THICK LAYERS OF PPY AND PTH - ELECTROSYNTHESIS AND MODIFICATION OF ELECTRICAL PARAMETERS BY ION-IMPLANTATION - P-N-JUNCTIONS

Thick layers of polypyrrole and polythiophene (d>10mum) were electroge nerated by square or trapezoidal waves of potential. These polymers we re electrogenerated on stainless steel, electrochemically reduced, and later translated on a non metal. In the last state the electric chara cterization is possible without any influence of the conducting electr ode. The electrogenerated films have a conductivity of p type, even af ter a deep electrochemical reduction and were employed to obtain a neg ative doping by implantation of alkali ions. Measurements of alternati ng conductivity (sigma approximately) showed that n doping is efficien t. The conductivity sigma approximately increases with fluence (number of ions deposited on the unit surface). This increase is more efficie nt when a lower energy of implantation was used, as in the case of oth er electroactive polymers. From electroreduced polythiophene having a conductivity of 10(-6)S.cm-1 and a > 600muV.K-1 thermoelectric power, a change of sign is obtained for the thermoelectric power after implan tation with Cs+ or Na+ ions. A stable p-n junction was constructed and controlled.