Toward flexible and omnidirectional self-powered near-ultraviolet photodetection by constructing a mixed-dimensional nanobelt/nanosheet heterojunction of CdS/PbI₂

Owing to the growing demand for scaling down and low-power consumption in the Internet of Things and wearable devices, there is an increasing need for miniaturized, self-powered flexible optoelectronics with omnidirectional photodetection ability. In this work, a mixed-dimensional heterojunction near-ultraviolet photodetector of CdS nanobelts/PbI₂ nanosheets was prepared <i>via</i> chemical vapor deposition and liquid-phase growth methods. Importantly, the as-fabricated self-powered near-ultraviolet photodetector displayed a low <i>I</i>_dark of 7 × 10^-14 A, high <i>I</i>_light/<i>I</i>_dark ratio of 2.06 × 10³, fast rise/decay times of 581 μs/581 μs and exceptional responsivity and detectivity of 3446.04 mA W^-1 and 9.05 × 10⁹ Jones, respectively, benefiting from the built-in field. In addition, the flexible near-ultraviolet photodetector exhibited impressive omnidirectional photodetection and robust bending endurance. Thus, all these results reveal the technological potential of the mixed-dimensional photodetector for next-generation high-performance near-ultraviolet optoelectronics.