Method for preparing solar cell by passivating perovskite thin film in situ through diphenylamine ammonium salt and derivative

Abstract

The invention discloses a method for passivating a perovskite solar cell by using diphenylamine ammonium salt and a derivative thereof, and belongs to the technical field of perovskite solar cells. According to the method, diphenylamine ammonium salt and a derivative thereof are introduced as an interface modification layer of perovskite through a solution spin-coating process, so that in-situ passivation is realized. The diphenylamino ammonium salt and the derivative thereof can effectively reduce surface defects of perovskite, passivate uncoordinated lead ions, supplement iodine vacancies, significantly reduce non-radiative recombination of a perovskite layer and promote charge extraction by virtue of unique properties of the diphenylamino ammonium salt and the derivative thereof, so that the open-circuit voltage and fill factors of the perovskite solar cell are improved. Meanwhile, large-volume ammonium cations can be gathered on a crystal boundary, so that the defect of the crystal boundary is filled, and ion migration is inhibited. In addition, after passivation, moisture can be effectively prevented from invading the three-dimensional perovskite structure, and the humidity stability and the storage stability of a cell device are remarkably improved. The invention aims at improving the photoelectric conversion efficiency of the perovskite solar cell and realizing the long-term stability of the device performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and relates to an in-situ passivation method for perovskite thin films and a preparation process for perovskite solar cells. Background Art

[0002] In today's world, the development and rational and efficient utilization of energy increasingly affect a country's development and are related to people's livelihood, well-being, and social progress. Due to the gradual depletion of non-renewable energy sources such as fossil fuels, people are increasingly concerned about the efficient utilization of clean and pollution-free renewable energy sources such as solar energy, wind energy, and water energy. As an emerging third-generation solar cell device, perovskite solar cells have been developing rapidly in recent years. As of 2025, the currently certified p-i-n type perovskite solar cell with the highest efficiency can reach 27.0%, which is basically comparable to single-crystalline silicon cells. In organic-inorganic hybrid perovskite materials, due to external mechanical stress, temperature and humidity changes, etc., phenomena such as lattice misalignment and ion migration will occur in the material itself, resulting in defects. These defects may occur between or inside the lattices, generating deep-level or shallow-level traps. Carriers are trapped by these traps, and non-radiative recombination occurs at the interface or in the bulk phase, thereby greatly affecting the transport of carriers, the open-circuit voltage and fill factor of the battery device, and further affecting the efficiency and stability of the battery. Summary of the Invention

[0003] The present invention provides a method for forming an in-situ passivation layer on the surface of a three-dimensional perovskite and applying it to perovskite solar cell devices. By using diphenylamine ammonium salts and their derivatives to passivate the defects on the surface and grain boundaries of perovskite thin films, the non-radiative recombination of carriers caused by deep-level traps caused by defects can be inhibited, thereby effectively improving the photoelectric conversion efficiency and stability of the devices and making them more in line with the requirements of large-scale production and preparation.

[0004] To solve the above problems such as the defects on the surface and grain boundaries of perovskite thin films, the technical solution adopted by the present invention is as follows: The present invention provides a method for modifying a three-dimensional perovskite layer with diphenylamine ammonium salts and their derivatives to in-situ passivate the defects of perovskite thin films, wherein the structural general formula of the diphenylamine ammonium salt is:

[0005] Wherein: R1, R2, R3, R4, R5, and R6 are each any one of hydrogen, an alkyl chain with 1-9 carbon atoms, a hydroxyl group, an alkoxy group, a dimethylamino group, a trifluoromethyl group, a trifluoromethoxy group, a halogen atom, a formyl group, an acetyl group, a nitro group, a cyano group, a phenyl group, a biphenyl group, a naphthyl group, and an amide group; Y is any one of carbon, oxygen, nitrogen, sulfur, and selenium; n is an integer from 1 to 12; and X is any one of halogen atoms.

[0006] The structure of the diphenylammonium salt derivative is as follows:

[0007]

[0008] Wherein: n is an integer from 1 to 12; X is any one of the halogens.

[0009] The present invention also provides a passivation layer film modified with a diphenylammonium salt and its derivative, and the modified passivation layer is located on the surface of the 3D perovskite film, and the passivation molecular structure used is the above-mentioned passivation molecule.

