Assembly of intrinsic chiral gold nanorods within a cholesteric liquid crystal host with tunable optical asymmetry

Abstract

A recent upsurge of interest has been observed in exploring the chiral nature of nanomaterials and their assembly. In this work, we conducted theoretical investigations into the optical asymmetry of chiral gold nanorod (c-Au NR) helical assemblies within a cholesteric liquid crystal (CLC) host. The research investigated the optical asymmetry of the assemblies from two perspectives: the enhanced optical asymmetry of the helical assemblies due to the chiral nature of the c-Au NRs, and the sufficient dynamic modulation ways of the optical asymmetry by tuning the geometrical properties of the helical assemblies. In the context of post-modulation, the azimuthal variation has been identified as the most effective factor with a range of 0 to π/3, resulting in a change in the g-factor up to 0.271, indicating a broadened modulation range by 44.72% at its original base. The silver shell on c-Au NRs has been observed to strongly blue-shift the optical asymmetric signal of the helical assemblies, but concurrently reduces the amplitudes. The findings presented herein not only demonstrate the ground truth method raising the optical symmetry of c-Au NR helical assemblies, but also indicate the pathway toward magnifying and dynamically tuning the optical asymmetry on a large scale.