EFFECT OF AGING ON THE TEMPERATURE-DEPENDENCE OF CONDUCTIVITY OF POLY(3-HEXYLTHIOPHENE) DOPED BY FECL3

We have observed that the decay rate of the dc-conductivity of poly(3- hexylthiophene) (P3HT) doped by FeCl3, upon ageing, follows the Arrhen ius law. The ageing enhances the temperature dependence of conductivit y eventhough the variation in room temperature conductivity was relati vely small. The negative magnetoresistance, at weak fields, increased slightly upon ageing. However, at strong fields the positive magnetore sistance remained unchanged upon ageing. These measurements indicate t hat the mechanism for ageing is different for P3HT as compared to othe r conducting polymers, such as polyacetylene doped by iodine.