Mechanical stability in flexible perovskite solar cells: Interface engineering and device design

Abstract Flexible perovskite solar cells (f‐PSCs) demonstrate significant potential for application in next‐generation wearable electronic devices and photovoltaic building integration due to their high power conversion efficiency and excellent power‐to‐weight ratio. However, the inherent brittleness of perovskite materials and the interlayer delamination caused by mechanical property mismatch in multilayer heterostructures severely limit their long‐term stability under bending deformation, becoming a key bottleneck hindering their commercialization. In this review, we analyze the physical mechanisms leading to mechanical failure of f‐PSCs, including the intrinsic brittleness of the materials and the stress concentration problem in the multilayer stacked structure. Then, we present the latest research advancements in interface engineering and device design. The focus is on discussing the regulation of perovskite crystallization kinetics, the introduction of self‐healing polymer networks, the toughening modification of charge transport layers, as well as the development strategies for new flexible substrates and electrodes. Finally, we summarize the current technical challenges and look forward to the future development directions of f‐PSCs in the process of moving toward large‐scale manufacturing and practical applications, aiming to provide scientific references for the construction of efficient and mechanically stable flexible photovoltaic devices.