V2CTx MXene-modified perovskite /SnO2 interface for efficient and stable perovskite solar cells

Perovskite solar cells (PSCs) suffer from a high density of defects at the buried bottom interface, which negatively impacts the efficiency in the PSCs and interface recombination. This is primarily due to carrier recombination losses occurring at the perovskite/SnO 2 . In this study, a two-dimensional lamellar V 2 CT x MXene materials, synthesized by hydrofluoric acid (HF) etching, was incorporated at the buried interface between the SnO 2 electron transport layer and the perovskite layer. The introduction of a V 2 CT x MXene modified layer at the perovskite/SnO 2 buried interface simultaneously modulates the crystallization and defect passivation within the perovskite material, leading to enhanced grain size and crystallinity. Consequently, highly efficient and stable PSCs were achieved. The presence of terminal group T x (OH − , F − ) in V 2 CT x facilitates the transfer of electrons to the 6p vacant orbitals of Pb 2+ ions, promoting the formation of Pb-F complexes. These complexes effectively suppress uncoordinated Pb ions at the perovskite interfaces, thereby significantly reducing defect density. As a result, the V 2 CT x -modified PSCs achieve an average power conversion efficiency (PCE) of 14.6 %, a notable improvement over the 12.8 % of the control devices, while also enhancing operational stability. This research provides a convenient and effective approach for enhancing crystallization and passivation defects in perovskite films, thereby improving device efficiency and stability.