Electrical transport in titania nanoparticles embedded in conducting polymer matrix

Abstract

Conducting polymer-wide band gap semiconductor nanocomposites are prepared by polymerizing pyrrole in the presence of colloidal titanium dioxide (TiO2) sol. Characterizations of nanocomposites are carried out by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Direct current (dc) and alternating current (ac) conductivities of nanocomposites have been investigated as a function of temperature and frequency for different concentrations of polypyrrole (PPY). The temperature dependence of ac conductivity suggests that small polaron tunneling occurs in the charge transfer process. A very large dielectric constant of about 13,000 at room temperature has been observed. The interface between PPY and TiO2 plays an important role in yielding a large dielectric constant in the composite.