Synergistic Piezophototronic and Bandgap Engineering in a Flexible MoTe 2 /In 2 Se 3 Heterojunction Photodetector

Two‐dimensional materials provide a versatile platform for flexible optoelectronics. However, previous strain‐engineered flexible photodetectors have generally exhibited a narrow spectral range, with most studies focusing solely on the visible range and lacking broadband response capability. Here, we present a flexible photodetector based on the MoTe 2 /In 2 Se 3 van der Waals heterojunction, where the piezophototronic effect and strain‐induced bandgap modulation are combined to achieve a strain‐enhanced broadband response from the visible to the short‐wave infrared. Under controlled uniaxial tensile strain, the induced piezo‐potential within the heterojunction significantly enhances the built‐in electric field at the interface, while the strain‐reduced bandgap of MoTe 2 synergistically promotes photocarrier generation and separation. Consequently, the device exhibits a broadband photoresponse and pronounced responsivity enhancements of 191% at 638 nm and 260% at 1310 nm under optimized tensile strain, along with an ultralow dark current of 9.4 pA. These results demonstrate an effective strain‐modulated photon‐to‐electron transition in flexible van der Waals heterostructures and offer a viable strategy for designing high‐performance flexible optoelectronic devices.