Magnetic-Fluorescent Nanocomposites Fe3O4@SiO2@ZnSe: Preparation and Characterization

Fe 3 O 4 @SiO 2 @ZnSe composite nanoparticles with superparamagnetism and luminescence have been prepared by a facile chemical method. Nontoxic fluorescent ZnSe quantum dots were assembled around the Fe 3 O 4 -silica core–shell nanocomposite via chemical bonds formed between –COOH and –NH 2 . Transmission electron microscopy images show that the nanocomposites are approximately spherical and between 50 nm and 80 nm in size. The bifunctional nanocomposites exhibit superparamagnetic behavior and good fluorescence intensity. Magnetic attraction test, vibrating sample magnetometer at 300 K, UV–visible absorption and fluorescence emission spectroscopy were applied to characterize the magnetic/fluorescent properties of the nanocomposites.