Sensitized red luminescence from Ce3+, Mn2+-doped glaserite-type alkaline-earth silicates

Bright red luminescence is observed from Ce, Mn-doped glaserite-type alkaline-earth silicates with M2BaMgSi2O8 (M: Ba, Sr, Ca) chemical composition. Under UV excitation, Ce-doped M2BaMgSi2O8 exhibits strong near-UV emission with asymmetric peak shape. UV-excited Mn-doped M2BaMgSi2O8 compounds show visible red emission only when Ce3+ ions are doped together. These results indicate that Mn2+-derived red emission is caused by an efficient energy transfer from Ce3+ to Mn2+. The red emission becomes intense with an increase in Ba-amount. This trend originates from the relaxation of the selection rule for 3d-3d transition in Mn2+ ions, which is caused by the structural deformation due to Ba2+ occupation for layer-pockets.