High‐Performance Flexible Self‐Powered Photodetector Based on Perovskite and Low‐Temperature Processed In2S3 Nanoflake Film

Flexible and self‐powered perovskite photodetectors have attracted great attention due to their potential applications in the field of portable devices, sensing, and communication. Considering the physical principle of self‐power and poor resistance to high temperature of flexible polymer substrates, it is challenging to develop low‐temperature processed inorganic materials as carrier transfer layers to integrate with perovskite. Herein, a flexible self‐powered perovskite photodetector on tin‐doped indium oxide/polyethylene naphthalate substrate based on indium sulfide (In2S3) nanoflake film grown at a low temperature below 373 K is demonstrated. The device shows a detectivity up to 1.1 × 1011 Jones at +0.5 V and response time less than 200 ms. A responsivity of 451 mA W−1 at 720 nm is also achieved, which is close to the performance of device on rigid fluorine‐doped tin oxide substrate. The device exhibits outstanding stability without obvious performance degradation after 500 cycles of bending or under a 0.0025 m bending radius. Interestingly, the device can work in the outdoor to track the sunlight change for 1 day. This result opens a door to explore the integration of inorganic semiconductors with perovskite toward flexible self‐powered photodetectors built on polymer substrates.