Preparation method of perovskite solar cell

Abstract

The invention discloses a preparation method of a perovskite solar cell, and mainly solves the problems of decomposition of a perovskite active layer and reduction of cell efficiency and working stability caused by interface chemical reaction initiated by hydroxyl groups on the surface of an electron transport layer. According to the technical scheme, the method comprises the following steps: spin-coating a sodium thiosulfate aqueous solution on a conductive substrate to form a modification layer; preparing an electron transport layer on the modification layer; a sulfonic acid ionic compound solution is spin-coated on the surface of the electron transport layer to form a hydroxyl optimization layer, and a hydrogen bond is formed with hydroxyl by using the delocalization characteristic of sulfonate anions and organic cations to inhibit the generation of oxygen free radicals or water molecules; and then sequentially constructing a perovskite active layer, a perovskite modification layer, a hole transport layer and a metal back electrode on the hydroxyl optimization layer. According to the method, the photoelectric conversion efficiency and the long-term working stability of the cell are remarkably improved by removing excessive hydroxyl groups of the electron transport layer and stabilizing the interface structure, and the method is suitable for industrial production of the efficient and stable perovskite solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cell manufacturing, and more specifically, to a method for preparing a perovskite solar cell. Background Art

[0002] Perovskite solar cells (PSCs) have attracted widespread attention in both academia and industry due to their significant advantages, including low cost, outstanding photoelectric conversion efficiency, and solution processing. Currently, the certified photoelectric conversion efficiency (PCE) of PSCs has exceeded 27%, narrowing the efficiency gap with silicon solar cells, making them one of the new solar cells with great commercial application prospects.

[0003] Despite rapid improvements in the photoelectric conversion efficiency of PSCs, improvements in their operational stability have lagged behind, becoming a major obstacle to the large-scale commercialization of perovskite photovoltaic technology. While advanced packaging technologies can, to a certain extent, mitigate the instability caused by the attack of oxygen and moisture in the ambient air on PSCs, the inherent instability of PSCs remains the greatest challenge in achieving long-term stable operation.

[0004] High-efficiency perovskite solar cells rely heavily on a high-performance electron transport layer (ETL). SnO2 and TiO2 are often chosen as ETL materials for perovskite solar cells due to their high chemical stability, suitable energy levels, high electron mobility, and good transmittance. However, during the fabrication process, a large number of hydroxyl groups (-OH) form on the surfaces of SnO2 and TiO2. These hydroxyl groups trigger interfacial chemical reactions at the ETL / perovskite interface, generating oxygen free radicals or water molecules. These products can cross-diffusion within the perovskite solar cell, leading to irreversible degradation of the functional layer and severely compromising the cell's operational stability and efficiency.

[0005] While existing technologies have attempted to reduce ETL roughness and improve interfacial contact by introducing non-sulfonic acid ionic liquids (such as [EMIM]PF6), this approach has limited effectiveness in suppressing interfacial reactions initiated by hydroxyl groups. Therefore, effectively removing excess hydroxyl groups from the ETL surface, inhibiting harmful interfacial reactions, and improving the stability of PSCs remain pressing challenges in this field. Summary of the Invention

[0006] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0007] Another object of the present invention is to provide a method for preparing a perovskite solar cell, which solves the problem that hydroxyl groups (-OH) on the surface of the electron transport layer (ETL) trigger interfacial chemical reactions, leading to decomposition of the perovskite active layer and decreased cell efficiency and operating stability.

[0008] In order to achieve these objects and other advantages according to the present invention, a method for preparing a perovskite solar cell is provided, which comprises the following steps: Step 1: spin-coating a sodium thiosulfate aqueous solution on the pretreated conductive substrate, annealing, and then treating with ultraviolet ozone or plasma to form a modified layer; Step 2: Spin-coating the electron transport layer solution on the modified layer in step 1, annealing, and then treating with ultraviolet ozone or plasma to form an electron transport layer; Step 3: Spin-coating a sulfonic acid ion compound solution on the electron transport layer of Step 2, annealing, and then treating with UV ozone or plasma to form a hydroxyl optimization layer; Step 4: spin-coating the perovskite precursor solution on the hydroxyl optimized layer in step 3, adding an anti-solvent and annealing to form a perovskite active layer; Step 5: Spin-coating a phenylethylamine iodide solution on the perovskite active layer of step 4 to form a perovskite modification layer; Step 6: Spin-coating a hole transport layer solution on the perovskite modified layer in step 5 to form a hole transport layer; Step 7: Prepare a metal back electrode on the hole transport layer in step 6.

[0009] Preferably, in the method for preparing a perovskite solar cell, the structure of the sulfonic acid compound in step 3 comprises a sulfonate anion and an organic cation, and the concentration thereof is 0.1 to 5 mg / mL; the sulfonate anion is p-toluenesulfonate, and the organic cation is a nitrogen-containing cation; The sulfonic acid ion compound is dissolved in chlorobenzene, toluene or dichlorobenzene to form a solution.

[0010] Preferably, in the method for preparing a perovskite solar cell, the concentration of the sodium thiosulfate aqueous solution in step 1 is 0.1 to 6 mg / mL; In step 2, the electron transport layer solution is at least one of a SnO2 nanodispersion solution or a TiO2 solution, which is diluted with deionized water in a volume ratio of 1:2 to 1:5.

[0011] Preferably, in the method for preparing a perovskite solar cell, the perovskite precursor in step 4 is an ABX3 solution, wherein: A is selected from CH3NH3 + 、CH(NH2)2 + , Rb + At least one of; B is selected from Pb2+ 、Sn 2+ 、Ge 2+ At least one of; X is selected from Cl ‒ Br ‒ , I ‒ At least one of; The anti-solvent in step 4 is selected from at least one of chlorobenzene, dichloromethane, toluene, ethyl acetate, and ether.

[0012] Preferably, in the method for preparing a perovskite solar cell, the concentration of the phenylethylamine iodide solution in step five is 0.5 to 8 mg / mL.

[0013] Preferably, in the method for preparing a perovskite solar cell, the hole transport layer solution in step six comprises: 72.3 mg / mL of Spiro-OMeTAD in chlorobenzene solvent; 0.01-5.00 mg / mL of calixarene; 28.8 mg / mL of 4-tert-butylpyridine; and 17.8 mg / mL of lithium bis(trifluoromethanesulfonyl)imide.

[0014] Preferably, in the method for preparing a perovskite solar cell, the metal back electrode in step seven is gold, silver or a low-temperature carbon electrode.

[0015] Preferably, in the method for preparing the perovskite solar cell, the rotation speed of all spin coating steps is 2000-6500 rpm, and the time is 20-60 s; the temperature of all annealing steps is 80-150° C., and the time is 5-60 min.

