Vapor phase polymerization of PEDOT on ITO/glass surfaces for nonenzymatic detection of dopamine

This study demonstrates the deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) as an electrically conductive polymer on the ITO-coated glass surfaces for the production of a non-enzymatic electrochemical sensor to detect dopamine. For this purpose, thin films of PEDOT were synthesized using vapor phase polymerization (VPP) from the corresponding monomer 3,4-ethylenedioxythiophene, in which iron(III)chloride was used as the oxidant. Films were deposited at different substrate temperatures, where the temperature dependence of doping and conjugation levels were studied using FTIR and XPS analyses. The highest doping and conjugation levels, as well as the highest film thickness (380 nm) was observed for the film deposited at 40 °C, which represented the highest conductivity of 111 S/cm. Significant differences were observed between the electrochemical responses of ITO/glass and PEDOT/ITO electrodes. Amperometric measurements indicated a limit of detection value of 2.02 µM for dopamine using as-synthesized PEDOT/ITO electrode.