A high performance quasi-solid-state self-powered UV photodetector based on TiO2 nanorod arrays.

Self-powered UV photodetectors based on TiO2 and ZnO nanorod arrays have attracted lots of attention in recent years due to their various advantages. Impressive performances were observed in photochemical cell based UV detectors. However, liquid electrolytes are not ideal for long-term operation and are inconvenient for practical applications. Hence there is an urgent demand for replacing liquid electrolytes with solid-state hole transfer materials. Herein we report a nanostructured quasi-solid-state UV photodetector fabricated using a liquid crystal (LC)-embedded electrolyte with a light-trapping scheme. Vertical rutile TiO2 nanorod arrays grown on fluorine-doped tin oxide conductive glass were used as the active photoanode. A high incident photon-to-current conversion efficiency of 29% at 383 nm and a quick response time of less than 0.03 s were observed. In addition, it was revealed that the quasi-solid-state UV photodetector showed visible-blind, high responsivity, fast time response and good photosensitivity linearity in a wide light intensity range. The LC-embedded electrolyte with a light-trapping scheme enhanced the light absorption and thus improved the photodetecting performance. This self-powered device is a promising candidate for application in high-sensitivity and high-speed UV light photodetectors.