Synthesis and characterisation of optically tuneable, magnetic phosphors

YVO4:Eu3+ phosphor particles have been encapsulated with silica using core-shell technology to produce particles of 400-600 nm in size. The surface of the outer silica shell was further functionalised by the introduction of iron oxide nanoparticles, thus producing a material possessing both magnetic and luminescent properties. The YVO4:Eu3+-SiO2-magnetite composite material was characterised by X-ray diffraction (XRD), Raman and Fourier transform IR spectroscopy, scanning electron microscopy and emission spectroscopy. Characterisation of the outer iron oxide coating with 57Fe Moessbauer spectroscopy, magnetization measurements and scanning electron microscopy reveals the presence of non-stoichiometric maghemite and magnetite nanoparticles of sizes less than ∼20 nm.