Processing and Characterization of Phosphorescent Strontium Aluminate Powders
We have demonstrated the synthesis of lanthanide co-doped nominally SrAl2O4 powders that phosphoresce over long durations. Previous work has reported that the color of phosphorescence depends on the nature of the alkaline earth cation, and that extended phosphorescence in Eu2+ and other lanthanide co-doped MAl2O4 (M= Sr, Ca, Ba) systems occurred with boron incorporation. To gain further insight into the mechanism of extended phosphorescence persistence, we investigated the incorporation of other glass-forming cations, Si and P. The Eu2+ and Dy3+ co-doped SrAl2O4 (SAED) powders were processed by solution polymerization and annealed at 1000oC under a reducing atmosphere. X-ray diffraction spectra revealed that these powders were multiphase. To characterize the optical properties, photoluminescence spectra and phosphorescence persistence curves were measured using a 325-nm wavelength excitation source. We report that the addition of B2O3 alone to SAED powders extended the persistence, while decreasing the luminosity, but more interestingly, the addition of B2O3 along with other glass formers dramatically increased the excitation luminosity.
C. W. Ow-Yang et al., "Processing and Characterization of Phosphorescent Strontium Aluminate Powders", Advances in Science and Technology, Vol. 45, pp. 2627-2632, 2006