Perovskite solar cell modification method based on pyridine benzene sulfonate

Abstract

The invention relates to the technical field of solar cells, and particularly discloses a perovskite solar cell modification method based on pyridine benzene sulfonate. According to the method, pyridine benzene sulfonate is used as a multifunctional molecular modifier, the multifunctional molecular modifier is introduced into the perovskite solar cell in a bulk phase doping or interface modification mode, and a cation part (pyridine ring) and Pb < 2 + > form Lewis coordination, so that metal ion defects are effectively passivated, and crystal growth is regulated and controlled; and the anion part (OTs-) can be stably adsorbed on a crystal boundary or an interface, so that the formation of an I-or A-site vacancy is inhibited, and the crystallization quality and the film stability are improved. Meanwhile, a pi conjugated structure and a hydrophobic tail group of molecules endow the device with excellent water-oxygen erosion resistance, and a dipole layer formed on an interface can adjust energy level alignment and promote carrier extraction and separation. The method is high in process compatibility, and an efficient and reliable solution is provided for large-scale preparation and application of the perovskite solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a method for preparing a perovskite solar cell and improving the same, and in particular to a method for modifying a perovskite solar cell based on pyridine benzene sulfonate. Background Art

[0002] Perovskite solar cells, owing to their superior light absorption, high carrier mobility, long carrier lifetime, and low-temperature solution processing, have achieved dramatic increases in photoelectric conversion efficiency over the past decade. Currently, laboratory devices have achieved photoelectric conversion efficiencies exceeding 26%. Despite this, perovskite materials themselves still present numerous challenges, notably: 1) High defect density: a large number of non-radiative recombination centers exist between perovskite grains and on their surfaces, severely degrading device performance; 2) Interface mismatch: energy level mismatch and defect states between the perovskite layer and the transport layer can cause carrier recombination and energy loss; and 3) Insufficient stability: devices are susceptible to degradation in humid, high-temperature, or light-exposed environments, hindering their commercial applications.

[0003] To alleviate these issues, researchers have developed a variety of interface modification and molecular passivation strategies in recent years. These include the introduction of Lewis bases / acids, organic amine salts, quaternary ammonium salts, and π-conjugated molecules to passivate defects, regulate energy levels, and inhibit ion migration. However, existing molecular modifiers still have the following shortcomings: most only have physical adsorption effects and poor chemical stability; the passivation effects vary, and there is a lack of systematic control strategies; and some molecules are inherently complex and costly to synthesize, making them unsuitable for large-scale application.

[0004] Therefore, there is still an urgent need to develop new molecular modifiers with clear structure, chemical stability, significant passivation effect and strong process compatibility to improve the overall performance of perovskite solar cells. Summary of the Invention

[0005] In order to solve the current problems of perovskites, the present invention proposes a preparation method of molecularly modified perovskite solar cells based on the current spin-coating technology. This method uses a new type of pyridine benzene sulfonate compound as a bulk doping or interface modifier of the perovskite layer, which can effectively passivate the internal and surface defects of the perovskite film, inhibit non-radiative recombination, improve the open-circuit voltage, short-circuit current and fill factor of the device, thereby improving the photoelectric conversion efficiency, and significantly enhancing the thermal stability and light stability of the device.

[0006] The technical solution of the present invention is:

[0007] A perovskite solar cell is characterized by comprising a conductive glass substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a charge buffer layer and a metal electrode layer stacked in sequence, and also comprising a molecular passivator and an interface modifier prepared from pyridine benzene sulfonate.

[0008] Further, the material of the hole transport layer is one or more of [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid and (2-(9H-carbazol-9-yl)ethyl)phosphonic acid;

[0009] The chemical formula of the perovskite light absorbing layer is ABX n , where: A is selected from FA + [CH(NH2) 2+ ]、MA + (CH3NH3 + ), Cs + , Rb + One or more of; B is selected from Pb 2+ 、Sn 2+ One or more of; X is selected from Cl - Br - , I - One or more of .

[0010] Furthermore, the preparation steps of the molecular passivator are as follows: in a nitrogen glove box without water or oxygen, dissolving pyridine benzene sulfonate in corresponding organic solvents to obtain a molecular passivator solution with a concentration of 0.1-50 mg / mL;

[0011] The organic solvent for dissolving pyridine benzene sulfonate is one or more of acetonitrile, isopropyl alcohol, N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone.

[0012] Furthermore, the preparation steps of the interface modifier are as follows: in an anhydrous and oxygen-free nitrogen glove box, dissolving pyridine benzene sulfonate in corresponding organic solvents to obtain interface modifier solutions with concentrations of 0.5, 1.0 and 1.5 mg / mL;

[0013] The organic solvent for dissolving pyridine benzene sulfonate is one or more of anhydrous methanol, isopropanol, 2-methoxypropanol and chlorobenzene.

[0014] Furthermore, the pyridine benzenesulfonate is one or more of 1-methylpyridine p-toluenesulfonate, 2-fluoro-1-methylpyridine p-toluenesulfonate, 2-chloro-1-methylpyridine p-toluenesulfonate, 2-bromo-1-methylpyridine p-toluenesulfonate and 2-iodo-1-methylpyridine p-toluenesulfonate, and the substituent functional groups at different positions on the pyridine ring contain 0-5 halogen atoms;

[0015] The halogen atom is one or more of F, Cl, Br, and I.

[0016] The present invention also provides a method for preparing the above-mentioned perovskite solar cell, characterized in that the specific steps include:

[0017] Step 1: Pre-treat the conductive glass substrate;

[0018] Step 2: Spin-coating a hole transport layer solution on a pre-treated conductive glass substrate, followed by annealing to obtain a hole transport layer;

[0019] Step 3: Prepare the perovskite light absorbing layer. There are two situations.

[0020] Case 1: The perovskite precursor solution is spin-coated on the hole transport layer and annealed to form a perovskite light-absorbing layer;

[0021] Case 2: After mixing the molecular passivator with the perovskite precursor solution, it is spin-coated on the hole transport layer and annealed to form the perovskite light absorption layer;

[0022] Step 4: Perform upper interface modification on the perovskite light-absorbing layer. There are two situations:

[0023] Case 1: If Step 3 is case 1, an interface modifier is spin-coated or scraped onto the perovskite light-absorbing layer, and then annealed to form an upper interface modification layer.

[0024] Case 2: If Step 3 is case 2, no operation is performed;

[0025] Step 5: Spin-coat or thermally evaporate the electron transport layer and charge buffer layer on the battery structure in sequence;

[0026] Step 6: Thermally evaporate a metal electrode above the charge buffer layer to obtain a perovskite solar cell modified by an interface modifier or passivated by a molecular passivator.

[0027] Furthermore, the hole transport layer solution is prepared by: dissolving the hole transport layer material in an organic solvent in an anhydrous and oxygen-free nitrogen glove box to prepare a solution with a concentration of 0.5-3.0 mg / mL;

[0028] The organic solvent for dissolving the hole transport layer material is one or more of dimethoxyethanol, anhydrous ethanol, anhydrous methanol and isopropyl alcohol.

