Regenerating Optical Properties of Individual Gold Nanoparticles in Alcoholic Solvents without any Surfactant

We compared the optical properties of gold nanoparticles (GNPs) in various solvents with those of strawberry-like composite particles (Au/SiO₂) consisting of a silica core and single attached GNPs. The results show that Au/SiO₂ without any surfactant could regenerate well optical properties of individual GNPs in alcoholic solvents. By the electrophoretic light-scattering measurements, the high dispersibility of Au/SiO₂ composite particles dispersed in alcoholic solvents has been demonstrated. In addition, using Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, we proposed a possible mechanism to qualitatively account for the dispersibility of Au/SiO₂ in organic solvents such as alcoholic solvents and cyclohexane, which may provide an opportunity to manipulate optical signals of single nanoparticle in organic solvents.