Structural, Optical Absorption and Conductivity of PIn/Co3O4 Composites

Abstract

This article presents the results obtained from structural, optical absorption and dc conductivity studies of pure polyindole (PIn) and its Co3O4 doped composites. Polyindole has been prepared by chemical oxidation method at room temperature using APS as an oxidant. The composites with varied concentrations of Co3O4 were prepared by in situ polymerization method. The obtained powder XRD patterns of both PIn and its composites indicated amorphous nature. Shifting of aromatic alkene peaks in FTIR reveals interaction between PIn and Co3O4. DC electrical conductivity has been measured in the temperature range 303–393 K and its observed variation inferred semiconducting nature of both pure PIn and the composites. Optical absorption studies have carried out and the band gap for both direct and indirect allowed transitions has been determined to be in the range from 1.79 to 2.34 eV and 2.38 to 3.19 eV respectively. These sizes of band gap values make them to be suitable for opto electronic applications. Activation energy for dc conduction has been determined using Arrhenius expression and it is found to be in the range of 0.3252–0.3806 eV. Conductivity increased and activation energy for conduction decreased with increase of Co3O4 concentration. This is interpreted to be due to decrease of hopping distance of charge carriers with increase of Co3O4 in the composites.