Patterning polythiophene films using electrochemical over-oxidation

Over-oxidative degradation of polythiophenes, which breaks the conjugation and destroys the electronic 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 subtractive patterning technique compatible with high-speed reel-to-reel printing technology. We demonstrate the use of electrochemical over-oxidation to pattern PEDOT:PSS films via an x-y plotter, silk-screen and high-resolution photolithographic techniques, resulting in patterning down to a resolution of 2 mu m and a conduction contrast between unpatterned and patterned areas of up to 10(8).