Non variable range hopping transport on doped polypyrrole films

Summary form only given. The conductivity of electrochemically synthesized polypyrrole films doped by p-toluenesulphonic acid was investigated in the temperature range 50-300K. For the most doped samples the room temperature conductivity is of the order of 20 S/cm and the conductivity vs. temperature curve has the usual convex shape. The analysis of the temperature dependence of these samples, however, reveals an anomalous behavior in which a variable range hopping model , with fixed integer dimensionality , does not describe the data throughout the whole temperature interval. A more detailed statistical analysis of the data suggests that for the present samples an extra term in the temperature dependence should be included in the functional form of the condutivity. The same statistical analysis is used for an extensive comparison of these results with previous experimental work on highly doped polypyrrole samples.