Electronic Conduction Mechanism in Polycarbazole Iodine Complexes

Recently we have made iodine complexes of nitrobenzene soluble polycarbazoles which are indefinitely stable in air at room temperature and have conductivities as high as 6 ohm−l cm−1. GPC analysis reveals that more than a three fold increase in molecular weight occurs upon complexing the solvent cast film with iodine gas. However, some crosslinking is suspected at the highest levels of iodine. The most rapid rise in the conductivity is coincident with the development of significant IR absorption. The increased positive charge that XPS shows developing on the carbazole nitrogen with iodine complexation is consistent with the presence of the type cations which are known to exist in model dicarbazolyl complexes. The mechanism of postpolymerization and conductivity will be discussed in the context of these cations.