Nanocrystals of Many Sizes
Solutions of CdSe-core, ZnS-shell nanocrystals. The changing color is a quantum size effect of the CdSe core, which increases in size from left (3nm) to right (6nm). The bright fluorescence arising from the ZnS shell was reported in 1995. Fluorescent nanocrystals are developed for bio-imaging and optical display.