Synthesis and Optical Properties of CdSe and CdSe/CdS Nanoparticles

Abstract

This paper described the optical properties of CdSe and CdSe/CdS nanoparticles, synthesized by the microemulsion method followed by refluxing in toluene/methanol (60:1). Both optical spectroscopy and structural characterization (XPS, XRD, and HRTEM) suggested the core/shell structure of CdSe/CdS samples. Most notable in this work was that capping CdSe nanoparticles with CdS materials yielded a strong narrow band-edge luminescence, indicating a successful passivation by removing surface deep trap luminescence. Proper surface 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 positions corresponding to those of their bulk wurtzite crystal structures.