Design and Synthesis of High-Quality CdS/ZnSe Type-II Core/Shell Nanocrystals

High-quality (narrow size distribution, high crystallinity, high luminescent efficiency) type-II core/shell nanocrystals have been designed and prepared based on ZnSe epitaxial growth around CdS core template. The CdS/ZnSe type-II core/shell nanocrystals were prepared by the alternate injection of Se/Zn precursors into a diluted pre-prepared CdS core nanocrystals reaction solution via the successive ion layer adsorption and reaction (SILAR) technique. The claimed core/shell structure was confirmed by the optical spectra, TEM analysis and XRD measurement. The emission colors of the obtained CdS/ZnSe nanostructures can be tuned from 510 nm to 590 nm by the variation of both the size of the CdS core and the thickness of the ZnSe shell. The photoluminescence properties of the obtained CdS/ZnSe core/shell nanocrystals (emission efficiency up to 50%) are comparable to the best result reported for the extensively studied CdSe based nanocrystals.