Fast ambipolar carrier transport in smectic phases of phenylnaphthalene liquid crystal

The carrier transport of a new calamitic liquid crystal, i.e., 2-(4′-octylphenyl)6-dodecyloxynaphthalene (8-PNP-O12) was investigated by the time-of-flight technique. The fast ambipolar electronic conduction was observed in two smectic phases of 8-PNP-O12. The carrier mobilities were determined to be 1.6×10−3 cm2/V⋅s in the lower temperature smectic phase (Sm1) between 79 and 100 °C and to be 2.5×10−4 cm2/V⋅s in the higher temperature phase (Sm2) between 100 and 121 °C, regardless of carrier signs, i.e., electron and hole. The slower ambipolar transport was observed in isotropic phase as well, whose mobility was 8×10−5 cm2/V⋅s. These mobilities were independent of applied electric fields and temperature.