[0010] A method for preparing a perovskite passivation layer film includes the following steps: Dissolve the diphenylammonium salt and its derivative in an organic solvent to obtain an ammonium salt solution, spin-coat the solution on the surface of the 3D perovskite, and anneal at room temperature or a higher temperature to obtain a perovskite film passivated with the ammonium salt. The general formula of the 3D perovskite layer structure is Cs x FA 1-x PbI 3-y-z Br y Cl z Or Cs x MA 1-x PbI 3-y-z Br y Cl z Or a combination of both, where 0 ≤ x ≤ 0.1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1.

[0011] The present invention also provides a method for preparing a perovskite solar cell in-situ passivated with a diphenylammonium salt and its derivative, which is characterized by including the following steps: (1) Ultrasonically clean the conductive glass substrate with a solvent; (2) Prepare an electron transport layer on the cleaned conductive glass substrate by chemical bath deposition or thermal sol spray method; (3) Spin-coat a perovskite precursor solution on the electron transport layer, anneal, and obtain a perovskite film for passivation with a diphenylammonium salt and its derivative according to the above steps; (4) Spin-coat a hole transport layer on the passivated perovskite film, and its components include but are not limited to the doped Spiro-OMeTAD solution, PTAA, where the Spiro-OMeTAD solution contains 2,2',7,7'-tetra N , N-Bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 4-tert-butylpyridine (TBP), and tris[4-tert-butyl-2-(1H-pyrazol-1-yl)pyridine]cobalt(III) (1,1,1-trifluoro- N -[(trifluoromethyl)sulfonyl]methanesulfonamide salt) (FK209 Co(III)-TFSI); solvents include but are not limited to chlorobenzene, acetonitrile; (5) The metal electrode is deposited on the perovskite film spin-coated with the hole transport layer by vacuum deposition. The electrodes used include but are not limited to gold, silver, copper, and carbon electrodes.

[0012] The perovskite film passivated via diphenylammonium salts and their derivatives, the concentration of the passivating molecular solution is 1-6 mg / mL; the solvents used are one or more of isopropanol, chloroform, acetonitrile, toluene, and chlorobenzene; The perovskite film passivated via diphenylammonium salts and their derivatives, the spin-coating speed is 3000-6000 rpm, the spin-coating time is 25-40 s, and the annealing temperature range after spin-coating is 20-120 °C.

[0013] Furthermore, the diphenylammonium salts that can be selected include but are not limited to the following structures. Taking the iodamine salt with n = 2 as an example:

[0014]

[0015] .

[0016] Furthermore, the condensed ring diphenylammonium salts that can be selected include but are not limited to the following structures. Taking the iodamine salt with n = 2 as an example:

[0017] .

[0018] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, diphenylammonium salts and their derivatives are used as passivators on the surface of three-dimensional perovskites. The large-volume cations can aggregate at grain boundaries or form hydrogen bond interactions with A-site cations, filling the vacancies of A-site ions to reduce defects. Anions such as iodide ions of ammonium iodide salts can fill the uncoordinated iodine defects in the perovskite bulk phase, reducing defect problems caused by lattice misalignment, etc. Further, non-radiative recombination of carriers in the perovskite light-absorbing layer is reduced, the trap density is lowered, and pinhole-like defects on the surface of the perovskite thin film and the quantum confinement effect caused by grain boundaries are reduced; introducing heteroatoms or aryl halogen atoms changes the overall electron cloud density of the molecule, which is beneficial to increasing the molecular dipole moment, enhancing the electron-donating ability of the conjugated part, and adjusting the perovskite energy band structure to make it more p type, which is beneficial to better matching with the energy levels of the hole transport layer; in addition, increasing the conjugated structure of the aromatic part is conducive to forming stacking and enhancing the interaction between molecules; finally, the alkyl chain has a certain hydrophobicity, which can reduce water intrusion, making the perovskite solar cell more resistant to high-humidity environments and improving the stability of the battery.

