Investigation of morphological, electro-optical and dielectric properties of micro and nano particle doped liquid crystal composite structures

In this study, cholesteric liquid crystal composite structures planned to be used in smart window system applications were formed and their physical properties were investigated. In the first stage of the study, four different cholesteric liquid crystal structures were produced by combining different ratios of S-811 chiral dopant and 5CB nematic liquid crystal. By obtaining important electro-optical and dielectric parameters such as transition voltage, response time and relaxation time of these structures, the sample providing optimum performance was determined. In the second stage of the study, new liquid crystal composite structures were formed by combining cholesteric liquid crystal structure with optimum performance with micro sized MR azo dye and nano sized CdSeS/ZnS quantum dot structures at certain concentrations. Thermal, electro-optical, dielectric and morphological properties of the composites were investigated in detail. In particular, significant changes were observed in both electro-optical and dielectric properties of the obtained structure due to the molecular interaction mechanisms that occur in the cholesteric liquid crystal composite, in which azo dye and quantum dot structures are used together. As a result of the evaluations, it has been observed that both cholesteric liquid crystal structures and azo dye and quantum dot doped cholesteric liquid crystal composites have opaque and transparent properties depending on the changing voltage, and it is concluded that these structures can be used as new type composite materials with light on/off feature in smart window system based device applications.