Bright white-light emission from semiconductor nanocrystals: by chance and by design

The synthesis and characterization of two bright white-light-emitting semiconductor nanocrystal (NC)-based systems is reported. CdS NCs emit white light because of the presence of surface states over the entire range of the visible spectrum, whereas CdSe/ ZnS/CdSe/ZnS core/shell/shell/shell NCs are designed to emit white light as a result of the combination of blue and orange emissions from the shell and the core, respectively (see figure).