Preparation and characterization of magnetic luminescent nanocomposite particles

Abstract 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 Fe 3 O 4 nanoparticles were coated with silica, forming SiO 2 /Fe 3 O 4 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 SiO 2 /Fe 3 O 4 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 SiO 2 /Fe 3 O 4 nanoparticles and the PL intensity increased.