SrAl_2O_4∶Eu^(2+),Nd^(3+) and Dy^(3+) Long Afterglow Phosphor

The SrAl 2O 4∶Eu 2+ , Nd 3+ and SrAl 2O 4∶Eu 2+ , Dy 3+ long afterglow phosphor were synthesized. Their excitation and emission spectra at different excitation and afterglow characteristics were analyzed after the excitation power was taken off. The effects of Eu 2+ , Dy 3+ , Nd 3+ mole concentrations on phosphorescence characteristics were also discussed. It is crucial to have trapping levels located at a suitable depth related to the thermal release rate at room temperature. The incorporation of Nd 3+ ions as an auxiliary activator into the SrAl 2O 4∶Eu 2+ system causes very intense and long phosphorescence. The response time of SrAl 2O 4∶Eu 2+ , Dy 3+ phosphors is quicker than that of SrAl 2O 4∶Eu 2+ , Nd 3+ . Phosphorescence characteristics of SrAl 2O 4∶Eu 2+, Nd 3+ is much better than those of SrAl 2O 4∶Eu 2+ , Dy 3+ . The integrate area of the excitation spectrum of SrAl 2O 4∶Eu 2+ , Nd 3+ phosphor is larger than that of SrAl 2O 4∶Eu 2+ , Dy 3+ phosphor within the range of 250～360 nm. For phosphorescence characteristics to the system of SrAl 2O 4∶Eu 2+ , Nd 3+ phosphor, the optimum concentration of Nd 3+ trivalent rare earth ions is 0.05 mol.