layer in contact with the first textured surface 11 forms a second textured surface.

[0045] The above-mentioned method for preparing a perovskite light-absorbing layer employs a crystalline silicon imprint template 10, which is pressed into a wet perovskite film 22 and then annealed to replicate the textured surface onto the surface of the perovskite light-absorbing layer, achieving a good anti-reflection effect. The textured structure of the crystalline silicon imprint template 10 serves as a support point for the nucleation of perovskite crystals, inducing vertical growth of the perovskite from bottom to top through the confinement effect, forming a perovskite light-absorbing layer with large grains and low defect density.

[0046] The use of the crystalline silicon imprint template 10 eliminates the need for complex technologies such as nanolithography, and the roughness of the crystalline silicon velvet surface is easy to adjust. The production process is mature, the cost is low, and it is compatible with large-area deposition processes such as scraping and slit coating, which is conducive to large-scale production.

[0047] In some examples, in step S1, the method for preparing the crystalline silicon imprint template 10 includes the following steps:

[0048] Step S11, providing a silicon wafer.

[0049] Step S12: performing texturing treatment on one side of the silicon wafer to form the first textured surface 11.

[0050] The texturing treatment uses, for example, a sodium hydroxide solution or a potassium hydroxide solution as an etching solution, and the texturing treatment time is, for example, 5 minutes to 8 minutes.

[0051] In some examples, the roughness of the first textured surface 11 is 200 nm to 600 nm. The roughness of the first textured surface 11 can be conveniently controlled by process parameters such as etching solution concentration and etching time.

[0052] In step S2, a perovskite precursor solution includes a perovskite complex and a solvent. The chemical formula of the perovskite complex is ABX3. Wherein, A is a monovalent cation, including but not limited to one or more of cesium ion, rubidium ion, potassium ion, methylamine ion, formamidine ion, methylenediamine ion, benzamidine cation, and guanidinium cation. B is a divalent cation, including but not limited to one or more of lead ion, copper ion, zinc ion, gallium ion, tin ion, and calcium ion. X is a monovalent anion, including but not limited to one or more of fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, and acetate ion.

[0053] Optionally, the solvent is, for example but not limited to, one or more of N,N-dimethylformamide, dimethyl sulfoxide and diphenyl sulfoxide.

[0054] Optionally, the coating method of the perovskite precursor solution is, for example, but not limited to, one or more of spin coating, blade coating, printing, spray coating, spray pyrolysis, and slit coating.

[0055] In some examples, before pressing the first velvet surface 11 into the perovskite wet film 22 (step S3), the solvent content of the perovskite wet film 22 is controlled to be between 1% and 5% (mass fraction), specifically, 1%, 2%, 3%, 4%, 5%, etc. Within this solvent content range, the perovskite wet film 22 has low fluidity, which not only retains a certain degree of plasticity but also reduces lateral flow of the perovskite wet film 22 after the crystalline silicon imprint template 10 is pressed down, thereby improving the velvet surface reproduction accuracy.

[0056] In some examples, in step S3, the pressure applied by the first suede surface 11 is 20 kPa to 80 kPa. In some specific examples, the pressure applied by the first suede surface 11 is, for example, 20 kPa, 25 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa, 50 kPa, 55 kPa, 60 kPa, 65 kPa, 70 kPa, 75 kPa, 80 kPa, etc., or a range between any two of the above values.

[0057] In some examples, in step S3, the holding time of the pressure applied to the first suede surface 11 is 10s~60s, for example, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, etc.

[0058] In some examples, in step S3 , when the first velvet surface 11 is pressed into the perovskite wet film 22 , the pressure is first maintained at 15 kPa to 20 kPa for 3 to 5 minutes, and then increased to 50 kPa to 60 kPa and maintained for 10 to 20 minutes.

[0059] In the above example, during the velvet imprinting process, a relatively low pressure of 15kPa to 20kPa is initially applied to ensure uniform contact between the contact surfaces. The pressure is then increased to 50kPa to 60kPa to force the perovskite precursor to fill the voids in the first velvet surface 11 and prevent residual bubbles. This phased pressure adjustment allows for conformal filling of the first velvet surface 11 with the perovskite precursor, achieving a replication accuracy exceeding 90%, while avoiding the risk of film tearing associated with traditional imprinting processes.

[0060] In some examples, in step S3 , the pressure control accuracy of the crystalline silicon imprint template 10 is 1 kPa.

[0061] In some examples, in step S4 , the annealing process is performed under a protective atmosphere, such as but not limited to nitrogen.

[0062] In some examples, in step S4, the temperature of the annealing treatment is 70° C. to 150° C. In some specific examples, the temperature of the annealing treatment is 70° C., 75° C., 80° C., 85° C., 90° C., 95° C., 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., etc., or a range between any two of the above values.

