Method for preparing perovskite thin film and perovskite cell

A method for preparing a perovskite thin film, comprising the following steps:

• coating a perovskite inorganic salt solution containing a thickener onto a cell substrate to form a first inorganic substrate layer, and combining the cell substrate with the first inorganic substrate layer to form a wet film substrate, wherein the perovskite inorganic salt solution is formed by mixing a perovskite inorganic salt material and a solvent, the perovskite inorganic salt material is obtained by mixing PbI2, PbBr2, CsI, and FAI in a certain ratio, the solvent in the perovskite inorganic salt solution is dimethyl sulfoxide, the thickener is methylammonium acetate, and the perovskite inorganic salt solution is formulated at 1 mol/L according to a volume ratio of the dimethyl sulfoxide to the methylammonium acetate being 1:50;
• cooling and standing the wet film substrate, and removing an organic solvent in the first inorganic substrate layer by a vacuum flash evaporation manner to form a pre-dried film layer, wherein the pre-dried film layer consists of the perovskite inorganic salt material and the thickener;
• performing first annealing treatment on the pre-dried film layer to remove cations in the thickener;
• performing second annealing treatment on the pre-dried film layer to remove anions in the thickener and obtain a second inorganic substrate layer;
• and
• coating an organic halide salt solution onto the second inorganic substrate layer, and performing drying and annealing treatment to obtain the perovskite thin film, wherein the organic halide salt solution is formed by mixing a solute and a solvent;
• and the solvent of the organic halide salt solution is n-butanol, the solute of the organic halide salt solution is obtained by mixing FAI, MAI, and FABr in a certain ratio, and a concentration of the organic halide salt solution is 15 mg/mL.