Synthesis and characterization of nanostructured ceramic luminescent materials.

摘要

This study has determined the factors that affect the luminescence of Y2O3:Tm,Yb and Y2O3:Eu nanophosphors. A combustion synthesis technique was used to prepare these materials, which yielded ultrafine powders. Upon annealing at varied temperatures and times, the powder crystallites grew to dimensions from a few nanometers to several hundred nanometers. The annealing process produced an increase in brightness. This was attributed to a decrease in defects and grain boundaries, which act as quenching centers. The growth of the crystallites was verified using x-ray diffraction spectra and transmission electron microscopy. Fourier transform infrared spectroscopy on the annealed powders showed that there was very little difference in impurity levels with heat treatment temperature and time. Therefore, it is concluded that impurities do not play a significant role in the increase in the brightness of these phosphors, while the elimination of grain boundaries and defects affects the luminescence of the phosphors directly.