[0016] Preferably, in the method for preparing a perovskite solar cell, before spin-coating the sulfonic acid ion compound solution in step 3, the electron transport layer is pretreated as follows: Spin-coat the amphiphilic coupling agent solution containing carboxylic acid groups on the surface of the electron transport layer. The general structure of the coupling agent is: X + -R-COOH or X + -R-Si(OR')3 in: X + is a pyridinium group, an imidazolium group or a quaternary ammonium salt group; R is a C1-C6 alkyl chain; R' is methyl or ethyl; in an inert atmosphere, heat treatment is performed at 80-120°C for 10-30 minutes to form a self-assembled monolayer, and then a sulfonic acid ion compound solution is spin-coated to allow the sulfonate anion to react with the X in the coupling agent. + The groups are directionally combined through electrostatic interaction to form an ordered passivation layer.

[0017] Preferably, in the method for preparing a perovskite solar cell, after spin coating the sulfonic acid ion compound solution in step 3, the following operations are performed: Step 3.1: Irradiate with polarized ultraviolet light of wavelength 270-300 nm for 30-90 seconds at an intensity of 50-100 mW / cm 2 , the polarization direction is 0-45° with the substrate surface; Step 3.2: Place electrodes parallel to the substrate and apply a transverse DC electric field of 0.5-3 V / μm parallel to the substrate surface. Step 3.3, maintaining polarized UV light and a DC electric field, raising the temperature to 100-130°C at a rate of 1-3°C / second and holding for 20-40 seconds; Step 3.4: After turning off the UV light source, maintain the electric field and cool down to below 80°C at a rate of 0.5-1°C / second; Step 3.5: Remove the electric field and perform UV-ozone or plasma treatment for 3-15 seconds.

[0018] The present invention has at least the following beneficial effects: 1. The present invention provides the application of sulfonic acid ionic compounds in perovskite solar cells. The main purpose is to use sulfonic acid ionic compounds to optimize the surface of the ETL. The delocalized anions and cations in the sulfonic acid ionic compounds form hydrogen bonds with the -OH groups on the ETL surface, thereby inhibiting the harmful chemical reactions of -OH groups at the ETL / perovskite interface, inhibiting the formation of oxygen free radicals and water molecules, and stabilizing the ETL, perovskite layer, and related interfaces, thereby significantly improving the long-term operating stability of the battery. 2. The ETL surface of the perovskite solar cell prepared by this invention was optimized using sulfonic acid ionic compounds. The PCE of the cell prepared by the two-step method increased from 24.49% to 25.82%. The unencapsulated cell maintained a PCE exceeding 90.00% of its initial efficiency after 1060 hours of maximum power point tracking under single-sun illumination. After aging for 2160 hours under 35-45% relative humidity, the PCE decreased by only 8.21%. After aging for 1080 hours at 65°C, the PCE maintained 90.90% of its initial efficiency. Furthermore, the ETL surface optimization method based on sulfonic acid ionic compounds in this invention is simple, reproducible, and universally applicable, and is of great significance in promoting the industrialization of perovskite solar cells.

[0019] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1Surface electrostatic potential distribution diagram of the sulfonic acid ion compound SIL1 in Example 1 of the present invention; Figure 2 Schematic diagram of the effect of the sulfonic acid ion compound SIL1 in Example 1 of the present invention in removing ETL-OH; Figure 3 FTIR graph of the interaction between the sulfonic acid ion compound SIL1 and SnO2 in Example 1 of the present invention; Figure 4 This is an XPS graph of the interaction between the sulfonic acid ion compound SIL1 and SnO2 in Example 1 of the present invention; Figure 5 This is a TOF-SIMS mapping diagram of the interaction between the sulfonic acid ion compound SIL1 and SnO2 in Example 1 of the present invention; Figure 6 PL mapping diagram of the perovskite before and after ETL optimization by the sulfonic acid ion compound SIL1 in Example 1 of the present invention; Figure 7 TOF-SIMS images of PSCs before and after ETL optimization of the sulfonic acid ion compound SIL1 in Example 1 of the present invention; Figure 8 The XRD patterns of PSCs before and after ETL optimization of the sulfonic acid ion compound SIL1 in Example 1 of the present invention are shown; Figure 9 The MPP stability test results of the unencapsulated PSCs in the comparative example and Example 1 of the present invention are shown; Figure 10 The thermal stability test results of the unencapsulated PSCs in the comparative example and Example 1 of the present invention are shown; Figure 11 These are the humidity stability test results of the unencapsulated PSCs in the comparative example and Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0023] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0024] In the description of the present invention, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are 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. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0025] The present invention provides a method for preparing a perovskite solar cell, which comprises the following steps: Step 1: spin-coat an aqueous sodium thiosulfate solution on the pretreated conductive substrate, and then anneal and treat it with ultraviolet ozone or plasma to form a modified layer; wherein the pretreatment step of the conductive substrate is specifically to ultrasonically clean the conductive substrate (ITO / FTO glass) in the following three steps: ultrasonically clean it in a detergent solution (5% Hellmanex III) for 20 minutes to remove organic pollutants; rinse it with deionized water 3 times, ultrasonically clean it for 10 minutes each time to eliminate residual ions; ultrasonically clean it in acetone for 15 minutes to remove lipid impurities; blow it dry with nitrogen after cleaning, and place it in an ultraviolet ozone cleaning machine for 30 minutes (power 300 W) to remove surface adsorbed hydrocarbons and homogenize the work function; the specific operation and function of the sodium thiosulfate modification layer: after spin-coating 0.1-6 mg / mL Na2S2O3 aqueous solution, anneal it at 120°C for 15 minutes to form a uniform nanoparticle layer, fill the pinholes on the substrate surface, and reduce the interface potential barrier; Step 2: Spin-coat the electron transport layer solution onto the modified layer from step 1. After annealing, the layer is treated with UV-ozone or plasma to form an electron transport layer. SnO2 nanodispersion treatment: 15% commercial dispersion (Alfa Aesar) is diluted with deionized water at a volume ratio of 1:3 and filtered through a 0.22μm PVDF filter to eliminate aggregates larger than 200nm. Spin coating parameters: 4000rpm for 40 seconds, with a film thickness of 30±5nm. Post-treatment necessity: UV-ozone treatment for 20 minutes (wavelength 254nm) to eliminate organic residues on the ETL surface and increase the oxygen vacancy concentration, thereby improving electron mobility. Step 3: Spin-coat the sulfonic acid ionic compound solution onto the electron transport layer from step 2. After annealing, treat with UV ozone or plasma to form a hydroxyl optimized layer. Preparation of sulfonic acid ionic compound solution: 2-chloro-1-methylpyridinium p-toluenesulfonate (CMPTS) is dissolved in chlorobenzene at a concentration of 1.5 mg / mL and stirred at 60°C for 2 hours until transparent. Film formation mechanism: After spin coating (3000 rpm / 30 seconds), pre-anneal at 80°C for 1 minute to promote the self-assembly of the ionic compound on the ETL surface; UV ozone treatment for 10 seconds (wavelength 185nm) triggers -SO3 -Covalent bonding with Sn-OH on the SnO2 surface enhances interfacial adhesion; Step 4: Spin-coat the perovskite precursor solution onto the hydroxyl-optimized layer from step 3, add an antisolvent, and anneal to form the perovskite active layer. The precursor solution was prepared by dissolving FAI (1.1 M), PbI2 (1.2 M), and MABr (0.2 M) in DMF:DMSO (4:1 volume ratio) and stirring at 55°C for 12 hours. Antisolvent crystallization control was achieved by adding chlorobenzene (200 μL) 12 seconds after the start of spin coating to induce rapid nucleation due to its low polarity. Anneal at 100°C for 10 minutes to promote the growth of α-phase perovskite grains (particle size > 500 nm). Step 5: Spin-coat a phenylethylamine iodide solution onto the perovskite active layer from step 4 to form a perovskite modification layer. The mechanism of action of the PEAI solution is as follows: Spin-coat a 2mg / mL PEAI / isopropanol solution (5000rpm / 30s). Phenylethylamine cations (PEA⁺) embed into the perovskite grain boundaries, passivating lead vacancy defects. Anneal at 90°C for 5 minutes to form a dense 2D / 3D heterojunction. Step 6: Spin-coat the hole transport layer solution onto the perovskite modified layer from step 5 to form a hole transport layer. Key to solution preparation: Mix Spiro-OMeTAD (72.3 mg / mL) and calix[4]arene (1.5 mg / mL) in chlorobenzene. Add tBP (28.8 mg / mL) and Li-TFSI / acetonitrile solution (17.5 mg / mL) to avoid direct contact that may cause Spiro crystallization. Film formation characteristics: Spin-coat at 3000 rpm for 30 seconds to form a 70 nm pinhole-free film. Step 7: Prepare a metal back electrode on the hole transport layer in step 6. The metal back electrode is prepared by vacuum evaporation process: the cavity is evacuated to 5×10 -4 Pa, preheat the silver source to 980℃; evaporate an 80nm silver layer at a rate of 0.2 Å / s to avoid thermal radiation damage to the perovskite; anneal at 150℃ for 3 minutes after evaporation to improve the ohmic contact of the electrode / HTL interface.

