rder parameter and linear dichroism study of two azo dyes in C7 liquid crystal mixture

In this work، the order parameter and dichroic ratios of two synthesized dyes in a C7 mixture are obtained. In our measurements، the different concentrations of dye dopants in the uniform planar cells are used and the orientation ordering is studied based on the guest-host phenomenon. The polarized absorption spectroscopy method is used to determine the linear dichroism and the order parameter of doped liquid crystal. The parallel and perpendicular components of absorption are obtained. Then، the results for some compositional percentage of the dyes are compared and the ordering behavior of the system is studied. Our obtained results confirm that the molecular structure of the dyes is a significant factor in orientation ordering of liquid crystal host. Moreover، it is found that even in low concentrations of the dyes، the order parameters are effectively changed. Dye doped liquid crystals are broadly used in various electro optical devices to enhance their physical and photo-physical properties. Hence، study of these materials that have initially attracted interest as a technological improvement of the optical devices، are crucial in applications like displays with faster switching rates and larger viewing angle.