Perovskite solar cell preparation method for realizing chemical and physical passivation through blade coating

Abstract

The invention discloses a perovskite solar cell preparation method for realizing chemical and physical passivation through blade coating, and belongs to the technical field of large-area photovoltaic cell preparation through a blade coating method. The method comprises the following steps: S1, cleaning an ITO glass substrate with acetone and ethanol, and forming a hole transport layer on the cleaned ITO glass substrate; s2, blade coating is carried out on the hole transport layer to prepare a perovskite light absorption layer; s3, performing blade coating and annealing treatment on the perovskite light absorption layer by using a p-toluenesulfonhydrazide solution dissolved by butanol to prepare a passivation molecular layer; s4, preparing an electron transport layer on the passivation molecular layer; and S5, preparing an electrode layer on the electron transport layer through evaporation to obtain the perovskite solar cell. Through chemical and physical passivation of the toluenesulfonhydrazide solution on the perovskite thin film, the performance of the perovskite solar cell is improved. All functional layers can be processed through a solution method, and the method is suitable for manufacturing large-area perovskite solar cells and has a good large-scale production prospect.

Description

Technical Field

[0001] This invention belongs to the field of large-area photovoltaic cell technology, and particularly relates to a method for preparing perovskite solar cells by chemical and physical passivation through a coating process. Background Technology

[0002] Organic-inorganic hybrid perovskite solar cells (PSCs), the third generation of photovoltaic solar cells, are considered one of the most promising photovoltaic technologies due to their high efficiency, low-cost solution processability, and tunable bandgap. In recent years, the best power conversion efficiency (PCE) of single-junction PSCs has reached 27%. Although the best photoelectric conversion efficiency of perovskite solar cells prepared by the blade coating method is currently only 23%, compared to traditional solution methods, blade coating offers significant advantages in industrial adaptability and process control flexibility due to its high material utilization, low equipment cost, ability to achieve square-scale uniform film formation, compatibility with existing printing technologies (such as flexographic printing), and fewer mass production barriers. These advantages make blade coating the preferred technology for moving perovskite solar cells from the laboratory to commercialization, and it is expected to dominate perovskite production processes in the future.

[0003] However, the open-circuit voltage (V) of solar cells currently fabricated by the blade coating method is... OC The photoelectric conversion efficiency is still below its theoretical limit. This may be because the coating process is completely exposed to air, resulting in a large number of defects on the surface of the perovskite film. This leads to a large amount of nonradiative recombination in the perovskite film, resulting in insufficient carrier separation and poor energy level matching, leading to a large Vt. OC Losses lead to reduced efficiency, preventing the efficient conversion of solar energy into electricity, which is a problem that urgently needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing perovskite solar cells by chemical and physical passivation through a coating process, in order to solve the technical problems in the prior art where the surface of the perovskite light-absorbing layer of perovskite solar cells is uneven and rough and has a large number of defects, which hinders carrier transport and leads to a significant reduction in turn-on voltage and efficiency.

[0005] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0006] A method for fabricating perovskite solar cells by chemical and physical passivation through a coating process, the method comprising the following steps:

[0007] Step S1: Clean the ITO glass substrate with acetone and ethanol to form a hole transport layer on the cleaned ITO glass substrate.

[0008] Step S2: Prepare a perovskite light-absorbing layer by coating the hole transport layer;

[0009] Step S3: Apply a butanol-dissolved p-toluenesulfonyl hydrazine solution to the perovskite light-absorbing layer and perform a scraping annealing treatment to prepare a passivation molecular layer;

[0010] Step S4: Prepare an electron transport layer on the passivated molecular layer;

[0011] Step S5: Evaporate an electrode layer onto the electron transport layer to obtain a perovskite solar cell.

[0012] Further, step S1 includes the following steps:

[0013] Step S11: Use acetone to ultrasonically clean the ITO glass substrate for 10-20 minutes, then use ethanol to ultrasonically clean the ITO glass substrate for 10-20 minutes, dry the ITO glass substrate in an oven, and finally treat the ITO glass substrate with ultraviolet ozone for 10-30 minutes to obtain the cleaned ITO glass substrate.

[0014] Step S12: A hole transport layer is prepared on the cleaned ITO glass substrate by spin coating annealing.