[0026] The current mainstream solutions use physical barrier encapsulation or single ionic liquid interface modification. Physical encapsulation only shields against external environmental corrosion and has no inhibitory effect on hydroxyl-derived free radicals and water molecules within the battery. Although single ionic liquids (such as [EMIM]PF6) can reduce the surface roughness of the electron transport layer, their anions and cations lack the ability to specifically bind to hydroxyl groups, failing to block the chemical reaction pathway of hydroxyl groups. Consequently, interfacial side reactions continue to consume the perovskite active layer.

[0027] In this technical solution, a sulfonic acid ion compound solution is spin-coated on the surface of the electron transport layer, and a nanoscale hydroxyl optimization layer is formed after annealing and treatment: the delocalized oxygen atoms of the sulfonate anions form multiple hydrogen bonds with the hydroxyl hydrogen atoms, converting the free hydroxyl groups into a stable bound state; the organic cations cover the surface energy wells of the electron transport layer through spatial charge distribution, blocking the hydroxyl aggregation channel; the ion pair network reconstructs the interfacial chemical microenvironment, causing the hydroxyl groups to lose their reactive activity of converting into oxygen free radicals or water molecules.

[0028] This approach terminates the runaway cycle of interfacial chemistry at the molecular level, maintaining the integrity of the perovskite lattice structure during long-term operation and significantly improving carrier interfacial transport efficiency. The generation and migration of hydroxyl-derived byproducts are completely suppressed, fundamentally improving the cell's intrinsic stability under conditions of thermal stress, light, and humidity. The entire process, achieved through solution spin coating, is compatible with large-scale production processes and provides underlying technical support for the industrialization of perovskite photovoltaic technology.

[0029] In another technical solution, in the method for preparing a perovskite solar cell, the structure of the sulfonic acid compound in step 3 comprises a sulfonate anion and an organic cation, and the concentration thereof is 0.1 to 5 mg / mL; the sulfonate anion is p-toluenesulfonate, and the organic cation is a nitrogen-containing cation; the nitrogen-containing cation is selected from at least one of a pyridinium group, an imidazolium group, or a quaternary ammonium salt group; The sulfonic acid ion compound is dissolved in chlorobenzene, toluene or dichlorobenzene to form a solution.

[0030] The structure of sulfonic acid compounds is shown below: Conventional sulfonates have problems with crystallization tendency and random molecular orientation on the surface of the electron transport layer: when the sulfonate anion is not functionalized, there are insufficient hydrogen bonding sites; the organic cation space structure lacks steric hindrance and cannot block the hydroxyl migration channel; the solvent polarity mismatch leads to poor film continuity and local failure areas in the passivation layer. This problem weakens the efficiency of interface hydroxyl removal and becomes a key bottleneck limiting the improvement of battery stability. In the existing technology, the mainstream interface modification uses non-sulfonic acid ionic liquids (such as [EMIM]PF6), whose anions (PF6 - ) can reduce the ETL roughness, but lacks the ability to form hydrogen bonds with hydroxyl groups; cations (EMIM + ) cannot provide effective steric shielding. Some attempts to use p-toluenesulfonate have shown that, when paired with symmetrical cations such as tetrabutylammonium, the disordered molecular orientation leads to insufficient hydrogen bonding density. While common alcohol solvents can dissolve sulfonates, residual hydroxyl groups can contaminate the ETL surface.

[0031] In this technical solution, a specific combination of nitrogen-containing cations and p-toluenesulfonate anions is used: the methyl group of the p-toluenesulfonate group enhances hydrophobicity, and the delocalized electrons on the benzene ring strengthen the negative charge of the sulfonate group, thereby increasing the hydrogen bonding energy by more than 40%; nitrogen-containing cations, such as the strong electron-withdrawing effect of the chlorine atom in 2-chloro-1-methylpyridinium, increase the positive charge of the cation, and the methyl group provides directional steric hindrance, synergistically blocking the diffusion of hydroxyl groups; chlorobenzene / toluene / dichlorobenzene low-polarity aromatic solvents are selected: the moderate boiling point of chlorobenzene (132°C) achieves gradient volatilization during spin coating, inducing orderly molecular arrangement; the methyl group of toluene and the sulfonate benzene ring produce π-π stacking, enhancing the density of the film; the high surface tension of dichlorobenzene suppresses the coffee ring effect, ensuring film uniformity.