[0029] Furthermore, the perovskite precursor solution is prepared by dissolving the perovskite precursor in an organic solvent in an anhydrous and oxygen-free nitrogen glove box to prepare a perovskite precursor solution with a concentration of 1.3-1.8 M, and heating and stirring at 20-80° C. for 2-24 hours;

[0030] The organic solvent for dissolving the perovskite precursor is one or more of N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone, and the volume ratio of the mixed solvent when the organic solvent is one or more of the organic solvents is 8:1 to 2:1.

[0031] Further,

[0032] The implementation of Step 1 is as follows: pre-treating the conductive glass substrate with ultraviolet ozone or plasma for 10-50 minutes;

[0033] There are two ways to implement Step 5:

[0034] Method 1: Spin coating to prepare the electron transport layer and charge buffer layer:

[0035] In a nitrogen glove box without water or oxygen, dissolving [6,6]-phenyl-C61-butyric acid isomethyl ester in chlorobenzene to prepare a 10-30 mg / mL electron transport layer solution, and then spin-coating the electron transport layer solution on the perovskite light absorption layer or the upper interface modification layer to form the electron transport layer;

[0036] The spin coating speed of the electron transport layer solution on the perovskite light absorbing layer or the upper interface modification layer is 1500-3000 rpm, the amount of the electron transport layer solution added dropwise is 30-100 μL, and the spin coating time is 20-40 s;

[0037] In a nitrogen glove box without water or oxygen, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline was dissolved in an organic solvent to prepare a charge buffer layer solution at a concentration of 0.5-3.0 mg / mL. The charge buffer layer solution was then spin-coated on the electron transport layer. After annealing and heat treatment, the charge buffer layer was formed.

[0038] The organic solvent for dissolving 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is one or more of 2-methoxypropanol, anhydrous ethanol, and isopropanol; the spin coating speed of the charge buffer layer solution on the electron transport layer is 3000-5000 rpm, the amount of the charge buffer layer solution added is 150-300 μL, the spin coating time is 20-40 seconds, the annealing temperature is 70-120° C., and the treatment time is 5-10 minutes;

[0039] Method 2: Using thermal evaporation to prepare the electron transport layer and charge buffer layer:

[0040] Fullerene is evaporated on the perovskite light absorbing layer or the upper interface modification layer, and the evaporation condition is a vacuum degree of less than 5×10 - 4 Pa, forming the electron transport layer with a thickness of 20-35 nm;

[0041] 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline was evaporated on the electron transport layer under the vacuum condition of less than 5×10 -4 Pa, forming the charge buffer layer with a thickness of 5-10 nm.

[0042] Further,

[0043] In the step 2, the hole transport layer solution is spin-coated on the conductive glass substrate at a speed of 2000-4000 rpm, the amount of the hole transport layer solution added is 20-80 μL, the spin coating time is 10-40 s, and the annealing heat treatment temperature is 70-120° C. for 5-20 min;

[0044] In Step 3, the perovskite precursor solution or the mixed solution of the molecular passivator and the perovskite precursor solution is spin-coated on the hole transport layer at a spin coating speed of 3000-6000 rpm, the amount of solution added is 20-80 μL, the spin coating time is 10-40 s, the annealing heat treatment temperature is 100-160° C., and the treatment time is 10-30 min; when the molecular passivator is mixed with the perovskite precursor solution, the mixing ratio of the passivator to the precursor is 1:50-1:5;

[0045] In the Step 4, the interface modifier is spin-coated on the perovskite light-absorbing layer at a spin-coating speed of 3000-5000 rpm, the amount of the interface modifier solution added is 30-100 μL, the spin-coating time is 10-40 s, the annealing temperature is 70-120° C., and the treatment time is 5-10 min.

[0046] The beneficial effects of the present invention are:

[0047] 1. Multi-site synergistic passivation significantly reduces the defect state density: The present invention uses pyridinium benzene sulfonate compounds for bulk addition or interface modification, in which the pyridinium cation can react with the uncoordinated Pb in the perovskite. 2+ Forming coordination bonds, the sulfonate anion can bind to the cation vacancy or I - Vacancies form electrostatic / hydrogen bonds, synergistically passivating bulk and interface defects, significantly reducing non-radiative recombination and increasing the device open circuit voltage (V oc ) and fill factor (FF);

[0048] 2. Regulating crystal growth and interface energy levels to promote efficient charge extraction: The addition of pyridine benzene sulfonate to the bulk phase of the present invention can regulate perovskite nucleation and grain growth, forming a denser and more uniform film. During interface modification, this type of molecule can construct a molecular dipole layer, effectively regulating the energy level alignment between the perovskite and the charge transport layer, promoting rapid carrier extraction and transport, and reducing interfacial energy loss.

[0049] 3. Enhance the hydrophobicity of the device and improve thermal and environmental stability: The p-toluenesulfonate anion of the present invention has hydrophobic properties and can form a hydrophobic protective layer on the surface of the perovskite, effectively inhibiting water vapor penetration and interface degradation. At the same time, it has a stable molecular structure and good thermal stability, which can significantly improve the operational stability of the device under high temperature, humidity and long-term light exposure.

[0050] 4. Simple synthesis, strong adaptability, and compatibility with large-scale preparation: The pyridine benzene sulfonate compounds of the present invention have a simple synthesis route, cheap raw materials, and are easy to prepare on a large scale. They also show good adaptability in perovskite device structures of different sizes and are expected to be promoted and applied in the commercial preparation of efficient and stable perovskite modules in the future. This technology has no selectivity requirements for processes such as spin coating and doctor blade coating, and the device efficiency is stable at >24%. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a structural diagram of an inverse perovskite solar cell prepared by bulk addition of pyridine benzene sulfonate and upper interface modification of the present invention;

[0052] Figure 2 (a), (b), (c), (d), and (e) are the structures of 1-methylpyridine p-toluenesulfonate, 2-fluoro-1-methylpyridine p-toluenesulfonate, 2-chloro-1-methylpyridine p-toluenesulfonate, 2-bromo-1-methylpyridine p-toluenesulfonate, and 2-iodo-1-methylpyridine p-toluenesulfonate, respectively;

[0053] Figure 3 This is a current-voltage curve of a perovskite solar cell with bulk addition of 1-methylpyridine-toluenesulfonate prepared in Experimental Example 1 of the present invention;

[0054] Figure 4 This is a current-voltage curve of a perovskite solar cell with bulk addition of 2-fluoro-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 2 of the present invention;

[0055] Figure 5 This is a current-voltage curve of a perovskite solar cell with bulk addition of 2-chloro-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 3 of the present invention;

[0056] Figure 6This is a current-voltage curve of a perovskite solar cell with bulk addition of 2-bromo-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 4 of the present invention;

[0057] Figure 7 This is a current-voltage curve of a perovskite solar cell with bulk addition of 2-iodo-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 5 of the present invention;

[0058] Figure 8 This is a current-voltage curve of the perovskite solar cell with interface modification on 1-methylpyridine p-toluenesulfonate prepared in Experimental Example 6 of the present invention;

