Highly efficient and air humidity stable perovskite solar cells with synergistically improved defects and ion migration

Abstract

A high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration, comprising a perovskite active layer, wherein the chemical formula of the perovskite material is FA. x MA y Cs z PbX3, x+y+z=1, where X is selected from one, two, or three elements from I, Br, and Cl; the perovskite active layer also contains a variable-valence material. This invention uses a variable-valence material as an additive in the perovskite precursor solution, utilizing cation passivation of Pb. 0 I 0 Defects, anions and uncoordinated Pb 2+ Defects can improve the phase stability of perovskite crystals; further, positive / negative charged polymers can be used for double-sided passivation on both sides of the perovskite film, utilizing the positive / negative charged polymers to passivate oxygen vacancies and Pb. 2+ Defects such as these are eliminated, and ion migration at the interface is also blocked; the perovskite solar cell device of the present invention has both high photoelectric conversion efficiency and high humidity stability.

Description

Technical Field

[0001] This invention relates to a perovskite solar cell, specifically to a high-efficiency, stable perovskite solar cell that synergistically improves defects and ion migration. Background Technology

[0002] Perovskite solar cells belong to the third generation of photovoltaic solar cell technology. Their structure consists of an electron transport layer (ETL, such as SnO2 or TiO2), a perovskite light-absorbing material (ABX3 (A = CH3NH3(MA) or Cs, etc., B = Pb, Sn, etc., X = I, Br, Cl)), a hole transport layer (HTL, such as spiro-OMeTAD), and a metal counter electrode. Due to their high efficiency, low cost, simple manufacturing process, and environmental friendliness, they have become a key research focus in the field of optoelectronic devices. In 2022, their photoelectric conversion efficiency reached 25.7%, demonstrating extremely high development and application potential. Although perovskite solar cells, as a novel photovoltaic device, have achieved photoelectric conversion efficiencies far exceeding other types of solar cells, devices using organic-inorganic hybrid perovskite as the light-absorbing material are extremely sensitive to photothermal and water / oxygen conditions, and are easily decomposed. This results in poor stability of such devices, limiting their practical application.

[0003] CN109545970A discloses a method for improving the efficiency and stability of perovskite solar cells, and a perovskite solar cell itself. The method improves the efficiency and stability of perovskite solar cells in air without encapsulation by adding a small amount of hydrophobic organic small molecules to the antisolvent used to prepare the perovskite light-absorbing layer. Perovskite solar cells are classified into two types based on their structure: formal and trans-form, both with an ABX3 structure for their perovskite light-absorbing layer. Results show that the small molecules added to the antisolvent are conjugated organic small molecules containing thiophene structural units or any one of the elements S, N, or O. These molecules can reduce grain boundaries and surface defects in the perovskite layer in both device structures, ultimately improving the efficiency and stability of the perovskite solar cell. This method adds conjugated organic small molecules containing thiophene structural units or any one of the elements S, N, or O to the antisolvent, which interact with the B-site elements (e.g., Pb) within the crystal lattice. 2+ This method involves forming coordination bonds to stabilize the perovskite lattice. It discusses solutions to perovskite stability from the perspective of the perovskite material lattice. However, its drawback is that it only addresses the instability of B-site elements, without proposing solutions for the instability of A-site elements within the lattice.

[0004] CN111740015A discloses a perovskite precursor solution for improving the stability of perovskite solar cells. Formamidine iodide and cesium iodide are added to a solvent, stirred, and then methyl bromide is added. After stirring, lead iodide and 3,4-dichloroaniline are added and stirred again to obtain the perovskite precursor solution for improving the stability of perovskite solar cells. The perovskite precursor solution for improving the stability of perovskite solar cells is spin-coated onto a substrate and thermally annealed to obtain a perovskite thin film, which serves as the light-absorbing layer of the solar cell. The prepared perovskite precursor solution for improving the stability of perovskite solar cells replaces the existing perovskite layer, overcoming the defects in existing perovskite mineralization technology. It provides a method for improving the stability of perovskite with low requirements for the process environment during cell fabrication, convenient preparation method, and the ability to maintain stable properties for a long time in ordinary environments. Compared to methylamine (CH3NH3), formamidine (N2H4CH) and cesium (Cs) exhibit better stability in perovskite lattices. This method improves the stability of perovskite materials by replacing part of the methylamine with formamidine and cesium at the A-site of the perovskite lattice. However, a drawback is that only A-site elements are discussed.

[0005] CN113416155A discloses a method for preparing an additive for perovskite solar cells and its application, comprising the following steps: 1) placing a tetrafluoroboric acid solution in a glass container, then slowly adding guanidine carbonate powder to the tetrafluoroboric acid solution while continuously stirring to ensure a full reaction until no more bubbles are generated; 2) filtering the mixture using a Buchner funnel to separate the precipitate generated by the reaction, then washing the precipitate with dichloromethane organic solvent to obtain a white precipitate of guanidine tetrafluoroborate; 3) drying the obtained white precipitate of guanidine tetrafluoroborate in a vacuum drying oven to obtain the guanidine tetrafluoroborate additive. Applying this additive to the perovskite active layer of a perovskite solar cell can effectively improve the photoelectric conversion efficiency of the perovskite solar cell and enable it to have a longer lifespan while maintaining a high photoelectric conversion efficiency, thus improving the stability of the perovskite solar cell. This method uses guanidine tetrafluoroborate as an additive in perovskite materials to improve charge transport and passivate internal defects in the perovskite materials, thereby achieving the purpose of improving the photoelectric conversion efficiency and stability of perovskite solar cells. A drawback of this method is the limited range of passivation effects. Although perovskite materials have a high tolerance for defects, various Schottky and Frankel defects within the material cannot be completely eliminated.

[0006] The above methods can improve the efficiency and stability of perovskite solar cells to some extent, but it is still difficult to achieve high efficiency and high stability. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a perovskite solar cell that has both high photoelectric conversion efficiency and high humidity stability.

