Efficient CdS buffered TiO2 electronic transport layer for Sb2S3 solar cells by a facile spinning coating process

TiO 2 is commonly used as electron transport layers (ETL) for Sb 2 S 3 solar cells. Since its poor compatibility, CdS is usually adopted as buffer layer to enhance the performance. Herein, we prepared TiO 2 ETL with a commonly spin-coating method first, and then we deposited CdS on the TiO 2 ETL with a facile spin coating method to construct TiO 2 /CdS double ETL. The spin coating processed CdS is found to exhibit flake morphology, which improved the electronic properties of TiO 2 and the grain morphology of Sb 2 S 3 films. The CdS buffer layers by spin coating process were found to afford a unique pathway for electron transport thus enhancing electron extraction. As a result, large Jsc was obtained in the Sb 2 S 3 solar cells on the CdS buffered ETL. A champion PCE of 5.59% was obtained. This work develops a facile and relatively environmentally friendly method to fabricate effective TiO 2 /CdS ETL.