Comparative study on two synthesis methods of core-shell structured SiO2@Y2O3:Eu3+ particles and their luminescence properties

SiO2@Y2O3:Eu3+ spherical particles with core-shell structure have been synthesized successfully by a hydrothermal method, followed heat treatment, leading to the formation of monodisperse SiO2@Y2O3:Eu3+ core-shell particles. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), Fourier Transform infrared spectroscopy (FT-IR) and photoluminescence spectra (PL) were used to characterize the as-obtained samples. The SEM indicates that the as-obtained core-shell particles show good spherical shape and non-agglomeration with a narrow size distribution (average size of 420 nm). Further studies about some experimental conditions show that the PL intensity is the highest when Y2O3:Eu3+ layers are coated on the surface of SiO2 particles with average size of about 150 nm annealed at 800 °C. For comparison, the core-shell particles are also synthesized by a simple precipitation method. The PL shows that under the excitation at 240 nm, the samples present strong red emission corresponding to the 5D0 → 7F2 transition of the Eu3+ ions at 613 nm. Moreover, the emission spectra intensity by hydrothermal method is much higher than that of sample by precipitation method, because the former present the better dispersion, less percentage of the interface, and more thickness shells than that of the latter.