Ultraviolet Light-emitting Diode-assisted Highly Sensitive Room Temperature NO Gas Sensors Based on Low-temperature Solution-processed ZnO/TiO Nanorods Decorated with Plasmonic Au Nanoparticles

Nanostructured semiconducting metal oxides such as SnO, ZnO, TiO, and CuO have been widely used to fabricate high performance gas sensors. To improve the sensitivity and stability of gas sensors, we developed NO gas sensors composed of ZnO/TiO core-shell nanorods (NRs) decorated with Au nanoparticles (NPs) synthesized via a simple low-temperature aqueous solution process, operated under ultraviolet irradiation to realize room temperature operation. The fabricated gas sensor with a 10 nm-thick TiO shell layer shows 9 times higher gas sensitivity and faster response and recovery times than ZnO NR-based gas sensors. This high performance of the fabricated gas sensor can be ascribed to band bending between the ZnO and TiO core-shell layers and the localized surface plasmon resonance effect of Au NPs with a sufficient Debye length of the TiO shell layer.