Active Passivation of Anion Vacancies in Antimony Selenide Film for Efficient Solar Cells.

Binary antimony selenide (Sb 2 Se 3 ) is a promising inorganic light-harvesting material with high stability, non-toxicity and wide light harvesting capability. In this photovoltaic material, it has been recognized that deep energy level defects with large carrier capture cross section, such as V Se (selenium vacancy), lead to serious open-circuit voltage (V OC ) deficit and in turn limit the achievable power conversion efficiency (PCE) of Sb 2 Se 3 solar cells. Understanding the nature of deep-level defects and establishing effective method to eliminate the defects are vital to improving V OC . In this study, we propose a novel directed defect passivation strategy to suppress the formation of V Se and maintaining the composition and morphology of Sb 2 Se 3 film. In particularly, through systematic study on the evolution of defect properties, we reveal the pathway of defect passivation reaction. Owing to the inhibition of defect-assisted recombination, the V OC increases, resulting in an improvement of PCE from 7.69% to 8.90%, where is the highest efficiency of Sb 2 Se 3 solar cells prepared by thermal evaporation method with superstrate device configuration. This study proposes a new understanding of the nature of deep-level defects and enlightens the fabrication of high quality Sb 2 Se 3 thin film for solar cell applications. This article is protected by copyright. All rights reserved.