Carrier Transport Properties In Highly Ordered Smectic Liquid Crystal Phase

We have designed and synthesized a new liquid crystalline phenylbenzothienobenzothiphene derivative, Ph-BTBT-4S-3, in order to investigate the carrier transport properties in highly ordered smectic liquid crystal phase at a wide temperature range lower than room temperature enough to analyze them. Ph-BTBT-4S-3 exhibits smectic E (SmE) phase, which is the one of highly ordered smectic liquid crystal phases, at the wide temperature range from 200 degrees C to under -130 degrees C. Thanks to its wide temperature range of SmE phase, we could reveal the carrier transport properties in the low temperature range, which were well explained on the basis of Gaussian disorder model having a Gaussian width, sigma, of 87 meV, which was larger than those of typical nonpolar liquid crystals of 40-60 meV and was attributed to additional dipole of a thioether group in the side chain.