Metalized Porphyrin‐Based COFs for Conductive Porous Layers in Perovskite Solar Cells to Enhance Electron Injection, Defect Passivation and Lead‐Protection

In perovskite solar cells (PSCs), the introduction of an intermediate layer to bridge the transport and photoactive layers has become a key strategy for enhancing carrier extraction efficiency. However, traditional approaches are often limited by the seesaw effect, making it challenging to achieve an optimal balance between electron transport and defect passivation. In this study, we employed a Cu2+‐loaded metalized porphyrin‐based covalent organic framework (Cu‐Por‐COF) as a conductive porous layer (CPL) at the perovskite bottom interface. Experimental results showed that a Cu‐Por‐COF coverage of 19% significantly enhanced electron transport and effectively suppressed long‐distance electron diffusion. Moreover, the carefully designed Cu‐Por‐COF provided abundant active sites, which improved the film‐forming quality of the perovskite layer, thereby facilitating the beneficial synergy of electron injection and defect passivation. The n‐i‐p type devices achieved a power conversion efficiency (PCE) of 25.41% (0.09 cm2) and 21.99% (1.01 cm2). Using Cu‐Por‐COF to stabilize the perovskite crystal structure, the unencapsulated devices retained over 83% of its initial efficiency after 2000 hours. Additionally, Cu‐Por‐COF effectively chelated lead ions and thus enhanced the environmental sustainability of PSCs.