Impedance Spectroscopy Study of the AC Conductivity and Dielectric properties of 3, 5-Dimethylpyridine-Iodine Charge Transfer Complex

Solid charge transfer complex of n-donor 3, 5-dimethylpyridine (3, 5-Lutidine) with acceptor iodine was prepared and characterised by using elemental analysis, UV-Vis, FTIR, H-1 NMR spectroscopy and powder XRD techniques. The electrical parameters of the prepared complex in the pellet form were studied at various temperatures and at wide frequency range by employing AC complex impedance spectroscopic technique. The Nyquist (cole-cole) plots have been successfully explained by employing (RC)(RC)(RC) equivalent circuit corresponding to grain, grain boundary and electrode contributions. The radii of the semicircular arc decrease with increase in temperature which suggests that the material exhibits negative temperature coefficient of resistance (NTCR) behaviour like semiconductors. Dielectric constant, epsilon' and dielectric loss, epsilon '' seems to decrease sharply with increase in frequency. The ac conductivity obeys the power law of frequency.