Ultrahigh‐Performance Self‐Powered Flexible Double‐Twisted Fibrous Broadband Perovskite Photodetector

Self‐powered flexible photodetectors without an external power source can meet the demands of next‐generation portable and wearable nanodevices; however, the performance is far from satisfactory becuase of the limited match of flexible substrates and light‐sensitive materials with proper energy levels. Herein, a novel self‐powered flexible fiber‐shaped photodetector based on double‐twisted perovskite–TiO₂–carbon fiber and CuO–Cu₂O–Cu wire is designed and fabricated. The device shows an ultrahigh detectivity of 2.15 × 10¹³ Jones under the illumination of 800 nm light at zero bias. CuO–Cu₂O electron block bilayer extends response range of perovskite from 850 to 1050 nm and suppresses dark current down to 10^?11 A. The fast response speed of less than 200 ms is nearly invariable after dozens of cycles of bending at the extremely 90 bending angle, demonstrating excellent flexibility and bending stability. These parameters are comparable and even better than reported flexible and even rigid photodetectors. The present results suggest a promising strategy to design photodetectors with integrated function of self‐power, flexibility, and broadband response.