Inorganic CsSnI<sub>3</sub> Perovskite Solar Cells with an Efficiency above 13.6%
Haixuan Yu, Zhiguo Zhang, Hongliang Dong, Xiongjie Li, Zhirong Liu, Junyi Huang, Yongqing Fu, Yan Shen, Mingkui Wang
Abstract
Due to the high Lewis acidity of Sn 2+, it is a major challenge to prepare high-quality CsSnI 3 films. To solve this critical problem, here we propose a pseudohalide anion alloying process to regulate the crystallization of inorganic CsSnI 3 perovskite and achieve large grain sizes in the micron range. The introduction of a pseudohalide anion changes the phase transition pathways through the formation of intermediates, thereby slowing the rate of CsSnI 3 crystallization. The substitutional alloying of HCOO – in the CsSnI 3 crystal lattice further improves the oxidation resistance of Sn 2+ due to the strong bonding between the HCOO – anions and Sn 2+ cations. The fabricated CsSnI 3 -based planar perovskite solar cell with an inverted configuration and active area of 4.05 mm 2 exhibits certified power conversion efficiency of 13.68% at AM 1.5 solar irradiation (100 mW cm –2 ), which is among the best reported for CsSnI 3 -based inorganic perovskite cells.