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.