Synthesis and characterisation of magnetic-fluorescent Fe3O 4@SiO2@ZnS nanocomposites

Abstract

Bifunctional magnetic-fluorescent Fe3O4@SiO 2@ZnS nanocomposites were synthesised by a chemical deposition method. The Fe3O4 magnetic nanoparticles as the core were obtained by means of a solvothermal reaction with SiO2 as the shell. ZnS particles were linked to Fe3O4@SiO2 core-shell nanostructures. The morphology and properties of the resultant Fe3O4@SiO2@ZnS nanocomposites were investigated by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, a vibration sample magnetometer and fluorescence microscopy. The results showed that bead-like structures were built from numerous Fe3O4@SiO 2@ZnS microspheres with an average size of 250 nm. The saturation magnetisation (Ms) value of Fe3O4@SiO 2@ZnS nanocomposites was 22.41 emu/g at room temperature. Furthermore, a strong blue light emission was observed from the nanocomposites under UV light irradiation. The combination of magnetic and fluorescent properties may lead to Fe3O4@SiO2@ZnS nanocomposites having a variety of potential applications in the field of biomedicine, such as bioimaging and cell separation. © The Institution of Engineering and Technology 2014.