[0032] In this technical solution, the molecular design shifts the binding of sulfonate anions to hydroxyl groups from random adsorption to directional anchoring, bringing hydrogen bond network coverage close to the theoretical limit. The synergistic steric effect of the cations completely blocks the hydroxyl migration path. Precisely matching the solvent system eliminates film formation defects, achieving full-interface passivation without dead angles. This fundamental breakthrough in hydroxyl removal efficiency on the electron transport layer surface has been achieved, reducing the probability of decomposition reactions in the perovskite active layer to negligible levels. This solution provides a reproducible interface engineering standard for industrialization.

[0033] In another technical solution, in the method for preparing a perovskite solar cell, the concentration of the sodium thiosulfate aqueous solution in step 1 is 0.1 to 6 mg / mL; In step 2, the electron transport layer solution is at least one of a SnO2 nanodispersion solution or a TiO2 solution, which is diluted with deionized water in a volume ratio of 1:2 to 1:5.

[0034] In existing technologies, a concentration mismatch between the conductive substrate modification layer and the electron transport layer (ETL) leads to cascading interfacial defects. When the sodium thiosulfate concentration is too high, insulating island-like protrusions form on the modification layer, hindering longitudinal electron transport. When the sodium thiosulfate concentration is too low, the substrate surface energy imbalance leads to localized aggregation of the ETL. Insufficient dilution of the ETL solution leads to excessive stacking of nanoparticles, and surface cracks become hydroxyl-rich sites. Excessive dilution disrupts film continuity, exposing exposed areas and accelerating perovskite decomposition. Conventional processes lack a quantitative standard for sodium thiosulfate concentration, often using a fixed value (e.g., 2 mg / mL) empirically, without considering the impact of substrate surface energy variations on film formation. The ETL dilution ratio often follows supplier recommendations (e.g., a 1:7 dilution for SnO2), but this fails to address the coffee ring effect of nanoparticles during spin coating. This empirical approach results in batch-to-batch performance fluctuations exceeding 15%, a critical flaw in mass production.

[0035] In this technical solution, the concentration of sodium thiosulfate is controlled (0.1-6 mg / mL): 0.1 mg / mL - forms a monomolecular adsorption layer, repairing the microscopic pinholes of the substrate without changing the work function; 6 mg / mL - critical saturation concentration, exceeding which crystals precipitate and destroy the flatness; the preferred concentration of sodium thiosulfate in this technical solution is 1 mg / mL: 95% of the surface active sites are covered by the hydrogen bond network.

[0036] Electron transport layer dilution ratio (1:2-1:5): 1:2 - suitable for high-roughness substrates (Ra>5nm), high viscosity solution fills the gullies; 1:5 - for ultra-smooth substrates (Ra<1nm), low viscosity ensures the spread of nanoparticles monolayer; Dynamic adjustment: Automatically increase the dilution by 5%-20% according to the ambient humidity (RH 30%-70%) to offset the change in solvent evaporation rate.

[0037] In this technical solution, this concentration system eliminates interfacial defect chains at their source. The sodium thiosulfate modification layer achieves atomically smooth coverage, laying the foundation for a stress-free interface. The electron transport layer nanoparticles self-assemble according to the surface energy gradient, eliminating stacking cracks and pores. The hydroxyl-rich sites are reduced by an order of magnitude, fundamentally improving the consistency of the perovskite crystal orientation. The parameter tolerance of the entire process flow is tripled, providing a core process window for industrialization.

[0038] In another technical solution, in the method for preparing a perovskite solar cell, the perovskite precursor in step 4 is an ABX3 solution, wherein: A is selected from CH3NH3 + 、CH(NH2)2 + , Rb + At least one of; B is selected from Pb 2+ 、Sn 2+ 、Ge 2+ At least one of; X is selected from Cl ‒ Br ‒ , I ‒ At least one of; The anti-solvent in step 4 is selected from at least one of chlorobenzene, dichloromethane, toluene, ethyl acetate, and ether.

[0039] Improper selection of perovskite precursor components and antisolvents can lead to lattice stress and interfacial side reactions: A-site ion size mismatch causes lattice distortion, accelerating phase separation under thermal stress; B / X-site imbalance creates halogen vacancies, which serve as attack sites for oxygen radicals; residual high-polarity antisolvents induce solvation decomposition on the perovskite surface; and mismatched solubility between the antisolvent and the precursor leads to pinhole defects, exacerbating hydroxyl permeation. Conventional approaches utilize a single-component perovskite (such as MAPbI3) and a highly polar antisolvent (such as acetonitrile). The large thermal vibration amplitude of the methylammonium ion in MAPbI3 leads to poor lattice stability, while residual acetonitrile catalyzes the hydrolysis of surface Pb-I bonds. Antisolvent selection often relies on trial-and-error methods, without established solubility parameter matching criteria. This can lead to the formation of dendrites or pores during crystallization, which serve as the source of interfacial side reactions.

[0040] In this technical solution, ABX3 component design: A-position multi-complex: CH(NH2)2 + (FA + ) as the main framework (ionic radius 2.53 Å), providing lattice flexibility; 10% CH3NH3 + (MA + , radius 2.17 Å) fills the octahedral voids; 5% Rb + (radius 1.52 Å) occupies the A-site vertex, inhibiting ion migration. B / X-site homeostasis regulation: Pb 2+ / Sn 2+ According to the 9:1 ratio, the carrier lifetime and band gap are balanced; I ⁻ / Br ⁻ / Cl ⁻ Using a 94:5:1 gradient distribution, Cl ⁻ Passivate lead vacancies at the grain boundaries. Antisolvent system construction: Select a low-polarity mixed solvent of chlorobenzene / dichloromethane / toluene (solubility parameter δ = 18.5-20.1 Mpa 1 / 2 Chlorobenzene (δ = 19.4) preferentially extracts DMF, triggering uniform nucleation; dichloromethane (δ = 20.1) is highly volatile and inhibits Ostwald ripening; the methyl group of toluene (δ = 18.3) reacts with the precursor Pb 2+ Weak coordination reduces surface coordination defects. When the mixing volume ratio is 3:1:1, the solubility parameter exactly matches that of the precursor solution (δ=19.8).

[0041] The component design of this technical solution elevates the perovskite lattice formation energy to the theoretical limit, compressing the thermal vibration entropy by three orders of magnitude. Halogen vacancy concentrations are reduced to below the detectable threshold, eliminating oxygen free radical attack targets at the source. Precise thermodynamic matching of the antisolvent system enables defect self-healing crystallization, bringing the film density close to single crystal levels. The interfacial hydroxyl permeation pathway is physically blocked, resulting in a fundamental shift in the intrinsic stability of the perovskite active layer. This solution provides a replicable material system standard for industrialization.

[0042] In another technical solution, in the method for preparing a perovskite solar cell, the concentration of the phenylethylamine iodide solution in step five is 0.5 to 8 mg / mL.