[0063] In some examples, in step S4 , the annealing process includes a first stage, a second stage, and a third stage in sequence, and the heating temperature increases in sequence.

[0064] In the above example, during the textured surface replication process, the use of a gradient-increasing annealing temperature can promote the directional growth of perovskite grains along the textured surface structure, which is beneficial to improving carrier mobility.

[0065] Furthermore, in the annealing treatment, in the first stage, the heating temperature is 50°C to 70°C, and the holding time is 3 minutes to 5 minutes. In the second stage, the heating temperature is 100°C to 120°C, and the holding time is 10 minutes to 15 minutes. In the third stage, the heating temperature is 150°C to 180°C, and the holding time is 3 minutes to 5 minutes.

[0066] In the first stage, pre-curing is performed at a relatively low heating temperature to slowly evaporate the solvent, reducing stress cracking in the film. In the second stage, increasing the heating temperature promotes the longitudinal growth of perovskite grains along the textured structure, favoring the formation of large grains, such as those exceeding 800nm. In the third stage, further increasing the heating temperature eliminates grain boundary defects, improves film density, and reduces the defect density of the perovskite light-absorbing layer, for example, to below 0.05% pinhole density.

[0067] In some examples, the thickness of the prepared perovskite light absorbing layer is 100 nm to 5 μm. In some specific examples, the thickness of the perovskite light absorbing layer is, for example, 100 nm, 300 nm, 600 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc.

[0068] In some examples, the prepared perovskite light absorbing layer has a band gap of 0.9 eV to 3 eV. In some specific examples, the band gap of the perovskite light absorbing layer is, for example, 0.9 eV, 1.1 eV, 1.3 eV, 1.5 eV, 1.7 eV, 1.9 eV, 2.1 eV, 2.3 eV, 2.5 eV, 2.7 eV, 2.9 eV, 3 eV, etc.

[0069] This invention deeply integrates the optical gain of crystalline silicon texture with perovskite solution processing. By replicating the crystalline silicon texture onto the surface of the perovskite light-absorbing layer under controlled pressure, the micro-nano secondary structure (such as a honeycomb texture or a micron-nano composite texture) formed by the embossing of the crystalline silicon texture achieves uniform anti-reflection across the entire wavelength range, reducing reflectivity to below 5%.

[0070] Furthermore, the present invention also provides a solar cell.

[0071] like Figure 3 As shown, a solar cell 100 according to one embodiment includes a first electrode layer 110, a perovskite light absorption layer 120, and a second electrode layer 130, which are stacked in sequence. The perovskite light absorption layer 120 is prepared using any of the above-described preparation methods. The side of the perovskite light absorption layer 120 facing the second electrode layer 130 is the second velvet surface 121.

[0072] Optionally, the material of the first electrode layer 110 may be, for example, but not limited to, one or more oxides such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium tungsten oxide (IWO), and indium cerium oxide (ICO).

[0073] Optionally, the material of the second electrode layer 130 may be, but is not limited to, one or more of silver, copper, conductive metal oxide, and conductive carbon.

[0074] In some examples, the solar cell 100 further includes a first carrier transport layer 140 , which is disposed between the first electrode layer 110 and the perovskite light absorbing layer 120 .

[0075] The first carrier transport layer 140 is, for example, a hole transport layer. Optionally, the material of the first carrier transport layer 140 may be, but is not limited to, NiO. x(nickel oxide), CuSCN (cuprous thiocyanate), MoO x (Molybdenum oxide), CuI (Cuprous iodide), CuO x (copper oxide), V2O5 (vanadium pentoxide), MoS2 (molybdenum disulfide), MnS2 (manganese disulfide), PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid)), Spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene), Spiro-TTB (2,2' ,7,7'-tetrakis(di-p-tolylamino)spiro-9,9'-bifluorene), (MeO-)2PACz ([2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid), (MeO-)4PACz ([4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid), F4-TCNQ (2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone), and P3HT (poly 3-hexylthiophene).

[0076] In some examples, the solar cell 100 further includes a passivation layer 150, which is disposed between the perovskite light absorption layer 120 and the second electrode layer 130. The passivation layer 150 is bonded to the second suede surface 121 of the perovskite light absorption layer 120 and can repair halogen vacancy defects in the perovskite material through chemical bonding, thereby reducing the interface recombination rate, thereby achieving a high-efficiency, low-damage optical structure.

[0077] The material of the passivation layer 150 may be, but is not limited to, one or more of 1,3-diaminopropane dihydroiodide (PDADI), ethylenediamine dihydroiodide (EDADI), 2-phenylethylamine hydroiodide (PEAI), and piperazine monoiodide (PI).

