Optical properties of CdS:Mn nanocrystals surface passivated with zinc hydroxide

For the further application performance, CdS:Mn nanocrystals coated with zinc hydroxide (Zn(OH)2) shells were prepared via wet chemical method. Effect of Zn(OH)2 shells on optical properties of CdS:Mn nanocrystals was investigated. X-ray diffraction (XRD) measurements showed that the CdS nanocrystals have hexagonal wurtzite structure. The morphology and components of CdS:Mn/Zn(OH)2 core/shell nanocrystals were successfully measured by transmission electron microscopy (TEM) with energy-dispersive X-ray (EDX). Luminescence properties (intensity and lifetime) of 4T1 → 6A1 transition of Mn2+ ions in CdS:Mn/Zn(OH)2 core/shell nanocrystals were significantly enhanced as compared with those of unpassivated CdS:Mn nanocrystals. This expected result was caused by the effective, robust passivation of CdS surface states with Zn(OH)2 shells, which consequently suppressed nonradiative recombination transitions.