[0019] Modifying the surface defects of perovskites with alkyl- or arylammonium halide molecular passivators can efficiently improve the stability and power conversion efficiency of the device. First, the alkyl chain has a certain hydrophobicity, which can reduce water intrusion. Second, the large-volume cations can aggregate at grain boundaries or enter the perovskite octahedra, filling the vacancies of A-site ions to reduce defects. Ammonium halide salts can also reduce the movement of halide anions, directly fill the vacancies of halide anions, adjust the band gap of the semiconductor material, and form a Type-II energy level structure with the electron or hole transport layer, which is beneficial to improving the carrier mobility and the perovskite efficiency.

[0020] In summary, compared with other ammonium salt passivation molecules with similar structures, introducing diphenylammonium salts and their derivatives as surface passivators effectively improves the thermal stability of perovskite solar cells within a certain temperature range, is beneficial to achieving energy level alignment, and further enhances the carrier transport ability in the thin film, thereby improving performance parameters such as the photoelectric conversion efficiency of perovskite solar cells, providing an effective method for further commercial development. Description of the Drawings

[0021] Figure 1 is N,N the general synthesis procedure of diphenylammonium salts of diphenyl-ethylamine hydroiodide (DPA-EAI).

[0022] Figure 2 For N,N the J - V curves of FAPbI3 perovskite solar cells before and after being passivated and modified with diphenyl-ethylamine hydroiodide.

[0023] Figure 3 The N,N SEM images of the surface of FAPbI3 perovskite thin films before and after being passivated with diphenylethylamine hydroiodide.

[0024] Figure 4 The N,N steady-state photoluminescence (PL) spectra of the surface of FAPbI3 perovskite thin films before and after being passivated with diphenylethylamine hydroiodide.

[0025] Figure 5 The N,N X-ray diffraction patterns of the thin films passivated with diphenylethylamine hydroiodide after annealing at 40 - 100 °C.

[0026] Figure 6 For the J - V curves of FAPbI3 perovskite solar cells before and after being passivated with 2-(10H-phenothiazin-10-yl)ethylamine hydroiodide. Specific Embodiments

[0027] The following specific embodiments are for better understanding the advantages of the present invention through some examples, as well as for further detailed description and supplementation of the present invention, but not for limiting the protection scope of the present invention.

[0028] Taking Figure 1 the above examples as a general process for synthesizing several diphenylammonium salts and their derivatives, the specific synthesis route is as follows: (1) Intermediate 1 N Synthesis of -(2,2-dimethoxyethyl)-2,2,2-trifluoroacetamide 1 H NMR (400 MHz, Chloroform- d , ppm) = 6.79 (s, 1H), 4.45 - 4.43 (t, J = 5.1 Hz, 1H), 3.50 - 3.47 (t, J= 5.5 Hz, 2H), 3.41 (s, 6H).

[0029] (2) Intermediate 2 N Synthesis of -[2-(diphenylamino)ethyl]-2,2,2-trifluoroacetamide Diphenylamine (2 mmol, 0.3384 g) and N-(2,2-dimethoxyethyl)-2,2,2-trifluoroacetamide (2.4 mmol, 0.4825 g) were dissolved in 20 mL of dry dichloromethane under nitrogen. Trifluoroacetic acid (TFA) (26 mmol, 3 mL) and triethylsilane (TES) (5 mmol, 0.8 mL) were added dropwise, and the mixture was stirred at room temperature for 2 hours. The reaction mixture was cooled to 0 °C, diluted with saturated aqueous sodium bicarbonate to pH 7 - 8, extracted three times with 20 mL of dichloromethane, the organic layer was separated, dried and filtered, and the organic phase was evaporated to dryness and passed through a silica gel column (petroleum ether: ethyl acetate v / v = 6 / 1), to obtain a white solid. 1 H NMR (400 MHz, Chloroform- d , ppm) = 7.34 - 7.26 (m, 4H), 7.06 - 6.95 (m, 6H), 6.48 (s, 1H), 3.97 - 3.94 (t, J = 6.3 Hz, 2H), 3.66 - 3.61 (q, J = 6.2 Hz, 2H).

