Composite of discotic liquid crystal and gold nanoparticles: A comperative band gap study

Nanocomposites of discotic liquid crystal namely 2, 3, 6, 7, 10, 11-hexabutyloxytryphenylene (HAT4) in existence of variable concentration of gold nanoparticles (GNPs) have been studied at room temperature and zero pressure. The absorption spectra of nanocomposites are captured by a Shimadzu UV–VIS Spectrophotometer, model UV-1800, in the wavelength range 900–200?nm. In this paper using the Tauc’s relation, the absorption spectra fitting method was applied to estimate the optical band gap. Nanocomposites are prepared by mixing of GNPs with four concentrations in pure HAT4 viz. 0.2, 0.6, 1.2 and 3?wt%. From the investigation of absorption spectra, it has been observed that with the enhance of GNPs concentration in pure HAT4 band gap has decreased for lower concentrations but for higher concentration (3?wt%) it increases.