Enhanced Charge Transport by Regulating the Electronic Structure in 2D Tin-Based Perovskite Solar Cells

Tin-based perovskite has been widely studied due to its green, nontoxic, and excellent photoelectric physical properties. However, the high sensitivity of Sn2+ cations against moisture and oxygen was a huge challenge for preparing stable solar cells. In this study, 4-(aminomethyl) pyridine (4AP) cation is introduced to construct two-dimensional (2D) and Dion–Jacobson (DJ) perovskite 4APSnX4 (X = Cl, Br, I). First, through halogen component regulation, the charge transfer efficiency is improved. Then, it is found that increasing the temperature could build the charge transfer channel through an organic component and further improve the charge transfer efficiency. Finally, we prepared stable quasi-2D tin-based perovskite solar cells with the champion efficiency of 5.03%. We tracked the performance of unencapsulated devices over 200 h in an ambient environment (R.H. = 30%, T = 25 °C) and found no appreciable decay in efficiency. This study provides a new strategy for solving the transmission and stability problem of 2D tin perovskite.