Preparation and characterization of PEDOT films for NO2 gas sensors

A novel NO2 gas sensor was constructed by depositing poly(3,4-ethylenedioxyphioen) (PEDOT) films on the surface of interdigital electrodes. The conducting polymer PEDOT films were prepared by chemical synthesis. The conductibility tests indicated that the resistances of PEDOT films increased with the increase of NO2 concentration. The mechanism of increasing resistance of PEDOT films could be suggested that electrons of NO2-gas acted as the electron donor to p-type semiconductor of PEDOT with the consequence of reducing the numbers of holes in the PEDOT and the increase resistance of the thin film. The linear relationship between the shift of resistance and the concentration of NO2 existed in a range from 10 mu g/g to 30 mu g/g. The sensitivity of PEDOT films to NO2 was 10 Omega/10(-6).