A Cadmium-Free Cu2ZnSnS4/ZnO Hetrojunction Solar Cell Prepared by Practicable Processes

A cadmium-free Cu2ZnSnS4/ZnO hetrojunction solar cell with conversion efficiency of 4.29% has been obtained. The Cu2ZnSnS4 absorber film was formed utilizing sulfurization of laminated metallic precursors, and the ZnO buffer layer was then deposited on it by ultrasonic spray pyrolysis. In comparison with a conventional Cu2ZnSnS4/CdS hetrojunction solar cell, the open circuit voltage as well as the relative quantum efficiency at the short-wavelength regions was increased. The in-plane homogeneity of p-n junction was improved by depositing the ZnO layer on Cu2ZnSnS4 film via ultrasonic spray pyrolysis. (C) 2011 The Japan Society of Applied Physics