Construction of simple gold nanoparticle aggregates with controlled plasmon-plasmon interactions

We have developed a colloidal assembly for the study of plasmon-plasmon int eractions between gold nanoparticles. Colloidal aggregates of controlled si ze and interparticle spacing were synthesized on silica nanoparticle substr ates. Following the immobilization of isolated gold nanoparticles onto sili ca nanoparticles, the surfaces of the adsorbed gold nanoparticles were func tionalized with 4-aminobenzenethiol. This molecular linker attached additio nal gold nanoparticles to the 'parent' gold nanoparticle, forming small nan oparticle aggregates. The optical absorption spectrum of these clusters dif fered from that of gold colloid in a manner consistent with plasmon-plasmon interactions between the gold nanoparticles. (C) 1999 Elsevier Science B.V . All rights reserved.