Enhanced performance of flexible ultraviolet photodetectors based on carbon nitride quantum dot/ZnO nanowire nanocomposites

While the ZnO based ultraviolet (UV) photodetectors are generally restrained by the slow response and the weak photosensitivity, present work develops a facile method to fabricate flexible UV photodetectors with high device performance based on graphitic carbon nitride (g-C₃N₄) quantum dot/ZnO nanowire nanocomposites. The sensors are prepared by spin-coating method followed by annealing on flexible substrates, which exhibit remarkable responsivity of 355 mA W⁻¹ under UV irradiation, a 1000% improvement over ZnO nanowire sensors (35.4 mA W⁻¹). Both on/off ratio and photoresponse current are significantly improved by introducing g-C₃N₄ quantum dots compared with pure ZnO nanowire sensors. Current report provides a new choice for UV material system to efficiently improve sensor performance, and it could be easily scaled up for large scale applications. (paper)