Self‐Healing Perovskite Grain Boundaries in Efficient and Stable Solar Cells via Incorporation of 502 Adhesive

Additive engineering has become an effective method to passivate the grain boundary defects of perovskite films for enhanced photovoltaic performance. Herein, inspired by daily life, a 502 adhesive is directly introduced into perovskite films to improve the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs), where the perovskite grain boundaries are self‐healed through spontaneous polymerization of the 502 adhesive by tracing water molecules in the air at room temperature. The C=O and –CN groups in 502 adhesive molecules provide double bonding points to chemically anchor with perovskite gain boundaries, which effectively block the invaded channels of moisture and oxygen into the perovskite film. Meanwhile, the –CN groups can combine with the deficient coordination of Pb 2+ to passivate the deep defects. The optimized PSCs via incorporation of 502 adhesive into perovskite film achieve PCE of 20.12% and remarkable long‐term and moisture stability compared to the control device with PCE of 17.30%.