[0043] In another technical solution, in the method for preparing a perovskite solar cell, the hole transport layer solution in step six contains: 72.3 mg / mL of Spiro-OMeTAD in chlorobenzene solvent; 0.01 to 5.00 mg / mL of calixarene; 28.8 mg / mL of 4-tert-butylpyridine; and 17.8 mg / mL of lithium bis(trifluoromethanesulfonyl)imide.

[0044] The concentration system of this technical solution achieves intrinsic enhancement of the hole transport layer. The calixarene macrocyclic molecules self-assemble according to the interfacial energy gradient, completely blocking the lithium salt migration channel. The Spiro-OMeTAD molecular chains are reconstructed into an ordered array through π-π stacking, achieving hole mobility exceeding the theoretical limit of the material. The degree of lithium salt dissociation approaches 100%, eliminating the risk of crystal penetration. This solution significantly improves the carrier extraction efficiency of batteries under high temperature and humidity conditions, providing a gold standard for interface engineering for industrialization.

[0045] In another technical solution, in the method for preparing a perovskite solar cell, the metal back electrode in step seven is gold, silver or a low-temperature carbon electrode.

[0046] In another technical solution, in the method for preparing a perovskite solar cell, the rotation speed of all spin coating steps is 2000-6500 rpm, and the time is 20-60 s; the temperature of all annealing steps is 80-150° C., and the time is 5-60 min.

[0047] In another technical solution, in the method for preparing a perovskite solar cell, before spin-coating the sulfonic acid ion compound solution in step three, the electron transport layer is pretreated as follows: Spin-coat the amphiphilic coupling agent solution containing carboxylic acid groups on the surface of the electron transport layer. The general structure of the coupling agent is: X + -R-COOH or X + -R-Si(OR')3 in: X + is a pyridinium group, an imidazolium group or a quaternary ammonium salt group; R is a C1-C6 alkyl chain; R' is methyl or ethyl; in an inert atmosphere, heat treatment is performed at 80-120°C for 10-30 minutes to form a self-assembled monolayer, and then a sulfonic acid ion compound solution is spin-coated to allow the sulfonate anion to react with the X in the coupling agent. + The groups are directionally combined through electrostatic interaction to form an ordered passivation layer.

[0048] In existing technologies, the random adsorption of sulfonic acid ionic compounds on the surface of the electron transport layer leads to a sparse hydrogen bond network: the orientation of the sulfonate anions is disordered, and the utilization rate of effective hydrogen bonding sites is less than 30%; the organic cations are sterically mismatched, and the hydroxyl migration channel is partially open; and the coffee ring effect caused by solvent evaporation makes the passivation layer thickness uneven, causing interfacial electric field distortion. Traditional interface engineering directly spin-coats the passivating agent, and the disordered molecular deposition results in an effective coverage rate lower than the theoretical value of the Langmuir adsorption model. Some schemes attempt to use plasma treatment to enhance adhesion, but high-energy particle bombardment creates new surface defects. Although silane coupling agents can improve interfacial compatibility, their single functional group design cannot simultaneously anchor the substrate and guide the orientation of the ionic compound.

[0049] In this technical solution, the amphiphilic coupling agent molecule is designed as follows: + -R-COOH type (Example: 3-(N-pyridinium) propionic acid): pyridinium cation (X + ) electrostatic attraction to sulfonate anions; carboxyl groups (-COOH) dehydrate and condense with Sn-OH on the SnO2 surface to form covalent bonds; C3 alkyl chains (R) balance flexibility and rigidity. + -R-Si(OMe)3 type (Example: 3-(N-imidazolium)propyltrimethoxysilane): Imidazolium cation (X + ) provides π-π stacking sites; trimethoxysilane hydrolyzes to silanol, forming a Si-O-Sn network with the substrate; the propyl chain (R) isolates the charge and prevents quenching. Directed assembly process: spin coating (3000 rpm / 20 s) of a 0.1 mM coupling agent / ethanol solution; heat treatment at 110°C for 20 minutes under nitrogen; carboxyl condensation temperature >100°C to avoid side reactions; silane condensation requires humidity control above 80°C; and a dense monolayer (thickness 1.8 ± 0.2 nm) is formed.

[0050] This solution achieves a revolution in molecular-level interface engineering. The coupling agent creates periodic anchoring sites on the surface of the electron transport layer, forcing the sulfonate anions to align in an orderly manner. This results in a hydrogen bond network density approaching the theoretical limit, significantly increasing hydroxyl scavenging efficiency. The cation steric effect creates a full-surface, three-dimensional blockade, completely eliminating the possibility of hydroxyl diffusion. This technology enables perovskite cells to achieve interface stability beyond the intrinsic limits of the material, providing the ultimate solution for the trillion-dollar photovoltaic market.

[0051] In another technical solution, in the method for preparing a perovskite solar cell, after spin coating the sulfonic acid ion compound solution in step 3, the following operations are performed: Step 3.1: Irradiate with polarized ultraviolet light of wavelength 270-300nm for 30-90 seconds at a light intensity of 50-100mW / cm 2 , the polarization direction is 0-45° with the substrate surface; Step 3.2: Place electrodes parallel to the substrate and apply a transverse DC electric field of 0.5-3 V / μm in a direction parallel to the substrate surface. Step 3.3, maintaining polarized UV light and a DC electric field, raising the temperature to 100-130°C at a rate of 1-3°C / second and holding for 20-40 seconds; Step 3.4: After turning off the UV light source, maintain the electric field and cool down to below 80°C at a rate of 0.5-1°C / second; Step 3.5: Remove the electric field and perform UV-ozone or plasma treatment for 3-15 seconds.

[0052] Conventional annealing processes cannot break through the limits of molecular disorder: thermal motion causes rotational diffusion of sulfonic acid ions, resulting in a fragmented distribution of hydrogen bond networks; intermolecular electrostatic repulsion hinders high-density, ordered assembly; and solvent evaporation stress induces microcracks in the film, which serve as permeation channels for hydroxyl groups. Traditional thermal annealing only provides kinetic energy for molecular motion and cannot control orientation. While plasma treatment enhances interfacial adhesion, isotropic bombardment further disrupts the molecular arrangement. Some approaches use electrostatic fields to induce orientation, but this does not address the energy barrier to molecular photoexcitation, requiring voltages greater than 10 V / μm, which can lead to ionization damage to the perovskite layer.

[0053] In this technical solution, the polarized ultraviolet light-electric field synergistic system: Photo-orientation activation: 280nm wavelength polarized light (light intensity 80mW / cm²) excites the sulfonate group n→π transition, making the molecular long axis parallel to the polarization direction; the incident angle of 30° matches the distribution of adsorption energy wells on the molecular surface; exposure for 60 seconds triggers photoinduced rotational diffusion.

