A Novel surface acoustic wave DMMP sensor coated with Zinc oxide quantum dots

Currently, many surface acoustic wave (SAW) gas sensors coated with Zinc oxide (ZnO), have high operating temperature and poor sensitivity for dimethyl methyl phosphonate (DMMP). Thus, we fabricate a novel SAW gas sensor to detect the DMMP at room temperature. Due to the excellent solution processability, low cost and ease of integration, quantum dots (QDs) are emerging as promising candidates for gas sensors. Zinc oxide quantum dots (ZnO QDs) were synthesized by using a succinct colloidal method. In order to construct gas sensors, ZnO QDs were drop-coated onto 128°YX LiNbO
₃
piezoelectric substrates. A differential SAW oscillator with excellent frequency stability was performed and a delay-line SAW resonator with low insertion loss was designed as the feedback element of the oscillator. Large sensor response and good repeatability were observed in the experiments at 25 °C. The detection limit and measured sensitivity were evaluated as 0.13 ppm and 46.4 Hz/ppm, respectively.