[0059] Figure 9 This is a current-voltage curve of the perovskite solar cell with interface modification on 2-fluoro-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 7 of the present invention;

[0060] Figure 10 This is a current-voltage curve of the perovskite solar cell with interface modification on 2-chloro-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 8 of the present invention;

[0061] Figure 11 This is a current-voltage curve of the perovskite solar cell with interface modification on 2-bromo-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 9 of the present invention;

[0062] Figure 12 This is a current-voltage curve of the perovskite solar cell with interface modification on 2-iodo-1-methylpyridine p-toluenesulfonate prepared in Experimental Example 10 of the present invention;

[0063] Figure 13 This is a current-voltage curve of the perovskite solar cell prepared in Comparative Example 1 of the present invention;

[0064] Figure 14 This is an SEM image of the perovskite layer of Comparative Example 1 of the present invention;

[0065] Figure 15 This is the SEM image of the perovskite layer of Experimental Example 2 of the present invention;

[0066] Figure 16 This is the SEM image of the perovskite layer of Experimental Example 7 of the present invention;

[0067] Figure 17 This is a comparison chart of the stability curves of the perovskite solar cells with bulk addition and upper interface modification of 2-fluoro-1-methylpyridine toluenesulfonate prepared under the conditions of Experimental Examples 2 and 7, respectively, and the perovskite solar cell prepared in Comparative Example 1, wherein the perovskite device efficiencies of Experimental Examples 2, 7 and Comparative Example 1 were all measured at the same time point. DETAILED DESCRIPTION

[0068] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0069] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for understanding and reading by those familiar with this technology, and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose of the present invention. At the same time, terms such as "upper", "inner", "outer", "bottom", "one", and "middle" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be considered as the scope of implementation of the present invention without substantially changing the technical content.

[0070] See attached Figure 1-2 The structure of the perovskite solar cell proposed in the present invention is sequentially stacked to form a conductive glass substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a charge buffer layer and a metal electrode layer, and also includes a molecular passivator and an interface modifier prepared from pyridine benzene sulfonate;

[0071] The material of the hole transport layer is one or more of [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid and (2-(9H-carbazol-9-yl)ethyl)phosphonic acid;

[0072] The chemical formula of the perovskite light absorbing layer is ABX n , where: A is selected from FA + [CH(NH2) 2+ ]、MA + (CH3NH3 + ), Cs + , Rb + One or more of; B is selected from Pb 2+ 、Sn 2+ One or more of; X is selected from Cl - Br - , I - One or more of;

[0073] The pyridinium benzene sulfonate is generally a crystalline organic molecule with stable structure, strong thermal stability and easy solubility in organic solvents, including 1-methylpyridine p-toluene sulfonate, 2-fluoro-1-methylpyridine p-toluene sulfonate, 2-chloro-1-methylpyridine p-toluene sulfonate, 2-bromo-1-methylpyridine p-toluene sulfonate and 2-iodo-1-methylpyridine p-toluene sulfonate. Through the controllable design of different substitution sites (ortho, meta, para) and substitution degrees on the pyridine ring, the steric hindrance and electronic properties of the molecule can be controlled and adjusted, and the molecular interface interaction and hydrophobicity are optimized. When added as a bulk phase, the pyridinium cation is doped into the perovskite lattice or distributed at the grain boundary, passivating Pb 2+ defects and guide ordered crystallization. The p-toluenesulfonate anion can be inserted into the lattice vacancies or distributed at the grain boundaries, passivating I - Vacancy or FA + Vacancies, while improving the chemical stability of the entire film, the two work together to improve the film quality, carrier lifetime and device performance; and when modified on the surface of the perovskite layer, the pyridinium cations are adsorbed on the perovskite surface and react with the surface Pb 2+ The formation of coordination, passivation of surface states, the p-toluenesulfonate anion is located between the perovskite / transport layer, constructing a dipole layer, optimizing the interface band alignment, inhibiting interface recombination, and forming a hydrophobic interface layer to improve the environmental stability of the device;

[0074] The molecular passivator is prepared by: in an anhydrous and oxygen-free nitrogen glove box, dissolving pyridine benzene sulfonate (including 1-methylpyridine p-toluenesulfonate, 2-fluoro-1-methylpyridine p-toluenesulfonate, 2-chloro-1-methylpyridine p-toluenesulfonate, 2-bromo-1-methylpyridine p-toluenesulfonate and 2-iodo-1-methylpyridine p-toluenesulfonate) in a corresponding organic solvent, wherein the organic solvent is one or more of acetonitrile, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone, to obtain a molecular passivator solution with a concentration of 0.1-50 mg / mL;

[0075] The preparation steps of the interface modifier are as follows: in an anhydrous and oxygen-free nitrogen glove box, pyridine benzene sulfonate (including 1-methylpyridine p-toluenesulfonate, 2-fluoro-1-methylpyridine p-toluenesulfonate, 2-chloro-1-methylpyridine p-toluenesulfonate, 2-bromo-1-methylpyridine p-toluenesulfonate and 2-iodo-1-methylpyridine p-toluenesulfonate) are respectively dissolved in corresponding organic solvents, wherein the organic solvent is one or more of anhydrous methanol, isopropanol, 2-methoxypropanol and chlorobenzene, to obtain interface modifier solutions with concentrations of 0.5, 1.0 and 1.5 mg / mL.

[0076] The steps of modifying the perovskite solar cell using the interface modifier and the molecular passivator include:

[0077] Step 1: Pre-treat the conductive glass substrate with UV ozone or plasma for 10-50 minutes;

[0078] Step 2: In an anhydrous and oxygen-free nitrogen glove box, the hole transport layer material is dissolved in an organic solvent, which is one or more of dimethoxyethanol, anhydrous ethanol, anhydrous methanol and isopropanol, to prepare a hole transport layer solution with a concentration of 0.5-3.0 mg / mL. The hole transport layer solution is then spin-coated on a pretreated conductive glass substrate at a spin-coating speed of 2000-4000 rpm, with a dropwise amount of 20-80 μL of solution added for 10-40 s. The substrate is then annealed at 70-120°C for 5-20 min to obtain a hole transport layer.

[0079] Step 3: First, in a nitrogen glove box without water or oxygen, dissolve the perovskite precursor in an organic solvent. The organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone, and the volume ratio of the mixed solvent is 8:1 to 2:1. The perovskite precursor solution with a concentration of 1.3-1.8M is prepared by heating and stirring at 20-80°C for 2-24h, and then the perovskite light-absorbing layer is prepared. There are two situations.

