Photoconductive behavior in smectic A phase of 2-(4'-heptyloxyphenyl)-6-dodecylthiobenzothiazole

A new liquid crystalline photoconductor, 2-(4'-heptyloxyphenyl)-6-dodecylthiobenzothiazole exhibiting a smectic A (SmA) phase between 90 degrees C and 100 degrees C was synthesized and its photoconductive behavior was characterized by steady-state current-voltage measurements under ultraviolet illumination. A large photocurrent with a clear response to the illumination is observed in SmA and isotropic liquid phases in contrast to a very small photocurrent in the polycrystalline phase. The experimental results suggest electronic conduction in the SmA phase of calamitic liquid crystal.