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 MAPbI
₃
film can reduce the Schottky barrier between the lower electrode and perovskite, and the Au particles doping into the MAPbI
₃
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/cm
²
under 635 nm illumination, a decent responsivity of 10 mAW
^-1
, a high specific detectivity of 3.3 × 10
¹¹
cmHz
¹
/2W
^-1
, and an external quantum efficiency of 2.1% are obtained. The on/off ratio reaches 10
⁴
and the response speed is less than 50 ms. Our results pave a new design concept to form a self-powered perovskite-based photodetector.