[0080] Case 1: The perovskite precursor solution is spin-coated on the hole transport layer at a spin-coating speed of 3000-6000 rpm, the amount of perovskite precursor solution added is 20-80 μL, and the spin-coating time is 10-40 seconds, followed by annealing heat treatment at a temperature of 100-160°C for 10-30 minutes to form a perovskite light-absorbing layer;

[0081] Case 2: Mix the molecular passivator with the perovskite precursor solution to ensure that the mixing ratio of the passivator to the precursor is 1:50-1:5, and then spin-coat it on the hole transport layer at a spin-coating speed of 3000-6000 rpm, with a droplet volume of 20-80 μL of solution and a spin-coating time of 10-40 seconds. Then, perform an annealing heat treatment at a temperature of 100-160°C for 10-30 minutes to form a perovskite light-absorbing layer;

[0082] Step 4: Perform upper interface modification on the perovskite light-absorbing layer. There are two situations:

[0083] Case 1: If Step 3 is case 1, the interface modifier is spin-coated or scraped on the perovskite light-absorbing layer at a spin-coating speed of 3000-5000 rpm, the amount of solution added is 30-100 μL, the spin-coating time is 10-40 s, and then an annealing heat treatment is performed at a temperature of 70-120°C for 5-10 minutes to form an upper interface modification layer;

[0084] Case 2: If Step 3 is case 2, no operation is performed;

[0085] Step 5: Spin-coat or thermally evaporate the electron transport layer and charge buffer layer on the battery structure in sequence;

[0086] Method 1: When the electron transport layer and the charge buffer layer are prepared by spin coating:

[0087] In an anhydrous and oxygen-free nitrogen glove box, [6,6]-phenyl-C61-butyric acid isomethyl ester is dissolved in chlorobenzene to prepare a 10-30 mg / mL electron transport layer solution, and then the electron transport layer solution is spin-coated on the perovskite light absorbing layer or the upper interface modification layer at a spin-coating speed of 1500-3000 rpm. The amount of the electron transport layer solution added dropwise is 30-100 μL, and the spin-coating time is 20-40 s to form an electron transport layer;

[0088] In an anhydrous and oxygen-free nitrogen glove box, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is dissolved in an organic solvent, which is one or more of 2-methoxypropanol, anhydrous ethanol, and isopropanol, to prepare a charge buffer layer solution of 0.5-3.0 mg / mL. The charge buffer layer solution is then spin-coated on the electron transport layer at a spin-coating speed of 3000-5000 rpm. The amount of the charge buffer layer solution added dropwise is 150-300 μL. The spin-coating time is 20-40 seconds, followed by an annealing heat treatment at a temperature of 70-120° C. for 5-10 minutes to form a charge buffer layer.

[0089] Method 2: When the electron transport layer and the charge buffer layer are prepared by thermal evaporation:

[0090] Fullerene is evaporated on the perovskite light absorbing layer or the upper interface modification layer, and the evaporation condition is a vacuum degree of less than 5×10 - 4 Pa, forming an electron transport layer with a thickness of 20-35 nm;

[0091] 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline was evaporated on the electron transport layer under the vacuum condition of less than 5×10 -4 Pa, forming a charge buffer layer with a thickness of 5-10 nm;

[0092] Step 6: Thermally evaporate a metal electrode above the charge buffer layer to obtain a perovskite solar cell modified by an interface modifier or passivated by a molecular passivator.

[0093] The novel pyridine benzene sulfonate compounds provided by the present invention can be used as bulk doping or interface modifiers for perovskite layers to effectively passivate internal and surface defects in perovskite films, inhibit non-radiative recombination, improve the open-circuit voltage, short-circuit current, and fill factor of the device, thereby improving the photoelectric conversion efficiency and significantly enhancing the thermal stability and light stability of the device. Specific effects include:

[0094] 1) The nitrogen atom on the pyridine ring has a lone pair of electrons and has a certain Lewis basicity, which can react with the uncoordinated Pb in the perovskite lattice. 2+ Form coordination bonds, fill surface defects of metal ions, and effectively reduce non-radiative recombination;

[0095] 2) Pyridinium cations have certain steric hindrance and hydrophobicity, which can affect the solvation structure and nucleation rate of the precursor in the perovskite precursor solution, helping to form larger grains and reduce the density of grain boundary defects;

[0096] 3) By introducing different halogens (F, Cl, Br, I) on the pyridine ring, the electron density and dipole moment of the pyridinium cation can be regulated, which helps to optimize the interfacial energy level alignment and enhance the selective extraction of electrons or holes;

[0097] 4) p-Toluenesulfonate contains highly polar -SO3 - groups, which can react with organic cations or I in perovskites - Form hydrogen bonds to passivate cation vacancy defects (V_FA + etc.) or boundary I - vacant seat;

[0098] 5) p-Toluenesulfonate has a large π-conjugated benzene ring structure, which can be stably adsorbed on the perovskite surface, providing a uniform negative charge distribution and helping to reduce the interface carrier recombination rate;

[0099] 6) The p-toluenesulfonic acid group has strong hydrophobicity and can give the surface a hydrophobic protective layer, thereby enhancing the perovskite film's resistance to water vapor corrosion, thereby improving the device's wet-heat stability.

[0100] The present invention uses the above-mentioned bulk or interface control strategy of the synergistic effect of anions and cations to improve the photoelectric conversion efficiency of the device while significantly enhancing its long-term stability, providing a new path for the preparation of efficient and stable perovskite solar cells.

[0101] The principles and features of the present invention are described through the following experimental cases in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0102] Experimental Example 1:

[0103] 1-Methylpyridine p-toluenesulfonate is doped into a perovskite precursor solution to prepare a perovskite solar cell. The solvent of the molecular passivator solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and the solution concentration is 1 mg / mL.

[0104] S1: Prepare a molecular passivation agent solution: In a nitrogen glove box, mix N,N-dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1, and dissolve an appropriate amount of 1-methylpyridine p-toluenesulfonate to obtain a molecular passivation agent solution with a concentration of 10 mg / mL;

[0105] S2: Preparation of molecular passivation-perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, and then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075. Then, the molecular passivator solution prepared in S1 was mixed with the perovskite precursor solution in a volume ratio of 1:9, and then stirred at 40 ° C for 12 hours. Finally, it was filtered through a PTFE 13*0.22um filter head to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0106] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, and then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, add it dropwise to the center of the FTO glass, spin-coat for 40 seconds, and heat-treat at 110°C for 10 minutes to obtain the hole transport layer substrate;

[0107] S4: Preparation of molecular passivation-perovskite light-absorbing layer: 50 μL of molecular passivation-perovskite precursor solution was dropped on the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as anti-solvent. The substrate was annealed at 130°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0108] S5: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) is evaporated on the perovskite layer as the electron transport layer. The evaporation condition is vacuum degree less than 5×10 -4 Pa;

[0109] S6: Preparation of charge buffer layer: Using thermal evaporation method, 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was evaporated on the perovskite layer as a charge buffer layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0110] S7: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver as the metal back electrode on the electron blocking layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0111] like Figure 3 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 23.08% with an effective area of ​​0.05 cm 2 .

[0112] Experimental Example 2:

[0113] 2-Fluoro-1-methylpyridinium p-toluenesulfonate was doped into a perovskite precursor solution to prepare a perovskite solar cell. The solvent of the molecular passivator solution was one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and the solution concentration was 1 mg / mL.

