Synthesis And Optical Properties Of Rare-Earth Doped Cdse QDs In Aqueous Solution

Semiconductor quantum dots(QDs) is a novel material and may find application in Memory, Solar cells and Biological fluorescent labeling.CdSe QDs have been successfully synthesized in aqueous solution. We obtained the CdSe QDs with different sizes and different monodispersity by controlling reaction conditions(temperature, time,3-Mercaptopropionic acid(MPA) concentration). The Photoluminescence(PL) spectra results show that the intensity of60℃sample was enhanced compared with that of30℃sample. And it also show that CdSe QDs size becomes larger with the reaction time.We further synthesized rare-earth ion Eu3+doped CdSe QDs, CdSe/ZnS (CdSe/CdS) core-shell QDs and initially attempted to dope Eu3+ions in ZnS shells. The PL spectra results show that the PL intensity was enhenced with the Eu3+ion doping concentration. It was found that the CdSe:Eu3+QDs with MPA capping exhibited the Eu3+ion related characteristic luminescence. When a larger band gap CdS shell was deposited at the surface of the CdSe, luminescence intensity was enhanced nearly two times. CdSe/CdS QDs fluorescence is still dominated by CdSe QDs, while generates a small amount of CdS QDs in the reaction.