[0008] The technical solution adopted by this invention to solve its technical problem is as follows: a high-efficiency, air humidity-stable perovskite solar cell that synergistically improves defects and ion migration, having a perovskite active layer, the chemical formula of which is FA. x MA y Cs z PbX3, x+y+z=1, where X is selected from one, two, or three elements from I, Br, and Cl; the perovskite active layer also contains a variable valence material;

[0009] The variable-valence material is: Ni-containing... 2+ and Ni 3+ substances containing Cu + and Cu 2+ substances containing Co 3+ and Co 2+ One or more of the following: substances, combinations of SeCN and Se(CN)2, combinations of disulfides and thiolates, and combinations of ferrocene and ferrocene salts.

[0010] Preferably, the Ni-containing 2+ and Ni 3+ The anions in the substance are polypyridine or F-containing groups.

[0011] Preferably, the Cu-containing + and Cu 2+ The anion in the substance is SCN. - and / or Br - .

[0012] Preferably, the Co-containing 3+ and Co 2+ The anions in the substance are polypyridine or F-containing groups.

[0013] This invention employs a type of "variable valence" electroactive material, the function of which is that the cations in the variable valence material can passivate Pb. 0 I 0 Defects such as anions and uncoordinated Pb improve the photoelectric efficiency of perovskite solar cells. 2+ Plasma interaction improves the phase stability of perovskite crystals; in variable valence materials, the content of variable valence ions of different valence states should be certain, such as the molar ratio of high valence ions to low valence ions = 1:5 to 5:1.

[0014] Preferably, the high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration further comprises an electron transport layer, a negatively charged polymer layer, a positively charged polymer layer, and a hole transport layer.

[0015] The negatively charged polymer layer is located between the electron transport layer and the perovskite active layer, and the positively charged polymer layer is located between the perovskite active layer and the hole transport layer. Both the negatively charged polymer layer and the positively charged polymer layer are adjacent to the perovskite active layer.

[0016] Perovskite solar cells have two charge transport layers above and below the perovskite layer, which determine charge extraction and transport. Therefore, an interface inevitably forms between the charge transport layer and the perovskite layer. These interfaces are prone to becoming non-radiative recombination centers, leading to significant energy loss and reduced device efficiency and stability. In this invention, positively charged and negatively charged polymers form positive and negative charge layers respectively at the upper and lower interfaces of the perovskite film, thereby creating an electric field on both sides of the perovskite film to accelerate carrier separation and transport. The negatively charged polymer at the bottom of the perovskite layer can react with the electron transport layer through Lewis coordination / electrostatic coupling, passivating oxygen vacancy defects. The positively charged polymer at the top of the perovskite layer can react with uncoordinated Pb on the perovskite surface. 2+ Defect ions act as a barrier, preventing the migration of elements in the perovskite to the metal electrode.

[0017] Preferably, the high-efficiency, air-humidity-stable perovskite solar cell with synergistic improvement of defects and ion migration is prepared by the following steps:

[0018] (1) Use clean, transparent conductive glass as a transparent conductive substrate;

[0019] (2) An electron transport layer is prepared on the surface of the transparent conductive substrate;

[0020] (3) Prepare a negatively charged polymer layer on the surface of the electron transport layer;

[0021] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer;

[0022] (5) Prepare a positively charged polymer layer on the surface of the perovskite active layer;

[0023] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer;

[0024] (7) An electrode layer is prepared on the surface of the hole transport layer.

[0025] Preferably, the transparent conductive substrate is FTO, ITO, or AZO. The transparent conductive glass can be cleaned by ultrasonic cleaning with deionized water, anhydrous ethanol, and isopropanol, respectively, and by ozone oxidation of organic groups on the surface of the transparent conductive glass.

[0026] Preferably, the material of the electron transport layer is one or more of TiO2, SnO2, ZrO2, and ZnO.

[0027] Preferably, the material of the negatively charged polymer layer is one or more of polyacrylol, polyacrylamide, and polyvinylidene fluoride.

[0028] Preferably, the material of the positively charged polymer layer is one or more of polyaniline, polypyrrole, polyethyleneimine, poly(p-phenylene), poly(p-phenylene) derivatives, and polythiophene.

[0029] Preferably, the material of the hole transport layer is one or more of Spiro-OMeTAD, P3HT, PTAA, CuSCN, cuprous iodide, polythiophene, and triarylamine.

[0030] Preferably, the electrode layer is made of one or more of gold, silver, aluminum, platinum, and copper.

[0031] Preferably, the thickness of the electron transport layer material is 20–1500 nm.

[0032] When the electron transport layer is made of TiO2, the thickness of the electron transport layer is more preferably 30–700 nm.

[0033] When the electron transport layer is made of SnO2, the thickness of the electron transport layer is more preferably 20–100 nm.

[0034] When the electron transport layer is made of ZrO2, the thickness of the electron transport layer is more preferably 500–1500 nm.

[0035] When the electron transport layer is made of ZnO, the thickness of the electron transport layer is more preferably 20–1000 nm.

[0036] Preferably, the thickness of the negatively charged polymer layer is 10–100 nm.

[0037] Preferably, the thickness of the positively charged polymer is 10–100 nm.

[0038] Preferably, the thickness of the hole transport layer is 20–400 nm.

[0039] Preferably, the thickness of the electrode layer is 50–150 nm.

[0040] Preferably, the electron transport layer is fabricated by spin coating, sputtering, printing or spraying processes.

[0041] Preferably, the negatively charged polymer layer is produced by spin coating, printing or spraying processes.

[0042] Preferably, the positively charged polymer layer is produced by spin coating, printing, or spraying.

[0043] Preferably, the hole transport layer is fabricated by spin coating, sputtering, printing or spraying processes.

[0044] Preferably, the electrode layer is fabricated by evaporation deposition or sputtering process.

[0045] Preferably, the thickness of the perovskite active layer is 200–1000 nm.

[0046] Preferably, the perovskite active layer is prepared by spin coating or coating method, with or without anti-solvent before spin coating or coating is completed, and heat treatment is performed to form a film after spin coating or coating is completed.

[0047] Preferably, the spin coating method is a one-step spin coating method or a two-step spin coating method.

