Interfacial engineering of oxygenated chemical bath–deposited CdS window layer for highly efficient Sb2Se3 thin-film solar cells

Abstract

Abstract Antimony chalcogenides with quasi-one-dimensional nanoribbon structures represent a new group of cost-effective, non-toxic, and earth-abundant materials for photovoltaics. In this work, interfacial engineering of oxygenated chemical bath–deposited (CBD) CdS buffer layers were used to tailor Sb2Se3 thin-film solar cells using close space sublimation (CSS) deposition process. Sb2Se3 solar cells with oxygenated CBD CdS have demonstrated a champion power conversion efficiency of 6.3% with graphite as back contact. Van der Waals (vdW) gap in Sb2Se3 is regulated via oxygen diffusion, which significantly influences the growth direction of (Sb4Se6)n quasi-one-dimensional nanoribbons. The improved interface quality and ribbon orientation, in turn, enhance the electrical and optical properties as well as device performance of the Sb2Se3 solar cells. The defect level and corresponding device performance associated with the oxygen environment were investigated by both theoretical and experimental approaches. This work provides an effective way to tune the microstructure and electronic structure of non-cubic chalcogenides by tailoring the interfacial area between the window layer and Sb2Se3 absorber.