Luminescence enhancement of Tb3+ in Sr3SiO5:Eu2+ phosphor

Sr3SiO5 phosphors co-doped with Eu2+ and Tb3+ were prepared by a conventional solid-state reaction method. The prepared Sr3SiO5:Eu2+,Tb3+,Li+ phosphors had characteristic luminescent spectra excited under near-UV excitation in which both the broadband spectrum assigned to Eu2+ and the line spectrum assigned to Tb3+ are observed, although Tb3+ is inactive with this photon energy in general. For Eu2+-Tb3+ codoped Sr3SiO5, energy transfer process takes place and the mechanism is ascribed to the overlap between the shorter Eu2+ luminescence band from the Sr3SiO5 crystal structure with two Sr sites and D-5(4) energy level of Tb3+ ion. Due to the energy transfer, PL intensity of Eu2+ emission increased about 26 %. We suggest that this enhancement mechanism could shed light on the potential applications in white light-emitting diodes excited by near-UV light. In addition, the emission peak position near the orange region indicates that our system is a step towards a new class of wavelength sources for artificial lighting with improved PL intensity and lower energy consumption.