An MBene Modulating the Buried SnO₂/Perovskite Interface in Perovskite Solar Cells

The interface of perovskite solar cells (PSCs) plays an important role in transferring and collecting charges. Interface defects are important factors affecting the efficiency and stability of PSCs. Here, the buried interface between SnO₂ and the perovskite layer is bridged by two-dimensional (2D) MBene, which improves charge transfer. MBene can deposit additional electrons on the surface of SnO₂, passivate its surface defects and facilitate the charge collection. Moreover, the dipole moment formed at the interface increases the electron transfer ability in the PSCs. MBene also regulates the growth of perovskite crystals, improves the quality of perovskite films, and reduces its grain boundary defects. As a result, PSCs based on FA_0.2MA_0.8PbI₃ and (FAPbI₃)_0.95(MAPbBr₃)_0.05 get the enhanced efficiencies of 22.34 % and 24.32 % with negligible hysteresis. Furthermore, the optimized device exhibits better stability. This work opens up the application of MBene materials in PSCs, reveals a deeper understanding of the mechanism behind using 2D materials as an interface modification layer, and shows opportunities for using MBene as potential material in photoelectric devices.