[0015] Further, step S12 includes the following steps:

[0016] Step S121: Prepare SAM precursor solution; the SAM precursor solution is any one of MeO-2PACz solution, 2PACz solution, Me-4PACz solution and 4PADCB solution;

[0017] Step S122: Spin-coat the SAM precursor solution onto the cleaned ITO glass substrate at a speed of 3000 r / s for 30 s to obtain a wet hole transport layer.

[0018] Step S123: Anneal the moist hole transport layer in a nitrogen atmosphere for 10-12 min to obtain the hole transport layer.

[0019] Furthermore, the MeO-2PACz solution, 2PACz solution, Me-4PACz solution, and 4PADCB solution were prepared by weighing 0.5 mg of MeO-2PACz powder, 2PACz powder, Me-4PACz powder, and 4PADCB powder, and then dissolving each of them in 1 mL of anhydrous ethanol.

[0020] Further, step S2 includes the following steps:

[0021] Step S21: Prepare perovskite precursor solution;

[0022] Specifically, 187.79 mg of FAI, 80.02 mg of CsI, 500.20 mg of PbI2, 115.57 mg of PbBr2, 4.72 mg of MACl, 19.49 mg of PbCl2 and 14.23 mg of DPSO were weighed and dissolved in 1 mL of a mixed solvent of DMF and NMP in a volume ratio of 19:1, and stirred for 12 h to obtain a perovskite precursor solution.

[0023] Step S22: Drop the perovskite precursor solution onto the hole transport layer and prepare a perovskite thin film by air coating.

[0024] Step S23: Anneal the perovskite film to obtain a perovskite light-absorbing layer.

[0025] Further, step S22 includes the following steps:

[0026] 20-30 μL of perovskite precursor solution was dropped onto the hole transport layer. The distance between the doctor blade and the hole transport layer was controlled at 500-3000 μm, the doctor blade speed was 2.5-4 mm / s, and the pressure of the nitrogen gas extraction was 0.1-0.12 MPa. Perovskite films were prepared by doctor blade coating in air.

[0027] Further, step S3 includes the following steps:

[0028] Step S31: Weigh 1 mg of p-toluenesulfonyl hydrazine, dissolve it in 1 mL of butanol, and stir for 12 h to prepare a 1 mg / mL p-toluenesulfonyl hydrazine solution;

[0029] Step S32: Add p-toluenesulfonyl hydrazine solution dropwise onto the perovskite light-absorbing layer and prepare a passivation molecular layer by scraping.

[0030] Further, step S32 includes the following steps:

[0031] 20-30 μL of toluenesulfonyl hydrazine solution was dropped onto the perovskite light-absorbing layer. The distance between the doctor blade and the perovskite light-absorbing layer was controlled at 500-1500 μm, the doctor blade speed was 6-8 mm / s, and the nitrogen gas extraction pressure was 0.12-0.14 MPa. A second doctor blade coating and polishing treatment was performed, and the annealing temperature was 100-120℃ for 5-10 min to prepare a passivated molecular layer.

[0032] Further, step S4 includes the following steps: using vacuum evaporation, a lithium fluoride layer with a thickness of 1-1.5 nm, a carbon 60 layer or a carbon 60 layer derivative with a thickness of 10-12 nm, and a 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline layer with a thickness of 1.5-1.8 nm are sequentially stacked on the passivation molecular layer to obtain an electron transport layer.

[0033] Compared with the prior art, the present invention has the following beneficial technical effects:

[0034] 1) This invention relates to a method for fabricating perovskite solar cells using a coating process to achieve chemical and physical passivation. After annealing the perovskite film during coating, a second coating treatment with a butanol-dissolved p-toluenesulfonyl hydrazine solution is performed. This effectively improves the uniformity and smoothness of the film surface and reduces the defect state density. Furthermore, the low polarity of butanol hinders the entry of moisture into the perovskite film during the coating process, thus reducing the amount of moisture absorbed by the film and minimizing damage caused by moisture during subsequent annealing. On the other hand, p-toluenesulfonyl hydrazine, possessing both amino and sulfur-oxygen bonds, can chemically react with substances such as lead iodide in the perovskite, passivating numerous defects on the perovskite film surface. The synergistic effect of these two methods effectively enhances the overall performance of the perovskite solar cell.

[0035] 2) The perovskite solar cell prepared by the scraping coating method of the present invention to achieve chemical and physical passivation can improve the yield of perovskite cells, obtain high open-circuit voltage and better cell conversion efficiency, and is more conducive to the large-area application and long-term use of cells.

