Dual-site passivation of tin-related defects enabling efficient lead-free tin perovskite solar cells. (1st December 2022)

• Record Type: Journal Article
• Authors: Jiang, Yiting; Lu, Zhengli; Zou, Shengli; Lai, Huagui; Zhang, Zhihao; Luo, Jincheng; Huang, Yuanfang; He, Rui; Jin, Jialun; Yi, Zongjin; Luo, Yi; Wang, Wenwu; Wang, Changlei; Hao, Xia; Chen, Cong; Wang, Xin; Wang, Ye; Ren, Shengqiang; Shi, Tingting; Fu, Fan; Zhao, Dewei
• Is Part Of: Nano energy. Volume 103(2022)Part A
• Publication Date: 2022-12-01
• Subjects: Perovskite solar cell -- Sn-based perovskite -- Defect passivation -- EDABr2 -- Stability; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2022.107818
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Tin (Sn) perovskites as photovoltaic materials show great promise due to their suitable bandgaps and lower toxicity. However, various defects in Sn perovskites induce significant losses in devices. In this work, we report a strategy of dual-site passivation of Sn-related defects in lead-free Sn perovskite solar cells. We adopt ethylenediammonium halide salts (i.e., EDAI2 and EDABr2 ) as additives in Sn perovskite and find that both EDAI2 and EDABr2 can suppress Sn oxidation and passivate trap states, however, EDABr2 works better than EDAI2 in terms of passivating undesired grain boundaries and surface Sn vacancies, and reducing background hole density, due to the synergistic roles of EDA 2+ cation and Br - anion. Moreover, EDABr2 exhibits more consummate passivation effect on SnI antisite defects as deep-level traps due to its larger electrostatic potential and shorter bonding length between -Br and -Sn. These enable great suppression of non-radiative recombination and enhancement of charge carrier transport. As a result, the best-performing EDABr2 -modified device achieves a power conversion efficiency of 14.23% with long-term durability of keeping ∼93% of its initial efficiency after storing for ∼4000 h and improved operational stability. Our work provides a promising approach to choose satisfactory passivators and fabricate efficient Sn perovskite solar cells. Graphical Abstract: Incorporation of EDABr2 additive in FASnI3 perovskite solar cells enables effective prevention of Sn 2+ oxidation and passivation of undesired grain boundaries caused by EDA 2+ cation, leading to remarkably suppressed non-radiative recombination and enhanced carrier transport capability. The best-performing EDABr2 -modified device achieves an improved PCE of 14.23%. ga1 Highlights: EDABr2 effectively prevents Sn 2+ oxidation, leading to reduction of Sn vacancies at surface and in bulk perovskite. EDABr2 exhibits more consummate passivation effect than EDAI2 on SnI antisite defects as deep-level traps. The champion EDABr2 -modified PSC achieves a greatly enhanced PCE of 14.23% and improved stability.