Active Passivation of Anion Vacancies in Antimony Selenide Film for Efficient Solar Cells
Zhiyuan Cai, Bo Che, Yuehao Gu, Peng Xiao, Lihui Wu, Wenhao Liang, Changfei Zhu, Tao ChenAbstract
Binary antimony selenide (Sb2Se3) 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 VSe (selenium vacancy), lead to serious open‐circuit voltage (VOC) deficit and in turn limit the achievable power conversion efficiency (PCE) of Sb2Se3 solar cells. Understanding the nature of deep‐level defects and establishing effective method to eliminate the defects are vital to improving VOC. In this study, we propose a novel directed defect passivation strategy to suppress the formation of VSe and maintaining the composition and morphology of Sb2Se3 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 VOC increases, resulting in an improvement of PCE from 7.69% to 8.90%, where is the highest efficiency of Sb2Se3 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 Sb2Se3 thin film for solar cell applications.
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