Electro-optical Performance Investigation of Cholesteric Liquid Crystal Containing Azo Dye: Light Shutter Device Application

Abstract

In this study, the effect of chiral dopant concentration on electro-optical and dielectric properties of a cholesteric liquid crystal (CLC) composite was investigated, and a dye-doped cholesteric liquid crystal (DDCLC) light shutter was developed. The electro-optical properties of samples were investigated by electro-optical switching method without the use of a polarizer. The dielectric characterization of the composites were also realized using dielectric spectroscopy technique with a wide frequency range. Significant electro-optical and dielectric parameters, such as transition voltages, complex dielectric constant, dielectric anisotropy and light transmission values of composites were found from the experimental data. The obtained results show that the chiral dopant causes changes in electro-optical and dielectric parameters of CLC, and the developed DDCLC light shutter can be used in optoelectronic device applications.

Qualitative chirality effects on the Casimir-Lifshitz torque with liquid crystals

“…This affects the static values (see the magenta crosses and the red circles), which were obtained from Ref. [56] Here we will use the results derived in section III to calculate the Casimir-Lifshitz torque given by Eq. ( 17).…”

“…More precisely, the smallest Matsubara frequency (n = 1) at 293 K is six orders of magnitude larger than the typical values of the Debye relaxation frequencies. [56,64] Therefore we propose to approximate it as the static term from Eq. ( 39):…”

“…Let the cholesteric liquid crystal consist of 96 mass % nematic 5CB (4-cyano-4'-pentyl-biphenyl) doped with 4 mass % chiral dopant S811. [56] The value of the static Debye term for this mixture was taken from a recent experiment [56]. The dielectric function of 5CB was established in Ref.…”

“…(indicated by the black squares and blue triangles) is modified to account for the presence of a chiral dopant. This affects the static values (see the magenta crosses and the red circles), which were obtained fromRef [56].…”

Inquisitive Optical and Electro-Optical Attributes of Azo-Dye Dispersed Nematic Liquid Crystal for Applications in Wavelength-Tunable Optical Filters

“…10 The exploration of electric properties of MR-doped LC leads to the conclusion that MR-doping enhances the AC conductivity of the system, 11 whereas dielectric anisotropy generally decreases 12 and, therefore, as evidenced by the preceding literature, the device parameters can be optimized using optimal concentration of dye. Although the primary concern has been on their use in display devices, dyes in LC hosts have been suggested as the basis for materials with an extensive range of applications, namely, advanced textiles, 13,14 augmented reality and virtual reality systems, 15,16 optical shutters, 17,18 biosensing, 19,20 LC lasers, 21 LC lenses, 22,23 soft actuators, 24,25 smart windows, 26,27 and optical storage devices 28,29 but for the best of our knowledge, the optical tunability and energy storage applications of MR-doped LC systems have not been discussed thoroughly so far.…”