Substantially improved performance in Sb 2 Se 3 solar cells on CdS buffered TiO 2 electron transport layer

The strong Ti-O bonds in TiO 2 and poor compatibility to Sb 2 Se 3 result in poor performance when used as electron transport layers (ETL) for Sb 2 Se 3 solar cells. Therefore, cadmium sulfide is usually used as a buffer layer to improve its compatibility. In the present work, we deposited a layer of CdS by spin coating method on TiO 2 ETL and fabricated TiO 2 /CdS dual ETL. The CdS layer improved the electronic properties of TiO 2 and grain orientation of Sb 2 Se 3 thin films. As a result, the average short circuit current and fill factor of Sb 2 Se 3 solar cells were improved, and the final champion power conversion efficiency was enhanced from 2.6–4.71%. This study supplied a route for the application of titanium dioxide as a broadband gap electron transfer material in Sb 2 Se 3 solar cells.