Preparation and characterization of magnetic luminescent nanocomposite particles

A new kind of magnetic luminescent nanocomposite (MLNC) particles was prepared by a combination process of sol-gel and electrostatic self-assembly techniques. In this process, superparamagnetic Fe3O4 nanoparticles were coated with silica, fort-ning SiO2/Fe3O4 core-shell structure particles. A surface-active agent, 3-aminopropyltrimethoxysilane was then used to terminate the silica surface of these particles with amino groups. Finally, thioglycolic acid (TGA)-capped CdSe Quantum Dots (QDs) were attached onto the surface Of SiO2/Fe3O4 particles by electrostatic self-assembly. X-ray diffraction (XRD), transmission electron microscopy (TEM), microelectrophoresis, UV-vis absorption and emission spectroscopy and magnetometry were applied to characterize the nanocomposite particles. The particles exhibited favorable superparamagnetic and photoluminescenct (PL) properties. With increasing the thickness of silica shell, more dense CdSe QDs were attached on the SiO2/Fe3O4 nanoparticles and the PL intensity increased. (c) 2008 Elsevier B.V. All fights reserved.