Dual-function of CdCl2 treated SnO2 in Sb2Se3 solar cells

The electron transport layer (ETL) of Sb 2 Se 3 thin film solar cells is not only responsible for electron extraction and transport but also manipulates the orientation of the Sb 2 Se 3 photoactive layer’s growth, which is crucial for performance optimization. In this study, the dual functionality of solution-processed SnO 2 film treated with CdCl 2 was achieved as the ETL in Sb 2 Se 3 solar cells. The CdCl 2 treatment simultaneously improves the efficacy of the SnO 2 ETL and induces the longitudinal growth of Sb 2 Se 3 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 CdCl 2 treatment optimizes the interface properties of the SnO 2 ETL, providing a facile and effective method for enhancing the performance of the Sb 2 Se 3 solar cell.