A promising vanadium sulfide counter electrode for efficient dye-sensitized solar cells

Abstract

In this study, we demonstrated the synthesis of vanadium sulfide (VS₂) via an in situ hydrothermal route, which was subsequently employed as a counter electrode (CE) for Pt-free dye-sensitized solar cells (DSSCs) for the first time. It was demonstrated from scanning electron microscopy that the size of VS₂ increased with the increasing temperature, and the morphology was also affected by temperature. Extensive electrochemical performance analysis, including cyclic voltammetry, electrochemical impedance, and Tafel polarization, revealed that the VS₂ CE possesses a high electrocatalytic activity for the reduction of triiodide to iodide and a low charge-transfer resistance at the electrolyte/CE interface. The DSSC based on the VS₂ CE exhibited a conversion efficiency of 6.24% under an illumination of 100 mW cm⁻² as compared to the DSSC based on the Pt CE.