Multi-color emission evolution and energy transfer behavior of La3GaGe5O16:Tb3+,Eu3+ phosphors

Abstract

A series of color-tunable green-red emitting La₃GaGe₅O₁₆:Tb³⁺,Eu³⁺ phosphors were prepared by a high temperature solid-state reaction, and their phase structure and photoluminescence (PL) properties were investigated in detail. A series of characteristic emission lines originated from the f–f transitions of Tb³⁺ and Eu³⁺ can be observed from the PL spectra and the emission intensities' variation of the two strong emission lines peaking at around 544 nm (green) and 617 nm (red) induced the multi-color emission evolution via the fine tuning of the Tb³⁺/Eu³⁺ content ratio. The energy transfer process between Tb³⁺ and Eu³⁺ was demonstrated to be a resonant type via a dipole–dipole mechanism, and the crystal distance R_c calculated by the quenching concentration method and the spectral overlap method was 15.24 and 17.32 Å, respectively. Thermal quenching luminescence results reveal that La₃GaGe₅O₁₆:Tb³⁺,Eu³⁺ exhibits good thermal stability.