Asymmetric Au Electrodes-Induced Self-Powered Organic–Inorganic Perovskite Photodetectors

Abstract

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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film can reduce the Schottky barrier between the lower electrode and perovskite, and the Au particles doping into the MAPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> under 635 nm illumination, a decent responsivity of 10 mAW <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , a high specific detectivity of 3.3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cmHz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> /2W <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and an external quantum efficiency of 2.1% are obtained. The on/off ratio reaches 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> and the response speed is less than 50 ms. Our results pave a new design concept to form a self-powered perovskite-based photodetector.