Tb3+ luminescence by energy transfer from Eu2+ in (Sr,Ba)2SiO4 phosphor

(Sr,Ba)2SiO4 phosphors co-doped with Tb3+ and Eu2+ were prepared by a conventional solid-state reaction method. Prepared (Sr,Ba)2SiO4:Tb,Eu phosphors had characteristic luminescent spectra excited under near-UV excitation in which both the broadband spectrum assigned to Eu2+ and the narrowband spectrum assigned to Tb3+ are observed, although Tb3+ is inactive with this photon energy in general. The sudden emergence of the Tb3+ luminescence shows that Eu2+–Tb3+ energy transfer is possible in the phosphor. We also studied the energy transfer mechanism in terms of the resonant energy transfer theory and found that the crystal structure of the host material Sr2SiO4 plays an important role in the luminescence properties of the phosphor. The Eu2+–Tb3+ energy transfer is ascribed to the overlap between the shorter Eu2+ luminescence band from the Sr2SiO4 crystal structure with two Sr sites and D54 energy level of Tb3+ ion. Therefore, this phosphor has a potential for application to white light-emitting diodes exci...