The application discloses a preparation method of a
germanium-doped
CZTS thin film. The preparation method comprises the following steps: preparing a CuS nano-particle; preparing a Ge-doped precursor
slurry; preparing Ge-doped precursor film; carrying out sulfidizing on the Ge-doped precursor film to obtain a Cu2ZnSn1-xGexS4 film; and carrying out selenylation
processing on the Cu2ZnSn1-xGexS4 film to obtain Cu2ZnSn1-xGex(S,Se)4 film. In addition, the application also discloses a
germanium-doped
CZTS thin film and a
solar cell. According to the invention, because the Cus nano-particle is used, grain
crystal growing and film densifying can be promoted; the Ge is doped when the precursor
slurry is prepared, so that the forbidden
band width of the
CZTS thin film can be adjusted and the
photoelectric conversion efficiency of the CZTS
cell can be improved; because an
organic solvent like methyl
alcohol or
ethanol and the like is used, the
sulfur source used for sulfidizing
processing is
solid powdered
sulfur, and the
selenium source used for selenizing
processing is
solid selenium powder, the whole production process is
environmentally friendly; and a
volume expansion effect using a Se atom portion to replace an S atom during the selenizing process is used for structural densifying of the film, and the forbidden
band width of the CZTS
absorption layer is adjusted, so that matching with a solar spectrum is realized well.