Interface engineering of co-evaporated Sb2Se3 solar cells using an ALD SnOx interlayer

Abstract

To compensate for the limited efficiency of co-evaporated Sb₂Se₃ solar cells, effective physical and chemical passivation of the interface between the Sb₂Se₃ absorber and the CdS buffer layer was achieved through the deposition of an ultrathin SnO_x interlayer via atomic layer deposition (ALD). Due to the passivation effect of the ALD SnO_x interlayer, carrier recombination at both the intra-grain and grain-boundary regions was suppressed, and Sb interdiffusion from the Sb₂Se₃ absorber to the cadmium sulfide (CdS) buffer was effectively blocked. Additionally, the rough surface of the co-evaporated Sb₂Se₃ absorber was mitigated by the conformal deposition of the ALD SnO_x interlayer, reducing the statistical variation in the photovoltaic parameters of the co-evaporated Sb₂Se₃ solar cells. The ultrathin ALD SnO_x interlayer was demonstrated to be a practical strategy for enhancing Sb₂Se₃ solar cell performance regardless of the absorber's morphology, achieving a substrate-type Sb₂Se₃ solar cell with an efficiency of 7.395% through the co-evaporation process.