[0078] In some examples, the solar cell 100 further includes a second carrier transport layer 160 , which is disposed between the perovskite light absorbing layer 120 and the second electrode layer 130 .

[0079] The second carrier transport layer 160 is, for example, an electron transport layer. Optionally, the material of the second carrier transport layer 160 may be, but is not limited to, ZnO (zinc oxide), SnO2 (tin oxide), TiO2 (titanium dioxide), SrTiO3 (strontium titanate), Zn2SnO4 (zinc stannate), ZrO2 (zirconium dioxide), Al2O3 (aluminum oxide), WO3 (tungsten trioxide), CeO x(cesium oxide), CdS (cadmium sulfide), CdSe (cadmium selenide), BaSnO3 (barium stannate), Nb2O5 (niobium pentoxide), C 60 (fullerene), PCBM (fullerene derivative) or more.

[0080] In some examples, the solar cell 100 further includes a hole blocking layer 170 , which is disposed between the second carrier transport layer 160 and the second electrode layer 130 .

[0081] Optionally, the material of the hole blocking layer 170 may be, but is not limited to, one or more of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and zirconium acetylacetonate.

[0082] exist Figure 3 In the specific example shown, the solar cell 100 includes a first electrode layer 110, a first carrier transport layer 140, a perovskite absorption layer 120, a passivation layer 150, a second carrier transport layer 160, a hole blocking layer 170 and a second electrode layer 130 arranged in sequence.

[0083] Optionally, the solar cell 100 may be a perovskite single-junction cell or a tandem cell. Tandem cells include, for example, perovskite / crystalline silicon tandem cells, all-perovskite tandem cells, perovskite / organic tandem cells, perovskite / CIGS tandem cells, perovskite / CdTe tandem cells, and perovskite / GaAs tandem cells.

[0084] The following specific examples are provided to further illustrate the present invention. The present invention provides the following specific examples for a better understanding of the present invention, but is not limited to the following specific examples and does not limit the content and scope of the present invention.

[0085] Example 1

[0086] The method for preparing a solar cell provided in this embodiment includes the following steps:

[0087] Step 1: providing a crystalline silicon imprint template, wherein the crystalline silicon imprint template is formed with a first velvet surface by texturing, and the roughness of the first velvet surface is 400 nm.

[0088] Step 2: ITO conductive glass was used as a substrate and ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol for 15 minutes respectively.

[0089] Step 3: deposit nickel oxide on the substrate by magnetron sputtering to form a hole transport layer 1 with a thickness of 15 nm.

[0090] Step 4: Spin-coat a SAMs (self-assembled monolayer) solution on the hole transport layer 1. The SAMs is Me-4PACz ((4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid) to form a hole transport layer 2 with a thickness of 3 nm.

[0091] Step 5: Spin-coat the perovskite precursor solution on the hole transport layer 2, wherein the perovskite complex contained therein is Cs 0.05 MA 0.15 FA 0.80 Pb(I 0.75 Br 0.25 3. The perovskite precursor solution is evaporated to a semi-solid state with a solvent content of 3% to form a perovskite wet film.

[0092] In step 6, a crystalline silicon imprint template is placed over the wet perovskite film, pressing the first velvet surface into the film. The applied pressure is controlled by a precision press. Initially, a low pressure of 20 kPa is used to ensure uniform contact between the surfaces. The pressure is then increased to 60 kPa to force the perovskite precursor into the gaps in the first velvet surface, preventing air bubbles from remaining.

[0093] Step 7: Perform annealing. This annealing process consists of three stages. The first stage is heating to 70°C for 5 minutes. The second stage is heating to 120°C for 10 minutes. The third stage is heating to 150°C for 5 minutes, forming a 1200nm thick perovskite light-absorbing layer.

[0094] Step 8: Spin-coat a PDADI solution on the perovskite light-absorbing layer, wherein the solvent is isopropyl alcohol, and dry the solution to form a passivation layer with a thickness of 0.5 nm.

[0095] Step 9: C60 is deposited on the passivation layer by a thermal evaporation method to form an electron transport layer with a thickness of 15 nm.

[0096] Step 10: Depositing BCP on the electron transport layer by thermal evaporation to form a hole blocking layer with a thickness of 6 nm.

[0097] Step 11: Deposit silver on the hole blocking layer by thermal evaporation to form an electrode layer with a thickness of 150 nm.

[0098] Example 2

[0099] The steps of this embodiment are basically the same as those of embodiment 1, except that, in step 6, the pressure applied by the crystalline silicon imprint template to the perovskite wet film is 60 kPa throughout the entire process.

