Controlled fabrication of bi-functional Fe3O4@SiO2@Gd2O3:Yb,Er nanoparticles and their magnetic, up-conversion luminescent properties

We develop a facile layer-by-layer deposition process to create bi-functional Fe3O4@SiO2@Gd2O3:Yb,Er nanostructures composed of magnetic Fe3O4 cores, variable SiO2 mid-layers, and up-converting Gd2O3 shells. The synthetic process is well-controlled and the obtained Fe3O4@SiO2@Gd2O3:Yb,Er nanoparticles show relative monodispersity and exhibit tunable magnetic and up-conversion luminescence depending on the thickness of SiO2 mid-layers. The influences of SiO2 mid-buffer-layers on morphology, magnetism, and up-conversion luminescence are well addressed. The obtained bi-functional Fe3O4@SiO2@Gd2O3:Yb,Er nanoparticles may be potentially applicable in magnetic, fluorescent, and biological applications. The synthetic route may be employed for fabricating other multifunctional nanostructures.