Fast identification of CO by using single Pt-modified WO3 sensing film based on optical modulation

CO sensor based on metal oxide has been developed for a long time. Although the gas sensitive response of sensor is greatly improved already, the poor selectivity and interference immunity limit the application. To achieve the purpose of fast identification of CO by a single sensing film, the optical modulation method is first proposed and applied herein. This method allows us to be capable of obtaining the characteristic parameters, the photoresponse and the photogenerated carrier lifetime, based on the optical modulation spectra. According to the characteristic parameters, CO can be successfully distinguished from the other gases, including H2, ethyl alcohol and acetic acid. The results show that the optical modulation provides an effective method for fast and accurately identifying gas species and opens up a way to investigate the selectivity of the MOX sensors.