Method for preparing copper-zinc-tin-sulfur absorption layer by using ionic liquid as solvent

The invention belongs to the technical field of thin-film solar cells, and relates to a copper-zinc-tin-sulfur absorption layer thin-film material, in particular to a preparation method of a copper-zinc-tin-sulfur absorption layer with ionic liquid as a solvent, which comprises the following steps: firstly, uniformly mixing choline chloride and ethylene glycol under heat treatment to form a liquid choline chloride/ethylene glycol eutectic solvent; then sequentially adding copper acetate, stannous chloride dihydrate and zinc acetate dihydrate, uniformly mixing, then adding thiourea, uniformly mixing again to obtain a copper-zinc-tin-sulfur precursor solution, and finally spin-coating the precursor solution on a substrate by adopting a direct solution spin-coating method to obtain the copper-zinc-tin-sulfur thin film. And after drying, carrying out vulcanization heat treatment to finally prepare the copper-zinc-tin-sulfur absorption layer thin film material. According to the method, the choline chloride/thioure