Tuning the energy bandgap of CdSe nanocrystals via Mg doping

CdSe nanocrystals with a zinc blende structure allowed apparent Mg doping (similar to 9.8 at. %). Inverse micelles were formed at a low temperature as templates for the zinc blende CdSe nanocrystals, and paraffin oil and oleic acid were used as a solvent and a surfactant, respectively. The Mg doping was shown by energy dispersive x-ray spectroscopy ( EDS) and inductively coupled plasma ( ICP) atomic emission analyses. Although the particle size of the CdSe and Mg-doped CdSe nanocrystals were similar to 6 and similar to 8 nm, respectively, the Mg-doped ones show the obvious blueshift in the UV-visible absorption spectra due to the increase in the bulk energy bandgap, which is decisive evidence for the real Mg doping in the CdSe lattices. The Mg-doped CdSe nanocrystals also showed the blueshift in the photoluminescence ( PL) spectra, and their PL intensity was comparable to or even higher than that of the undoped CdSe. This impurity doping using the zinc blende structure is suggested as a simple and effective way to tune the energy bandgap of CdSe nanocrystals and, in turn, to control their light emission colour.