Improved performances in Sb2Se3 solar cells based on CdS buffered TiO2 electron transport layer

Abstract The strong Ti-O bonds in TiO 2 and poor compatibility with 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% to 4.71%. This study supplied a route for the application of titanium dioxide as a broad band gap electron transfer material for Sb 2 Se 3 solar cells. Graphical Abstract In this work, we deposited a 120 nm CdS layer on TiO 2 ETL. The CdS layer improved the electronic properties of TiO 2 and optimized the grain orientation of Sb 2 Se 3 thin films. The Jsc and Voc of Sb 2 Se 3 solar cells were also improved, and the ultimate champion power conversion efficiency was enhanced from 2.60 to 4.71%. Our work provides an effective method to improve the photovoltaic performance of Sb 2 Se 3 solar cells.