Asymmetric Contact‐Induced Self‐Driven Perovskite‐Microwire‐Array Photodetectors

Abstract Combining both 1D geometry and the features of hybrid perovskite materials, perovskite micro/nanowires have recently attracted particular attention for a variety of optoelectronic device applications. Herein, by taking advantage of the strong built‐in potential induced by asymmetric contact with varied work functions, highly sensitive visible photodetectors based on a CH 3 NH 3 PbI 3 microwire array that display pronounced photovoltaic activities are reported. These photodetectors afford the capability to work without an external power supply. A representative detector with Au/Ag electrodes achieves a reasonable responsivity of 161.1 mA W −1 with a fast response speed of 13.8/16.1 µs under 520 nm illumination at zero bias. In addition, such a device is also characterized by an ultralow dark current of tens of femtoamps, enabling a high specific detectivity of 1.3 × 10 12 Jones. Furthermore, a flexible photodetector is successfully prepared, which shows comparable photoresponse performance and outstanding flexibility and bending durability. Given the good device performance and simple device geometry, the present self‐driven photodetectors hold great promise for future highly sensitive and low‐energy‐consumption photodetection systems.