[0114] S1: Prepare a molecular passivation agent solution: In a nitrogen glove box, mix N,N-dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1, and dissolve an appropriate amount of 2-fluoro-1-methylpyridine p-toluenesulfonate to obtain a molecular passivation agent solution with a concentration of 10 mg / mL;

[0115] S2: Preparation of molecular passivation-perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, and then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075. Then, the molecular passivator solution prepared in S1 was mixed with the perovskite precursor solution in a volume ratio of 1:9, and then stirred at 40 ° C for 12 hours. Finally, it was filtered through a PTFE 13*0.22um filter head to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95Pb(I 0.95 Br 0.05 )3;

[0116] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, and then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, add it dropwise to the center of the FTO glass, spin-coat for 40 seconds, and heat-treat at 110°C for 10 minutes to obtain the hole transport layer substrate;

[0117] S4: Preparation of molecular passivation-perovskite light-absorbing layer: 50 μL of molecular passivation-perovskite precursor solution was dropped on the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as anti-solvent. The substrate was annealed at 130°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0118] S5: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) is evaporated on the perovskite layer as the electron transport layer. The evaporation condition is vacuum degree less than 5×10 -4 Pa;

[0119] S6: Preparation of charge buffer layer: Using thermal evaporation method, 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was evaporated on the perovskite layer as a charge buffer layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0120] S7: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver as the metal back electrode on the electron blocking layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0121] like Figure 4 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 23.87% with an effective area of ​​0.05 cm 2 .

[0122] Experimental Example 3:

[0123] 2-Chloro-1-methylpyridinium p-toluenesulfonate was doped into a perovskite precursor solution to prepare a perovskite solar cell. The solvent of the molecular passivator solution was one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and the solution concentration was 1 mg / mL.

[0124] S1: Prepare a molecular passivation agent solution: In a nitrogen glove box, mix N,N-dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1, and dissolve an appropriate amount of 2-chloro-1-methylpyridine p-toluenesulfonate to obtain a molecular passivation agent solution with a concentration of 10 mg / mL;

[0125] S2: Preparation of molecular passivation-perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, and then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075. Then, the molecular passivator solution prepared in S1 was mixed with the perovskite precursor solution in a volume ratio of 1:9, and then stirred at 40 ° C for 12 hours. Finally, it was filtered through a PTFE 13*0.22um filter head to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0126] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, and then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, add it dropwise to the center of the FTO glass, spin-coat for 40 seconds, and heat-treat at 110°C for 10 minutes to obtain the hole transport layer substrate;

[0127] S4: Preparation of molecular passivation-perovskite light-absorbing layer: 50 μL of molecular passivation-perovskite precursor solution was dropped on the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as anti-solvent. The substrate was annealed at 130°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0128] S5: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) is evaporated on the perovskite layer as the electron transport layer. The evaporation condition is vacuum degree less than 5×10 -4 Pa;

[0129] S6: Preparation of charge buffer layer: Using thermal evaporation method, 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was evaporated on the perovskite layer as a charge buffer layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0130] S7: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver as the metal back electrode on the electron blocking layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0131] like Figure 5 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 23.75% with an effective area of ​​0.05 cm 2 .

[0132] Experimental Example 4:

[0133] 2-Bromo-1-methylpyridine p-toluenesulfonate was doped into a perovskite precursor solution to prepare a perovskite solar cell. The solvent of the molecular passivator solution was one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and the solution concentration was 1 mg / mL.

[0134] S1: Prepare a molecular passivation agent solution: In a nitrogen glove box, mix N,N-dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1, and dissolve an appropriate amount of 2-bromo-1-methylpyridine p-toluenesulfonate to obtain a molecular passivation agent solution with a concentration of 10 mg / mL;

[0135] S2: Preparation of molecular passivation-perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, and then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075. Then, the molecular passivator solution prepared in S1 was mixed with the perovskite precursor solution in a volume ratio of 1:9, and then stirred at 40 ° C for 12 hours. Finally, it was filtered through a PTFE 13*0.22um filter head to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0136] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, and then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, add it dropwise to the center of the FTO glass, spin-coat for 40 seconds, and heat-treat at 110°C for 10 minutes to obtain the hole transport layer substrate;

[0137] S4: Preparation of molecular passivation-perovskite light-absorbing layer: 50 μL of molecular passivation-perovskite precursor solution was dropped on the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as anti-solvent. The substrate was annealed at 130°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0138] S5: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) is evaporated on the perovskite layer as the electron transport layer. The evaporation condition is vacuum degree less than 5×10 -4 Pa;

[0139] S6: Preparation of charge buffer layer: Using thermal evaporation method, 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was evaporated on the perovskite layer as a charge buffer layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0140] S7: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver as the metal back electrode on the electron blocking layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0141] like Figure 6 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 23.40% with an effective area of ​​0.05 cm 2 .

[0142] Experimental Example 5:

[0143] 2-iodo-1-methylpyridinium p-toluenesulfonate was doped into a perovskite precursor solution to prepare a perovskite solar cell. The solvent of the molecular passivator solution was one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and the solution concentration was 1 mg / mL.

[0144] S1: Prepare a molecular passivation agent solution: In a nitrogen glove box, mix N,N-dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1, and dissolve an appropriate amount of 2-iodo-1-methylpyridine p-toluenesulfonate to obtain a molecular passivation agent solution with a concentration of 10 mg / mL;

[0145] S2: Preparation of molecular passivation-perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, and then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075. Then, the molecular passivator solution prepared in S1 was mixed with the perovskite precursor solution in a volume ratio of 1:9, and then stirred at 40 ° C for 12 hours. Finally, it was filtered through a PTFE 13*0.22um filter head to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0146] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, and then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, add it dropwise to the center of the FTO glass, spin-coat for 40 seconds, and heat-treat at 110°C for 10 minutes to obtain the hole transport layer substrate;

[0147] S4: Preparation of molecular passivation-perovskite light-absorbing layer: 50 μL of molecular passivation-perovskite precursor solution was dropped on the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as anti-solvent. The substrate was annealed at 130°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0148] S5: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) is evaporated on the perovskite layer as the electron transport layer. The evaporation condition is vacuum degree less than 5×10 -4 Pa;

[0149] S6: Preparation of charge buffer layer: Using thermal evaporation method, 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was evaporated on the perovskite layer as a charge buffer layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0150] S7: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver as the metal back electrode on the electron blocking layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0151] like Figure 7 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 23.35% with an effective area of ​​0.05 cm 2 .

[0152] Experimental Example 6:

[0153] 1-Methylpyridine p-toluenesulfonate was used as an interface modifier to prepare perovskite solar cells. Isopropyl alcohol was used as a solvent to dissolve the prepared molecular modifiers at a concentration of 0.5 mg / mL.

