Abstract
A series of cadmium selenide (CdSe) nanoparticles with rich cadmium ions capped with a bifunctional molecule, which contains both thiols and carboxylic acid groups has been prepared. Nanoparticles have been characterized by Raman, ultraviolet visible (UV–VIS) absorption and photoluminescence spectroscopy and X-ray diffraction (XRD). The Raman spectra showed that the surfactant molecules in the monolayer surrounding the CdSe nanoparticles are in a close-packed, crystalline state. Otherwise, the Cd ion on the nanoparticles surface can bind to both carboxylate and thiolate ions, and the nanoparticles having an increasing number of broken Cd-OOC bonds showed that the trapping centers form the surface were predominant in the photoluminescence emissions. On the other hand, the calculated Huang Rhys factor (
S) from both Raman spectra and Stokes shift showed that
S increases with decreasing nanoparticles size.