Optical and electrical characterization of polyaniline-silicon dioxide nanocomposite

Optical absorption spectra of polyaniline (PANI)-silicon dioxide (PANI-SiO2) nanocomposites have been studied for different concentrations of silica. The incorporation of silica nanoparticles gives rise to the blue shift of pi-pi* transition of polyaniline. Dc and ac conductivities have been investigated as a function of frequency and temperature. Dc conductivity follows three-dimensional variable range hopping. Ac conductivity has been interpreted by the equivalent circuit and satisfies power law of frequency at higher frequency region. Temperature variation of frequency exponent suggests correlated barrier hopping conduction process in nanocomposites. (c) 2006 Elsevier B.V. All rights reserved.