Assembly-Dependent Regulation of the Chiroptical Responses of Chiral Gold Nanoparticles

Plasmonic nanoparticles (NPs) can concentrate light around their surface, which enhances the chiral interaction between light and matter. Chiral plasmonic NPs therefore have attracted a great deal of attention. The chiroptical properties of these synthesized chiral nanoparticles have been meticulously investigated through systematic variations in their helical morphologies. However, the chiroptical responses of assembled plasmonic chiral NPs remain less understood. Herein, we report the intricate correlation between the assembled plasmonic chiral NPs and their resulting chiroptical responses. The dissymmetry factor (g-factor) of the assembled anisotropic chiral Au nanorod array is inverted and partly reduced. Meanwhile, the chiroptical response of the assembled isotropic Au nanocube array merely diminishes without undergoing inversion. Numerical simulations are proposed to analyze the observed variations in the chiroptical signals of the chiral NPs. Our study provides valuable insight into the modulating chiroptical signals of plasmonic nanostructures to enhance signal intensity for applications such as chiral catalysis, bioimaging, and quantum optics.