[0030] (3) Product 3 N,N Synthesis of diphenylethylamine hydroiodide (DPA-EAI) N-[2-(diphenylamino)ethyl]-2,2,2-trifluoroacetamide (1.5 mmol, 0.4621 g) and potassium carbonate (12 mmol, 1.6585 g) were dissolved in a mixed solvent of methanol and water with volumes of 12 and 6 mL respectively, and stirred at room temperature overnight. After evaporation to dryness, the precipitate was diluted with 20 mL of water, extracted three times with 20 mL of dichloromethane, the organic layer was separated, dried and filtered, and the organic phase was evaporated to dryness to obtain a dark yellow viscous oil. The oil and hydroiodic acid (molar ratio 1:1.05) were dissolved in 150 mL of ethanol, cooled in an ice-water bath for 2 h, evaporated to dryness, and the solid was washed with ether to obtain the final product as a white solid. 1 H NMR (400 MHz, DMSO- d 6, ppm) = 7.75 (s, 3H), 7.34 - 7.30 (m, 4H), 7.03 - 6.99 (dd, 6H), 3.93 - 3.90 (t, 2H), 3.01 - 2.97 (t, 2H).

[0031] Example 1 containing N, N The preparation method of a perovskite solar cell passivated with N,N'-diphenyl-N,N'-bis(2-aminoethyl)amine hydroiodide (DPA-EAI) is as follows: (1) Preparation of the conductive glass substrate: The FTO (fluorine-doped tin oxide) conductive glass was ultrasonically cleaned with deionized water added with dishwashing liquid, deionized water, acetone, and ethanol for 45 min respectively.

[0032] (2) Preparation of the electron transport layer: The tin dioxide electron transport layer was prepared by chemical bath deposition (CBD). 50 mL of deionized water was added into a glass container, and 137.5 mg of stannous chloride dihydrate, 625 mg of urea, 625 mL of 37.5% hydrochloric acid, and 12.5 mL of mercaptoacetic acid were added in sequence. After stirring evenly, the treated conductive glass was added and the glass substrate was submerged below the liquid surface. The water bath containing the glass substrate was heated to 90 °C and maintained for 4 hours. The FTO conductive glass was ultrasonically cleaned with deionized water and isopropanol for 20 min respectively to remove the tin dioxide suspended substances and organic impurities on the surface. Then the glass substrate was transferred to a hot plate at 170 °C and annealed for 1 hour.

[0033] (3) Preparation of the perovskite precursor solution: 0.0059 g of methylammonium tribromide MAPbBr3, 0.0332 g of methylammonium chloride MACl, 0.2410 g of formamidinium iodide FAI, and 0.7034 g of lead iodide PbI2 were dissolved in 1 mL N , N N,N'-dimethylformamide and N , N N,N'-dimethylsulfoxide (volume ratio 8:1) mixed solvent, and stirred at room temperature overnight. Before spin-coating the perovskite precursor solution in one step on the electron transport layer, the solution needs to be filtered. The spin-coating process is divided into two stages: the first stage is spin-coated at 2000 rpm for 10 s, with an acceleration of 2000 rpm s -1 , the second stage is at 6000 rpm, spin-coated for 30 s, with an acceleration of 2000 rpm s -1 . 200 mL of chlorobenzene was added dropwise onto the perovskite film 20 s before the end of the second stage, and then annealed on a hot plate at 100 °C for 1 h.

[0034] (4) Preparation of the passivation layer: After the perovskite film was cooled to room temperature, an isopropanol solution of DPA-EAI with a concentration of 3 mg mL -1 was prepared for standby. Using the dynamic spin-coating method, 50 μL of the above passivation solution was spin-coated on the perovskite film at a rotation speed of 5000 rpm for 30 s, with an acceleration of 2000 rpm s-1 , anneal at room temperature for 10 min to obtain a passivated perovskite film.

[0035] (5) Preparation of the hole transport layer: The hole transport layer uses a doped Spiro-OMeTAD solution, and its components are: 54 mg of Spiro-OMeTAD, 23.7 mL of 4-tert-butylpyridine (TBP), -1 14.7 mL of an acetonitrile solution of Li-TFSI (concentration: 520 mg / mL -1 ), and 6.5 mL of an acetonitrile solution of Co(III)-TFSI (375 mg / mL

[0036] ), and 600 mL of chlorobenzene. After stirring evenly, take 15 - 20 mL of the above Spiro-OMeTAD solution and spin-coat it on the passivated perovskite film at a rotation speed of 3000 rpm for 30 s.

