Abstract

Intrinsically stretchable perovskite solar cells (IS-PSCs) are promising autonomous power sources for wearable electronics and aerospace platforms; however, their practical implementation is hindered by rapid performance degradation under mechanical strain. This failure stems largely from a pronounced Young’s modulus (E) mismatch across multilayer stacks, which intensifies stress localization and triggers catastrophic, electrically disruptive cracking. Here, we report an E-gradient shear-lag design that stabilizes IS-PSCs by strategically converging the E values of both the substrate and perovskite layer toward the intermediate E of the PH1000/NiOx electrode region (4.70 GPa). This is achieved by stiffening the thermoplastic polyurethane (TPU) substrate through increased hard-segment fraction, increasing E from 199 to 1560 MPa, while softening the perovskite film via TPU additive engineering, reducing E from 19.2 to 8.39 GPa. This mechanically graded architecture suppresses strain localization and redistributes tensile stress, thereby preserving the continuity of carrier transport even under significant deformation. Consequently, the optimized IS-PSC achieves a power conversion efficiency of 22.14% (certified: 21.52%) and retains 80% of its initial performance at 60% tensile strain, demonstrating the efficacy of E-gradient engineering in overcoming the inherent brittleness of perovskite photovoltaics.