UV-activated CO2 sensor based on ZnO nanoparticles at low temperatures

Carbon dioxide gas sensing can be performed using non-dispersive infrared (NDIR) and metal oxide semi-conductor (MOS) sensors. The NDIR sensors are not economical for mass production, and MOS sensors have many challenges to overcome, such as signal stability, noise to signal ratio and high work temperature. This study indicated that UV-exited sensors based on nanoparticles are practical approaches to solving these problems and affecting their feasibility in domestic and industrial applications. The CO2-sensing devices were fabricated by ZnO nanoparticles as the sensing material. In order to the characterization of as-prepared sensors, changes in electrical resistance of sensors were investigated under UV-irradiation at low temperatures (< 100 degrees C). Our study pointed that the UV-activated sensor based on MOS nanostructures was of good sensitivity, stability, and short response/recovery time at low temperatures. Also, the selectivity can be tuned by adjusting the intensity of UV illumination. In this work, the response up to 16.3% toward CO2 with concentration of 0.8 %was obtained under UV excitation (1.8 mW/cm(2)) at RT.