Core–shell structured SiO2@YVO4:Dy3+/Sm3+ phosphor particles: Sol–gel preparation and characterization

Spherical SiO2 particles have been coated with YVO4:Dy3+/Sm3+ phosphor layers by a Pechini sol–gel process, leading to the formation of core–shell structured SiO2@YVO4:Dy3+/Sm3+ particles. X-ray diffraction (XRD), Fourier-transform IR spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as lifetimes were used to characterize the resulting SiO2@YVO4:Dy3+/Sm3+ core–shell phosphors. The obtained core–shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 300 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (20 nm for one deposition cycle). The core–shell particles show strong characteristic emission from Dy3+ for SiO2@YVO4:Dy3+ and from Sm3+ for SiO2@YVO4:Sm3+ due to an efficient energy transfer from YVO4 host to them. The PL intensity of Dy3+ and Sm3+ increases with raising the annealing temperature and the number of coating cycles.

Graphical abstractSpherical SiO2 particles have been coated with YVO4:Dy3+/Sm3+ phosphor layers by a Pechini sol–gel process. The PL intensity of Dy3+ and Sm3+ increases with raising the annealing temperature and the number of coating cycles.Figure optionsDownload full-size imageDownload as PowerPoint slide