Wrinkling of Quasi‐2D Perovskite for High‐Performance and Flexible Photodetectors

Abstract Flexible photodetectors have garnered significant attention in recent years due to their potential applications in emerging fields such as artificial intelligence, medical diagnostics, and wearable devices. Quasi‐2D perovskites exhibit remarkable optoelectronic properties, excellent environmental stability, and mechanical flexibility, making them promising materials for flexible photodetectors. Achieving precise control over the morphology of these materials is crucial for enhancing device performance. In this study, periodic wrinkle structures are introduced into quasi‐2D perovskite films by applying pre‐stretching stress to a flexible substrate. These results indicate that these ordered wrinkle structures facilitate grain movement during formation, enabling smaller grains to fill pores and surround larger grains. This process leads to a denser film with a mixed 2D‐3D phase architecture, enhancing charge transfer efficiency and prolonging carrier lifetime in the perovskite films. Consequently, the responsivity of the resulting flexible perovskite photodetector significantly increased, reaching 86.7 A W −1 , which is 2.5 times higher than that of the unstretched device. Furthermore, the wrinkled structures enhanced mechanical tolerance, allowing the photodetector to retain 80% of its initial responsivity even after 10 000 stretching cycles. These findings highlight the potential of wrinkled structures to significantly enhance the performance of flexible perovskite optoelectronic devices.