NO2 sensing with CdS nanowires at room temperature under green light illumination

Detection of ppb-level NO2 gas under atmosphere is urgent to meet the requirements of the rapidly developing Internet of Things (IoT). Compared with traditional sensing methods, light illumination has been considered as a key approach for excellent gas sensor performance under moderate conditions. Herein, we developed a green-light-assisted gas sensor based on cadmium sulfide nanowires (CdS NWs) that has good NO2 sensing capability at ambient temperature. The response values of NO2 are 236 % and 11 % to 10 ppm and 12.5 ppb, respectively. Furthermore, the CdS NWs sensor has a high selectivity for NO2 over a variety of interference gases, as well as good stability. The cleaning light activation and the sulfur vacancy-trapped charge behavior of CdS NWs are observed, which suggest a light-assisted sensing mechanism. These results suggest that light-induced charge separation behavior might significantly improve gas-sensing characteristics.