Reversible Gelation of II–VI Nanocrystals: The Nature of Interparticle Bonding and the Origin of Nanocrystal Photochemical Instability

Abstract

Programmable assembly and disassembly: Chemical and spectroscopic studies show that SeSe bond formation is responsible for the oxidation-induced aggregation of thiolate-capped CdSe nanocrystals to gels. Treatment with reducing agents leads to SeSe bond cleavage and dispersion of the gel. This process can be cycled, resulting in successively smaller particles (see picture; MUA = 11-mercaptoundecanoic acid, TMAH = tetramethylammonium hydroxide).