Low‐Dimensional Inorganic Tin Perovskite Solar Cells Prepared by Templated Growth

The manipulation of the dimensionality and nanostructures based on the precise control of the crystal growth kinetics boosts the flourishing development of perovskite optoelectronic materials and devices. Herein, a low‐dimensional inorganic tin halide perovskite, CsSnBrI 2− x (SCN) x , with a mixed 2D and 3D structure is fabricated. A kinetic study indicates that Sn(SCN) 2 and phenylethylamine hydroiodate can form a 2D perovskite structure that acts as a template for the growth of the 3D perovskite CsSnBrI 2− x (SCN) x . The film shows an out‐of‐plane orientation and a large grain size, giving rise to reduced defect density, superior thermostability, and oxidation resistance. A solar cell based on this low‐dimensional film reaches a power conversion efficiency of 5.01 %, which is the highest value for CsSnBr x I 3− x perovskite solar cells. Furthermore, the device shows enhanced stability in ambient air.