Thermal control of transmission property by phase transition in cholesteric liquid crystals

Abstract

Cholesteric liquid crystals (LCs) responsive to external stimuli, such as temperature or light, can be used for color switching or tuning through the change in the cholesteric pitch. This paper presents the thermal control of the transmission property via the phase transition of cholesteric LCs without any change in the cholesteric pitch. We used the chiral smectic A, chiral nematic, and isotropic phases as the transparent, high-haze opaque, and haze-free opaque states of a dye-doped cholesteric LC cell. We showed that the proposed device could be used as a temperature sensor or self-shading smart window for energy saving.