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% (V_oc = 609 mV, J_sc = 18.4 mA/cm², FF = 56.1%) threshold, which is higher than that of 4.69% (V_oc = 561 mV, J_sc = 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.