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 SnOx interlayer via atomic layer deposition (ALD). Due to the passivation effect of the ALD SnOx 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 SnOx interlayer, reducing the statistical variation in the photovoltaic parameters of the co-evaporated Sb2Se3 solar cells. The ultrathin ALD SnOx 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.