Synthesis and optical properties of CdSe and CdSe/CdS nanoparticles

This paper described the optical properties of CdSe and CdSe/CdS nanopartic les, synthesized by the microemulsion method followed by refluxing in tolue ne/methanol (60:1). Both optical spectroscopy and structural characterizati on (XPS, XRD, and HRTEM) suggested the core/shell structure of CdSe/CdS sam ples. Most notable in this work was that capping CdSe nanoparticles with Cd S materials yielded a strong narrow band-edge luminescence, indicating a su ccessful passivation by removing surface deep trap luminescence. Proper sur face modification with cadmium ions resulted in the further enhancement of the photoluminescence quantum yields of the CdSe and CdSe/CdS nanoparticles . The XPS data confirmed the elemental composition of the CdSe and CdSe/CdS nanoparticles. The CdSe and CdS diffraction patterns exhibited peak positi ons corresponding to those of their bulk wurtzite crystal structures.