Photoelectrochemical properties and microstructuring of polythiophenes

Photoelectrochemical microstructuring processes have been applied to variou s classes of semiconductors and especially to intrinsically conducting poly mers such as polythiophenes. In this work, a new technique was developed fo r photoelectrochemical post-structuring of conducting polymers deposited on Pt and p-Si. The surface of a conducting polymer is illuminated with a foc used laser beam in a non-aqueous solution in the presence of tetrabutylammo nium (TBA) salts. This results in local photoelectrochemical cathodic dopin g of the polymer and corresponding conductivity increase. Poly-3-phenylthio phene (P3PhT) and polybithiophene (PBT) were investigated in this work. In the case of P3PhT, colourless conducting films are formed, and the post-str ucturing process could be visualised using conventional optical microscopy. The obtained micropatterns were stable in air and in the anodic doping reg ion, but could be removed by repeated cycling in a potential range includin g both anodic and cathodic doping. The microstructures were characterised b y SEM, EDAX, SECM and other techniques. (C) 2001 Elsevier Science Ltd. All rights reserved.