Growth of polythiophene nano-walls and their unique electrochemical and optical properties

Abstract

It has been a persistent challenge to develop ordered conducting polymer nano- and micro-structures with a high active area. We herein report the method to produce and characterise a network of nanometre-sized walls (nano-walls) which forms on the surface of a conducting co-polymer composite film based on bithiophene and terthiophene prepared using vapour-phase polymerisation (VPP). The density and dimension of the walls are tunable in order to suit the application demands. The presence of nano-walls on the film surface increases the capacitance of the coating up to 3.4 times, making it a very promising candidate for energy and organic electronics applications. The nano-walls have also proved to be great candidates for photonic applications, efficiently guiding light. A two-step growth mechanism is proposed, which includes the reduction of Fe(III) and part of the tosylate ligands in the Fe(III) para-toluene sulphonate oxidant. This is the first report of a self-assembling conducting polymer material with nano-wall features induced by the conditions during VPP.