Cu2ZnSnSe4 thin films prepared by selenization of one-step electrochemically deposited Cu-Zn-Sn-Se precursors

► Selenization one-step electrochemical deposition Cu-Zn-Sn-Se precursors to fabricate CZTSe thin films for the first time. ► Studied the effect of different rate of each element in electrolyte and the influence of pH. ► Prepared Cu2ZnSnSe4 that is pure and close to stoichiometric. ► Proved the structure of CZTSe is Kesterite-type.