An enhanced solar-blind ultraviolet photodetector based on polyvinyl alcohol/carbon nanodots film

The combination of polymer and nanoparticles can create unique physicochemical properties, which is expected to be applied in the field of photodetection. Studies have found that synthetic polymer polyvinyl alcohol (PVA) can passivate nanoparticles and enhance the optical properties of the composite. In this paper, carbon nanodots (CNDs) mixed with PVA were used as the active layer film to prepare a metal–semiconductor–metal (MSM)-structured solar-blind ultraviolet (UV) photodetector. The responsivity and external quantum efficiency reached 267.1 mAW−1 and 158%, respectively. Compared with pure CNDs’ photodetector, the photocurrent of the PVA/CNDs’ photodetector was obviously improved. The enhanced performance could be attributed to the surface passivation by PVA, which modified surface functional groups of CNDs and attenuated the H2O absorption on the film surface. Moreover, the concentration of the active layer had great influence of the photocurrent; the optimal volume ratio of CNDs to PVA was 2.2% according to the comparison of the three devices with different concentrations. This work provided a promising way to fabricate high-performance, low-cost solar-blind UV photodetectors.