Asymmetric au electrodes-induced self-powered organic-inorganic perovskite photodetectors

In general, self-powered photodetectors are tedious and costly. Here, high-performance self-powered visible photodetectors based on MAPbI3 films were fabricated by using asymmetric Au electrodes. For this construction of photodetector, the illumination passing through the translucent MAPbI3 film can reduce the Schottky barrier between the lower electrode and perovskite, and the Au particles doping into the MAPbI3 at the contact areas between the upper electrode and films can also change the Schottky barrier, which leads to the formation of built-in potential. Without an applied bias, the photodetectors exhibit an ultralow dark current of ∼ 3 pA. At the power intensity of 2.92 mW/cm2 under 635 nm illumination, a decent responsivity of 10 mAW-1, a high specific detectivity of 3.3 × 1011 cmHz1/2W-1, and an external quantum efficiency of 2.1% are obtained. The on/off ratio reaches 104 and the response speed is less than 50 ms. Our results pave a new design concept to form a self-powered perovskite-based photodetector.