[0154] S1: Preparation of the interface modifier: In a nitrogen glove box, dissolve 1-methylpyridine p-toluenesulfonate in isopropanol as a solvent to obtain a molecular modifier solution with a concentration of 0.5 mg / mL;

[0155] S2: Preparation of perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075, then stir at 40 ° C for 12 hours, and finally filter through a PTFE 13*0.22um filter to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0156] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, drop it on the center of the FTO glass, spin coat for 40 seconds, and heat treat at 110°C to obtain a hole transport layer substrate;

[0157] S4: Preparation of perovskite light-absorbing layer: 50 μL of perovskite precursor solution was dropped onto the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as an anti-solvent. The substrate was annealed at 140°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0158] S5: Preparation of upper interface modification layer: 50 μL of the interface modifier solution prepared in S1 was added dropwise to the perovskite light absorbing layer, and the mixture was rotated at 2000-4000 rpm for 30 seconds, followed by heat treatment at 100°C for 10 minutes to obtain the upper interface modification layer;

[0159] S6: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) was evaporated on the perovskite layer as the electron transport layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0160] S7: Prepare a charge buffer layer: Use thermal evaporation to deposit 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) on the perovskite layer as a charge buffer layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa;

[0161] S8: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver on the electron blocking layer as the metal back electrode. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0162] like Figure 8 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 23.91%, with an effective area of ​​0.05 cm 2 .

[0163] Experimental Example 7:

[0164] 2-Fluoro-1-methylpyridine p-toluenesulfonate was used as an interface modifier to prepare perovskite solar cells. Isopropyl alcohol was used as a solvent to dissolve the molecules. The concentration of the prepared molecular modifiers was 0.5 mg / mL:

[0165] S1: Preparation of the interface modifier: In a nitrogen glove box, dissolve 2-fluoro-1-methylpyridine p-toluenesulfonate in isopropanol as a solvent to obtain a molecular modifier solution with a concentration of 0.5 mg / mL;

[0166] S2: Preparation of perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075, then stir at 40 ° C for 12 hours, and finally filter through a PTFE 13*0.22um filter to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0167] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, drop it on the center of the FTO glass, spin coat for 40 seconds, and heat treat at 110°C to obtain a hole transport layer substrate;

[0168] S4: Preparation of perovskite light-absorbing layer: 50 μL of perovskite precursor solution was dropped onto the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as an anti-solvent. The substrate was annealed at 140°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0169] S5: Preparation of upper interface modification layer: 50 μL of the interface modifier solution prepared in S1 was added dropwise to the perovskite light absorbing layer, and the mixture was rotated at 2000-4000 rpm for 30 seconds, followed by heat treatment at 100°C for 10 minutes to obtain the upper interface modification layer;

[0170] S6: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) was evaporated on the perovskite layer as the electron transport layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0171] S7: Prepare a charge buffer layer: Use thermal evaporation to deposit 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) on the perovskite layer as a charge buffer layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa;

[0172] S8: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver on the electron blocking layer as the metal back electrode. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0173] like Figure 9 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 24.92% with an effective area of ​​0.05 cm 2 .

[0174] Experimental Example 8:

[0175] 2-Chloro-1-methylpyridine p-toluenesulfonate was used as an interface modifier to prepare perovskite solar cells. Isopropyl alcohol was used as a solvent to dissolve the prepared molecular modifiers at a concentration of 0.5 mg / mL.

[0176] S1: Preparation of the interface modifier: In a nitrogen glove box, dissolve 2-chloro-1-methylpyridine p-toluenesulfonate in isopropanol as a solvent to obtain a molecular modifier solution with a concentration of 0.5 mg / mL;

[0177] S2: Preparation of perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075, then stir at 40 ° C for 12 hours, and finally filter through a PTFE 13*0.22um filter to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0178] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, drop it on the center of the FTO glass, spin coat for 40 seconds, and heat treat at 110°C to obtain a hole transport layer substrate;

[0179] S4: Preparation of perovskite light-absorbing layer: 50 μL of perovskite precursor solution was dropped onto the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as an anti-solvent. The substrate was annealed at 140°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0180] S5: Preparation of upper interface modification layer: 50 μL of the interface modifier solution prepared in S1 was added dropwise to the perovskite light absorbing layer, and the mixture was rotated at 2000-4000 rpm for 30 seconds, followed by heat treatment at 100°C for 10 minutes to obtain the upper interface modification layer;

[0181] S6: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) was evaporated on the perovskite layer as the electron transport layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0182] S7: Prepare a charge buffer layer: Use thermal evaporation to deposit 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) on the perovskite layer as a charge buffer layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa;

[0183] S8: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver on the electron blocking layer as the metal back electrode. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0184] like Figure 10 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 24.10%, with an effective area of ​​0.05 cm 2 .

[0185] Experimental Example 9:

[0186] 2-Bromo-1-methylpyridine p-toluenesulfonate was used as an interface modifier to prepare perovskite solar cells. Isopropyl alcohol was used as a solvent to dissolve the molecules. The concentration of the prepared molecular modifiers was 0.5 mg / mL:

[0187] S1: Preparation of the interface modifier: In a nitrogen glove box, dissolve 2-bromo-1-methylpyridine p-toluenesulfonate in isopropanol as a solvent to obtain a molecular modifier solution with a concentration of 0.5 mg / mL;

[0188] S2: Preparation of perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075, then stir at 40 ° C for 12 hours, and finally filter through a PTFE 13*0.22um filter to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0189] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, drop it on the center of the FTO glass, spin coat for 40 seconds, and heat treat at 110°C to obtain a hole transport layer substrate;

[0190] S4: Preparation of perovskite light-absorbing layer: 50 μL of perovskite precursor solution was dropped onto the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as an anti-solvent. The substrate was annealed at 140°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0191] S5: Preparation of upper interface modification layer: 50 μL of the interface modifier solution prepared in S1 was added dropwise to the perovskite light absorbing layer, and the mixture was rotated at 2000-4000 rpm for 30 seconds, followed by heat treatment at 100°C for 10 minutes to obtain the upper interface modification layer;

[0192] S6: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) was evaporated on the perovskite layer as the electron transport layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0193] S7: Prepare a charge buffer layer: Use thermal evaporation to deposit 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) on the perovskite layer as a charge buffer layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa;

[0194] S8: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver on the electron blocking layer as the metal back electrode. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0195] like Figure 11 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 24.41%, with an effective area of ​​0.05 cm 2 .

[0196] Experimental Example 10:

[0197] 2-iodo-1-methylpyridine p-toluenesulfonate was used as an interface modifier to prepare perovskite solar cells. Isopropyl alcohol was used as a solvent to dissolve the molecules. The concentration of the prepared molecular modifiers was 0.5 mg / mL:

[0198] S1: Preparation of the interface modifier: In a nitrogen glove box, dissolve 2-iodo-1-methylpyridine p-toluenesulfonate in isopropanol as a solvent to obtain a molecular modifier solution with a concentration of 0.5 mg / mL;

[0199] S2: Preparation of perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075, then stir at 40 ° C for 12 hours, and finally filter through a PTFE 13*0.22um filter to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0200] S3: Preparation of hole transport layer: Place the FTO conductive glass in a UV ozone cleaning machine for 30 minutes, then transfer it to a dry nitrogen glove box; dissolve [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) in dimethoxyethanol solution to prepare a hole transport layer solution, draw 50 μL of the hole transport layer solution, drop it on the center of the FTO glass, spin coat for 40 seconds, and heat treat at 110°C to obtain a hole transport layer substrate;

[0201] S4: Preparation of perovskite light-absorbing layer: 50 μL of perovskite precursor solution was dropped onto the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. 15 seconds before the end of spin coating, 200 μL of ethyl acetate was added as an anti-solvent. The substrate was annealed at 140°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0202] S5: Preparation of upper interface modification layer: 50 μL of the interface modifier solution prepared in S1 was added dropwise to the perovskite light absorbing layer, and the mixture was rotated at 2000-4000 rpm for 30 seconds, followed by heat treatment at 100°C for 10 minutes to obtain the upper interface modification layer;

[0203] S6: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) was evaporated on the perovskite layer as the electron transport layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0204] S7: Prepare a charge buffer layer: Use thermal evaporation to deposit 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) on the perovskite layer as a charge buffer layer. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa;

[0205] S8: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver on the electron blocking layer as the metal back electrode. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0206] like Figure 12 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 24.36% with an effective area of ​​0.05 cm 2 .

