NON VARIABLE-RANGE-HOPPING TRANSPORT ON DOPED POLYPYRROLE FILMS

The conductivity of electrochemically synthesized polypyrrole films do ped by p-toluene sulphonic acid was investigated in the temperature ra nge 50-300K. For the most doped sample the room temperature conductivi ty is of the order of 20S/cm and the conductivity vs, temperature curv e has the usual convex shape. However, the analysis of the temperature dependence of these samples reveals an anomalous behavior: A variable range hopping model with fixed integer dimensionality does not descri be the data throughout the entire temperature interval. A more detaile d statistical analysis of the data suggests that for the present sampl es art extra term should be included in the functional form of the tem perature dependence of the conductivity, The same statistical analysis is used for an extensive comparison of these results with previous ex perimental work on doped polypyrrole samples.