Oxidative Chemical Vapor Deposition of Electrically Conducting Poly(3,4-ethylenedioxythiophene) Films

An oxidative chemical vapor deposition (CVD) process is presented as an alternative to conventional solution-based processing of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. This solventless technique yields PEDOT with higher conductivities and conformally coats fibers and other high area morphologies, important for enhancing efficiencies in some organic electronic devices. The CVD method eliminates corrosive poly(styrenesulfonate) that is used to disperse PEDOT in an aqueous suspension for solution-based processing. A mechanistic approach is presented that favors the deposition of the conjugated, conducting form of PEDOT. We achieved conductivities as high as 105 S/cm and demonstrated films about 100 nm thick that do not crack upon bending and are more than 84% transparent to visible light. The compatibility of oxidative CVD deposition of PEDOT is demonstrated on silicon, glass, plastic, and paper substrates.