[0036] 3) The perovskite solar cell prepared by the scraping coating method of the present invention to achieve chemical and physical passivation has a smooth, uniform upper surface with fewer defects, which can optimize the interface contact between the perovskite solar cell and the electron transport layer, thereby solving the problem of poor stability caused by the lithium fluoride passivation layer. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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.

[0038] Figure 1 This is a schematic diagram of the perovskite light-absorbing layer coating and annealing process and its synergistic chemical and physical passivation in the perovskite solar cell prepared according to an embodiment of the present invention.

[0039] Figure 2This is a schematic diagram of the structure of a perovskite solar cell prepared according to an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of an atomic force microscope (AFM) image of the perovskite thin film obtained in the comparative examples and embodiments of the present invention.

[0041] Figure 4 This is a schematic diagram of a scanning electron microscope (SEM image) of the perovskite thin film obtained in the comparative examples and embodiments of the present invention.

[0042] Figure 5 This is a schematic diagram of the XRD patterns of the perovskite thin films obtained in the comparative examples and embodiments of the present invention.

[0043] Figure 6 This is a box-type schematic diagram showing the open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of the perovskite solar cells obtained in the comparative examples and embodiments of the present invention. Detailed Implementation

[0044] To further understand the present invention, preferred embodiments are described below with reference to examples, wherein the accompanying drawings constitute a part of the present invention and are used together with the invention to illustrate the principles of the invention. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the invention and are not intended to limit the scope of the claims. All raw materials used in the present invention are not particularly limited in their source and can be purchased commercially or prepared according to conventional methods known to those skilled in the art.

[0045] This invention proposes a method for fabricating perovskite solar cells by chemical and physical passivation through a coating process, the method comprising the following steps:

[0046] Step S1: Clean the ITO glass substrate with acetone and ethanol to form a hole transport layer on the cleaned ITO glass substrate.

[0047] ITO glass substrates refer to glass substrates whose surface is covered with ITO (Indium Tin Oxide).

[0048] Step S11: Clean the ITO glass substrate with acetone using ultrasonic cleaning for 10-20 min, then clean the ITO glass substrate with ethanol using ultrasonic cleaning for 10-20 min, dry the ITO glass substrate in an oven, and finally treat the ITO glass substrate with ultraviolet ozone (UV) for 10-30 min to obtain the cleaned ITO glass substrate.

[0049] Step S12: A SAM (Self-Assembled Monolayer) is prepared on a cleaned ITO glass substrate using spin-coating annealing to obtain a hole transport layer.

[0050] Step S121: Prepare SAM precursor solution.

[0051] The SAM precursor solution is any one of MeO-2PACz solution, 2PACz solution, Me-4PACz solution, and 4PADCB solution.

[0052] The MeO-2PACz solution is prepared as follows: Weigh 0.5 mg of MeO-2PACz ([2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid) powder, measure 1 mL of anhydrous ethanol, and dissolve the weighed MeO-2PACz powder in 1 mL of anhydrous ethanol to prepare a MeO-2PACz solution with a concentration of 0.5 mg / mL.

[0053] The 2PACz solution was prepared as follows: 0.5 mg of 2PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) powder was weighed, and 1 mL of anhydrous ethanol was measured. The weighed 2PAC powder was dissolved in 1 mL of anhydrous ethanol to prepare a 2PACz solution with a concentration of 0.5 mg / mL.

[0054] The Me-4PACz solution was prepared as follows: 0.5 mg of Me-4PACz ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid) powder was weighed, and 1 mL of anhydrous ethanol was measured. The weighed Me-4PACz powder was dissolved in 1 mL of anhydrous ethanol to prepare a Me-4PACz solution with a concentration of 0.5 mg / mL.

[0055] The 4PADCB solution was prepared as follows: 0.5 mg of 4PADCB ([4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid) powder was weighed, and 1 mL of anhydrous ethanol was measured. The weighed 4PADCB powder was dissolved in 1 mL of anhydrous ethanol to prepare a 4PADCB solution with a concentration of 0.5 mg / mL.

[0056] Step S122: Spin-coat the SAM precursor solution onto the cleaned ITO glass substrate at a speed of 3000 r / s for 30 s to obtain a wetted hole transport layer.

[0057] Step S123: Anneal the moist hole transport layer in a nitrogen atmosphere for 10-12 min to obtain the hole transport layer.

