Synthesis and characterization of SrAl2O4:Eu2+, Dy3+ nanocrystalline phosphorescent pigments

In this research, the Eu2+ and Dy3+ co-doped strontium aluminate (SrAl2O4) nanocrystalline phosphorescent pigments with high brightness and long afterglow was successfully synthesized by urea-nitrate solution combustion method (SCS) at 600 deg C, followed by heating the resultant combustion ash at 1200 deg C in an atmosphere which was weak reducing (5% H2 + 95%N2). The pure SrAl2O4 monoclinic phase as host structure could be formed by combustion method in which the temperature is very much lower than solid-state method. A broad-band UV-excited luminescence of the SrAl2O4:Eu2+, Dy3+ phosphorescent pigments was observed at λmax = 517 nm due to transitions from 4f65d1 to 4f7 configuration of the emission center (Eu2+ ions). The excitation spectra showed two main peaks at 240 and 256 nm. Eventually, the average grain size of the combustion ash powder and SrAl2O4:Eu2+, Dy3+ phosphor particles were obtained as 40 and 62 nm, respectively via Scherrer's formula and these particles were in thin flake form. (author)