Investigation of electro-optical and dielectric properties of nematic liquid crystal dispersed with biowaste based porous carbon nanoparticles: Increased birefringence for display applications

Abstract

Porous carbon nanoparticles (PCNPs) of diameter 80–100 nm are obtained from teakwood materials waste, using catalyst free pyrolysis method. These PCNPs are dispersed in a pure nematic liquid crystal (NLC) with different concentrations. Polarizing optical microscopic (POM) textures are recorded for pure NLC and NLC - PCNP composites showed better homogeneous alignment when nanoparticles were dispersed in the composites as compared with the pure NLC. The birefringence measurement using the transmittance technique showed interesting properties. It is found that birefringence is increased for the NLC - PCNP composites when compared to pure NLC. Contrast ratio for the NLC - PCNP composites increased after the dispersion of PCNPs. The Relative permittivity increases for NLC - PCNP composites in comparison with the pure NLC. Dielectric measurements showed that the dielectric anisotropy increases for NLC - PCNP composites when compare to pure NLC. The electro-optical study revealed that the threshold voltage of the system decreases after the dispersion of PCNPs. Presented data of the nano composite mixtures found to be very useful in flat panel displays (FPDs) and phase shutters.