[0058] Step S2: Prepare a perovskite light-absorbing layer by scraping and coating the hole transport layer.

[0059] Step S21: Prepare perovskite precursor solution.

[0060] Specifically, 187.79 mg of FAI (formamidinium iodide), 80.02 mg of CsI (cesium iodide), 500.20 mg of PbI2 (lead iodide), 115.57 mg of PbBr2 (lead bromide), 4.72 mg of MACl (methylamine chloride), 19.49 mg of PbCl2 (lead chloride), and 14.23 mg of DPSO (diphenyl sulfoxide) were dissolved in 1 mL of a mixed solvent consisting of DMF (N,N-dimethylformamide) and NMP (N-methylpyrrolidone) in a volume ratio of 19:1, and stirred for 12 h to obtain a perovskite precursor solution.

[0061] Step S22: The perovskite precursor solution is dropped onto the hole transport layer and coated to prepare a perovskite thin film.

[0062] Specifically, 20-30 μL of perovskite precursor solution is dropped onto the hole transport layer. The distance between the doctor blade and the hole transport layer is controlled to be 500-3000 μm, the doctor blade speed is 2.5-4 mm / s, and the gas pressure of nitrogen gas extraction is 0.1-0.12 MPa. The perovskite film is prepared by doctor blade coating in air to obtain a substrate covered with the perovskite film.

[0063] Step S23: Anneal the perovskite film to obtain a perovskite light-absorbing layer.

[0064] Specifically, the substrate covered with the perovskite film is placed on a hot stage and annealed in air at a temperature of 100-150°C for 20-25 minutes.

[0065] Step S3: Apply a butanol-dissolved p-toluenesulfonyl hydrazine solution to the perovskite light-absorbing layer and perform a scraping annealing treatment to prepare a passivation molecular layer.

[0066] Step S31: Weigh 1 mg of p-toluenesulfonyl hydrazine (TSH), dissolve it in 1 mL of butanol, and stir for 12 h to prepare a 1 mg / mL p-toluenesulfonyl hydrazine solution.

[0067] Step S32: Add p-toluenesulfonyl hydrazine solution dropwise onto the perovskite light-absorbing layer and prepare a passivation molecular layer by scraping.

[0068] Specifically, 20-30 μL of toluenesulfonyl hydrazine solution is dropped onto the perovskite light-absorbing layer. The distance between the doctor blade and the perovskite light-absorbing layer is controlled at 500-1500 μm, the doctor blade speed is 6-8 mm / s, and the nitrogen gas extraction pressure is 0.12-0.14 MPa. A second doctor blade coating and polishing treatment is performed, and the annealing temperature is 100-120℃ for 5-10 min to prepare a passivated electronic layer.

[0069] Figure 1This diagram illustrates the process of coating the perovskite light-absorbing layer and its synergistic chemical and physical passivation process. The preparation of the perovskite film and the secondary coating process can be clearly seen from the diagram.

[0070] The p-toluenesulfonyl hydrazine solution used in this invention can, on the one hand, physically passivate the perovskite film through a coating process; on the other hand, the p-toluenesulfonyl hydrazine molecules can chemically passivate the perovskite film through a chemical reaction, achieving synergistic passivation between the chemical action of the passivation molecules and the physical action of butanol, significantly reducing the surface defect state density and improving the interlayer contact quality between the perovskite light-absorbing layer and the electron transport layer. Furthermore, this structure can more effectively utilize wide-bandgap sunlight, improving the open-circuit voltage and photoelectric conversion efficiency of the cell. The perovskite film treated with chemical and physical passivation can be used to prepare high-performance perovskite solar cell devices.

[0071] A synergistic chemiphysical passivation process using a butanol-dissolved p-toluenesulfonyl hydrazine solution is achieved through a secondary coating process. This method combines the physical-mechanical planarization effect of butanol with the chemical passivation effect of p-toluenesulfonyl hydrazine. The low polarity of butanol hinders moisture penetration into the perovskite light-absorbing layer during coating, and the appropriate evaporation rate controls the contact time between the film and air, thus reducing the moisture absorbed by the film during coating and minimizing its potential damage to the perovskite film during subsequent annealing (decomposition to produce lead iodide and even pores). Meanwhile, p-toluenesulfonyl hydrazine, possessing both amino and sulfur-oxygen bonds, can chemically react with substances such as lead iodide in the perovskite. This method effectively reduces the surface roughness of the perovskite film and passivates numerous surface defects, improving the quality and uniformity of the perovskite film on large-area glass. The secondary coating process yields perovskite films with better surface uniformity, lower roughness, and lower defect density, achieving superior interlayer energy level matching and effectively improving the open-circuit voltage and photoelectric conversion efficiency of perovskite solar cell devices.

