Effect of microwave heat-treatment on up-conversion luminescence of Er3+/Yb3+co-doped NaYF4 oxy-fluoride glass-ceramics

The microscopic properties of fluoride grains are known to play critical roles in the up -conversion luminescence properties of phosphors carrying rare -earth -based luminescence centers. To study the effect of different heating methods during preparation on the microstructure and up -conversion luminescence performance of oxy-fluoride glass -ceramics, we synthesized Er3+/Yb3+ co -doped NaYF4nanocrystals containing transparent glass -ceramics by microwave heat -treatment and the normally heating methods. We characterized the internal structure of glassceramics by X-ray diffraction, transmission electron microscopy, mid -infrared spectroscopy, and Raman spectroscopy. While glass -ceramics samples prepared by both methods have extremely high optical transmittance similar to that of a glass, the microwave heat -treatment promoted faster grain growth rate, the glass -ceramics sample had better crystallinity and much improved up -conversion luminescence intensity compared to the sample obtained by the normally heating method.