Electrical properties of domain boundary in photoconductive smectic mesophases and their crystal phases

We have investigated the charge transport proper-ties in smectic photocondu ctive liquid crystal of 2-phenylnaphthalene derivatives in focus on the ele ctrical nature of the boundaries at the phase transition from liquid crysta lline phase into the crystal phase. With systematic studies of charge trans port and collection by transient photocurrent measurements and molecular al ignment by X-ray diffraction at the phase transition, it was revealed that the defective nature of the crystalline boundaries takes the shape of shall ow traps at the initial stage and of deep traps successively, and finally t he polydomain allowance for the carrier transport in mesophases disappears completely when the phase transition takes place into the crystalline phase s.