[0048] Preferably, the one-step spin coating method involves preparing a perovskite precursor solution from the perovskite raw material and then spin coating it, wherein the variable valence material is added to the perovskite precursor solution.

[0049] Preferably, in the two-step spin coating method, the perovskite precursor solution is divided into a Pb-containing precursor solution A and a precursor solution B containing residual raw materials.

[0050] Preferably, the two-step spin coating method involves first spin coating precursor liquid A, and then spin coating precursor B, wherein the variable valence material is added to precursor liquid A.

[0051] Preferably, the coating method is a one-step coating method or a two-step coating method.

[0052] Preferably, the one-step coating method involves preparing a perovskite precursor solution from the perovskite raw material and then coating it, wherein the variable valence material is added to the perovskite precursor solution.

[0053] Preferably, in the two-step coating method, the perovskite precursor solution is divided into a Pb-containing precursor solution A and a precursor solution B containing residual raw materials.

[0054] Preferably, the two-step coating method involves first coating the precursor liquid A, and then coating the precursor B, wherein the variable valence material is added to the precursor liquid A.

[0055] Preferably, when using one-step spin coating, the perovskite precursor solution is spin-coated at 3000-6000 rpm for 20-60 seconds, and then heat-treated at 120-240℃ for 5-30 minutes.

[0056] Preferably, when using a two-step spin coating, in the first step, the precursor liquid A is spin-coated at 500-2000 rpm for 5-30 seconds, and then heat-treated at 55-85°C for 30-80 seconds. In the second step, the precursor liquid B is spin-coated at 2000-6000 rpm for 20-60 seconds, and then heat-treated at 120-240°C for 5-30 minutes.

[0057] Preferably, when using the coating method, the coating temperature is 80–240°C and the heat treatment time is 5–30 min.

[0058] Preferably, when using an anti-solvent, the anti-solvent is added dropwise 5 to 30 seconds before the end of spin coating or coating.

[0059] Preferably, the antisolvent is one or more of chlorobenzene, methyl acetate, and ethyl acetate.

[0060] Preferably, the amount of the variable-valence material in the perovskite active layer is equivalent to 0.1 to 1.0 wt% of the perovskite material.

[0061] Beneficial effects of this invention:

[0062] (1) This invention uses a variable valence material as an additive in the perovskite precursor solution, and utilizes cation passivation of Pb. 0 I 0 Defects, anions and uncoordinated Pb 2+ Defects such as these improve the phase stability of perovskite crystals;

[0063] (2) The present invention can further employ positive / negative charged polymers to perform double-sided passivation on both sides of the perovskite film, utilizing positive / negative charged polymers to passivate oxygen vacancies and Pb. 2+ Defects such as these hinder ion migration at the interface;

[0064] (3) The perovskite solar cell device of the present invention has both high photoelectric conversion efficiency and high humidity stability. Detailed Implementation

[0065] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0066] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0067] Unless otherwise specified, all reagents and raw materials used in this invention are commercially available products or products that can be prepared by known methods.

[0068] Example 1

[0069] This embodiment of a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration consists of, from bottom to top, a transparent conductive substrate, an electron transport layer, a negatively charged polymer layer, a perovskite active layer, a positively charged polymer layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.85 MA 0.15 PbI3; the perovskite active layer also contains a combination of variable-valence materials CuBr and Cu2Br (molar ratio 2:1). The negatively charged polymer is polyacrylol, and the positively charged polymer is polyaniline.

[0070] This embodiment describes a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration. The fabrication method includes the following steps:

[0071] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0072] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water). Under air humidity of 65%, 70 μL of the diluted solution was added dropwise to the ITO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0073] (3) A negatively charged polymer layer was prepared on the surface of the electron transport layer: the negatively charged polymer material used was polyacrylamide, dissolved in isopropanol, with a concentration of 0.3 wt%; under air humidity of 65%, 50 μL of polyacrylamide solution was spin-coated onto the electron transport layer at 5000 rpm for 30 s using a spin coating method, and then heated at 120°C for 15 min on a heating stage to form a negatively charged polymer film on the electron transport layer. The thickness of the negatively charged polymer layer was 30 nm.

[0074] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer:

[0075] (4-I)FA 0.85 MA 0.15Preparation of PbI3 perovskite precursor solution: FAI, MAI, CsI, and PbI2 were dissolved in a 4:1 volume ratio of dimethyl sulfoxide / N,N-dimethylformamide mixed solution at a molar ratio of 0.85:0.15:0:1 to prepare a 1.0 M solution; then, variable valence materials (CuBr and Cu2Br) were added to the solution, with an amount equivalent to 0.2 wt% of the perovskite; the solution was stirred at 65 °C for 12 h to achieve uniform dispersion, yielding FAI. 0.85 MA 0.15 PbI3 perovskite precursor solution;

[0076] (4-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, the FA obtained in step (4-I) is... 0.85 MA 0.15 The PbI3 perovskite precursor solution was drop-added and spin-coated onto the negatively charged polymer layer obtained in step (3). The spin-coating operation was as follows: the drop-added amount was 35 μL, and the film was formed by spin-coating at 5000 rpm for 30 s. 5 s before the end of spin-coating (i.e., the 25th s), 200 μL of chlorobenzene was added as an anti-solvent, and the mixture was heat-treated at 150℃ for 30 min to prepare FA. 0.85 MA 0.15 PbI3 perovskite thin film; the thickness of the perovskite active layer is 700 nm.

[0077] (5) Prepare a positively charged polymer layer on the surface of the perovskite active layer: in FA 0.85 MA 0.15 A positively charged polymer film was prepared on a PbI3 perovskite film. The positively charged polymer material was polyaniline, dissolved in chlorobenzene at a concentration of 0.1 wt%. 50 μL of the positively charged polymer solution was spin-coated onto the perovskite film at 5000 rpm for 40 s using a spin-coating method, thus forming a positively charged polymer film on the perovskite film. The thickness of the positively charged polymer layer was 20 nm.

[0078] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the surface of the positively charged polymer layer at a spin speed of 5000 rpm for 30 s, and then kept at 35°C for 15 h to promote oxidation film formation. The thickness of the hole transport layer is 150 nm.

