Effect of ZnO surface defects on efficiency and stability of ZnO-based perovskite solar cells

Abstract

ZnO as an alternative electron transport layer (ETL) material for perovskite solar cell applications has drawn increasing research interest due to its comparable energy levels to TiO2, relatively high electron mobility, as well as its feasibility to be processed at low temperatures for potential applications in flexible devices. Nevertheless, ZnO based perovskite devices usually exhibit inferior performance and severe stability drawbacks which are related to the surface defects of ZnO ETL. In this study, to investigate the correlation between ZnO defect composition and resulting device performance, different approaches of preparing ZnO ETL are compared in terms of the perovskite morphology and device performance. In addition, direct manipulations of ZnO surface defects are performed by various surface treatments, and the photovoltaic performance of devices with ZnO ETL subjected to different surface treatments is compared. Surface modification of ZnO ETL by ethanolamine (EA) is demonstrated to efficiently enhance the photovoltaic performance of resulting ZnO based devices. © (2017) COPYRIGHT Society