Alternating current conductivity and dielectrical properties of -5-sulfono-7-(4-x phenyl azo)-8-hydroxy quinoline derivatives

Abstract

The influence of NO2, CH3 and Cl substitutions on structure, dielectric constants and alternating current conductivity, σac, of -5-sulfono-7-(4-x phenyl azo)-8-hydroxy quinoline (SAHQ) ligands is investigated in the frequency range 1–100kHz and in the temperature range 200–373K. SAHQ-x; x = -NO2 or -CH3 or -Cl ligands have monoclinic crystal system with different lattice parameters and crystallite size depending on the substitutions. The thermal behavior of SAHQ-x depends on the substitution. The AC electrical conduction mechanism for (SAHQ- NO2) and (SAHQ- Cl) ligands are found to follow the correlated barrier hopping model (CBH). The parameters such as barrier height, hopping distance, density of states near Fermi level and relaxation time have been reported. Overlapping large polaron tunneling model has been applied for explaining conduction behavior of SAHQ-CH3 ligand. The hopping energy and the polaron radius have been determined.