II–VI semiconductor nanocrystals in thin films and colloidal crystals

Semiconductor nanocrystals whose optical properties are largely determined by the quantum confinement effect are currently being extensively studied in both physics and chemistry. Highly luminescent thiol-capped CdTe and HgTe nanocrystals with desirable sizes ranging from less than two to approximately 8 nm have been recently synthesized in aqueous solutions by a wet chemical route. They were used for the preparation of composite multilayer thin films by the layer-by-layer (LBL) deposition technique. Films containing luminescent nanocrystals were made both on planar substrates and on submicron-sized monodisperse polystyrene spheres. Alternatively, nanocrystals have been incorporated as cores into silica spheres of desirable sizes. Composite nanocrystal/silica and core-shell latex/nanocrystal spheres have been used as building blocks for 3-D colloidal photonic crystals.