| dc.description.abstract | With the rapid development of science and technology, the liquid crystal (LC) optoelectronic technology, including the techniques of displays, smart windows, and so on, has become an indispensable part in human’s daily life. In addition, environmental protection and energy conservation issues are more and more important over the recent decades. Therefore, the study of multi-stable LC components has been attracting substantial attention.
The contents of the thesis include three topics about multi-stable LC light modulators and smart windows. The first topic is the study of the optically and electrically controllable electro-optical characteristics of dichroic dyes-doped cholesteric LCs. The photo-isomerization processes of the doped chiral azobenzene dopant play the most important role. On the basis of the photo- isomerization of the azobenzene between the cis- and trans-isomers, the helical twisting power (HTP) of the azobenzene chiral dopant can be tuned to achieve the bistable states, including the absorption state (no light scattering) and transparent state (no light scattering and absorption). Applying an AC electric field onto the LC device can switch the gray levels of its absorption-scattering states. The second topic is the study of electrically tunable electro-optical characteristics of dichroic dyes and chiral dopant-doped dual frequency nematic LCs, filled into two different kinds of LC cells. One LC cell was treated with homeotropic alignment layer, the other with homogeneous one (also known as White-Taylor cell). The last topic is the study of electrically switchable light scattering modes based on ion-doped nematic LCs. The electro-optical properties of nematic LCs (Δε<0) doped with different concentrations of ions with the application of electric filed were investigated. Additionally, the induced torques, resulting from the ion flow and the applied electric fields, to cause the rotation of LCs have also been discussed. The transparent and scattering modes of the described LC samples were compared with each other. | en_US |