Synergistic Surface Reconstruction to Suppresses Interfacial Losses in Inverted Perovskite Photovoltaics

ABSTRACT Inverted perovskite solar cells have become a leading photovoltaic architecture with considerable promise for scalable manufacturing, yet the resulting top surface often contains residual precursor species, heterogeneous defect terminations, and unfavorable energetics that intensify nonradiative recombination at the interface. Here, we introduce a surface reconstruction strategy based on piperazinium iodide (PipI) and piperazinium bromide (PipBr). The two salts share a bifunctional piperazinium scaffold while providing distinct I − and Br − counterions, enabling coordinated regulation of surface binding and the local halide environment. These structural and electronic changes decrease trap‐assisted nonradiative recombination and improve charge transfer across the perovskite/C 60 interface. Notably, the perovskite films are fabricated through an antisolvent‐free process, eliminating the additional antisolvent dripping step and thereby simplifying film processing and improving its compatibility with large‐area fabrication. The optimized inverted perovskite solar cell achieves a power conversion efficiency of 25.68% over an active area of 0.09 cm 2 , with an open‐circuit voltage of 1.154 V and a fill factor of 86.54%. The strategy is further transferred to a 4 cm 2 mini‐module, delivering an efficiency of 22.78%. These results provide an effective molecular design method for low‐loss and scalable electron‐selective interfaces in antisolvent‐free perovskite photovoltaics.