Effect of high concentration of colloidal gold nanoparticles on the thermodynamic, optical, and electrical properties of 2, 3, 6, 7, 10, 11-hexabutyloxytryphenylene discotic liquid crystalline material

Abstract

In this work, colloidal gold nanoparticles (GNPs) have been dispersed in a plastic columnar discotic liquid crystal (DLC), namely 2,3,6,7,10,11-hexabutyloxytryphenylene (HAT4). Thermodynamic, dielectric, and optical properties of nanocomposites verify the incorporation of the nanoparticles (NPs) into columnar matrix. Due to addition of GNPs in the triphenylene-based DLC (HAT4), columnar hexagonal to isotropic liquid phase, transition temperature appreciably decreases; however, the crystal to columnar hexagonal phase transition temperature does not change drastically. Interestingly, the ionic conductivity of nanocomposite shows an increment by two orders of magnitude due to doping of GNPs. Dielectric permittivity measured parallel to the column axis in the homeotropic aligned sample has improved. Optical study suggests that band gap has decreased due to dispersion of GNPs.