Achievable efficiency improvement of Sb2Se3 thin-film solar cells through interface engineering

Antimony selenide (Sb₂Se₃) is a promising light-absorbing material for the thin-film solar cells (TFSCs). However, the low efficiency output of the Sb₂Se₃-based TFSC is still one of the largest obstacles to restrain its development. In this work, tin oxide (SnO₂) nanoparticle film is used as the electron transport layer (ETL) for the Sb₂Se₃-based TFSC. To further enhance the device performance, spin coated CdCl₂ films are employed to modify the SnO₂ ETL. As a result, preferable orientation with an increased intensity of (2 2 1) peak and a reduced intensity of (1 2 0) peak in the XRD patterns are observed for the Sb₂Se₃ film, which enhances the carrier transport within the Sb₂Se₃ absorber. Meanwhile, the CdCl₂ suppresses the carrier recombination at the interface between the Sb₂Se₃ and SnO₂. Therefore, the optimized device shows an improved power conversion efficiency from 2.02% to 4.03%, and also exhibits a strong stability in ambient air.