[0037] Comparative Example 1 Take a FAPbI3 perovskite solar cell without a perovskite passivation layer as a comparison, and its specific preparation process is as follows: (1) Preparation of the conductive glass substrate: Ultrasonically clean the FTO (fluorine-doped tin oxide) conductive glass with deionized water with dishwashing liquid, deionized water, acetone, and ethanol for 45 min respectively.

[0038] (2) Preparation of the electron transport layer: Use the chemical bath deposition method (CBD) to prepare a tin dioxide electron transport layer. Add 50 mL of deionized water to a glass container, and sequentially add 137.5 mg of stannous chloride dihydrate, 625 mg of urea, 625 mL of 37.5% hydrochloric acid, and 12.5 mL of mercaptoacetic acid. Stir evenly, add the treated conductive glass, and submerge the glass substrate below the liquid level. Heat the water bath containing the glass substrate to 90°C and keep it for 4 hours. Ultrasonically clean the FTO conductive glass with deionized water and isopropanol for 20 min respectively to remove the tin dioxide suspended matter and organic impurities on the surface. Transfer the glass substrate to a hot plate at 170°C and anneal for 1 hour.

[0039] (3) Preparation of the perovskite precursor solution: Dissolve 0.0059 g of methylammonium tribromide (MAPbBr3), 0.0332 g of methylammonium chloride (MACl), 0.2410 g of formamidinium iodide (FAI), and 0.7034 g of lead iodide (PbI2) in 1 mL N , N - dimethylformamide and N ,N in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide (volume ratio 8:1), stirred overnight at room temperature. Before spin-coating the perovskite precursor solution in one step on the electron transport layer, the solution needs to be filtered. The spin-coating process is divided into two stages: the first stage is spin-coated at 2000 rpm for 10 s with an acceleration of 2000 rpm s -1 , and the second stage is at 6000 rpm for 30 s with an acceleration of 2000 rpms -1 . 200 mL of chlorobenzene is added dropwise onto the perovskite film as an anti-solvent 20 s before the end of the second stage, and then annealed on a hot plate at 100 °C for 1 h.

[0040] (4) Preparation of the hole transport layer: The hole transport layer uses the doped Spiro-OMeTAD solution, and its components are: 54 mg of Spiro-OMeTAD, 23.7 mL of 4-tert-butylpyridine (TBP), acetonitrile solution of Li-TFSI (concentration 520 mg mL -1 ) 14.7 mL, acetonitrile solution of Co(III)-TFSI (375 mg mL -1 ) 6.5 mL, 600 mL of chlorobenzene. After stirring evenly, 15 - 20 mL of the above Spiro-OMeTAD solution is spin-coated onto the perovskite film at a speed of 3000 rpm for 30 s.

[0041] (5) Preparation of the metal electrode: 100 nm of Au is deposited on the film surface by vacuum evaporation to obtain the perovskite solar cell device.

[0042] Figure 2 For N,N the J-V curves of the FAPbI3 perovskite solar cells before and after passivation with -diphenylethylamine hydroiodide, where the effective area of the cell is 0.075 cm J - V , and the photoelectric conversion efficiency of the passivated cell in Example 1 is 24.64%, where the open-circuit voltage 2 is 1.168 V, the short-circuit current density V oc is 25.75 mA cm J sc , and the fill factor FF is 81.89%. While the photoelectric conversion efficiency of the unpassivated perovskite solar cell in Comparative Example 1 is 21.40%, where the open-circuit voltage -2 is 1.127 V, the short-circuit current density V oc is 25.07 mA cm J sc and the fill factor FF is 81.89%.-2 , the fill factor FF is 75.72%, indicating that the open-circuit voltage and fill factor of the battery are effectively improved after passivation.

[0043] Figure 3 For N,N - The surface scanning electron microscope images of the FAPbI3 perovskite thin film before and after passivation modified by diphenylethylamine hydroiodide. It can be seen from the images that the grain boundaries of the perovskite thin film after passivation are occupied by passivation molecules, the grain boundaries are significantly reduced, the surface pinholes are also reduced, and the overall film is smoother and more uniform.

