Effect of gold nanoparticles on intrinsic material parameters and luminescent characteristics of nematic liquid crystals

Abstract

In the present work, gold nanoparticles (GNPs) have been dispersed into the pure nematic liquid crystal (NLC) mesopahse ZLI 3497–100 (based on cyclohexyl cyclohcxanes and aromatic esters) in different concentration. We have investigated the characteristic dielectric, electro-optical, visco-elastic and luminescent properties emanated by GNP-NLC matrix. Inclusion of GNPs has greatly enhanced the alignment of NLC molecules and affects the molecular orientation as observed by improvement in the switching time of the GNP-NLC matrix along with decrement in visco-elastic parameters. Relative permittivity along with diffusion coefficient and ionic concentration is found to be decreasing for the GNP dispersed NLC system as compared to the pure NLC. This decrement in the permittivity value can be inferred due to dipolar contributions of GNPs in NLC and reduction in ionic contribution on dispersion of GNPs. The ion-entrapping ability of GNPs is determined through the comparative measurement of bias voltage characteristics for pure NLC and the synthesized composites. Variation in molecular dynamics and luminescence behavior under the influence of GNPs is confirmed by photoluminescence and Fourier transformed infrared spectroscopy (FTIR). The outcome of the present investigation can be employed in fabrication of photonic applications and photovoltaic devices.