Long Lasting Yellow Phosphorescence in Sr_3SiO_5∶Eu~(2+) and Sr_3SiO_5∶Eu~(2+),Dy~(3+) Phosphors

Sr3SiO5∶Eu2+ and Sr3SiO5∶Eu2+,Dy3+ phosphors have been synthesized through the solid-state reaction technique.We observed long lasting yellow phosphorescence in Sr3SiO5∶Eu2+ and Sr3SiO5∶Eu2+,Dy3+ phosphors,originating from 4f65d-4f7 transition of Eu2+,after UV exposure.The phosphorescence in Sr3SiO5∶Eu2+ can be observed by naked eyes for more than 4 hours after the termination of excitation light.The decay patterns of phosphorescence and thermoluminescence curves demonstrate that introduction of Dy3+ into Sr3SiO5∶Eu2+ can generate lots of shallow traps and deep traps.The generated deep traps prolong the phosphorescence up to 6 hours after UV irradiation.The depths of traps are obtained by fitting the thermoluminescence experimental data to the general order kinetics formula.