Photostability of MAPbI₃ Perovskite Solar Cells by Incorporating Black Phosphorus

Photostability is one of the most vital challenges for organic–inorganic hybrid perovskite solar cells (PSCs). With the incorporation of black phosphorus (BP), well known for self‐healing and its superior property to regulate charge recombination, into CH 3 NH 3 PbI 3 perovskites (MAPbI 3 /BP), the associated PSCs exhibit significant enhancement in photostability in addition to the photovoltaic (PV) performance. The MAPbI 3 /BP‐based PSCs retain ≈94% of initial efficiency after 1000 h continuous white light LED illumination in a dry N 2 glovebox whereas their counterparts without the incorporation of BP decrease to ≈30%. Although BP has very small influence on the morphology and structure of the perovskite crystals, Pb 0 defects are effectively inhibited and hot carrier recombination is found to be retarded as confirmed by femtosecond optical spectroscopy. The utilization of the material to simultaneously inhibit Pb 0 defect formation and retard charge recombination, such as BP, is a promising strategy to enhance the photostability of organic–inorganic hybrid perovskite‐based PSCs and their siblings.