Optical spectroscopic studies of the dispersibility of gold nanoparticle solutions

We present an in situ study on the dispersibility of gold nanoparticles in different solvents by comparing the measured optical absorption spectra to the calculated absorption. Both uncapped and capped particles dispersed in a variety of solvents are investigated. In organic solvents such as chloroform and alcohols, dodecanethiol-capped particles can be dissolved better and with more stability than uncapped nanoparticles. The results of this work demonstrate that surface capping with alkanethiol molecules can dramatically improve the dispersibility of gold nanoparticles in organic solvents. The dissolution nature of the capper and the solvent dominate the dispersibility. We propose a useful method for selecting solvents in order to achieve a high dispersibility of nanoparticle solutions. (C) 2002 American Institute of Physics.