Ce3+ to Mn2+ energy transfer in Sr3Y2Ge3O12:Ce3+, Mn2+ garnet phosphor

•The Sr3Y2Ge3O12:Ce, Mn garnet phosphors were obtained by the solid state reaction.•Efficient Ce3+ → Mn2+ energy transfer occurs via dipole–dipole interaction.•The emission color can be tune from green to orange.

Ce3+ and Mn2+ singly doped and co-doped Sr3Y2Ge3O12 phosphors were synthesized by the solid–state reaction. In these phosphors Ce3+ ions occupy exclusively the Sr2+ site while Mn2+ ions mostly the Y3+ site with some traces in the Sr2+ site. Under excitation at 430 nm into the Ce3+ absorption band the Sr3Y2Ge3O12: Ce3+, Mn2+ phosphor emits green light from Ce3+ (530 nm) and red light from Mn2+ (630 nm) due to the Ce3+ → Mn2+ energy transfer. By appropriate ratio of the active ion concentrations the Ce3+ and Mn2+ co-doped Sr3Y2Ge3O12 phosphor can generate lights from green to orange region. We showed that the mechanism of energy transfer from Ce3+ to Mn2+ is of the resonance type and it occurs via an electric dipole–dipole interaction. Furthermore, we calculated the critical distance for Ce3+ → Mn2+ energy transfer to be 16.90 Å by concentration quenching methods.

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