Dispersion of nanoparticles into the low birefringent nematic liquid crystal: study of optical and electro-optical parameters and its applicability towards liquid crystal displays

Abstract

In the present reported work, TiO2 nanoparticles (NPs) are dispersed into the pure nematic liquid crystal (NLC) in three different concentrations. The used NLC consisted of 4′-(trans, trans-4-alkylbicyclohexyl) carbonates and 4′-(4-(trans, trans-4-alkyl)-4-cyanobicyclohexane, which is an optically sensitive material. Optical parameters like photoluminescence and UV absorbance for this material can be tuned by doping of TiO2 NPs. Study of photoluminescence parameter is crucial for liquid crystalline materials. Therefore, optical and electro-optical parameters are measured here for pure and NP-dispersed NLC system. UV absorbance was found to be decreased for the TiO2-dispersed system when compared to pure NLC. Band gap was also calculated by using Tauc plot method, and it is found to be decreased for the NP-dispersed system. Photoluminescence study revealed that PL intensity increases after the dispersion of NPs into the pure NLC. This is the key output of the present reported work. Response time measurement was measured by Optical Switching method, and it is found to be reduced for NP-dispersed system when compared to pure NLC. Contrast ratio of the NP-dispersed system was also found to be increased. Threshold voltage showed that it decreases after the dispersion of NPs into the pure NLC. Enhanced photoluminescence, fast optical response time and high contrast ratio are the promising results of the present reported work because these parameters have many applications in the liquid crystal displays, opto-electronics devices and photonic devices.