In Situ Dual‐Region Selective Anchoring of Zwitterionic Gel Enables Efficient and Mechanically Durable Flexible Perovskite Solar Cell

ABSTRACT Flexible perovskite solar cells (f‐PSCs) are promising for wearable electronics, vehicles, and IoT devices, yet their mechanical reliability under diverse application scenarios remains poorly understood. However, real‐world applications expose f‐PSCs to diverse stress modes—dynamic bending, large‐ and small‐curvature static deformation—causing stress accumulation at different microstructural sites. Yet, unified strategies to address these scenario‐specific failures remain rare. In this work, we develop an in situ dual‐region anchoring strategy using the zwitterionic gel monomer 3‐(1‐vinyl‐3‐imidazolio) propanesulfonate (VIPS) to address this challenge. Benefiting from strong coordination between its sulfonate group and Pb 2 ⁺, as well as π ‐conjugation with self‐assembled monolayers, VIPS is selectively localized at both perovskite grain boundaries and buried interfaces. Upon in situ polymerization, it forms a flexible network that simultaneously relieves internal lattice strain and interfacial stress. This targeted distribution ensures that regardless of stress concentration zones in different deformation modes, mechanical reinforcement is effectively delivered. VIPS‐modified devices achieve competitive efficiencies of 25.45% at 0.11 cm 2 , 22.47% at 20.21 cm 2 (certified 21.45%), and 17.75% at 749 cm 2 . Under indoor lighting conditions, VIPS‐modified flexible devices deliver efficiencies exceeding 40%. Excellent mechanical and environmental stability further validate the strategy. This scalable strategy bridges the gap between flexible perovskite research and scenario‐aware device design.