Flexible UV detector based on carbon fibers, ZnO nanorods, and Ag nanowires

A novel device concept is proposed for a flexible UV photodetector based on carbon fibers integrated with zinc oxide (ZnO) nanorods and Ag nanowire film. Carbon fibers were uni-directionally aligned to provide both a flexible substrate and bottom electrode simultaneously. Arrays of ZnO nanorods were hydrothermally synthesized along the radial direction on the carbon fiber surfaces to function as active regions. Ag nanowire film was spray-coated on the ZnO nanorod arrays as a flexible, transparent, and air-permeable top electrode. The device exhibited Schottky-type current-voltage behavior and an ambience-dependent photoresponse. While the ratio of on/off photocurrent was higher under vacuum, response times were shorter in air, implying that oxygen-related adsorbates on the ZnO nanorods had a role in controlling the minority carrier lifetime. The device also demonstrated mechanical stability under repeated bending as revealed from the stabilized performances after about 6000 cycles of bending with a radius of 5 mm.