Enhanced optical, electronic and dielectric properties of DBSA-doped polyaniline-calcium titanate composites

In this study, calcium titanate (CaTiO₃) doped (0, 15, 25 and 35%) polyaniline (PANI) composites in the presence of dodecylbenzene sulphonic acid (DBSA) were successfully synthesized by the means of in-situ emulsion polymerization of aniline monomer. The structural, morphological and optical characterization of as-prepared composites were determined using X-ray diffraction (XRD), field effect scanning electron microscopy, Fourier-transform infrared spectroscopy, UV-vis analysis, and electronic conductivity was determined using two-point probe method. The structural analysis confirms that PANI-DBSA is amorphous, but sharp peaks present in XRD patterns in composites are of crystalline nature. The morphological study reveals efficacious integration of CaTiO₃ particles into the PANI-DBSA matrix. Further, the integration of CaTiO₃ remarkably reduced the optical bandgap (2.7-2.2 eV) by making composites with PANI-DBSA. Room temperature alternating current conductivity was found to obey universal power law and correlated barrier hopping was found most appropriate model to describe the sample's charge transport mechanism. With the increasing wt% of CaTiO₃, the dielectric permittivity and loss both varied according to the interfacial polarization law of Maxwell-Wagner. Moreover, the I-V graphs showed augmented electrical conductivity of composites with an increase in CaTiO₃ particle content than that of pure PANI-DBSA. This is a simple way by which PANI-DBSA/CaTiO₃ composites having low optical bandgap, high electrical conductivity and permittivity may be fabricated for a widespread technological application. (author)