Red long lasting phosphorescence in Ca2Ge7O16:Sm3+ via persistent energy transfer from the host to Sm3+

Abstract A red long-lasting phosphorescence phosphor Ca 2 Ge 7 O 16 :Sm 3+ was synthesized by a high temperature solid state reaction. The persistent energy transfer process from Ca 2 Ge 7 O 16 host to Sm 3+ was confirmed to be much more efficient than that in the photoluminescence process. The color of the persistent luminescence could be adjusted from blue to red with increasing concentration of Sm 3+ accordingly. Based on the analysis of the thermoluminescence curves, it was found that Sm 3+ doped Ca 2 Ge 7 O 16 also provided a possibility to be a kind of photo-storage phosphor. Detailed mechanism were studied and illustrated.