On the mechanism of conductivity enhancement in plasma treated poly(3,4-ethylenedioxythiophene) films

The conductive poly(3,4-ethylenedioxythiophene): p-toluene sulfonate (PEDOT : PTS) films were prepared by gas-phase polymerization using CVD technique. PEDOT : PTS films with better electrical performance were produced by the additional doping with O2 plasma after vapor phase polymerization. The mechanism for this conductivity enhancement is studied through surface structural analyses using Raman and X-ray photoelectron spectroscopy (XPS). The increase in conductivity is likely to be due to the generation of new functional groups such as carboxyl and hydroxyl groups that are acted as a dopant and the removal of the impurities on PEDOT: PTS surface with plasma treatment.