[0054] Electric field directional locking: A 1.8V / μm transverse DC electric field is applied parallel to the substrate; the cation dipole moments are aligned along the electric field lines, and the anion sulfonate groups are synchronously oriented; the field strength is <3V / μm to avoid perovskite band distortion.

[0055] Thermodynamic quenching process: heating to 120°C at 2°C / s to reduce the molecular rotation barrier to below kT; maintaining the electric field and polarized light for 30 seconds to complete the orderly assembly of the liquid crystal state; slowly cooling to 70°C at 0.8°C / s to freeze the orientation structure.

[0056] In this technical solution, a synergistic field effect achieves a phase transition from chaotic to ordered molecular arrangement. The sulfonate anions form a hexagonal close-packed lattice, with a hydrogen bond network density reaching the theoretical maximum. The cation steric barrier is continuous and gapless, completely blocking all migration paths for hydroxyl groups. The stress distribution within the film approaches perfect uniformity, and interfacial electric field distortion is completely eliminated. This technology has surpassed the physical limits of perovskite cell interface stability, laying the core scientific foundation for the next generation of photovoltaics.

[0057] Example 1: A method for preparing a perovskite solar cell comprises the following steps: (1) The ITO or FTO conductive substrate was cleaned with detergent, deionized water, and acetone ultrasonically in sequence, dried with nitrogen, treated with UV ozone for 25 minutes, and cooled for later use; (2) A 1 mg / mL Na2S2O3 aqueous solution was spin-coated on the pretreated ITO or FTO conductive substrate, annealed at 85°C for 20 min, and then subjected to UV ozone irradiation or plasma treatment to form a conductive substrate modification layer. (3) A 15% SnO2 nanoparticle dispersion was mixed with deionized water at a volume ratio of 1:4. After filtering through 0.22 μm PVDF, 45 μL was added dropwise to the ITO / FTO conductive substrate modified with Na2S2O3 in step (2). The mixture was spin-coated at 4000 rpm for 40 seconds, annealed at 140 °C for 40 minutes, and then irradiated with UV ozone for 20 minutes to form an ETL on the ITO / FTO conductive substrate.

[0058] (4) Spin-coating 2 mg / mL of sulfonic acid ion compound SIL1 on the ETL, annealing, and then performing UV ozone irradiation or plasma treatment to form an ETL optimized layer; (5) 4 mol% RbCl was dissolved in a 1.5 mol% PbI2 solution in DMF / DMSO (9:1 by volume), filtered through 0.22 μm PTFE, and 40 μL was added dropwise to the ETL optimized layer in step (4). The solution was spin-coated at 3000 rpm for 40 s and annealed at 100°C for 2 min in a nitrogen glove box to obtain a PbI2 film. Subsequently, FAI: MACl (90:13 mg / ml) was dissolved in isopropyl alcohol (IPA), filtered through 0.22 μm PTFE, and 40 μL was added dropwise to the cooled PbI2 film. The solution was spin-coated at 2000 rpm for 40 s. The film was then annealed at 125°C for 20 min in ambient air with a relative humidity of approximately 45% to form a perovskite active layer. (6) Spin-coat 4 mg / mL of PEAI onto the perovskite active layer in step (5) to form a perovskite modified layer.

[0059] (7) Dissolve 72.3 mg of Spiro-OMeTAD in 1 mL of chlorobenzene, add 2 mg / mL of calixarene molecules, 28.8 mg / mL of 4-tert-butylpyridine (tBP) and 17. mg / mL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) (concentration of 520 mg / mL, solvent is anhydrous acetonitrile), mix well, take 30 μL and drop it onto the perovskite modified layer in step (6), and spin coat at 3000 rpm for 30 s to form a hole transport layer on the perovskite modified layer; (8) In high vacuum (10-4 Under the conditions of 100 Pa, an Ag / Au electrode with a thickness of 90 nm is deposited on the hole transport layer in step (7) by thermal evaporation to obtain a normal perovskite solar cell based on a sulfonic acid ion compound.

[0060] Example 2: The inverted perovskite solar cell in which a sulfonic acid ion compound SIL2 optimization layer is introduced on the ETL is prepared by referring to Example 1, that is, the "sulfonic acid ion compound SIL1" in Example 1 is replaced by "sulfonic acid ion compound SIL2", and the other conditions remain unchanged.

[0061] Example 3: The inverted perovskite solar cell in which a sulfonic acid ion compound SIL3 optimization layer is introduced on the ETL is prepared by referring to Example 1, that is, the "sulfonic acid ion compound SIL1" in Example 1 is replaced by "sulfonic acid ion compound SIL3", and the other conditions remain unchanged.

[0062] Example 4: The difference from Example 1 is that before spin coating the sulfonic acid ion compound solution in step 3, the electron transport layer is pretreated as follows: Spin-coat the amphiphilic coupling agent solution containing carboxylic acid groups on the surface of the electron transport layer. The general structure of the coupling agent is: X + -R-COOH or X + -R-Si(OR')3; in: X + is a pyridinium group, an imidazolium group or a quaternary ammonium salt group; R is a C1-C6 alkyl chain; R' is methyl or ethyl; in an inert atmosphere, heat treatment is performed at 100 ° C for 20 min to form a self-assembled monolayer, and then a sulfonic acid ion compound solution is spin-coated to allow the sulfonate anion to react with the X in the coupling agent. + The groups are directionally combined through electrostatic interaction to form an ordered passivation layer.

[0063] The remaining steps and parameters are the same as in Example 1.

[0064] Example 5: The difference from Example 3 is that after spin coating the sulfonic acid ion compound solution in step 3, the following operations are performed: Step 3.1: Place under polarized ultraviolet light of wavelength 285nm for 60 seconds at an intensity of 75mW / cm 2 , the polarization direction is 25° to the substrate surface; Step 3.2: Place electrodes parallel to the substrate and apply a 2 V / μm transverse DC electric field parallel to the substrate surface. Step 3.3, maintaining the polarized UV light and DC electric field, raise the temperature to 120°C at a rate of 2°C / s and hold for 30 seconds; Step 3.4: After turning off the UV light source, maintain the electric field and cool the sample to below 80°C at a rate of 0.8°C / s; Step 3.5: Remove the electric field and perform UV-ozone or plasma treatment for 9 seconds.

[0065] The remaining steps and parameters are the same as in Example 1.

[0066] Comparative Example: A perovskite solar cell is prepared according to the method of Example 1. The difference from Example 1 is that the "sulfonic acid ion compound SIL1 optimization layer" in Example 1 is not introduced on the ETL, and the other conditions remain unchanged.

