A thin-film tin-oxide carbon monoxide sensor for exhaust gas analysis

A sputtered thin-film tin oxide:platinum sensor operating at 125 °C was successfully used to detect carbon monoxide gas from a car exhaust. Detection in the range 0.2 to 8% was demonstrated. Although ohmic contacts to the sensor were achieved, preliminary life tests showed that corrosion occurs in humid atmospheres. An alternative contact material is suggested. Further work on the change in response with thickness is required and this should include porosity studies.