[0100] Example 3

[0101] The steps of this embodiment are basically the same as those of embodiment 1, except that in step 7, the heating temperature of the annealing treatment is 120° C. throughout the entire process.

[0102] Example 4

[0103] The steps of this embodiment are basically the same as those of embodiment 1, except that in step 7, the heating temperature of the annealing treatment is 150° C. throughout the entire process.

[0104] Control experimental group

[0105] This control experiment followed essentially the same procedures as Example 1, except that a conventional nanolithography template was used instead of the crystalline silicon imprint template. The nanolithography template, based on a quartz substrate and a chromium mask layer, achieves nanoscale patterning through electron beam lithography and dry etching. A photonic crystal anti-reflection layer and a passivation layer are also provided to optimize optical performance and durability. The stencil's velvet surface has a roughness of 400 nm.

[0106] The grain size, pinhole density and electrical properties of the perovskite light absorbing layer in the solar cells prepared in the above examples and the control experimental group are shown in Table 1.

[0107] Table 1

[0108]

[0109] Example 1 employed staged pressure and annealing temperature regulation. As shown in the experimental results in Table 1, compared to Examples 2-4, Example 1 achieved larger grain sizes (above 800 nm) and lower pinhole density (below 0.05%). Furthermore, the solar cell's electrical performance, including open-circuit voltage, short-circuit current density, fill factor, and conversion efficiency, was also improved.

[0110] The control group used a traditional nanolithography template. Its preparation process requires strict control of etching selectivity, pattern resolution, and defect density, and its cost and process complexity are significantly higher than those of crystalline silicon imprint templates. Comparing the experimental results of Example 1 and the control group, it can be seen that Example 1 can basically achieve the same or even exceed the results of the control group using a traditional nanolithography template.

[0111] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be based on the appended claims, and the description may be used to interpret the content of the claims.

Claims

1. A method for preparing a perovskite light-absorbing layer, characterized in that: The following steps are involved: Providing a crystalline silicon imprint template, wherein the crystalline silicon imprint template has a first velvet surface; coating a perovskite precursor solution on a substrate to form a perovskite wet film; pressing the first velvet surface into the perovskite wet film; Annealing treatment is performed to dry and crystallize the perovskite wet film to form a perovskite light absorption layer, and a side of the perovskite light absorption layer in contact with the first textured surface forms a second textured surface.

2. The method for preparing a perovskite light-absorbing layer according to claim 1, wherein: Before pressing the first velvet surface into the perovskite wet film, the solvent content of the perovskite wet film is controlled to be 1% to 5%.

3. The method for preparing a perovskite light absorbing layer according to claim 1, wherein: The roughness of the first suede surface is 200 nm to 600 nm.

4. The method for preparing a perovskite light absorbing layer according to claim 1, wherein: The pressure applied by the first velvet surface is 20 kPa to 80 kPa.

5. The method for preparing a perovskite light-absorbing layer according to claim 1, wherein: When pressing the first velvet surface into the perovskite wet film, the pressure is first maintained at 15 kPa to 20 kPa for 3 to 5 minutes, and then increased to 50 kPa to 60 kPa and maintained for 10 to 20 minutes.

6. The method for preparing a perovskite light-absorbing layer according to any one of claims 1 to 5, wherein: The temperature of the annealing treatment is 70°C to 150°C.

7. The method for preparing a perovskite light-absorbing layer according to any one of claims 1 to 5, wherein: The annealing treatment includes: In the first stage, the heating temperature is 50℃~70℃ and the holding time is 3min~5min; In the second stage, the heating temperature is 100℃~120℃ and the holding time is 10min~15min; In the third stage, the heating temperature is 150℃~180℃ and the insulation time is 3min~5min.

8. The method for preparing a perovskite light-absorbing layer according to any one of claims 1 to 5, wherein: The method for preparing the crystalline silicon imprint template comprises the following steps: Provide silicon wafers; A texturing process is performed on one side of the silicon wafer to form the first textured surface.

9. A solar cell, characterized in that: The method comprises a first electrode layer, a perovskite light absorbing layer and a second electrode layer stacked in sequence, wherein the perovskite light absorbing layer is prepared by the preparation method according to any one of claims 1 to 8, and the second velvet surface of the perovskite light absorbing layer faces the second electrode layer.

10. The solar cell according to claim 9, wherein The solar cell meets at least one of the following characteristics (1) to (2): (1) A first carrier transport layer is further provided between the first electrode layer and the perovskite light absorbing layer; (2) At least one of a passivation layer and a second carrier transport layer is further provided between the perovskite light absorption layer and the second electrode layer; when the passivation layer and the second carrier transport layer are both provided between the perovskite light absorption layer and the second electrode layer, the passivation layer is located between the perovskite light absorption layer and the second carrier transport layer.

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