In situ prepared Cu2ZnSnS4 ultrathin film counter electrode in dye-sensitized solar cells

A Cu 2 ZnSnS 4 (CZTS) ultrathin film counter electrode (CE) was prepared in situ by the sol–gel method. As the film was only 200 nm thickness, it showed a degree of transparence. The dye-sensitized solar cell (DSSC) with the prepared CE was the bifacially active transparent cell, which exhibited η of 5.63% and 1.60% corresponding to front- and back-side illumination respectively. It showed improved performance compared to DSSC with Pt CE, Electrochemical impedance spectroscopy (EIS) and Cyclic voltammetry (CV) measurements indicated the CZTS ultrathin film CE had a superior electrocatalytic activity than Pt CE.