Zn2+ addition: A facile way to obtain CdTe nanocrystals powders with enhanced fluorescence emission

The CdTe nanocrystals are synthesized in aqueous solution with a capping ligand of thioglycollic acid. The optical properties of the nanocrystals are investigated by the measurements of ultraviolet–visible absorption and fluorescence emission. Our results show that the addition of Zn2+ can greatly enhance the fluorescence emission of the colloid nanocrystals by one order of magnitude. Meanwhile, it can make the nanocrystals settle rapidly. Thus, the CdTe powder nanocrystals with high fluorescence emission can be easily obtained via a simple centrifugation and subsequent drying process. In addition, the successful dissolution of the powder in NaOH solution reveals a good reuse of the nanocrystals in a colloid state.