Development of a paper-based wearable UV photo-detector device using ZnO nanostructure

Abstract

We depict an exceedingly low-cost and flexible photodetector in this work employing ZnO nanostructures grown on Whatman filter paper as the substrate and pencil-drawn graphite as the electrodes with a gap of 1 mm between the electrodes. A semi-non-aqueous solution containing Zinc acetate ((CH3COO)2Zn·2H2O) is used to deposit ZnO thin film on paper. The graphite/ZnO/graphite device shows a noticeable increase in the photo-current under UV (253 nm) light of the intensities in the range from 6 to 100 µW/cm2 with a higher Ip/Id ratio of 7800 at 30 V. This device shows higher responsivity of 1.94 A/W for the lowest incident intensity of UV light (6 µW/cm2). The best rise (tr) and decay time (td) for this photodetector was ∼ 13 ms. Based on the results and the non-toxic/hazardous nature of the substrate, this device shows promising UV photodetection performance under ambient conditions and is found suitable for wearable devices to protect humans from getting exposed to harmful UV radiation.