The electrical properties of a fullerene and CI Acid Red 2 (methyl red) doped E7 nematic liquid crystal

The electrical properties of a C.I. Acid Red 2 (4-dimethylaminoazobenzene-2'-carboxylic acid) and fullerene mixture of the nematic liquid crystal E7 were studied using complex dielectric spectroscopy as a function of the frequency of the applied AC-DC signal at various temperatures. Both the real and imaginary components of the dielectric constant decreased with increased frequency of the applied field whilst the AC conductivity increased with increasing frequency of the applied field. The alternating current conductivity sigma(omega) varied with angular frequency, omega as omega(s), with s <= 1, suggesting that a dominant hopping conduction process operated. The temperature dependence of both the AC conductivity and the exponents can be reasonably well interpreted using a correlated barrier hopping model. (C) 2009 Elsevier Ltd. All rights reserved