Core-size-dependent properties of CdSe/CdS core/shell QDs

In this study, the core-size dependent optical properties of CdSe and its surface passivation effects are investigated. In order to evaluate the size-dependence of CdSe crystals, the synthesis temperatures are varied from 240 degrees C to 300 degrees C. The PL intensity of the synthesized CdSe QDs is increased by employing the core/shell structure, i.e., CdSe/CdS. It is can be explained by considering of the defect states passivation effects on the CdSe surface. Smaller-core quantum dots (QDs), which were synthesized at 240 degrees C, show effective photoluminescence enhancement and a stable core/shell structure. It is expected that the smaller QDs with a short wavelength are strongly affected by the shell due to the relatively unstable surface. Also, the thicknesses of shell on cores decide the phase information such as XRD patterns. Crown Copyright (c) 2013 Published by Elsevier B.V. All rights reserved.This research was conducted under the industrial infrastructure program for fundamental technologies (N000600001), which is funded by the Ministry of Knowledge Economy (MKE, Republic of Korea)