7 - Fluorescence in Nanostructured Oxyfluoride Glasses Doped with Rare Earth Ions

Abstract

Glasses and glass-ceramics doped with rare earth ions were prepared and distribution of rare earth ions in nanocrystals was investigated to understand its effect on the emission properties. X-ray diffraction, fluorescence spectroscopy, and electron energy loss spectroscopy analysis indicated that rare earth ions are preferentially incorporated into the fluoride nanocrystals. Distribution of rare earth ions inside the fluoride nanocrystals, however, was not homogeneous; regions with high concentration of rare earth ions were distributed randomly inside the nanocrystals. Presence of such regions with high rare earth concentration not only led to the fluorescence quenching, but also induced the structural variation. Codoping of YF3 reduced the cross relaxation among Er3+ ions and increased the intensities of near- and middle-infrared fluorescence. It is most likely due to the decrease in the degree of inhomogeneity of Er3+ ions inside the nanocrystals.