Role of specific and nonspecific intermolecular interaction in electro-optical response of doped 6CHBT nematic liquid crystal with azo dyes

Abstract

Investigations done so far have shown that dopant material have a considerable effect on the electro-optical responses of dye-doped liquid crystal. But the type of inter or intra-molecular interaction roles in electro-optical properties and nonlinearity of doped liquid crystalline systems has uncovered. In this work, to study of the kind of molecular interaction effects on electro-optical properties of doped LC, two dyes with dissimilar interactional and functional groups were used as LC dopants. Therefore, doping these dyes into liquid crystals allows us to understand and analyze the effect of interaction type on electro-optical responses of the pure and doped samples. The electro-optical Kerr behavior, the pre-transition temperature and third order nonlinear susceptibility of pure and doped LC by two dyes with different interactional groups were having studied. The obtained results revealed that the electro-optical response of nematic liquid crystal can be strongly enhanced or decreased, depending on dopant's nature, concentration and type of specific and nonspecific interaction between doped dye and liquid crystal molecules. In other words, it will be shown that dopants molecular interactions with each other and liquid crystal molecules are important factors for controlling of electro-optical responses of dye doped liquid crystal system.