Silica Supported Submicron SiO₂@Y₂SiO₅:Eu³⁺ and SiO₂@Y₂SiO₅:Ce³⁺/Tb³⁺ Spherical Particles with a Core–Shell Structure: Sol–Gel Synthesis and Characterization

Abstract

Abstract X 1 ‐Y 2 SiO 5 :Eu 3+ and X 1 ‐Y 2 SiO 5 :Ce 3+ and/or Tb 3+ phosphor layers have been coated on nonaggregated, monodisperse, submicron spherical SiO 2 particles by a sol–gel process, followed by surface reaction at high temperature (1000 °C), to give core/shell structured SiO 2 @Y 2 SiO 5 :Eu 3+ and SiO 2 @Y 2 SiO 5 :Ce 3+ /Tb 3+ particles. X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), TEM, photoluminescence (PL), low voltage cathodoluminescence (CL), and time‐resolved PL spectra and lifetimes are used to characterize these materials. The XRD results indicate that X 1 ‐Y 2 SiO 5 layers have been successfully coated on the surface of SiO 2 particles, as further verified by the FESEM and TEM images. The PL and CL studies suggest that SiO 2 @Y 2 SiO 5 :Eu 3+ , SiO 2 @Y 2 SiO 5 :Tb 3+ (or Ce 3+ /Tb 3+ ), and SiO 2 @Y 2 SiO 5 :Ce 3+ core/shell particles exhibit red (Eu 3+ , 613 nm: 5 D 0 – 7 F 2 ), green (Tb 3+ , 542 nm: 5 D 4 – 7 F 5 ), or blue (Ce 3+ , 450 nm: 5d‐4f) luminescence, respectively. PL excitation, emission, and time‐resolved spectra demonstrate that there is an energy transfer from Ce 3+ to Tb 3+ in the SiO 2 @Y 2 SiO 5 :Ce 3+ ,Tb 3+ core/shell particles. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)