High‐Performance Carbon‐Based CsPbIBr2 Solar Cells by SnO2–MXene‐Regulating Perovskite Vertical Growth

Due to its unique photoelectric properties, MXene has a wide range of potential applications. Herein, different MXene contents (0, 0.10, 0.15, 0.20, 0.25, 0.4 wt%) of SnO 2 –MXene nanocomposites are used as the electron transport layer. The introduction of MXene not only inhibits SnO 2 agglomeration and induces the vertical growth of CsPbIBr 2 , but also passivates defects of the SnO 2 /CsPbIBr 2 interface. It effectively increases the power conversion efficiency from 8.98% to 11.21%. In addition, even after 1000 h of storage with a relative humidity of more than 50% in the ambient air, the unsealed device still maintains about 92% of its initial efficiency. This strategy provides a promising way to improve the efficiency of solar cells.