[0072] Step S4: Prepare an electron transport layer on the passivated molecular layer.

[0073] Specifically, a lithium fluoride (LiF) layer with a thickness of 1-1.5 nm and a carbon 60 layer with a thickness of 10-12 nm are sequentially stacked on a passivation molecular layer using a vacuum evaporation method. 60 Alternatively, an electron transport layer can be obtained by using a carbon 60 layer derivative (PCBM) or a 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline layer (BCP) with a thickness of 1.5-1.8 nm.

[0074] Step S5: Evaporate an electrode layer onto the electron transport layer to obtain a perovskite solar cell.

[0075] Specifically, an electrode layer is obtained by depositing metal on the surface of the electron transport layer using a mask through vacuum thermal evaporation. The thickness of the electrode layer ranges from 100 to 120 nm. The metal used to prepare the electrode layer is silver (Ag) or gold (Au), and the evaporation rate of the electrode layer is 1 to 3 A / s.

[0076] Example

[0077] This embodiment uses the perovskite solar cell fabrication method for chemical and physical passivation through coating proposed in this invention to prepare a perovskite solar cell, including the following steps:

[0078] Step a: Clean the ITO glass substrate with acetone and sonicate for 15 minutes, then clean the ITO glass substrate with ethanol and sonicate for 15 minutes.

[0079] Step b: Dry the cleaned ITO glass substrate in an oven, and then treat it with ultraviolet ozone (UV) for 20 minutes.

[0080] Step c: Weigh 0.5 mg of 4PADCB and dissolve it in 1 mL of anhydrous ethanol to prepare a 0.5 mg / mL 4PADCB solution. Take 75 μL of the 0.5 mg / mL ADCB solution and spin-coat it onto ITO at 3000 rpm for 30 s. Then anneal it on a hot plate at 100 °C for 10 min to obtain the hole transport layer.

[0081] Step d: Weigh 187.79 mg of FAI, 80.02 mg of CsI, 500.20 mg of PbI2, 115.57 mg of PbBr2, 4.72 mg of MACl, 19.49 mg of PbCl2 and 14.23 mg of DPSO and dissolve them in 1 mL of mixed solvent and stir for 12 h to obtain a perovskite precursor solution. The mixed solvent consists of DMF and NMP, and the volume ratio of DMF to NMP is 19:1.

[0082] Step e: 20 μL of perovskite precursor solution is dropped onto the hole transport layer. The gap between the doctor blade and the hole transport layer is adjusted to 1260 μm, the doctor blade speed is 3.5 mm / s, and the nitrogen gas extraction pressure is 0.1-0.12 MPa for the coating process to obtain a substrate covered with a perovskite film. After the coating is completed, the substrate covered with the perovskite film is placed on a hot stage for annealing at 150 °C for 20 min to obtain a perovskite light-absorbing layer.

[0083] Step f: Weigh 1 mg of p-toluenesulfonyl hydrazine, dissolve it in 1 mL of butanol, and stir for 12 h to prepare a 1 mg / mL p-toluenesulfonyl hydrazine solution.

[0084] Step g: A second coating of the perovskite absorbing layer was performed using a p-toluenesulfonyl hydrazine solution. 20 μL of the p-toluenesulfonyl hydrazine solution was dropped onto the perovskite absorbing layer. The distance between the doctor blade and the perovskite absorbing layer was controlled at 1000 μm, the doctor blade speed at 6 mm / s, and the nitrogen gas extraction pressure at 0.12 MPa. The second coating and polishing treatment was then performed, with an annealing temperature of 100℃ and a time of 5 min to prepare a passivated electron layer. A 1 nm layer of lithium fluoride (LiF) and a 10 nm layer of carbon were then sequentially deposited on the surface of the prepared passivated electron layer via vacuum thermal evaporation. 60 An electron transport layer was obtained by combining a 15nm BCP.

[0085] Step h: An electrode layer is prepared on the electron transport layer. Silver is deposited on the surface of the electron transport layer by vacuum thermal evaporation using a mask. The thickness is about 120 nm, thus obtaining a complete inverted perovskite solar cell.

