ELECTRICAL-PROPERTIES OF DISCOTIC LIQUID-CRYSTAL HEXAHEXYLOXYTRIPHENYLENE

Carrier transport of 2,3;6:7,10,11-hexahexyloxytriphenylene (HHOTP) in the discotic phase and the effects of C-60 doping and shear stress ha ve been studied by a time-of-flight method. The relatively high mobili ty of positive carriers insensitive to temperature and also C-60 dopin g are interpreted to be the hole mobility. The hole mobility decreases on applying shear stress which deforms the columnar structure in the discotic phase. Small and temperature-dependent mobility (with activat ion energy of 0.3eV) of negative carriers which are influenced by C-60 doping is interpreted to be that of ionic carriers. Electronic band s chemes of HHOTP in various phases (solid, discotic and isotropic) have been evaluated by absorption and photoelectron emission spectra measu rements.