Improvement of Electrochemical Properties of Poly(3,4-ethylene dioxythiophene) (PEDOT) Thin Film by UV Irradiation.

Abstract

Electrochemical redox supercapcitor is one of promising rechargeable power sources for portable electronic, display or telecommunication devices since it has a large energy density, very fast charge/discharge time and long life cycle. In this study, poly(3,4-ethylene dioxythiophene) (PEDOT) thin film as the electrode of electrochemical supercapacitor was deposited on a metal current collector by in-situ polymerization method. Symmetrical electrochemical capacitor was then assembled using PEDOT films as working and counter electrodes, where 0.1 M lithium perchlorate (LiClO₄) solution in acetonitrile was used as the electrolyte solution. Typical specific discharge capacitance of the capacitor was about 70 F/g and showed little decrease after 1,000 charge/discharge cycles. We also found that UV irradiation improved the electrochemical properties of redox capacitor by formation of hydrophilic polar groups on PEDOT film surface. After UV irradiation on the surface of PEDOT film for 2 hours with the intensity of 30 mW/cm², the specific discharge capacitance increased by about 10% compared to capacitance of pristine PEDOT film.