A self-doping strategy to improve the photoelectrochemical performance of Cu2ZnSnS4 nanocrystal films for water splitting.

A series of self-doped Cu2ZnSnS4 (CZTS) nanocrystal films with Sn ions partially replaced by Zn ions were prepared from their colloidal solutions by electrophoretic deposition. The self-doped CZTS photocathodes yielded higher photocurrents than the pristine one, which was ascribed to the upper shift in the conduction band and the formation of a shallow defect level.