Kyoko Kogo

Polarized light emission from a calamitic liquid crystalline semiconductor doped with dyes

Liquid crystal cells containing a homogeneously aligned calamitic liquid crystalline semiconductor, 2-(4-octylphenyl)-6-dodecyloxynaphthalene, doped with dyes such as 3-(2-benzothiazolyl)7-diethylaminocoumarin, emitted a visible light when a dc bias was applied. This light emission occurred irrespective of phase, and polarized light emission was well established in the Smectic B phase. The unique features of the calamitic liquid crystalline semiconductors are also discussed from a practical viewpoint.

Photoelectrical properties of a ferroelectric liquid crystalline photoconductor

An organic ferroelectric photoconductor, 2-[(S)-4-(6-methylheptyloxy)phenyl]-6-decylnaphthalene, was prepared and its photoconductive and ferroelectric behaviors were characterized by steady-state and transient electrical measurements. This material exhibited fast carrier transport with an ambipolar mobility of 2.6×10−4 cm2/V s, independent of temperature and electric field. Under a polarized microscope, a fast switching with memory effect was observed visually and the spontaneous polarization was evaluated to be 0.6 nC/cm2 in chiral smectic C phase.