Defect Passivation and Carrier Transport Modulation of Excellent Cu3V(S,Se)4 Solar Cells via Introducing Cd2+ Ions

Cations incorporation have been emerged as the effective approach to enhancing the efficiency of copper based solar cells. In this work, the Cd 2+ ions were introduced to boost the performance of the Cu 3 V(S,Se) 4 thin films solar cells for the first time. Through systematically investigating the effect of Cd doping on the performance of Cu 3 V(S,Se) 4 thin film solar cells, the appropriate amount of Cd-doping (0.51%) can improve the crystallinity and reduce the roughness of Cu 3 V(S,Se) 4 films, enhancing electron-hole separation, promoting the carrier transport properties at the front interface, and passivating the unwanted bulk defect of devices. These excellent improvements help to achieve a champion device with photoelectric conversion efficiency (PCE) of 2.43%, which is the highest PCE of solution-based Cu 3 V(S,Se) 4 thin film solar cells at present. This study not only provides an approach for optimizing the performance of Cu 3 V(S,Se) 4 solar cells, but also confirms the commonality of optimization measures for copper based thin-film solar cells.