Effect of sol–gel combustion temperature on the luminescent properties of trivalent Dy doped SrAl2O4

Trivalent dysprosium doped strontium aluminates (SrA12O4:Dy3+) were synthesized by firing the sol–gel at 600, 700 and 800 °C. The morphology, crystal structure, photoluminescence and long afterglow of the synthesized SrAl2O4:Dy3+ phosphors were characterized with scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and photoluminescence spectroscopy, respectively. It is found that SrA12O4:Dy3+ phosphors exhibit broadband afterglows with its peak at about 510 nm. As the sol–gel synthesis temperature increases from 600 to 800 °C, the green afterglow of the SrA12O4:Dy3+ phosphors becomes weaker in intensity and shorter in lifetime. The results are discussed in terms of thermally generated point defects in the host material.