Continuous Percolation in Organic Conducting Blends

Abstract

Electronic transport properties of organic conductive blends made of doped poly(aniline) and conventional insulating matrices exhibit non-standard dependences on temperature T and conducting phase contents p. We propose a new analysis of conductivity data that accounts for the interplay of microscopic mechanisms – essentially hopping – and percolation effects. The continuous percolation scheme allows us to understand the T dependence of the conductivity exponent of percolation. This in turn is responsible for the apparent p dependence of the hopping parameters. It is possible to derive these effective parameters from those of the pure poly(aniline). We thus end up with a closed form formula to fit the whole set of conductivity data σ(p,T). The consequences of this analysis are discussed.