[0207] Comparative Example 1:

[0208] The perovskite solar cell is prepared without adding any molecules as interface modifiers and molecular passivators.

[0209] S1: Preparation of perovskite precursor solution: In a nitrogen-filled environment, first mix N,N-dimethylformamide and dimethyl sulfoxide mixed solvents in a volume ratio of 4:1, then dissolve CsI, MAI, FAI, PbI2 and PbBr2 in it in a molar ratio of 0.05:0.9025:0.0475:0.925:0.075, then stir at 40 ° C for 12 hours, and finally filter through a PTFE 13*0.22um filter to obtain a 1.55M perovskite precursor solution Cs 0.05 (MA 0.05 FA 0.95 ) 0.95 FA 0.95 Pb(I 0.95 Br 0.05 )3;

[0210] S2: Preparation of hole transport layer: FTO conductive glass was placed in a UV ozone cleaning machine for 30 minutes, and then transferred to a dry nitrogen glove box; [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz) was dissolved in dimethoxyethanol solution to prepare a hole transport layer solution, 50 μL of the hole transport layer solution was drawn and dropped onto the center of the FTO glass, spin-coated for 40 seconds, and then heat-treated at 110°C for 10 minutes to obtain a hole transport layer substrate;

[0211] S3: Preparation of perovskite light-absorbing layer: 50 μL of perovskite precursor solution was dropped on the center of the hole transport layer substrate, and the substrate was rotated at 5000 rpm for 50 seconds. When the substrate was 15 seconds old, 200 μL of ethyl acetate was added as an anti-solvent. The substrate was annealed at 130°C for 30 minutes to form a perovskite film, which was then placed in a dry place for cooling.

[0212] S4: Preparation of electron transport layer: Using thermal evaporation method, 25nm of fullerene (C60) is evaporated on the perovskite layer as the electron transport layer. The evaporation condition is vacuum degree less than 5×10 -4 Pa;

[0213] S5: Preparation of charge buffer layer: Using thermal evaporation method, 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was evaporated on the perovskite layer as a charge buffer layer. The evaporation condition was a vacuum degree of less than 5×10 -4 Pa;

[0214] S6: Prepare the metal electrode layer: Use thermal evaporation to evaporate 110nm of silver on the electron blocking layer as the metal back electrode. The evaporation condition is a vacuum degree of less than 5×10 -4 Pa.

[0215] like Figure 13 As shown in Figure 2, the photoelectric conversion efficiency of the perovskite solar cell was measured to be 21.47% with an effective area of ​​0.05 cm 2 .

[0216] By comparing the data in Comparative Example 1 with those in Experimental Examples 1-10, it can be found that after bulk or interface modification, the open circuit voltage and short circuit current of the device are both improved, indicating that after using 1-methylpyridine toluenesulfonate, 2-fluoro-1-methylpyridine toluenesulfonate, 2-chloro-1-methylpyridine toluenesulfonate, 2-bromo-1-methylpyridine toluenesulfonate and 2-iodo-1-methylpyridine toluenesulfonate, respectively, the deep energy level defects in the perovskite are significantly passivated and non-radiative recombination is suppressed. After the above-mentioned multifunctional molecular modification, the photoelectric conversion efficiency of the perovskite solar cell can be effectively improved.

[0217] according to Figure 14 、 15 As shown in Figures 16, when 2-fluoro-1-methylpyridine toluenesulfonate is used for bulk doping of the perovskite layer, the morphology of the perovskite film changes significantly. Compared with the undoped sample, the grain size of the film after treatment is significantly larger, the boundaries between the grains are clearer, the arrangement is tighter, and the overall film surface presents a denser and smoother feature. This shows that the added 2-fluoro-1-methylpyridine toluenesulfonate plays a regulatory role in the nucleation and grain growth of perovskite, effectively inhibiting the formation of non-uniform nucleation and grain boundary defects, thereby reducing the scattering and recombination channels of carriers at the grain boundaries. Furthermore, when 2-fluoro-1-methylpyridine toluenesulfonate is used for interface modification on perovskite, it is observed that an elongated nanostructure is generated in the boundary region of the perovskite grains. This is a one-dimensional perovskite phase (low-dimensional RP phase or one-dimensional chain structure) with a certain orientation. This structure originates from the interaction between pyridinium cations and uncoordinated Pb at the boundary. 2+ The specific binding of the localized phase transition induced by the one-dimensional phase can effectively passivate grain boundary defects, optimize interface energy level matching, and enhance stability.

[0218] like Figure 17 Shown is a comparison of the stability curves of the perovskite solar cells prepared under the conditions of Experimental Examples 2 and 7, respectively, with 2-fluoro-1-methylpyridine toluenesulfonate as the bulk phase addition and upper interface modification, and the perovskite solar cell prepared in Comparative Example 1. The efficiency of the perovskite devices in Experimental Examples 2, 7, and Comparative Example 1 was measured at the same time point. It can be seen that compared with the perovskite devices using 2-fluoro-1-methylpyridine toluenesulfonate as the bulk phase addition (Experimental Example 2) and upper interface modification (Experimental Example 7), the stability performance of Comparative Example 1 is poor.

[0219] These research results demonstrate that the pyridine benzenesulfonates developed by this research group—including 1-methylpyridine p-toluenesulfonate, 2-fluoro-1-methylpyridine p-toluenesulfonate, 2-chloro-1-methylpyridine p-toluenesulfonate, 2-bromo-1-methylpyridine p-toluenesulfonate, and 2-iodo-1-methylpyridine p-toluenesulfonate—can significantly enhance the photoelectric conversion efficiency and long-term stability of perovskite solar cells. Mechanistic studies indicate that these compounds improve the surface quality of the thin films, effectively enhancing the photoelectric performance of the devices. Notably, based on industrial-grade testing standards, the optimized devices maintained over 90% of their initial efficiency after 1500 hours of high-temperature aging in a nitrogen environment, demonstrating significant potential for commercial application.

[0220] The above description is only a preferred experimental example of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A perovskite solar cell, characterized in that The invention comprises a conductive glass substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a charge buffer layer and a metal electrode layer which are stacked in sequence, and also comprises a molecular passivator and an interface modifier prepared from pyridine benzene sulfonate.

