Aqueous Gold Sols of Rod-Shaped Particles

Abstract

Aqueous dispersions of rodlike gold particles are obtained by electrodeposition in nanopores of anodized alumina attached to a conductive support followed by dissolution of the alumina and stabilization of the rods with poly(vinylpyrrolydon). The obtained sol of monodisperse gold rods is examined by electron microscopy and visible (VIS) and near-infrared (NIR) spectroscopy. In the VIS/NIR absorption spectra two absorption maxima are present. With increasing aspect ratio, the maximum around 520 nm shifts to shorter wavelength, while the other maximum shifts into the near-infrared regime, which is in agreement with theoretical predictions.