Light-activated gas sensing activity of ZnO nanotetrapods enhanced by plasmonic resonant energy from Au nanoparticles

High response and low working temperature are two essential requirements for promising chemi-resistive gas sensors, considering the issues of practical usage, safety, stability, energy conservation, etc, while traditional sensors usually work at high temperatures. One typical approach to solve this drawback is using photon activated process, but its overall activation response is not high enough for room-temperature operation. Utilization of localized surface plasmon resonance (LSPR) can increase light absorption and energetic carrier generation. Based on this, we developed a high-response and room-temperature sensor by decorating 3-dimensional-structured ZnO nanotetrapods (ZnO NTPs) with Au nanoparticles (Au NPs) through a facile sputtering-annealing process. Compared to pure ZnO NTPs, this hybrid nanostructure enhanced detection of volatile vapor components including ethanol, formaldehyde, acetone and methanol under 6 mW/mm2 white light illumination at room temperature. Representatively, the sensing response increased remarkably from 5.5 to 62 towards 500 ppm ethanol vapor. It also exhibits decent long-term stability and a better sensing performance than a commercial thermal-activated alcohol sensor operating at an optimal temperature of 370 °C. The reported LSPR assisted approach holds strong potential for practical devices and pave a new way for the development of room-temperature gas sensor with high-performance.