[0079] (7) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (5) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0080] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2 The photoelectric conversion efficiency is 22.5%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency decreased to 90% of its initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 17.6%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 78% of the initial value.

[0081] Example 2

[0082] This embodiment of a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration consists of, from bottom to top, a transparent conductive substrate, an electron transport layer, a negatively charged polymer layer, a perovskite active layer, a positively charged polymer layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.75 MA 0.25 PbI 3-x Cl x The perovskite active layer also contains a variable-valence material: a combination of SeCN and Se(CN)2 (molar ratio 2:1). The negatively charged polymer is polyacrylamide, and the positively charged polymer is polyaniline. Unlike Example 1, the perovskite film in this example is prepared by a two-step spin-coating method.

[0083] This embodiment describes a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration. The fabrication method includes the following steps:

[0084] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0085] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water). Under air humidity of 65%, 70 μL of the diluted solution was added dropwise to the ITO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0086] (3) A negatively charged polymer layer was prepared on the surface of the electron transport layer: the negatively charged polymer material used was polyacrylamide, dissolved in isopropanol, with a concentration of 0.3 wt%; under air humidity of 65%, 50 μL of polyacrylamide solution was spin-coated onto the electron transport layer at 5000 rpm for 30 s using a spin coating method, and then heated at 120°C for 15 min on a heating stage to form a negatively charged polymer film on the electron transport layer. The thickness of the negatively charged polymer layer was 30 nm.

[0087] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer:

[0088] (4-I) Preparation of perovskite precursor solution: Precursor solution A (PbI2 solution): Dissolve 691.52 mg PbI2 in 1 mL of a mixed solution of dimethyl sulfoxide / N,N-dimethylformamide with a volume ratio of 9:1 to prepare a 1.5 M solution. Then add the variable valence materials (SeCN and Se(CN)2) to the solution, with an amount equivalent to 0.2 wt% of the perovskite. Stir at 65 °C for 12 h to disperse evenly. Precursor B: Dissolve FAI, MAI, and MACl in 1 mL of isopropanol solution at a molar ratio of 0.53:0.04:0.14 and stir at room temperature for 12 h.

[0089] (4-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, precursor liquid A is dropped and spin-coated onto the negatively charged polymer layer obtained in step (3). The spin-coating operation is as follows: the amount of drop is 35 μL, the film is formed by spin-coating at 1500 rpm for 30 s, and the heat treatment is carried out at a temperature of 70℃ for 1 min. After cooling, precursor B is dropped and spin-coated onto PbI2. The spin-coating operation is as follows: the amount of drop is 35 μL, the film is formed by spin-coating at 2000 rpm for 30 s, and the heat treatment is carried out at a temperature of 150℃ for 15 min, thus forming a perovskite film; the thickness of the perovskite active layer is 600 nm.

[0090] (5) A positively charged polymer layer is prepared on the surface of the perovskite active layer: A positively charged polymer film is prepared on the perovskite film. The positively charged polymer material is polyaniline, dissolved in chlorobenzene, with a concentration of 0.1 wt%. 50 μL of the positively charged polymer solution is spin-coated onto the perovskite film at 5000 rpm for 40 s using a spin-coating method, thus forming a positively charged polymer film on the perovskite film. The thickness of the positively charged polymer layer is 20 nm.

[0091] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the surface of the positively charged polymer layer at a spin speed of 5000 rpm for 30 s, and then kept at 35°C for 15 h to promote oxidation film formation. The thickness of the hole transport layer is 150 nm.

[0092] (7) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (5) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0093] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2 The photoelectric conversion efficiency is 23.9%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency drops to 93% of its initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 18.7%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 83% of the initial value.

[0094] Example 3

[0095] This embodiment of a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration consists of, from bottom to top, a transparent conductive substrate, an electron transport layer, a negatively charged polymer layer, a perovskite active layer, a positively charged polymer layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.9 Cs 0.1 PbI3; the perovskite active layer also contains a variable-valence material: a combination of tris(2,2'-dipyridinium)cobalt(II)bis(hexafluorophosphate) and tris(2,2'-dipyridinium)cobalt(III)tri(hexafluorophosphate) (molar ratio 2:1). The negatively charged polymer is polyvinylidene fluoride, and the positively charged polymer is poly(p-phenylene).

[0096] This embodiment describes a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration. The fabrication method includes the following steps:

[0097] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0098] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water). Under air humidity of 65%, 70 μL of the diluted solution was added dropwise to the ITO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0099] (3) A negatively charged polymer layer was prepared on the surface of the electron transport layer: the negatively charged polymer material used was polyvinylidene fluoride (PVDF), dissolved in isopropanol at a concentration of 0.3 wt%. Under air humidity of 65%, 50 μL of PVDF solution was spin-coated onto the electron transport layer at 5000 rpm for 30 s using a spin coating method. The solution was then heated at 120°C for 15 min on a heating stage to form a negatively charged polymer film on the electron transport layer. The thickness of the negatively charged polymer layer was 30 nm.

[0100] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer:

[0101] (4-I)FA 0.9 Cs 0.1 Preparation of PbI3 perovskite precursor solution: FAI, MAI, CsI, and PbI2 were dissolved in a 9:1 volume ratio of dimethyl sulfoxide / N,N-dimethylformamide mixed solution at a molar ratio of 0.9:0:0.1:1 to prepare a 1.5M solution; then, variable valence materials (tris(2,2'-dipyridinium)cobalt(II)bis(hexafluorophosphate) and tris(2,2'-dipyridinium)cobalt(III)tris(hexafluorophosphate)) were added to the solution, with the amount equivalent to 0.2 wt% of the perovskite; the mixture was stirred at 65°C for 12 h to obtain FAI. 0.9 Cs 0.1 PbI3 perovskite precursor solution;

[0102] (4-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, the FA obtained in step (4-I) is... 0.9 Cs 0.1The PbI3 perovskite precursor solution was drop-added and spin-coated onto the negatively charged polymer layer obtained in step (3). The spin-coating operation was as follows: 35 μL was added, and the film was formed by spin-coating at 5000 rpm for 15 seconds. 5 seconds before the end of the spin-coating, 200 μL of chlorobenzene was added as an anti-solvent, and the mixture was heat-treated at 150°C for 15 minutes. Then, it was heat-treated at 100°C for 10 minutes to prepare FA. 0.9 Cs 0.1 PbI3 perovskite thin film; the thickness of the perovskite active layer is 700 nm.

