A Multisite Molecular Salt Enables Surface Passivation and Energetics Management for Efficient Inverted Perovskite Solar Cells

Surface defect chemistry and interfacial energetics remain the primary bottlenecks limiting both voltage output and operational durability in inverted perovskite solar cells. Here we develop a broadly applicable post‐deposition surface modification that installs an ultrathin multifunctional molecular layer of 1‐(4’‐sulfophenyl)‐3‐carboxyl‐5‐pyrazolone sodium salt (SCP) at the perovskite electron‐contact interface. The sulfonate/carboxylate and pyrazolone O/N motifs cooperatively coordinate undercoordinated Pb 2+ , and the Na + provides additional ionic compensation, contributing to reduced trap‐assisted recombination and suppressed interfacial ionic activity. Meanwhile, SCP reconstructs the near‐surface electronic structure and band bending, enabling improved energy‐level alignment and faster electron extraction. Consequently, the modified devices deliver a champion efficiency of 27.25%. Notably, a third‐party certified steady‐state PCE (IEC 60904‐1:2020, AM1.5G, 25°C) achieved a mean value of 26.84% after 300s aging. The devices further retain 90% of their initial performance after 1485 h of maximum‐power‐point tracking. This work highlights a general surface‐energetics engineering paradigm that couples chemical passivation with interfacial electronic reconstruction, offering a scalable route toward high‐performance, durable perovskite photovoltaics.