Copper, zinc, tin, germanium and selenium thin film and preparation method thereof and copper, zinc, tin, germanium and selenium thin-film solar cell

The invention relates to a copper, zinc, tin, germanium and selenium thin film which comprises a light-in layer comprising a first light-in face and a first shady face opposite to the first light-in face, wherein the molar ratio of germanium to tin in the material of the light-in layer decreases gradually along a direction from the first light-in face to the first shady face; a shady layer comprising a second light-in face connected with the first shady face and a second shady face separated from the first shady face, wherein the molar ratio of germanium to tin in the material of the shady layer increases gradually from the second light-in face to the second shady face. In the copper, zinc, tin, germanium and selenium thin film, the width of an energy gap of the copper, zinc, tin, germanium and selenium thin film material is in a variation tendency of rise-fall so that a photon-generated electrons and cavity pairs are separated in a high composite region to avoid composition among photon-generated carriers and improve the collecting efficiency of the photon-generated carriers, so as to further improve the photoelectric conversion efficiency of a copper, zinc, tin, germanium and selenium thin-film solar cell. Meanwhile, the invention further provides a preparation method of the copper, zinc, tin, germanium and selenium thin film and the solar cell using the thin film.