Green upconversion luminescence in Er3+:BaTiO3 films

Abstract

Green upconversion emissions at 548 and 528 nm have been obtained from sol-gel derived nanocrystalline ${\mathrm{Er}}^{\mathrm{3+}}{\mathrm{:BaTiO}}_{\mathrm{3}}$ films under 980 nm excitation. The green emissions are attributed to the ground-state ${(}^4{I}_{\text{15/2}})$ -directed transitions from ${}^2{H}_{\text{11/2}}$ (528 nm) and ${}^4{S}_{\text{3/2}}$ (548 nm) of ${\mathrm{Er}}^{\mathrm{3+}}$ ions. Analysis of the temporal evolution of the emission at 548 nm shows that both excited state absorption of individual ion and energy transfer between the two neighboring ions contribute to the upconversion emissions in ${\mathrm{Er}}^{\mathrm{3+}}{\mathrm{ (3 mol \%):BaTiO}}_{\mathrm{3}}$ film. The lifetime of the dominant emission at 548 nm is about 90 μs.