Synthesis and self–assembly of colloidal nanoparticles

Abstract

We describe recent developments in the synthesis of semiconductor nanoparticles, which lead to a substantial improvement of the luminescence quantum efficiency. Concerning a theoretical model for the growth of an ensemble of nanoparticles, the highest quantum efficiencies are achieved in particles that grow under conditions of a rapid exchange of monomers at the particle surface, leading to a smooth surface structure. Selective etching, core–shell formation and doping of nanoparticles are also discussed as fluorescence–enhancing preparative techniques. Examples of self–assembly of almost–uniformly–sized nanoparticles are given, which result in two–dimensional and three–dimensional superlattices, colloidal crystals and crystalline structures built–up from particles of different sizes. Finally, the self–assembled oriented attachment of quasi–spherical ZnO nanoparticles onto single–crystalline nanorods is presented.