[0044] Figure 4 For N,N - The surface steady-state photoluminescence spectra of the FAPbI3 perovskite thin film before and after passivation modified by diphenylethylamine hydroiodide. The PL peak of the thin film after passivation by diphenylethylamine hydroiodide is significantly enhanced, indicating that the non-radiative recombination of carriers in the thin film is reduced after passivation, and the defect density is greatly reduced.

[0045] Figure 5 For N,N - The X-ray diffraction pattern of the thin film passivated by diphenylethylamine hydroiodide after annealing at 40 - 100 °C. It can be seen from the image that no two-dimensional diffraction peaks appear at small angles for the passivated thin film annealed at 40 - 80 °C, while only a two-dimensional diffraction peak appears at 2 θ = 4.7° when annealed to 100 °C, indicating that at a certain temperature, the ammonium salt will not enter the three-dimensional perovskite bulk phase to react and change the phase state, indicating its excellent thermodynamic stability.

[0046] Example 2 The preparation method of the perovskite solar cell passivated by 2-(10H-phenothiazin-10-yl)ethylamine hydroiodide (PTZ-EAI) is as follows: Its structure is:

[0047] The battery preparation process is: (1) Preparation of the conductive glass substrate: The FTO (fluorine-doped tin oxide) conductive glass is ultrasonically cleaned with deionized water with dishwashing liquid, deionized water, acetone, and ethanol for 45 min respectively.

[0048] (2) Preparation of the electron transport layer: The tin dioxide electron transport layer was prepared by chemical bath deposition (CBD). 50 mL of deionized water was added into a glass container, and 137.5 mg of stannous chloride dihydrate, 625 mg of urea, 625 mL of 37.5% hydrochloric acid, and 12.5 mL of mercaptoacetic acid were added in sequence. After stirring evenly, the treated conductive glass was added and the glass substrate was submerged below the liquid level. The water bath containing the glass substrate was heated to 90 °C and maintained for 4 hours. The FTO conductive glass was ultrasonically cleaned with deionized water and isopropyl alcohol for 20 min respectively to remove the surface tin dioxide suspended substances and organic impurities. Then the glass substrate was transferred to a hot plate at 170 °C and annealed for 1 hour.

[0049] (3) Preparation of the perovskite precursor solution: 0.0059 g of methylammonium tribromide MAPbBr3, 0.0332 g of methylammonium chloride MACl, 0.2410 g of formamidinium iodide FAI, and 0.7034 g of lead iodide PbI2 were dissolved in 1 mL N , N - dimethylformamide and N , N - dimethyl sulfoxide (volume ratio 8:1) mixed solvent, and stirred at room temperature overnight. Before spin - coating the perovskite precursor solution on the electron transport layer in one - step, the solution needs to be filtered. The spin - coating process is divided into two stages: the first stage is spin - coating at 2000 rpm for 10 s with an acceleration of 2000 rpm s -1 , the second stage is at 6000 rpm, spin - coating for 30 s with an acceleration of 2000 rpm s -1 . 200 mL of chlorobenzene was added dropwise onto the perovskite film as an anti - solvent 20 s before the end of the second stage, and then annealed on a hot plate at 100 °C for 1 h.

[0050] (4) Preparation of the passivation layer: After the perovskite film was cooled to room temperature, an isopropyl alcohol solution of PTZ - EAI with a concentration of 3 mg mL -1 was prepared for standby. By using the dynamic spin - coating method, 50 μL of the above - mentioned passivation solution was spin - coated on the perovskite film at a rotation speed of 5000 rpm for 30 s with an acceleration of 2000 rpm s -1 , and annealed at 100 °C for 10 min to obtain the passivated perovskite film.

[0051] (5) Preparation of the hole transport layer: The hole transport layer uses the doped Spiro - OMeTAD solution, and its components are: 54 mg of Spiro - OMeTAD, 23.7 mL of 4 - tert - butylpyridine TBP, and an acetonitrile solution of Li - TFSI (concentration 520 mg mL -1) 14.7 mL, acetonitrile solution of Co(III)-TFSI (375 mg mL -1 ) 6.5 mL, 600 mL chlorobenzene. After stirring evenly, 15 - 20 mL of the above Spiro-OMeTAD solution was aspirated and spin-coated on the passivated perovskite thin film at a rotation speed of 3000 rpm for 30 s.

