Solution-processed, flexible and broadband photodetector based on CsPbBr₃/PbSe quantum dot heterostructures

Due to their promising applications in foldable displays, optical communication equipment and environmental monitoring systems, flexible and broadband optoelectronic devices have gained extensive attention in recent years. Here, a flexible and broadband photodetector based on CsPbBr₃/PbSe quantum dot (QD) heterostructures is firstly presented. The integrated QD heterostructures possess consecutive detection range from ultraviolet (UV) to long-wavelength infrared (LW-IR) regions with efficient light absorption and chemical stability, in comparison with the pristine PbSe QDs. Systematic material characterizations reveal the improved exciton dissociation, carrier transport and carrier lifetime of the QD heterostructures. Flexible photodetector Ag/CsPbBr₃/PbSe/Ag demonstrate a high responsivity of 7.17 A/W with a specific detectivity of 8.97 × 10¹² Jones under 25 μW/cm² 365 nm illumination at 5 V. Furthermore, it could maintain 91.2 % (or 94.9 %) of its initial performance even after bending for thousands of times (or exposing in ambient air for 4 weeks). More importantly, its response time is shortened more than three orders of magnitude as that of pristine PbSe QDs-based photodetectors. Therefore, it provides a feasible and promising method for the next-generation high-performance broadband photodetectors via constructing heterostructures of various QDs.