Dynamic Molecular Scaffold Enables Thermomechanical Stress Regulation and Adaptive Defect Healing for Stable Perovskite Solar Cells

Thermally induced stress accumulation is a major origin of lattice disorder, defect evolution, and ion migration in perovskite solar cells (PSCs), limiting their long-term operational stability. We develop a dynamic molecular scaffold strategy based on the adduct of α-lipoic acid and N-hydroxysuccinimide ester to mitigate thermomechanical degradation through simultaneous thermomechanical stress buffering, lattice anchoring, and adaptive defect healing. During film formation, DL-α-lipoic acid-N-hydroxysuccinimide ester (LA-NHS) undergoes in situ polymerization to establish a crosslinked polydisulfide scaffold at grain boundaries. The dynamic scaffold accommodates thermally induced lattice expansion and contraction, dissipates accumulated stress, anchors the perovskite lattice, and continuously passivates stress-generated defects through reversible disulfide-bond exchange, thereby preserving lattice ordering and improving the thermal durability. Consequently, the optimized PSCs achieve a champion power conversion efficiency (PCE) of 27.19%. The devices retain 91.71% of their initial efficiency after 150 thermal cycles between 15°C and 100°C, and 85.72% after 1500 h at 85°C. The strategy is successfully translated to large-area PSCs (25.02% for 1 cm² and 22.06% for 10 × 10 cm²). This work establishes a dynamic molecularscaffold framework for managing thermomechanical degradation through stress buffering, lattice anchoring, and adaptive defect healing, providing a route toward efficient, durable, and scalable perovskite photovoltaics.