Effect of Eu, Tb codoping on the luminescent properties of multifunctional nanocomposites

Abstract

The synthesis (by a facile two-step co-precipitation process) and characterization, are reported for good dispersed core–shell structured Fe₃O₄@SiO₂@Y₂O₃:Eu³⁺, Tb³⁺ nanocomposites with luminescent and magnetic properties. XRD patterns show that Fe₃O₄ core has crystallized with a good face-centered cubic structure; SiO₂ layer is amorphous and Y₂O₃ layer is cubic. TEM images show the synthesis of core–shell structured composite microspheres of uniform size with rough surface. For nanocomposites with same host (Y₂O₃), upon excitation with UV irradiation, fluorescent spectra show that there is a strong emission at around 610 nm corresponding to the forced electric dipole ⁵D₀–⁷F₂ transition of Eu³⁺ and at around 545 nm corresponding to ⁵D₄–⁷F₅ transition of Tb³⁺. We speculate that there exists energy transfer from Tb³⁺ to Eu³⁺ ions from excitation spectra. Therefore, the multifunctional nanocomposites are expected to develop many potential applications in biomedical fields.