Interfacial engineering by applying double CdS structure electron transport layer for high-performance Sb2(S,Se)3 solar cells

Antimony sulfoselenide (Sb2(S,Se)3) has been demonstrated as a promising photoabsorber for stable inorganic thin film photovoltaics with high performance. Optimizing interfacial contact and reduce the defects are essential in restraining the recombination of photo-induced carrier at heterojunction interface. In particular, the electron transport layer (ETL) directly affects the quality of Sb2(S,Se)3 absorber layer as well as the performance of the device. Herein, an available and highly effective double CdS ETL is proposed to modify the heterojunction interface contact which moreover enhance the efficiency of Sb2(S,Se)3 solar cells. The optimal matching of the two CdS ETLs were fully investigated, and by following this process, the ETL with high crystallinity and density is obtained, rendering high-quality Sb2(S,Se)3 thin films as well. Besides, the final devices exhibit lower series resistance and larger Jsc, FF, enabling improvement of the efficiency from 3.09% to 6.94%. This study provides an effective method for the surface engineering of CdS ETLs to achieve high-performance Sb2(S,Se)3 solar cells.