Intrinsic and extrinsic stability factors in Sb2S3-x – based solar cells

The glass/FTO/TiO2/Sb2S3-x/P3HT/Au solar cells were investigated, with a focus on identifying the origin of performance degradation after exposure to high relative humidity and to mild heat stress. Analyzing the photovoltaic output and Deep-Level Transient Spectroscopy (DLTS) results, we probed the evolution of defect states after thermal exposure and after long-term storage of Sb2S3-x-based devices. The DLTS analysis revealed that shallow hole traps govern the stability of the Sb2S3-x cells. Significantly, it was shown that this shallow defect is not related to chlorine in the absorber, indicating an intrinsic origin. In the broader context of Sb2S3-x photovoltaics, this study underlines the paramount importance of defect engineering towards achieving more stable and efficient Sb2S3-x solar cells.