Self-Powered MoS₂–PDPP3T Heterotransistor-Based Broadband Photodetectors

Photodetectors based on monolayer molybdenum disulfide (MoS₂) have been demonstrated to exhibit good photodetecting capabilities. However, the relatively large bandgap of monolayer MoS₂ has inhibited its application in near-infrared (NIR) photodetectors. Here, the narrow-bandgap organic semiconductor poly(diketopyrrolopyrrole-terthiophene) (PDPP3T) is firstly introduced to the monolayer MoS₂ transistor as a NIR light absorbing layer. The MoS₂–PDPP3T heterojunction-based transistor (heterotransistor) shows a broadband photodetecting range from ultraviolet (UV) to NIR region. About one or two orders of magnitude improvement of photoresponsivities have been realized for the MoS₂–PDPP3T heterotransistor compared with that of MoS₂ transistor. Moreover, due to the formation of MoS₂–PDPP3T heterojunction and asymmetric electrodes, the MoS₂–PDPP3T heterotransistor shows the self-powered behavior under zero bias voltage. Flexible MoS₂–PDPP3T heterostructure photodetector is also fabricated on the poly(ethylene terephthalate) substrate with reliable performance, which enables a promising photodetection platform for future wearable optoelectronics.