[0103] (5) Prepare a positively charged polymer layer on the surface of the perovskite active layer: in FA 0.9 Cs 0.1 A positively charged polymer film was prepared on a PbI3 perovskite film. The positively charged polymer material was poly(p-benzoyne), dissolved in chlorobenzene at a concentration of 0.1 wt%. 50 μL of the positively charged polymer solution was spin-coated onto the perovskite film at 5000 rpm for 40 s using a spin-coating method, thus forming a positively charged polymer film on the perovskite film. The thickness of the positively charged polymer layer was 20 nm.

[0104] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the surface of the positively charged polymer layer at a spin speed of 5000 rpm for 30 s, and then kept at 35°C for 15 h to promote oxidation film formation. The thickness of the hole transport layer is 150 nm.

[0105] (7) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (5) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0106] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2 The photoelectric conversion efficiency is 23.5%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency decreased to 95% of its initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 18.3%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 82% of the initial value.

[0107] Example 4

[0108] This embodiment of a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration consists of, from bottom to top, a transparent conductive substrate, an electron transport layer, a negatively charged polymer layer, a perovskite active layer, a positively charged polymer layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.70 MA 0.25 Cs 0.05 PbI₂Br; the perovskite active layer also contains a combination of variable-valence materials SeCN and Se(CN)₂ (molar ratio 2:1). The negatively charged polymer is polyacrylol, and the positively charged polymer is polyaniline.

[0109] This embodiment describes a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration. The fabrication method includes the following steps:

[0110] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent FTO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent FTO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0111] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water volume ratio). Under air humidity of 65%, 70 μL of the diluent was added dropwise to the FTO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0112] (3) A negatively charged polymer layer was prepared on the surface of the electron transport layer: the negatively charged polymer material used was polyacrylamide, dissolved in isopropanol, with a concentration of 0.3 wt%; under air humidity of 65%, 50 μL of polyacrylamide solution was spin-coated onto the electron transport layer at 5000 rpm for 30 s using a spin coating method, and then heated at 120°C for 15 min on a heating stage to form a negatively charged polymer film on the electron transport layer. The thickness of the negatively charged polymer layer was 30 nm.

[0113] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer:

[0114] (4-I)FA 0.70 MA 0.25 Cs 0.05Preparation of PbI₂Br perovskite precursor solution: FABr, MAI, CsI, and PbI₂ were dissolved in a 4:1 volume ratio of dimethyl sulfoxide / N,N-dimethylformamide mixed solution at a molar ratio of 0.70:0.25:0.05:1 to prepare a 1.0 M solution. Then, variable valence materials (SeCN and Se(CN)₂) were added to the solution, with an amount equivalent to 0.2 wt% of the perovskite. The solution was stirred at 65 °C for 12 h to achieve uniform dispersion, yielding FABr. 0.70 MA 0.25 Cs 0.05 PbI2Br perovskite precursor solution;

[0115] (4-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, the FA obtained in step (4-I) is... 0.70 MA 0.25 Cs 0.05 The PbI2Br perovskite precursor solution was drop-added and spin-coated onto the negatively charged polymer layer obtained in step (3). The spin-coating operation was as follows: the drop-added amount was 35 μL, and the film was formed by spin-coating at 5000 rpm for 30 s. 5 s before the end of spin-coating (i.e., the 25th s), 200 μL of chlorobenzene was added as an anti-solvent, and the mixture was heat-treated at 150℃ for 30 min to prepare FA. 0.70 MA 0.25 Cs 0.05 PbI2Br perovskite thin film; the thickness of the perovskite active layer is 700 nm.

[0116] (5) Prepare a positively charged polymer layer on the surface of the perovskite active layer: in FA 0.70 MA 0.25 Cs 0.05 A positively charged polymer film was prepared on a PbI₂Br perovskite film. The positively charged polymer material was polyaniline, dissolved in chlorobenzene at a concentration of 0.1 wt%. 50 μL of the positively charged polymer solution was spin-coated onto the perovskite film at 5000 rpm for 40 s using a spin-coating method, thus forming a positively charged polymer film on the perovskite film. The thickness of the positively charged polymer layer was 20 nm.

[0117] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the surface of the positively charged polymer layer at a spin speed of 5000 rpm for 30 s, and then kept at 35°C for 15 h to promote oxidation film formation. The thickness of the hole transport layer is 150 nm.

[0118] (7) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (5) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0119] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2 The photoelectric conversion efficiency is 23.7%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency drops to 85% of its initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 18.2%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 77% of the initial value.

[0120] Example 5

[0121] This embodiment of a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration consists of, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite active layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.85 MA 0.15 PbI3; the perovskite active layer also contains a variable-valence material: a combination of bis(tetrabutylammonium)-bis(maleiconitrile dithiol)nickel(II) complex and a tetrabutylammonium bis(maleiconitrile dithiol)nickel(III) complex (molar ratio 2:1). Compared to Example 1, the perovskite active layer of this example contains a variable-valence material, but the perovskite solar cell does not contain a negatively charged polymer layer and a positively charged polymer layer.

