Synthesis of ZnSe/CdS/ZnSe Nanobarbells Showing Photoinduced Charge Separation

We report on a colloidal synthesis of barbell-shaped nanocrystals comprising a type II heterojunction of ZnSe and CdS domains and showing compelling evidence of photoinduced charge separation at the interface of ZnSe and CdS materials. The nanobarbells were fabricated in a two-step procedure by growing ZnSe caps onto polar facets of CdS nanorods. Under present synthetic conditions, minimal growth of ZnSe shell in the lateral direction and focusing of the barbell length distribution were observed. Formation of epitaxial interfaces between nearly lattice-matched ZnSe and CdS crystal phases was primarily evidenced by the observation of “spatially indirect” fluorescence and long radiative lifetimes corresponding to the decay of charge transfer states.