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

Tong, Lizhu, Ren, Xiaozhen, Chen, Xiaodong, Ding, Hong, Yang, Hua
RSC advances 2014 v.4 no.43 pp. 22792-22797
X-ray diffraction, coprecipitation, crystallization, energy transfer, europium, fluorescence, ions, iron oxides, magnetic properties, microparticles, nanocomposites, silica, terbium, transmission electron microscopy, ultraviolet radiation
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.