Preparation of CdSe@SiO_2 Fluorescent Nanomaterials by Direct Synthesis Method

Zinc blende CdSe@SiO2 luminescent nanoparticles was directly synthesized using 3-mercaptopropyl-trimethoxysilane(MPS) as a capping molecule.The method simplified the preparation process of silanized quantum dots and reduced the preparation time.The properties of the as-prepared nanoparticles were characterized by fluorescence spectra(FL),X-ray diffraction(XRD) and transmission electron microscopy(TEM).The results indicated that the optical properties of synthesized CdSe@SiO2 quantum dots are obviously dependent on the conditions of tool ratio of n(Cd2+)∶n(SeSO2-3)and the pH value of reaction system.The luminescent nanoparticles obtained on the oputium contions are monodisperse with an even size of 20 nm.As compared to the CdSe quantum dots,CdSe@SiO2 luminescent nanoparticles have better photochemical stability.Moreover,the silica-coated CdSe quantum dots have improved stability and photobleaching resistance.