2. The perovskite solar cell according to claim 1, wherein The material of the hole transport layer is one or more of [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid and (2-(9H-carbazol-9-yl)ethyl)phosphonic acid; The chemical formula of the perovskite light absorbing layer is ABX n , where: A is selected from FA + [CH(NH2) 2+ ]、MA + (CH3NH3 + ), Cs + , Rb + One or more of; B is selected from Pb 2+ 、Sn 2+ One or more of; X is selected from Cl - Br - , I - One or more of .

3. The perovskite solar cell according to claim 1, wherein The preparation steps of the molecular passivator are as follows: in a nitrogen glove box without water or oxygen, dissolving pyridine benzene sulfonate in corresponding organic solvents to obtain a molecular passivator solution with a concentration of 0.1-50 mg / mL; The organic solvent for dissolving pyridine benzene sulfonate is one or more of acetonitrile, isopropyl alcohol, N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone.

4. The perovskite solar cell according to claim 1, wherein The preparation steps of the interface modifier are as follows: in a nitrogen glove box without water or oxygen, pyridine benzene sulfonate is dissolved in corresponding organic solvents to obtain interface modifier solutions with concentrations of 0.5, 1.0 and 1.5 mg / mL; The organic solvent for dissolving pyridine benzene sulfonate is one or more of anhydrous methanol, isopropanol, 2-methoxypropanol and chlorobenzene.

5. The perovskite solar cell according to claim 3 or 4, wherein: The pyridine benzene sulfonate is one or more of 1-methylpyridine p-toluene sulfonate, 2-fluoro-1-methylpyridine p-toluene sulfonate, 2-chloro-1-methylpyridine p-toluene sulfonate, 2-bromo-1-methylpyridine p-toluene sulfonate and 2-iodo-1-methylpyridine p-toluene sulfonate, and the substituent functional groups at different positions on the pyridine ring contain 0-5 halogen atoms; The halogen atom is one or more of F, Cl, Br, and I.

6. A method for preparing a perovskite solar cell according to claims 1-5, characterized in that: The specific steps include: Step 1: Pre-treat the conductive glass substrate; Step 2: Spin-coating a hole transport layer solution on a pre-treated conductive glass substrate, followed by annealing to obtain a hole transport layer; Step 3: Prepare the perovskite light absorbing layer. There are two situations. Case 1: The perovskite precursor solution is spin-coated on the hole transport layer and annealed to form a perovskite light-absorbing layer; Case 2: After mixing the molecular passivator with the perovskite precursor solution, it is spin-coated on the hole transport layer and annealed to form the perovskite light absorption layer; Step 4: Perform upper interface modification on the perovskite light-absorbing layer. There are two situations: Case 1: If Step 3 is case 1, an interface modifier is spin-coated or scraped onto the perovskite light-absorbing layer, and then annealed to form an upper interface modification layer. Case 2: If Step 3 is case 2, no operation is performed; Step 5: Spin-coat or thermally evaporate the electron transport layer and charge buffer layer on the battery structure in sequence; Step 6: Thermally evaporate a metal electrode above the charge buffer layer to obtain a perovskite solar cell modified by an interface modifier or passivated by a molecular passivator.

7. The method for preparing a perovskite solar cell according to claim 6, wherein: The hole transport layer solution is prepared by dissolving the hole transport layer material in an organic solvent in a nitrogen glove box without water or oxygen to prepare a solution with a concentration of 0.5-3.0 mg / mL; The organic solvent for dissolving the hole transport layer material is one or more of dimethoxyethanol, anhydrous ethanol, anhydrous methanol and isopropyl alcohol.

8. The method for preparing a perovskite solar cell according to claim 6, wherein: The perovskite precursor solution is prepared by dissolving the perovskite precursor in an organic solvent in an anhydrous and oxygen-free nitrogen glove box to prepare a perovskite precursor solution with a concentration of 1.3-1.8M, and heating and stirring at 20-80°C for 2-24 hours; The organic solvent for dissolving the perovskite precursor is one or more of N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone, and the volume ratio of the mixed solvent when the organic solvent is one or more of the organic solvents is 8:1 to 2:

1.

9. The method for preparing a perovskite solar cell according to claim 6, wherein: The implementation of Step 1 is as follows: pre-treating the conductive glass substrate with ultraviolet ozone or plasma for 10-50 minutes; There are two ways to implement Step 5: Method 1: Spin coating to prepare the electron transport layer and charge buffer layer: In a nitrogen glove box without water or oxygen, dissolving [6,6]-phenyl-C61-butyric acid isomethyl ester in chlorobenzene to prepare a 10-30 mg / mL electron transport layer solution, and then spin-coating the electron transport layer solution on the perovskite light absorption layer or the upper interface modification layer to form the electron transport layer; The spin coating speed of the electron transport layer solution on the perovskite light absorbing layer or the upper interface modification layer is 1500-3000 rpm, the amount of the electron transport layer solution added dropwise is 30-100 μL, and the spin coating time is 20-40 s; In a nitrogen glove box without water or oxygen, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline was dissolved in an organic solvent to prepare a charge buffer layer solution at a concentration of 0.5-3.0 mg / mL. The charge buffer layer solution was then spin-coated on the electron transport layer. After annealing and heat treatment, the charge buffer layer was formed. The organic solvent for dissolving 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is one or more of 2-methoxypropanol, anhydrous ethanol, and isopropanol; the spin coating speed of the charge buffer layer solution on the electron transport layer is 3000-5000 rpm, the amount of the charge buffer layer solution added is 150-300 μL, the spin coating time is 20-40 seconds, the annealing temperature is 70-120° C., and the treatment time is 5-10 minutes; Method 2: Using thermal evaporation to prepare the electron transport layer and charge buffer layer: Fullerene is evaporated on the perovskite light absorbing layer or the upper interface modification layer, and the evaporation condition is a vacuum degree of less than 5×10 -4 Pa, forming the electron transport layer with a thickness of 20-35 nm; 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline was evaporated on the electron transport layer under the vacuum condition of less than 5×10 -4 Pa, forming the charge buffer layer with a thickness of 5-10 nm.

10. The method for preparing a perovskite solar cell according to claim 6, wherein: In the step 2, the hole transport layer solution is spin-coated on the conductive glass substrate at a speed of 2000-4000 rpm, the amount of the hole transport layer solution added is 20-80 μL, the spin coating time is 10-40 s, and the annealing heat treatment temperature is 70-120° C. for 5-20 min; In Step 3, the perovskite precursor solution or the mixed solution of the molecular passivator and the perovskite precursor solution is spin-coated on the hole transport layer at a spin coating speed of 3000-6000 rpm, the amount of solution added is 20-80 μL, the spin coating time is 10-40 s, the annealing heat treatment temperature is 100-160° C., and the treatment time is 10-30 min; when the molecular passivator is mixed with the perovskite precursor solution, the mixing ratio of the passivator to the precursor is 1:50-1:5; In the Step 4, the interface modifier is spin-coated on the perovskite light-absorbing layer at a spin-coating speed of 3000-5000 rpm, the amount of the interface modifier solution added is 30-100 μL, the spin-coating time is 10-40 s, the annealing temperature is 70-120° C., and the treatment time is 5-10 min.

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