Gel combustion synthesis and luminescence properties of nanoparticles of monoclinic SrAl2O4:Eu2+,Dy3+

Nanoparticles of strontium aluminate phosphors co-activated by Eu2+ and Dy3+ have been prepared by heating the precursors obtained from nitrate salt–ammonium acetic–urea–gel combustion process at temperature of 1150 °C in a weak reductive atmosphere of thermal carbon. Transmission electron microscope (TEM) images revealed that the hollow nanoparticles of SrAl2O4:Eu2+,Dy3+ were formed below 1150 °C, while the needle or rod-shaped particles were formed at 1200 °C. The XRD patterns indicated that the resulted SrAl2O4:Eu2+,Dy3+ nanoparticles contained distorted monoclinic lattice. The environment of rare earth ion in SrAl2O4 lattice was investigated by using Eu3+ as ion probe, and the results indicated that there were two kinds of sites occupied by Eu3+, one was centro-symmetrical environment, while the other not. The luminescence and the afterglow properties of the hollow nanoparticles of SrAl2O4:Eu2+,Dy3+ were also investigated.