Luminescence and energy transfer of Eu2+/Tb3+/Eu3+ in LiBaBO3 phosphors with tunable-color emission

Abstract

A series of LiBaBO₃:RE (RE = Eu²⁺/Tb³⁺/Eu³⁺) phosphors have been synthesized using the high-temperature solid-state reaction method. The X-ray diffraction (XRD), emission spectra, excitation spectra, decay lifetimes, and diffuse reflection spectra were utilized to characterize the phosphors. The as-prepared samples have been characterized via XRD measurement and showed that Eu²⁺/Tb³⁺/Eu³⁺ can be efficiently doped into the host. The obtained phosphors can emit different colors of light when doping with different activators. The energy transfer from Tb³⁺ to Eu³⁺ occurs in LiBaBO₃:0.03Eu³⁺,yTb³⁺ prepared in the air. While an abnormal reduction phenomenon was reported when Eu and Tb ions were co-doped in LiBaBO₃ and prepared in an inferior reductive atmosphere, which showed tunable-color from blue to red based on energy transfer of Eu²⁺ → Tb³⁺ → Eu³⁺ ions. And the energy transfer not only can occur between Eu²⁺ and Tb³⁺ ions, but also between Tb³⁺ and Eu³⁺ ions. All these results reveal that Tb³⁺ can play the role of storing the energy for Eu³⁺, and LiBaBO₃ may be a potential candidate phosphor for LEDs.