MECHANISM OF SPIN AND CHARGE-TRANSPORT IN POLY(ANILINE)

Spin dynamics and the conductivity mechanism in poly(aniline) samples with different doping levels were studied by the conductometry and mul tifrequency EPR techniques. In the neutral polymer, the charge transpo rt occurs predominantly through interchain transfer by hopping between pinned and mobile small polarons. A slight doping of the polymer lead s to isoenergetic charge transfer between the polaron and bipolaron st ates according to the Kivelson theory. Ultimately high doping of poly( aniline) leads to the formation of highly conducting quasi-three;dimen sional clusters. In the low-temperature range, the charge transfer in these clusters proceeds by the mechanism of interchain tunneling and c orrelates with macromolecular librations of the polymer chain. At high temperatures, the microconductivity of the clusters is determined by the scattering of electrons on the optical lattice phonons.