Dual-function of CdCl2 treated SnO2 in Sb2Se3 solar cells

The electron transport layer (ETL) of Sb2Se3 thin film solar cells is not only responsible for electron extraction and transport but also manipulates the orientation of the Sb2Se3 photoactive layer's growth, which is crucial for performance optimization. In this study, the dual functionality of solution-processed SnO2 film treated with CdCl2 was achieved as the ETL in Sb2Se3 solar cells. The CdCl2 treatment simultaneously improves the efficacy of the SnO 2 ETL and induces the longitudinal growth of Sb2Se3 grains. These two aspects effectively enhance electron transport and/or extraction, thereby reducing the charge recombination, which contributes to the improvement of all device parameters. The results demonstrate that CdCl2 treatment optimizes the interface properties of the SnO2 ETL, providing a facile and effective method for enhancing the performance of the Sb2Se3 solar cell.