[0086] The perovskite solar cell prepared in this embodiment is as follows: Figure 2 As shown, the perovskite solar cell comprises, in sequence, an ITO glass substrate, a hole transport layer, a perovskite light-absorbing layer, a passivation molecular layer, an electron transport layer, and an electrode layer.

[0087] The perovskite solar cell prepared by this invention uses a butanol-dissolved p-toluenesulfonyl hydrazine solution to coat the perovskite light-absorbing layer twice to form a passivation electron layer, which can improve the yield of perovskite cells, obtain high open-circuit voltage and better cell conversion efficiency, and is more conducive to the commercial application and long-term use of the cells.

[0088] To facilitate electron transport, the electron transport layer is made of a wide bandgap semiconductor. For example, a carbon-60 layer (C60...) 60 ( ) and carbon 60 layer derivatives (PCBM). The electron transport layer may include multiple stacked transport sublayers, with a total thickness of 10~50 nm.

[0089] In order to better extract the charge carriers generated by the perovskite layer under light irradiation, the thickness of the hole transport layer is 20 nm to 40 nm.

[0090] To verify the performance of the perovskite solar cell prepared by this invention, a comparative example was used for verification.

[0091] Comparative Example

[0092] This comparative example fabricates a wide-bandgap perovskite solar cell. The fabrication process is similar to that of the examples, except that the secondary coating process in step g is omitted. Instead, LiF and C are deposited directly on the perovskite light-absorbing layer obtained in step e using vacuum thermal evaporation. 60The electron transport layer is obtained through BCP; the other steps are exactly the same. This leads to an inverse wide-bandgap perovskite solar cell.

[0093] The performance of the perovskite solar cells prepared in the above embodiments and comparative examples is shown in Table 1:

[0094] Table 1. Performance of perovskite solar cells prepared in the examples and comparative examples.

[0095]

[0096] As shown in Table 1, the examples exhibit higher open-circuit voltage and higher photoelectric conversion efficiency compared to the comparative examples, and possess a higher fill factor. This demonstrates that the perovskite surface and electron transport layer achieve better contact and carrier transport effects after secondary coating with a butanol-dissolved p-toluenesulfonyl hydrazine solution.

[0097] AFM analysis was performed on the perovskite light-absorbing layer of the perovskite solar cells prepared in the examples and comparative examples, and the results are as follows: Figure 3 As shown, compared to the comparative example, after a second coating with a butanol-dissolved p-toluenesulfonyl hydrazine solution, the surface roughness of the perovskite film in the embodiment was significantly reduced and became smoother, indicating that the perovskite light-absorbing layer of the embodiment has a lower surface roughness.

[0098] The cross-sections of the films prepared in the examples and comparative examples were analyzed by scanning electron microscopy, and the results are as follows: Figure 4 As shown; compared with the comparative example, after the second coating with p-toluenesulfonyl hydrazine solution dissolved in butanol in the example, the lead iodide on the surface of the perovskite film was significantly reduced, and a large number of passivation molecules were attached to the film surface, indicating that the second coating with p-toluenesulfonyl hydrazine solution dissolved in butanol in the example removed part of the lead iodide on the surface.

[0099] The thin films prepared in the comparative example and the embodiment were characterized by XRD, and the results are as follows: Figure 5 As shown; compared with the comparative example, after the example was coated twice with a p-toluenesulfonyl hydrazine solution dissolved in butanol, the characteristic peak of lead iodide at 12.8° was significantly lower than that of the characteristic peak of perovskite phase at 14.2°. This indicates that the perovskite film has better crystallinity after the second coating and reduces the formation of lead iodide phase, thereby improving the crystallinity quality of the perovskite film.

[0100] The performance of the perovskite solar cell devices prepared in the comparative and implementation examples was analyzed separately, and the results are as follows: Figure 6 As shown, after the perovskite thin film is subjected to a secondary coating treatment with a butanol-dissolved p-toluenesulfonyl hydrazine solution, the perovskite solar cell device exhibits significant improvements in open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency.

