Fully Inorganic CsSnI<sub>3</sub> Mesoporous Perovskite Solar Cells with High Efficiency and Stability via Coadditive Engineering
Huaxia Ban, Tao Zhang, Xiu Gong, Qiang Sun, Xiaoli Zhang, Nuttapol Pootrakulchote, Yan Shen, Mingkui Wang
Abstract
The small optical bandgap of a CsSnI 3 ‐based inorganic perovskite film makes it a hopeful candidate as an absorber layer in solar cell applications. Herein, a coadditive 2‐aminopyrazine (APZ) in the precursor solution to form SnF 2 −APZ complex with the aim to restrain Sn 2+ oxidation and thus improve the CsSnI 3 ‐based device performance is proposed. It is found that the amino group of APZ significantly suppresses oxidation of Sn 2+ through a Lewis acid–base addition reaction. Consequently, the CsSnI 3 ‐based mesoporous perovskite solar cells that use a printable c‐TiO 2 /m‐TiO 2 /Al 2 O 3 /NiO/carbon framework with high reproducibility achieve a power conversion efficiency of 5.12%. This is a champion efficiency for fully inorganic CsSnI 3 ‐based mesoporous devices reported up to now. Furthermore, after 60 days of storage in a N 2 ‐filled glovebox, the device still maintains an initial efficiency of 92%.