Thermally Crosslinked F‐rich Polymer to Inhibit Lead Leakage for Sustainable Perovskite Solar Cells and Modules

High‐performance perovskite solar cells have demonstrated commercial viability, but still face the risk of contamination from lead leakage and long‐term stability problems caused by defects. Here, an organic small molecule (octafluoro‐1,6‐hexanediol diacrylate) is introduced into the perovskite film to form a polymer through in situ thermal crosslinking, of which the carbonyl group anchors the uncoordinated Pb2+ of perovskite and reduces the leakage of lead, along with the −CF2− hydrophobic group protecting the Pb2+ from water invasion. Additionally, the polymer passivates varieties of Pb‐related and I‐related defects through coordination and hydrogen bonding interactions, regulating the crystallization of perovskite film with reduced trap density, releasing lattice strain, and promoting carrier transport and extraction. The optimal efficiencies of polymer‐incorporated devices are 24.76 % (0.09 cm2) and 20.66 % (14 cm2). More importantly, the storage stability, thermal stability, and operational stability have been significantly improved. An organic small‐molecule octafluoro‐1,6‐hexanediol diacrylate (OF‐HDDA) is introduced to in situ crosslink forming a polymer (POF‐HDDA), which anchors uncoordinated lead ions and prevents lead leakage from water and oxygen invasion, and concurrently improves the long‐term stability of the corresponding devices.