Conjugated Amine Ligand‐Induced Robust‐Conductive Interlayer Enables Efficient and Durable n‐i‐p Perovskite Solar Cells

ABSTRACT Low‐dimensional/three‐dimensional (LD/3D) perovskite heterojunctions have demonstrated exceptional promise in photovoltaics, yet their performance remains constrained by the inherent compromise between interfacial defect passivation and charge extraction efficiency. To address this challenge, we prompt the exploration of ammonium ligands with moderate reactivity to facilitate heterojunction charge transport while suppressing cation migration, thereby reconciling high efficiency with outstanding operational stability. Specially, we designed a π ‐conjugated quaternary ammonium ligand PCOZI (4‐phenyl‐1,3‐oxazol‐2‐yl‐heptyl‐dimethylammonium iodide) as a surface modifier for 3D perovskite films, leading to the formation of a stable 1D (PCOZ)PbI 3 protecting layer. The resulting near‐conformal and structurally ordered interface effectively balances defect passivation with unimpeded charge transfer, significantly mitigating non‐radiative recombination and ion redistribution under operational stressors. Remarkably, the optimized devices incorporating the PCOZI interlayer yield a record‐breaking power conversion efficiency (PCE) of 26.33%, certified at 26.29%, setting a new benchmark for 1D/3D n‐i‐p PSCs, while the device also exhibits outstanding operational stability, retaining 94.2% of its initial efficiency after 1000 h of continuous operation under the ISOS‐L‐3 protocol. Notably, a minimodule with an aperture area of 10.24 cm 2 also achieves a remarkable PCE of 23.15%, underscoring the scalability and practical relevance of this interfacial stabilization approach.