Synthesis and luminescence properties of monodisperse SiO2@SiO2:Eu3+ microspheres

Monodisperse coreshell structured SiO2@SiO2:Eu3+ microspheres were synthesized in a seeded growth way. In that way, a thin shell of Eu3+-doped silica was grown on the prepared monodisperse silica colloids. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), thermal analysis (TGA-DSC) and photoluminescence (PL) spectroscopy. The results reveal that the SiO2 spheres have been successfully coated by SiO2:Eu3+ phosphors and the obtained SiO2@SiO2:Eu3+ particles have perfect spherical shape with narrow size distribution. Additionally, the monodisperse SiO2@SiO2:Eu3+ microspheres exhibit considerably strong photoluminescence (PL) of Eu3+ under the excitation of 393 nm compared with the SiO2:Eu3+ samples with polydispersed or irregular shapes and sizes obtained by base-catalyzed Stliber method. Furthermore, the PL intensity increases with the increasing of Eu3+ concentration in SiO2 microspheres shell, and concentration quenching occurs when Eu3+ concentration exceeds 5.0 mol%. (C) 2014 Elsevier B.V. All rights reserved.