Luminescence Properties of Er3+ Ions in Nanocrystalline Glass-Ceramics

In this work, we analyze the influence of the nanocrystallization process on the luminescence properties of Er3+ ions in transparent oxyfluoride tellurite glass-ceramics obtained by heat treatment of the precursor Er-doped glass. The comparison between the fluorescence properties of Er-doped glass and glass-ceramics suggests that a fraction of Er3+ ions are forming nanocrystals while the rest remain in a glass environment. The presence of fluoride nanocrystals has a strong effect in the upconverted red emission from F-4(9/2) level. This emission increases significantly as compared with the green one in the glass-ceramic sample. The time evolution of the upconverted red emission shows that energy transfer upconversion processes are responsible for the increase of this emission in the glass-ceramic samples.