Emission of Eu3+ in SiO2-ZnO glass and SiO2-SnO2 glass-ceramic: Correlation between structure and optical properties of Eu3+ ions

SiO2:Eu3+ based free-crack transparent bulk composites containing two types of semiconductor nanoparticles (SnO2 or ZnO) were synthesized by sol-gel process. The results of vibrational spectra (Raman, FT-IR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) indicate that the SiO2-SnO2 matrix possess the structure of a glass-ceramic due to the presence of SnO2 nanocrystals with average size of 7 +/- 2 nm homogeneously distributed in silica matrix whereas the SiO2-ZnO still remain amorphous structure after a heat treatment at 600 degrees C for 1 h. The energy transfer from nanoparticles to Eu3+ ions is observed in both composites, but this process is more efficient in the glass-ceramic systems. Moreover, the competition between magnetic dipole and electric dipole transitions of Eu3+ as well as the shape of emission bands depends strongly on the structure of host matrix. (C) 2017 Elsevier B.V. All rights reserved.