Abstract
Interface engineering is imperative to boost the extraction capability in perovskite solar cells (PSCs). We propose a promising approach to enhance the electron mobility and charge transfer ability of tin oxide (SnO2) electron transport layer (ETL) by introducing a two-dimensional carbide (MXene) with strong interface interaction. The MXene-modified SnO2 ETL also offers a preferable growth platform for perovskite films with reduced trap density. Through a spatially resolved imaging technique, profoundly reduced non-radiative recombination and charge transport losses in PSCs based on MXene-modified SnO2 are also observed. As a result, the PSC achieves an enhanced efficiency of 20.65% with ultralow saturated current density and negligible hysteresis. We provide an in-depth mechanistic understanding of MXene interface engineering, offering an alternative approach to obtain efficient PSCs.