[0052] (6) Preparation of metal electrode: 100 nm of Au was deposited on the film surface by vacuum evaporation to obtain the perovskite solar cell device.

[0053] Comparative Example 2 The FAPbI3 perovskite solar cell without a perovskite passivation layer was used as a comparison, and its specific preparation process is as follows: (1) Preparation of conductive glass substrate: The FTO (fluorine-doped tin oxide) conductive glass was ultrasonically cleaned with deionized water with detergent, deionized water, acetone, and ethanol for 45 min respectively.

[0054] (2) Preparation of electron transport layer: The tin dioxide electron transport layer was prepared by chemical bath deposition (CBD). 50 mL of deionized water was added to a glass container, and 137.5 mg of stannous chloride dihydrate, 625 mg of urea, 625 mL of 37.5% hydrochloric acid, and 12.5 mL of thioglycolic acid were added in sequence, stirred evenly, and the treated conductive glass was added, and the glass substrate was immersed below the liquid level. The water bath containing the glass substrate was heated to 90 °C and maintained for 4 hours. The FTO conductive glass was ultrasonically cleaned with deionized water and isopropyl alcohol for 20 min respectively to remove the surface tin dioxide suspension and organic impurities, and the glass substrate was transferred to a hot plate at 170 °C for annealing for 1 hour.

[0055] (3) Preparation of perovskite precursor solution: 0.0059 g of methylammonium tribromide MAPbBr3, 0.0332 g of methylammonium chloride MACl, 0.2410 g of formamidinium iodide FAI, and 0.7034 g of lead iodide PbI2 were dissolved in 1 mL N , N - dimethylformamide and N , N - dimethyl sulfoxide (volume ratio 8:1) mixed solvent, stirred overnight at room temperature. Before spin-coating the perovskite precursor solution in one step on the electron transport layer, the solution needs to be filtered. The spin-coating process is divided into two stages: the first stage is spin-coated at 2000 rpm for 10 s, with an acceleration of 2000 rpm s -1 , the second stage is 6000 rpm, spin-coated for 30 s, with an acceleration of 2000 rpms -1. 200 mL of chlorobenzene was added dropwise as an antisolvent onto the perovskite film 20 s before the end of the second stage, and then annealed on a hot plate at 100 °C for 1 h.

[0056] (4) Preparation of the hole transport layer: The hole transport layer used a doped Spiro-OMeTAD solution, and its components were: 54 mg of Spiro-OMeTAD, 23.7 mL of 4-tert-butylpyridine (TBP), 14.7 mL of an acetonitrile solution of Li-TFSI (concentration: 520 mg / mL -1 ), 6.5 mL of an acetonitrile solution of Co(III)-TFSI (375 mg / mL -1 ), and 600 mL of chlorobenzene. After stirring evenly, 15 - 20 mL of the above Spiro-OMeTAD solution was spin-coated onto the perovskite film at a rotation speed of 3000 rpm for 30 s.

[0057] (5) Preparation of the metal electrode: 100 nm of Au was deposited onto the film surface by vacuum evaporation to obtain the perovskite solar cell device.

[0058] Figure 6 are the J - V curves of FAPbI3 perovskite solar cells before and after being passivated with 2-(10H-phenothiazin-10-yl)ethylamine hydroiodide. The effective area of the cell is 0.075 cm 2 . The photoelectric conversion efficiency of the passivated cell in Example 2 is 24.29%, where the open-circuit voltage V oc is 1.192 V, the short-circuit current density J sc is 25.48 mA / cm -2 , and the fill factor FF is 79.96%. For the unpassivated perovskite solar cell in Comparative Example 2, the photoelectric conversion efficiency is 21.93%, where the open-circuit voltage V oc is 1.113 V, the short-circuit current density J sc is 25.17 mA / cm -2 , and the fill factor FF is 78.23%. It shows that after passivation, the open-circuit voltage increases by 79 mV and the photoelectric conversion efficiency increases by 2.36%.

