Sulfur-annealed Cu₂SnS₃ (CTS) thin films for solar cell applications

In this study, chemical bath deposition process was used to deposit Cu₂SnS₃ (CTS) thin film onto stainless-steel substrate at room temperature. The investigation focused on the impact of sulfur annealing on the optoelectrical characteristics of the films, with the potential for solar cell applications. X-ray diffraction analyses revealed the formation of tetragonal CTS after sulfurization at 400 °C. This confirms the presence of a ternary phase. Notably, absorption studies revealed direct transitions within the thin films, along with improved bandgap energies. These characteristics render that the as-deposited CTS thin films are well suited for potential use in solar cell applications. Upon annealing at 400 °C, the open-circuit voltage (V_oc), short-circuit current (I_sc), maximum voltage (mV), and maximum current (I_M) of the CTS thin films experienced enhancement. Electrochemical impedance spectroscopy results reveal that the post-treatment of the film enhances the carrier transport mechanism between semiconductor–electrolyte junctions.