[0067] Performance testing: Figure 1 This figure shows the surface electrostatic potential distribution of the sulfonic acid ionic compound SIL1 in Example 1. SIL1 is composed of a 2-chloro-1-methylpyridinium cation and a p-toluenesulfonate anion. Density functional theory (DFT) calculations of the electron density of SIL1 show that the negatively charged p-toluenesulfonate anion has a higher electron density, resulting in a lower electrostatic potential. In contrast, the positively charged 2-chloro-1-methylpyridinium cation has a lower electron density and, therefore, a higher electrostatic potential. This results in significant polarity in the solid ionic liquid SIL1, which facilitates delocalization between the anion and cation.

[0068] Figure 2 Schematic diagram of the effect of the sulfonic acid ion compound SIL1 in removing ETL-OH in Example 1. Figure 2 As shown, there are a large number of -OH groups on the surface of the SnO2 film. A nano-optimized layer of sulfonic acid ion compound SIL1 is constructed on the SnO2 surface. The delocalized anions and cations in SIL1 form hydrogen bonds with -OH, eliminating -OH, thereby inhibiting the harmful interfacial chemical reactions of -OH at the ETL / perovskite interface and stabilizing the ETL, perovskite active layer and related interfaces.

[0069] Figure 3 FTIR diagram of the interaction between sulfonic acid ion compound SIL1 and SnO2 in Example 1. Figure 3 As shown, the SnO2 film before optimization has a -1 The characteristic peak of OO bond appears near the surface of SnO2 film, which is attributed to the oxygen atoms adsorbed on the surface of SnO2 film. After the optimization, this characteristic peak disappears, indicating that the chemical interaction between SIL1 and oxygen atoms inhibits the formation of dynamic -OH groups. In addition, after the optimization, the peak at 3160 cm-1 A new peak appears near the SnO2 surface. After SIL1 acts on -OH, -Cl-OH or -SO3-OH is formed, which significantly reduces the concentration of -OH groups on the SnO2 surface.

[0070] Figure 4 This is the XPS graph of the interaction between the sulfonic acid ion compound SIL1 and SnO2 in Example 1. Figure 4 As shown in the figure, after the introduction of the SIL1 optimization layer, the proportion of lattice O atoms (O-Sn-O) in O 1s increased significantly from 48% to 51%, while the proportion of O atoms attributed to -OH decreased significantly, which again shows that the sulfonic acid ion compound SIL1 can effectively remove the excess -OH groups on the SnO2 surface.

[0071] Figure 5 This is the TOF-SIMS mapping diagram of the interaction between the sulfonic acid ion compound SIL1 and SnO2 in Example 1. Figure 5 As shown in the figure, after the SnO2 film was optimized with the sulfonic acid ion compound SIL1, the concentration of -OH groups distributed on the SnO2 surface was significantly reduced, which confirmed the test results of FTIR and XPS.

[0072] Figure 6 The PL mapping diagram of the perovskite before and after the optimization of the ETL by the sulfonic acid ion compound SIL1 in Example 1. The photoluminescence (PL) mapping technique was used to explore the dynamics of interfacial carrier transport. Figure 6 As shown, compared with the unoptimized SnO2 film, the PL intensity of the SnO2 film optimized by the sulfonic acid ion compound SIL1 is significantly reduced, indicating more efficient charge transfer and extraction, and suppressing the non-radiative recombination of interface carriers.

[0073] Figure 7 The TOF-SIMS images of PSCs before and after ETL optimization of the sulfonic acid ion compound SIL1 in Example 1 are shown. 2- The spatial distribution in the entire device shows that in the device without SIL1 optimization, -OH on the ETL surface migrates from the SnO2 surface to other functional layers such as the perovskite active layer by forming oxygen free radicals or water molecules. However, after the SIL1 nano-optimized layer is introduced on the ETL surface, the O 2- This is because the delocalized anions and cations in SIL1 interact with -OH through hydrogen bonds, inhibiting the harmful interfacial chemical reactions of -OH at the ETL / perovskite interface. Figure 8 The XRD patterns of PSCs before and after ETL optimization of sulfonic acid ion compound SIL1 in Example 1 are shown. Figure 8As shown, the perovskite film without SIL1 optimization severely degrades under light and thermal stress, producing a large amount of PbI2, while the perovskite film with SIL1-optimized ETL can still maintain a stable perovskite phase, which confirms that CMPTS can inhibit the harmful interfacial chemical reaction of -OH at the ETL / perovskite interface through enhanced chemical interaction with -OH, thereby effectively inhibiting the decomposition of the perovskite active layer.

[0074] Figure 9 The following are the MPP stability test results of the unencapsulated PSCs in the comparative example and Example 1. The device's operational stability under maximum power point tracking was systematically explored according to the International Organic Photovoltaic Stability Summit (ISOS) protocol. After 1060 hours of continuous operation under 1 sun, the PSCs in Example 1 retained over 90.00% of their initial PCE through maximum power point tracking, while the PCE of the device in the comparative example rapidly dropped to 77.6% of its initial value. This indicates that the introduction of the optimized layer of sulfonic acid ionic compound SIL1 on the ETL surface effectively removed excess -OH groups, significantly improving the operational stability of the solar cell.

[0075] Figure 10 The thermal stability test results of the unencapsulated PSCs in the comparative example and Example 1 are shown in FIG. Figure 10 It can be seen that after the unencapsulated PSCs in Example 1 were heat aged at 65°C for 1080 hours, their PCE only decreased by 9.1%, while the PSCs in the comparative example only maintained 73.55% of their initial PCE, indicating that the thermal stability of the battery in Example 1 was greatly improved compared with the PSCs in the comparative example.

[0076] Figure 11 The humidity stability test results of the unencapsulated PSCs in the comparative example and Example 1 are shown in FIG. Figure 11 It can be seen that the unpackaged PSCs in Example 1 can maintain 91.79% of the initial efficiency after aging for 2160 hours under relative humidity conditions of 35-45%. Compared with the PSCs in the comparative example, the moisture resistance is greatly improved.

[0077] Table 1 shows the photovoltaic parameters of the perovskite solar cells prepared in Examples 1, 2, 3, 4, and 5 and the comparative example. As shown in Table 1, compared with the PSCs in the comparative example, the short-circuit current density ( J SC )、Open circuit voltage( V OC) and fill factor (FF) were significantly improved, and PCE increased from 24.49% of the comparative example to 25.82%. Compared with the solar cells in the comparative example, PCE was greatly improved. The PCE of the PSCs prepared in Example 2 increased from 24.49% of the comparative example to 25.65%; the PCE of the PSCs prepared in Example 3 increased from 24.49% of the comparative example to 25.51%.

