Effects of Ag nanoparticles decorated on ZnO nanorods under visible light illumination on flexible acetylene gas sensing properties

In this work, piezoelectric and plasmonic effects on a flexible acetylene (C2H2) gas sensor based on silver (Ag) nanparticles (NPs)-coated ZnO nanorods (Ag-ZnO) were realized. Using visible light illumination, the sensing properties can be modulated and the power consumption can be reduced significantly. Upon exposure to 1000 ppm C2H2 under 8.36 mW cm−2 light illumination, the power consumption of the sensor noticeably reduced from 3.48 W (in dark) to 1.64 W. A large number of light-induced chemisorbed oxygen ions were generated in the Ag-ZnO forest due to the strong coupling effect between the plasmonic Ag NPs and the ZnO NRs. This resulted in increased surface charge densities, which facilitated the sensor to react with the C2H2 molecules at lower operating temperature, hence reduced the power requirement. Moreover, the sensor exhibited reliable detection of C2H2 gas within the concentration of 3–1000 ppm including a maximum sensor response of 26.2, response-recovery time of 66/68 s, the excellent mechanical stability at a bending angle up to 90o, and 104 cycles of repeated deformation processes. These results might facilitate research in developing a low power C2H2 gas sensor and will open up new approaches for future light modulated gas sensors.