Claims

1. A three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives, characterized in that: The three-dimensional perovskite layer is in-situ passivated using diphenylamine ammonium salt or its derivatives; The general structural formula of the diphenylamine ammonium salt is: ； Wherein: R1, R2, R3, R4, R5, R6 are any one of hydrogen, C1-C9 alkyl chain, hydroxyl, alkoxy, dimethylamino, trifluoromethyl, trifluoromethoxy, halogen atom, formyl, acetyl, nitro, cyano, phenyl, biphenyl, naphthyl, amide; Y is any one of carbon, oxygen, nitrogen, sulfur, selenium, if Y is carbon, two substituents are connected, if Y is nitrogen, one substituent is connected; the substituent is hydrogen or C1-C9 alkyl chain; n is an integer of 1 to 12; X is a halogen atom; The derivative structure of diphenylamine ammonium salt is: ； ； ； Wherein: n is an integer of 1-12; X is a halogen atom.

2. The three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives according to claim 1, characterized in that: The diphenylamine ammonium salt is selected from the following structures: ； ； 。 3. The three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives according to claim 1, characterized in that: The derivative of the diphenylamine ammonium salt is selected from the following structures: ； 。 4. The three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives according to claim 1, characterized in that: The passivation layer in which the diphenylamine ammonium salt and its derivatives are in-situ passivated in the three-dimensional perovskite layer is located on the surface of the 3D perovskite layer.

5. A three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives according to any one of claims 1 to 4, characterized in that: The preparation method of the passivation layer of diphenylamine ammonium salt and its derivatives in situ passivation is as follows: The diphenylamine ammonium salt and its derivatives are dissolved in an organic solvent to obtain an ammonium salt solution, and the solution is spin-coated on the surface of the 3D perovskite layer and annealed to obtain a perovskite film passivated by ammonium salt; the general structure formula of the 3D perovskite layer is Cs x FA 1-x PbI 3-y-z Br y Cl z and / or Cs x MA 1-x PbI 3-y-z Br y Cl z , where 0≤x≤0.1, 0≤y≤1, 0≤z≤1.

6. The three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives according to claim 5, characterized in that: The concentration of the ammonium salt solution is 1-6 mg / mL; the organic solvent is one or more of isopropanol, chloroform, acetonitrile, toluene, and chlorobenzene.

7. The three-dimensional perovskite layer modified with diphenylamine ammonium salt and its derivatives according to claim 6, characterized in that: The spin coating speed is 3000-6000 rpm, the spin coating time is 25-40 s, and the annealing temperature ranges from 20-120° C. after spin coating.

8. A method for preparing a perovskite solar cell with in-situ passivation of diphenylammonium salt and its derivatives, characterized in that: The steps include: (1) ultrasonically cleaning a conductive glass substrate with a solvent; (2) preparing an electron transport layer on a cleaned conductive glass substrate by chemical bath deposition or hot melt spraying; (3) spin coating a perovskite precursor solution on the electron transport layer, annealing, and preparing a passivation layer of in-situ passivation of diphenylamine ammonium salt and its derivatives by the method of claim 5 to obtain a passivated perovskite film; (4) spin coating a hole transport layer on the passivated perovskite film; (5) A metal electrode is vacuum deposited on the perovskite film of the spin-coated hole transport layer.

9. The method for preparing a perovskite solar cell with in-situ passivation of diphenylammonium salt and its derivatives according to claim 8, characterized in that: The components of the hole transport layer include a Spiro-OMeTAD solution and PTAA, wherein the Spiro-OMeTAD solution contains 2,2',7,7'-tetra[ N , N -bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, lithium bis(trifluoromethane)sulfonyl imide, 4-tert-butylpyridine and tris[4-tert-butyl-2-(1H-pyrazol-1-yl)pyridinium]cobalt[III](1,1,1-trifluoro- N -[(trifluoromethyl)sulfonyl]methanesulfonamide salt).

10. The method for preparing a perovskite solar cell with in-situ passivation of diphenylammonium salt and its derivatives according to claim 9, characterized in that: The electrodes include gold, silver, copper and carbon electrodes.

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