Highly improved photocurrent of a flexible MoS photodetector a backside Al metal mirror and its in- and outward folding states.

High-performance foldable and flexible photodetectors have been extensively studied for next-generation hinged electronics and AR/VR technology. The need to maintain efficiency in the folded state restricts the development of strategies aimed at further improving the efficiency of photodetectors. For the first time, we introduce a simple and effective method for the photocurrent improvement of a molybdenum disulfide (MoS) flexible photodetector by attaching a backside Al metal mirror and folding it in- and outward. Under light illumination, the Al film underneath the MoS photodetector acts as a flat reflective metal mirror and further functions as a concave mirror under the inward folded state. In this state, the proposed device with the backside Al metal mirror improved photocurrent from 4.04 μA to 8.53 μA under illumination (a of 405 nm with a of 0.3 mW cm) compared to the device on a flat polyimide (PI) substrate without the Al metal mirror. Our work provides new insights into high-performance flexible photodetectors in the inward and outward folded states, which will be beneficial for future foldable/hinged electronics and AR/VR devices.