Comparative study of Cu2ZnSnS4 thin film solar cells fabricated by direct current and pulse reverse co-electrodeposition

Cu2ZnSnS4 (CZTS) thin films have been fabricated by sulfurization of direct current and pulse reverse co-electrodeposited CZTS precursors on Mo-coated glass substrates. The CZTS thin film synthesized using pulse reverse co-electrodeposition exhibits homogeneous and large grains, Cu-poor and Zn-rich compositions and free of Cu2S secondary phase compared with that obtained from direct current co-electrodeposition. By using pulse reverse co-electrodeposition, the performance of p-n junction is improved with low diode quality factor (A) and reverse saturation current density (J0), and the CZTS device first reaches an efficiency of 6.28% (Voc = 609 mV, Jsc = 18.4 mA/cm2, FF = 56.1%) threshold, which is higher than that of 4.69% (Voc = 561 mV, Jsc = 16.4 mA/cm2, FF = 50.9%) using direct current co-electrodeposition. This result offers a novel research direction for preparing high-efficiency CZTS thin film solar cells.