[0122] This embodiment describes a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration. The fabrication method includes the following steps:

[0123] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0124] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water). Under air humidity of 65%, 70 μL of the diluted solution was added dropwise to the ITO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0125] (3) Prepare a perovskite active layer on the surface of the electron transport layer:

[0126] (3-I)FA 0.85 MA 0.15 Preparation of PbI3 perovskite precursor solution: FAI, MAI, CsI, and PbI2 were dissolved in a 4:1 volume ratio of dimethyl sulfoxide / N,N-dimethylformamide mixed solution at a molar ratio of 0.85:0.15:0:1 to prepare a 1.0 M solution; then, variable valence materials (bis(tetrabutylammonium)-bis(maleiconitrile dithiol)nickel(II) complex and tetrabutylammonium bis(maleiconitrile dithiol)nickel(III) complex) were added to the solution, with the amount equivalent to 0.2 wt% of the perovskite; the mixture was stirred at 65 °C for 12 h to disperse the perovskite evenly, yielding FAI. 0.85 MA 0.15 PbI3 perovskite precursor solution;

[0127] (3-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, the FA obtained in step (3-I) is... 0.85 MA 0.15 The PbI3 perovskite precursor solution was drop-added and spin-coated onto the electron transport layer obtained in step (2). The spin-coating operation was as follows: the drop-added amount was 35 μL, and the film was formed by spin-coating at 5000 rpm for 30 s. 5 s before the end of spin-coating (i.e., the 25th s), 200 μL of chlorobenzene was added as an anti-solvent, and the film was heat-treated at 150℃ for 30 min to obtain FA. 0.85 MA 0.15 PbI3 perovskite thin film; the thickness of the perovskite active layer is 700 nm.

[0128] (4) A hole transport layer is prepared on the surface of the perovskite active layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the FA. 0.85 MA 0.15On the surface of the PbI3 perovskite thin film, spin coating was performed at a speed of 5000 rpm for 30 seconds, followed by holding at 35°C for 15 hours to promote oxidation film formation. The hole transport layer thickness was 150 nm.

[0129] (5) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (4) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0130] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2 The photoelectric conversion efficiency is 23.6%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency drops to 87% of its initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 17.9%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency drops to 79% of the initial value.

[0131] Example 6

[0132] This embodiment of a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration consists of, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite active layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.85 MA 0.15 PbI3; the perovskite active layer also contains a variable-valence material: a combination of bis(tetrabutylammonium)-bis(maleiconitrile dithiol)nickel(II) complex and a tetrabutylammonium bis(maleiconitrile dithiol)nickel(III) complex (molar ratio 2:1). The negatively charged polymer is polyacrylol, and the positively charged polymer is polyaniline.

[0133] This embodiment describes a high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration. The fabrication method includes the following steps:

[0134] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0135] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15wt% SnO2 dispersion with deionized water at a volume ratio of 1:3 (15wt% SnO2 solution to deionized water). Under air humidity of 65%, an electron transport layer was prepared on the ITO substrate by coating. The layer was then heated at 150°C for 30 minutes on a heating stage to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0136] (3) A negatively charged polymer layer is prepared on the surface of the electron transport layer: the negatively charged polymer material used is polyacrylamide, dissolved in isopropanol, with a concentration of 0.3 wt%; the polyacrylamide negatively charged polymer layer is prepared on the electron transport layer by coating under air humidity of 65% and heated at 120°C for 15 min on a heating stage to form a negatively charged polymer film on the electron transport layer. The thickness of the negatively charged polymer layer is 30 nm.

[0137] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer:

[0138] (4-I) Preparation of perovskite precursor solution: Precursor solution A (PbI2 solution): 691.52 mg PbI2 was dissolved in 1 mL of a mixed solution of dimethyl sulfoxide / N,N-dimethylformamide with a volume ratio of 9:1 to prepare a 1.5 M solution. Then, variable valence materials (bis(tetrabutylammonium) bis(maleiconitrile dithiol) nickel(II) complex and tetrabutylammonium bis(maleiconitrile dithiol) nickel(III) complex) were added to the solution, with the amount equivalent to 0.2 wt% of the perovskite. The mixture was stirred at 65 °C for 12 h to disperse evenly. Precursor B: FAI, MAI, and MACl were dissolved in 1 mL of isopropanol solution at a molar ratio of 0.53:0.04:0.14 and stirred at room temperature for 12 h.

[0139] (4-II) In air, the precursor liquid A is dropped onto the negatively charged polymer layer obtained in step (3) by coating. The layer is then heat-treated at 70°C for 1 min. After cooling, the precursor B is dropped onto PbI2 by coating. The layer is then heat-treated at 150°C for 15 min to form a perovskite film. The thickness of the perovskite active layer is 600 nm.

[0140] (5) A positively charged polymer layer is prepared on the surface of the perovskite active layer: A positively charged polymer film is prepared on the perovskite film. The positively charged polymer material is polyaniline, dissolved by chlorobenzene, and its concentration is 0.1 wt%. The positively charged polymer film is prepared on the perovskite film by coating. The thickness of the positively charged polymer layer is 20 nm.

[0141] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer: the hole transport layer material is Spiro-OMeTAD; a precursor solution of the hole transport layer is coated on the surface of the positively charged polymer layer to form the hole transport layer. The thickness of the hole transport layer is 150 nm.

[0142] (7) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (5) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0143] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 9cm². 2 The photoelectric conversion efficiency is 16.6%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 79% of the initial value.

[0144] Comparative Example 1

[0145] This comparative perovskite solar cell, from bottom to top, consists of a transparent conductive substrate, an electron transport layer, a perovskite active layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.85 MA 0.15 PbI3. Compared to Example 1, the perovskite active layer of this comparative example does not contain variable valence materials, and the perovskite solar cell does not contain negatively charged polymer layers or positively charged polymer layers.

[0146] The comparative preparation method includes the following steps:

[0147] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0148] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water). Under air humidity of 65%, 70 μL of the diluted solution was added dropwise to the ITO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0149] (3) Prepare a perovskite active layer on the surface of the electron transport layer:

[0150] (3-I)FA 0.85 MA 0.15 Preparation of PbI3 perovskite precursor solution: FAI, MAI, CsI, and PbI2 were dissolved in a 4:1 (v / v) dimethyl sulfoxide / N,N-dimethylformamide mixed solution at a molar ratio of 0.85:0.15:0:1 to prepare a 1.0 M solution; the solution was stirred at 65 °C for 12 h to achieve uniform dispersion, yielding FA. 0.85 MA 0.15 PbI3 perovskite precursor solution;

[0151] (3-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, the FA obtained in step (3-I) is... 0.85 MA 0.15 The PbI3 perovskite precursor solution was drop-added and spin-coated onto the electron transport layer obtained in step (2). The spin-coating operation was as follows: the drop-added amount was 35 μL, and the film was formed by spin-coating at 5000 rpm for 30 s. 5 s before the end of spin-coating (i.e., the 25th s), 200 μL of chlorobenzene was added as an anti-solvent, and the film was heat-treated at 150℃ for 30 min to obtain FA. 0.85 MA 0.15 PbI3 perovskite thin film; the thickness of the perovskite active layer is 700 nm.