[0101] The above description is merely a specific embodiment of this patent, enabling those skilled in the art to understand or implement this application. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for fabricating perovskite solar cells by electroplating to achieve chemical and physical passivation, characterized in that: The method includes the following steps: Step S1: Clean the ITO glass substrate with acetone and ethanol to form a hole transport layer on the cleaned ITO glass substrate. Step S2: Prepare a perovskite light-absorbing layer by coating the hole transport layer; Step S3: Apply a butanol-dissolved p-toluenesulfonyl hydrazine solution to the perovskite light-absorbing layer and perform a scraping annealing treatment to prepare a passivation molecular layer; Step S4: Prepare an electron transport layer on the passivated molecular layer; Step S5: Evaporate an electrode layer onto the electron transport layer to obtain a perovskite solar cell.

2. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 1, characterized in that, Step S1 includes the following steps: Step S11: Use acetone to ultrasonically clean the ITO glass substrate for 10-20 min, then use ethanol to ultrasonically clean the ITO glass substrate for 10-20 min, dry the ITO glass substrate in an oven, and finally treat the ITO glass substrate with ultraviolet ozone for 10-30 min to obtain the cleaned ITO glass substrate. Step S12: A hole transport layer is prepared on the cleaned ITO glass substrate by spin coating annealing.

3. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 2, characterized in that, Step S12 includes the following steps: Step S121: Prepare SAM precursor solution; the SAM precursor solution is any one of MeO-2PACz solution, 2PACz solution, Me-4PACz solution and 4PADCB solution; Step S122: Spin-coat the SAM precursor solution onto the cleaned ITO glass substrate at a speed of 3000 r / s for 30s to obtain a wet hole transport layer. Step S123: Anneal the moist hole transport layer in a nitrogen atmosphere for 10-12 min to obtain the hole transport layer.

4. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 3, characterized in that, MeO-2PACz solution, 2PACz solution, Me-4PACz solution, and 4PADCB solution were prepared by weighing 0.5 mg of MeO-2PACz powder, 2PACz powder, Me-4PACz powder, and 4PADCB powder, and then dissolving each powder in 1 mL of anhydrous ethanol.

5. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 1, characterized in that, Step S2 includes the following steps: Step S21: Prepare perovskite precursor solution; Specifically, 187.79 mg of FAI, 80.02 mg of CsI, 500.20 mg of PbI2, 115.57 mg of PbBr2, 4.72 mg of MACl, 19.49 mg of PbCl2 and 14.23 mg of DPSO were weighed and dissolved in 1 mL of a mixed solvent of DMF and NMP in a volume ratio of 19:1, and stirred for 12 h to obtain a perovskite precursor solution. Step S22: Drop the perovskite precursor solution onto the hole transport layer and prepare a perovskite thin film by air coating. Step S23: Anneal the perovskite film to obtain a perovskite light-absorbing layer.

6. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 5, characterized in that, Step S22 includes the following steps: 20-30 μL of perovskite precursor solution was dropped onto the hole transport layer. The distance between the doctor blade and the hole transport layer was controlled at 500-3000 μm, the doctor blade speed was 2.5-4 mm / s, and the pressure of the nitrogen gas extraction was 0.1-0.12 MPa. Perovskite films were prepared by doctor blade coating in air.

7. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 1, characterized in that, Step S3 includes the following steps: Step S31: Weigh 1 mg of p-toluenesulfonyl hydrazine, dissolve it in 1 mL of butanol, and stir for 12 h to prepare a 1 mg / mL p-toluenesulfonyl hydrazine solution; Step S32: Add p-toluenesulfonyl hydrazine solution dropwise onto the perovskite light-absorbing layer and prepare a passivation molecular layer by scraping.

8. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 7, characterized in that, Step S32 includes the following steps: 20-30 μL of toluenesulfonyl hydrazine solution was dropped onto the perovskite light-absorbing layer. The distance between the doctor blade and the perovskite light-absorbing layer was controlled at 500-1500 μm, the doctor blade speed was 6-8 mm / s, and the nitrogen gas extraction pressure was 0.12-0.14 MPa. A second doctor blade coating and polishing treatment was performed, and the annealing temperature was 100-120℃ for 5-10 min to prepare a passivated molecular layer.

9. The method for fabricating perovskite solar cells with chemical and physical passivation achieved by coating according to claim 1, characterized in that, Step S4 includes the following steps: using vacuum evaporation, lithium fluoride with a thickness of 1-1.5 nm, a carbon 60 layer or a carbon 60 layer derivative with a thickness of 10-12 nm, and a 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline layer with a thickness of 1.5-1.8 nm are sequentially stacked on the passivation molecular layer to obtain an electron transport layer.

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