Halide ion induced tuning and self-organization of gold nanostars

Abstract

The simple addition of different halide ions to the precursor polymer–solvent solution for the synthesis of gold nanostars drastically changes their optical properties owing to the blue/red shifting of the longitudinal surface plasmon resonance (LSPR) bands as well as the emergence of new plasmon bands, aesthetically illustrating the simultaneous size/shape tuning enhanced with intriguing self organization, as confirmed from the TEM measurements. Such a synchronized morphology tuning has been very well understood in terms of the distinct reaction kinetics imparted by the different adsorption affinities of inorganic halide ions towards metal ions/surfaces. The systematic results of which are discussed rigorously in the present work in conjunction with the uncommon/unusual assemblies of anisotropic/elongated gold nanostructures, the first of its kind to the best of our knowledge, that are envisioned as ‘hot spots’ for exotic applications in surface enhanced Raman scattering (SERS) as well as plasmonic waveguiding.