[0152] (4) A hole transport layer is prepared on the surface of the perovskite active layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the FA. 0.85 MA 0.15 On the surface of the PbI3 perovskite thin film, spin coating was performed at a speed of 5000 rpm for 30 seconds, followed by holding at 35°C for 15 hours to promote oxidation film formation. The hole transport layer thickness was 150 nm.

[0153] (5) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (4) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0154] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2The photoelectric conversion efficiency is 19.7%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency drops to 43% of the initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 14.6%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 27% of the initial value.

[0155] Comparative Example 2

[0156] The perovskite solar cell in this comparative example, from bottom to top, consists of a transparent conductive substrate, an electron transport layer, a negatively charged polymer layer, a perovskite active layer, a positively charged polymer layer, a hole transport layer, and an electrode layer; the chemical formula of the perovskite material is FA. 0.85 MA 0.15 PbI3. The negatively charged polymer is polyacrylamide, and the positively charged polymer is polyaniline. Compared to Example 1, the perovskite active layer in this comparative example does not contain variable-valence materials.

[0157] The comparative preparation method includes the following steps:

[0158] (1) Using clean transparent conductive glass as a transparent conductive substrate: the transparent ITO conductive etching glass was cleaned by ultrasonic vibration with deionized water, anhydrous ethanol and isopropanol respectively. After vibration for 20 minutes, the surface organic solvent was dried in a forced-air drying oven at 80°C. The organic groups on the surface of the transparent ITO conductive glass were oxidized with ozone to obtain a clean transparent conductive substrate.

[0159] (2) An electron transport layer was prepared on the surface of the transparent conductive substrate: A SnO2 electron transport layer was prepared by diluting a 15 wt% SnO2 dispersion with deionized water at a ratio of 1:3 (15 wt% SnO2 solution to deionized water). Under air humidity of 65%, 70 μL of the diluted solution was added dropwise to the ITO substrate at 4000 rpm for 30 seconds using a spin coating method. The substrate was then heated at 150°C for 30 minutes to form the SnO2 electron transport layer. The thickness of the electron transport layer was 40 nm.

[0160] (3) A negatively charged polymer layer was prepared on the surface of the electron transport layer: the negatively charged polymer material used was polyacrylamide, dissolved in isopropanol, with a concentration of 0.3 wt%; under air humidity of 65%, 50 μL of polyacrylamide solution was spin-coated onto the electron transport layer at 5000 rpm for 30 s using a spin coating method, and then heated at 120°C for 15 min on a heating stage to form a negatively charged polymer film on the electron transport layer. The thickness of the negatively charged polymer layer was 30 nm.

[0161] (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer:

[0162] (4-I)FA 0.85 MA 0.15 Preparation of PbI3 perovskite precursor solution: FAI, MAI, CsI, and PbI2 were dissolved in a 4:1 (v / v) dimethyl sulfoxide / N,N-dimethylformamide mixed solution at a molar ratio of 0.85:0.15:0:1 to prepare a 1.0 M solution; the solution was stirred at 65 °C for 12 h to achieve uniform dispersion, yielding FA. 0.85 MA 0.15 PbI3 perovskite precursor solution;

[0163] (4-II) Under a nitrogen atmosphere (water content less than 0.001 g / m³) 3 In a nitrogen atmosphere with an oxygen content of less than 0.01%, the FA obtained in step (4-I) is... 0.85 MA 0.15 The PbI3 perovskite precursor solution was drop-added and spin-coated onto the negatively charged polymer layer obtained in step (3). The spin-coating operation was as follows: the drop-added amount was 35 μL, and the film was formed by spin-coating at 5000 rpm for 30 s. 5 s before the end of spin-coating (i.e., the 25th s), 200 μL of chlorobenzene was added as an anti-solvent, and the mixture was heat-treated at 150℃ for 30 min to prepare FA. 0.85 MA 0.15 PbI3 perovskite thin film; the thickness of the perovskite active layer is 700 nm.

[0164] (5) Prepare a positively charged polymer layer on the surface of the perovskite active layer: in FA 0.85 MA 0.15 A positively charged polymer film was prepared on a PbI3 perovskite film. The positively charged polymer material was polyaniline, dissolved in chlorobenzene at a concentration of 0.1 wt%. 50 μL of the positively charged polymer solution was spin-coated onto the perovskite film at 5000 rpm for 40 s using a spin-coating method, thus forming a positively charged polymer film on the perovskite film. The thickness of the positively charged polymer layer was 20 nm.

[0165] (6) A hole transport layer is prepared on the surface of the positively charged polymer layer: the hole transport layer material is Spiro-OMeTAD; the precursor solution of the hole transport layer is spin-coated onto the surface of the positively charged polymer layer at a spin speed of 5000 rpm for 30 s, and then kept at 35°C for 15 h to promote oxidation film formation. The thickness of the hole transport layer is 150 nm.

[0166] (7) An electrode layer is prepared on the surface of the hole transport layer: the metal counter electrode is made of silver; silver is deposited on the hole transport layer film obtained in step (5) by evaporation coating method, the electrode layer thickness is 100nm, and a perovskite solar cell is obtained.

[0167] The performance of the perovskite solar cell in this embodiment was tested at room temperature using a xenon lamp to simulate sunlight at an intensity of 100 mW / cm². 2 The effective light-illuminated area is 0.17 cm². 2 The photoelectric conversion efficiency is 21.7%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40%–90%), the photoelectric efficiency drops to 81% of its initial value. The effective illumination area is 4 cm². 2 The photoelectric conversion efficiency is 17.2%. After 10,000 hours of air humidity stability testing without encapsulation (room temperature, humidity 40% to 90%), the photoelectric efficiency drops to 67% of the initial value.

