CaWO4:Yb3+,Tm3+ Crystals and SrAl2O4:Eu2+,Dy3+ Phosphors in Glass-Based Composites for Green Afterglow after NIR Excitation

Here, we present the preparation of composites with green persistent luminescence using melting process. The composites are phosphate glass (75NaPO 3 -25CaF 2 and 90NaPO 3 -10NaF (in mol%)) with embedded phosphors: CaWO 4 : Yb 3+ , Tm 3+ crystals with blue upconversion and SrAl 2 O 4 :Eu 2+ ,Dy 3+ with green persistent luminescence. Green persistent luminescence above 0.3 mcd/m 2 can be seen for ~ 30 minutes after charging with 980 nm due to energy transfer between the blue upconverter crystals and the persistent luminescent phosphors. Challenges related to the fabrication of such composites are discussed.