Patterning polythiophene films using electrochemical over-oxidation

Abstract

Over-oxidative degradation of polythiophenes, which breaks the conjugation and destroys theelectronic conductivity of the polymer, is well documented as a liability in these materials.We use this ‘weakness’, via controlled electrochemical over-oxidation, in a novel subtractivepatterning technique compatible with high-speed reel-to-reel printing technology. Wedemonstrate the use of electrochemical over-oxidation to pattern PEDOT:PSS films via anx–y plotter,silk-screen and high-resolution photolithographic techniques, resulting in patterning down to a resolutionof 2 µm and a conduction contrast between unpatterned and patterned areas of up to108.