[0168] It should be noted that the above description is only a part of the embodiments of the present invention, and all equivalent changes or modifications made to the system described in this invention are included within the protection scope of the present invention. Those skilled in the art can make similar substitutions to the specific examples described herein, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, all of which fall within the protection scope of the present invention.

Claims

1. A high-efficiency, humidity-stable perovskite solar cell that synergistically improves defects and ion migration, comprising a perovskite active layer, characterized in that, The chemical formula of perovskite material is FA. x MA y Cs z PbX3, x+y+z=1, where X is selected from one, two, or three elements from I, Br, and Cl; the perovskite active layer also contains a variable valence material; The variable-valence material is: Ni-containing... 2+ and Ni 3+ substances containing Cu + and Cu 2+ substances containing Co 3+ and Co 2+ One or more of the following: substances, combinations of SeCN and Se(CN)2, combinations of disulfides and thiolates, and combinations of ferrocene and ferrocene salts; It also includes an electron transport layer, a negatively charged polymer layer, a positively charged polymer layer, and a hole transport layer; The negatively charged polymer layer is located between the electron transport layer and the perovskite active layer, and the positively charged polymer layer is located between the perovskite active layer and the hole transport layer. Both the negatively charged polymer layer and the positively charged polymer layer are adjacent to the perovskite active layer. The preparation method includes the following steps: (1) Use clean, transparent conductive glass as a transparent conductive substrate; (2) An electron transport layer is prepared on the surface of the transparent conductive substrate; (3) Prepare a negatively charged polymer layer on the surface of the electron transport layer; (4) Prepare a perovskite active layer on the surface of the negatively charged polymer layer; (5) Prepare a positively charged polymer layer on the surface of the perovskite active layer; (6) A hole transport layer is prepared on the surface of the positively charged polymer layer; (7) An electrode layer is prepared on the surface of the hole transport layer; The transparent conductive substrate is FTO, ITO, or AZO; the electron transport layer is made of one or more of TiO2, SnO2, ZrO2, and ZnO; the negatively charged polymer layer is made of one or more of polyacrylol, polyacrylamide, and polyvinylidene fluoride; the positively charged polymer layer is made of one or more of polyaniline, polypyrrole, polyethyleneimine, poly(p-phenylene), poly(p-phenylene) derivatives, and polythiophene; the hole transport layer is made of one or more of Spiro-OMeTAD, P3HT, PTAA, CuSCN, cuprous iodide, polythiophene compounds, and triarylamines; and the electrode layer is made of one or more of gold, silver, aluminum, platinum, and copper. The electron transport layer has a thickness of 20-1500 nm; the negatively charged polymer layer has a thickness of 10-100 nm; the positively charged polymer layer has a thickness of 10-100 nm; the hole transport layer has a thickness of 20-400 nm; and the electrode layer has a thickness of 50-150 nm. The electron transport layer is fabricated by spin coating, sputtering, printing, or spraying; the negatively charged polymer layer is fabricated by spin coating, printing, or spraying; the positively charged polymer layer is fabricated by spin coating, printing, or spraying; the hole transport layer is fabricated by spin coating, sputtering, printing, or spraying; and the electrode layer is fabricated by evaporation deposition or sputtering. The thickness of the perovskite active layer is 200~1000 nm; the preparation method of the perovskite active layer is: spin coating or coating method is used, and anti-solvent may or may not be used before spin coating or coating is completed, and heat treatment is performed to form a film after spin coating or coating is completed. The spin coating method is either a one-step spin coating method or a two-step spin coating method; The one-step spin coating method involves preparing a perovskite precursor solution from the perovskite raw material and then spin coating it, with the variable valence material added to the perovskite precursor solution. In the two-step spin coating method, the perovskite precursor solution is divided into a precursor solution A containing Pb and a precursor B containing residual raw materials; the two-step spin coating method is to first spin coat the precursor solution A and then spin coat the precursor B, and the variable valence material is added to the precursor solution A. The coating method is either a one-step coating method or a two-step coating method; The one-step coating method involves preparing a perovskite precursor solution from the perovskite raw material and then coating it, with the variable valence material added to the perovskite precursor solution. In the two-step coating method, the perovskite precursor solution is divided into a precursor solution A containing Pb and a precursor B containing the remaining raw materials; the two-step coating method is to first coat the precursor solution A and then coat the precursor B, and the variable valence material is added to the precursor solution A.

2. The high-efficiency, humidity-stable perovskite solar cell with synergistic improvement of defects and ion migration according to claim 1, characterized in that, When using a one-step spin coating method, spin coat the perovskite precursor solution at 3000~6000 rpm for 20~60 s, followed by heat treatment at 120~240 ℃ for 5~30 min. When using a two-step spin coating method, firstly, spin coat the precursor solution A at 500~2000 rpm for 5~30 s, followed by heat treatment at 55~85 ℃ for 30~80 s. Secondly, spin coat the precursor solution B at 2000~6000 rpm for 20~60 s, followed by heat treatment at 120~240 ℃ for 5~30 min. When using a coating method, the coating temperature is 80~240 ℃, and the heat treatment time is 5~30 min.

3. The high-efficiency, air humidity-stable perovskite solar cell with synergistic improvement of defects and ion migration according to claim 2, characterized in that, Add the antisolvent dropwise 5-30 seconds before the end of spin coating or coating; the antisolvent is one or more of chlorobenzene, methyl acetate, and ethyl acetate.

4. A high-efficiency, air-humidity-stable perovskite solar cell with synergistic improvement of defects and ion migration according to any one of claims 1 to 3, characterized in that, The amount of the variable-valence material in the perovskite active layer is equivalent to 0.1 to 1.0% of the perovskite material. wt %; the Ni-containing 2+ and Ni 3+ The anion in the substance is a polypyridine-containing or F-containing group; the Cu-containing group... + and Cu 2+ The anion in the substance is SCN. - and / or Br - The Co-containing 3+ and Co 2+ The anions in the substance are polypyridine or F-containing groups.