Implanted polymer junctions obtained with electrogenerated polythiophene films

Abstract

Using polythiophene films (∼5 μm thick) electrogenerated by trapezoidal waves of potential, then partially reduced, we realised metal‐polythiophene contacts on the one hand. The electrical characteristics of a steel/polythiophene/gold sandwich structure are presented. We consider that the rectifying contact takes place between steel and p‐type polythiophene. On the other hand, we showed that p‐type polythiophene could be compensated after an implantation of alkali ions (Cs+ or Na+) in order to lead to the realisation of PN junctions. We particularly prove that the use of Na+ ions results in junctions yielding currents which are higher than with Cs+ ions. Current‐voltage and capacitance‐voltage characteristics have been presented so as to show that the junction effect is due to the efficiency of the doping by ionic implantation. These electrical measurements seem to be stable after several weeks in air.