Photoluminescence properties and energy transfer mechanism of new high-performance color-tunable LiLaSiO4: aTb3+, bEu3+ phosphors

Abstract

A series of Tb3+-Eu3+ co-doped LiLaSiO4 single-phase phosphors were synthesized by the high-temperature solid-phase method. When the monitoring wavelength is 378 nm, LiLaSiO4:aTb3+ phosphors have strong green light emission at 552 nm. The optimal doping molar mass fraction of Tb3+ ions is a = 0.08, in LiLaSiO4: aTb3+, bEu3+ phosphors, the emission peak of Tb3+ not only exists at 552 nm, but also the emission peak of Eu3+ at 618 nm. As the doping molar mass fraction of Eu3+ ions increasingly, the luminous intensity of Tb3+ ions reduce, while the luminous intensity of Eu3+ ions first increased and then gradually decreased. The luminescence color can be changed from green to red by adjusting the doping ratio of Tb3+-Eu3+ ions. Fluorescence lifetime and the emission spectra of the co-doped phosphors were characterized to verify the existence of energy transfer between Tb3+ and Eu3+ in this single-phase phosphor.Energy transfer efficiency and energy transfer mechanism were investigated in detail. Compared with previous reports, it has higher energy transfer efficiency, quantum yield and thermal stability. This synthesized single-phase LiLaSiO4:aTb3+, bEu3+ phosphor is an excellent candidate for the white light-emitting diodes.