Quenching effect in luminescent and magnetic properties of Fe3O4/α-Fe2O3/Y2O3:Eu3+ nanocomposites

In this paper, Fe3O4/α-Fe2O3/Y2O3:Eu3+ multifunctional nanocomposites were synthesized using a hydrothermal method. Fe3O4/α-Fe2O3/Y2O3:Eu3+ nanocomposites are core-shell nanostructures consisting of a superparamagnetic nanomagnetite core, which is converted to hematite during the synthesis. As a theranostic material, hematite could be used in drug-release processes, while nanomagnetite generates heat in a hyperthermia cancer treatment. An outer shell of Y2O3:Eu3+ nanophosphor is added to give nanocomposites photoluminescent properties and to render them visible in bioimaging. Structural, optical, and magnetic features of nanocompositesare studied using X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), Raman, photoluminescence (PL), vibrating-sample magnetometer (VSM), and high-resolution transmission electron microscope (HRTEM) techniques. Photoluminescence properties of nanocomposites show a quenching effect related to the proportion of magnetite and Y2O3:Eu3+. A luminescence quenching mechanism is proposed based on the optical effects of a core-shell structure. Magnetic saturation grows proportionally with the amount of magnetite present, which indicates that Fe3O4 magnetic structure is not altered, even by the hematite that forms around it. The synthesized nanocomposites possess a core-shell morphology modified by the different proportions of their components. The optical, structural, and magnetic nanocomposite properties found will be of interest in theranostic materials research in the biomedical field.