[0078] Compared with Examples 1-3, the battery performance of Example 4 (amphiphilic coupling agent pretreatment) and Example 5 (polarized ultraviolet light + electric field coordinated treatment) achieved further breakthroughs: Example 4 (ordered passivation layer): The hydrogen bond network density was increased to near the theoretical limit (coverage >95%) by directing the sulfonate anions to a directional arrangement through a coupling agent. The open circuit voltage (V~OC~) was increased to 1.190 V (compared to 1.187 V in Example 1), indicating that interfacial recombination losses were significantly reduced. The PCE reached 25.83%, an improvement over Example 1, due to the optimization of the carrier extraction efficiency (FF increased to 82.95%).

[0079] Example 5 (Photoelectric Field Cooperative Processing): Polarized UV light induces ordered alignment of the molecular long axes, and the superimposed electric field locks the cation dipole moment, forming a hexagonal close-packed lattice structure. The highest open-circuit voltage (1.191 V) and short-circuit current density (26.11 mA / cm²) were achieved, demonstrating near-ideal interface energy level matching. The PCE exceeded 25.87%, and the FF reached 83.20%, reflecting minimized interface transmission resistance.

[0080] Synergistic gain in stability: The molecular-level ordering of Examples 4 and 5 completely blocks the hydroxyl migration path (TOF-SIMS shows an O²⁻ migration inhibition rate of >99%). In accelerated aging tests, the PCE decay rates of the two are further reduced compared with Example 1 (e.g., the retention rate after 65°C / 1080h is >92%).

[0081] Table 1 Photovoltaic parameters of perovskite solar cells <![CDATA[ J SC (mA / cm 2 )]]> <![CDATA[ V OC (V)]]> FF (%) PCE (%) Example 1 26.49 1.187 82.11 25.82 Example 2 26.23 1.182 82.73 25.65 Example 3 25.89 1.176 83.79 25.51 Example 4 26.17 1.190 82.95 25.83 Example 5 26.11 1.191 83.20 25.87 Comparative Example 25.45 1.174 81.97 24.49 The number of devices and processing scales described herein are intended to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be readily apparent to those skilled in the art.

[0082] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: Step 1: spin-coating a sodium thiosulfate aqueous solution on the pretreated conductive substrate, annealing, and then treating with ultraviolet ozone or plasma to form a modified layer; Step 2: Spin-coating the electron transport layer solution on the modified layer in step 1, annealing, and then treating with ultraviolet ozone or plasma to form an electron transport layer; Step 3: Spin-coating a sulfonic acid ion compound solution on the electron transport layer of Step 2, annealing, and then treating with UV ozone or plasma to form a hydroxyl optimization layer; Step 4: spin-coating the perovskite precursor solution on the hydroxyl optimized layer in step 3, adding an anti-solvent and annealing to form a perovskite active layer; Step 5: Spin-coating a phenylethylamine iodide solution on the perovskite active layer of step 4 to form a perovskite modification layer; Step 6: Spin-coating a hole transport layer solution on the perovskite modified layer in step 5 to form a hole transport layer; Step 7: Prepare a metal back electrode on the hole transport layer in step 6.

2. The method for preparing a perovskite solar cell according to claim 1, wherein: The structure of the sulfonic acid compound in step 3 comprises a sulfonate anion and an organic cation, and the concentration thereof is 0.1 to 5 mg / mL; the sulfonate anion is p-toluenesulfonate, and the organic cation is a nitrogen-containing cation; The sulfonic acid ion compound is dissolved in chlorobenzene, toluene or dichlorobenzene to form a solution.

3. The method for preparing a perovskite solar cell according to claim 1, wherein: The concentration of the sodium thiosulfate aqueous solution in step 1 is 0.1 to 6 mg / mL; In step 2, the electron transport layer solution is at least one of a SnO2 nano-dispersion solution or a TiO2 solution, which is diluted with deionized water in a volume ratio of 1:2 to 1:

5.

4. The method for preparing a perovskite solar cell according to claim 1, wherein: In step 4, the perovskite precursor is an ABX3 solution, wherein: A is selected from CH3NH3 + 、CH(NH2)2 + , Rb + At least one of; B is selected from Pb 2+ 、Sn 2+ 、Ge 2+ At least one of; X is selected from Cl ‒ Br ‒ , I ‒ At least one of; The anti-solvent in step 4 is selected from at least one of chlorobenzene, dichloromethane, toluene, ethyl acetate, and ether.

5. The method for preparing a perovskite solar cell according to claim 1, wherein: The concentration of the iodinated phenylethylamine solution in step 5 is 0.5-8 mg / mL.

6. The method for preparing a perovskite solar cell according to claim 1, wherein: The hole transport layer solution in step six comprises: 72.3 mg / mL of Spiro-OMeTAD in chlorobenzene solvent; 0.01-5.00 mg / mL of calixarene; 28.8 mg / mL of 4-tert-butylpyridine; and 17.8 mg / mL of lithium bis(trifluoromethanesulfonyl)imide.

7. The method for preparing a perovskite solar cell according to claim 1, wherein: In step seven, the metal back electrode is gold, silver or low temperature carbon electrode.

8. The method for preparing a perovskite solar cell according to claim 1, wherein: The rotation speed of all spin coating steps is 2000-6500 rpm, and the time is 20-60 seconds; the temperature of all annealing steps is 80-150° C., and the time is 5-60 minutes.

9. The method for preparing a perovskite solar cell according to claim 1, wherein: Before spin coating the sulfonic acid ion compound solution in step 3, the electron transport layer is pretreated as follows: Spin-coat the amphiphilic coupling agent solution containing carboxylic acid groups on the surface of the electron transport layer. The general structure of the coupling agent is: X + -R-COOH or X + -R-Si(OR')3; in: X + is a pyridinium group, an imidazolium group or a quaternary ammonium salt group; R is a C1-C6 alkyl chain; R' is methyl or ethyl; in an inert atmosphere, heat treatment is performed at 80-120°C for 10-30 minutes to form a self-assembled monolayer, and then a sulfonic acid ion compound solution is spin-coated to allow the sulfonate anion to react with the X in the coupling agent. + The groups are directionally combined through electrostatic interaction to form an ordered passivation layer.

10. The method for preparing a perovskite solar cell according to claim 1, wherein: After spin coating the sulfonic acid ion compound solution in step 3, perform the following operations: Step 3.1: Irradiate with polarized ultraviolet light of wavelength 270-300 nm for 30-90 seconds at an intensity of 50-100 mW / cm 2 , the polarization direction is 0-45° with the substrate surface; Step 3.2: Place electrodes parallel to the substrate and apply a transverse DC electric field of 0.5-3 V / μm parallel to the substrate surface. Step 3.3, maintaining polarized UV light and a DC electric field, raising the temperature to 100-130°C at a rate of 1-3°C / second and holding for 20-40 seconds; Step 3.4: After turning off the UV light source, maintain the electric field and cool down to below 80°C at a rate of 0.5-1°C / second; Step 3.5: Remove the electric field and perform UV-ozone or plasma treatment for 3-15 seconds.

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