Photoelectrochemical properties of thin films of polythiophene and derivatives: Doping level and structure effects

Abstract

Photoelectrochemical cells were prepared by the electrochemical grafting of thin films of polythiophene and substituted polythiophenes onto platinum and gold. The current density versus voltage (j-V) curves in the dark and under illumination 3the action spectrum) were determined. The results show that (i) the Schottky barrier is located at the interface of the polymer and the electrolytic medium, (ii) the photocurrent depends closely on the structure and on the regularity of the polymer, (iii) no decrease in the photocurrent is observed after many hours of irradiation, confirming the high stability of these polymer, and (iv) the photocurrent varies with the nature of the dopant used during the synthesis and is directly related to the residual doping level. Capacitance measurements give a flat-bond potential of +0.35 V with respect to the saturated calomel electrode and ionized carrier densities of 1016 cm-3 and 4 × 1016 cm-3 for BF4- and PF6- respectively. © 1984.