Preparation and characterization of silica@Eu spheres

An unsophisticated preparation of silica@Eu spheres has been investigated. Many experimental tests, such as transmission electron microscopy and energy dispersive spectrometer mapping, were carried out to confirm that the rare earth complex coats the surface of silica spheres and also confirming the formation of silica@Eu. The combination of silica and a rare earth complex is realized by a simple binding force of nitrogen and fluorine in the ligand and the hydrogen bond on the surface of silica from an x-ray photoelectron spectroscopy test. The synthetic composite fluorescent microsphere greatly improves the thermal stability, as compared with a pure complex. The relationship between emission intensity and diameters of silica is also investigated. The results of the study found that as the size of silica increases, the fluorescence intensity enhances. Furthermore, the increase in size also extends the fluorescence lifetime to some extent. With the embedded structure, the europium complex has better dispersion and other properties, which means that it has broader application prospects, such as bioimaging, fluorescent markers, and optoelectronic devices.