New red-emitting Li3Bi3Te2O6:Eu3+ phosphors with high color purity for white light-emitting diodes

This work is the first to synthesize the red-emitting Li₃Bi₃Te₂O₆ phosphors using the conventional high-temperature solid-state reaction. The phase purity, particle morphology, and luminescent properties are analyzed in detail. Upon the near-ultraviolet (n-UV) excitation on 395 nm, Li₃Bi₃Te₂O₆:Eu³⁺ phosphors show four emission peaks due to ⁵D₀ → ⁷F_J (J = 1, 2, 3, 4) transitions and the strongest peak is at 610 nm (⁵D₀ → ⁷F₂). The best doping concentration of Eu³⁺ ions is found to be 0.45 mol. The critical transfer distance (R_c) of the energy transfer between the Eu³⁺ ions reaches 11 Å and the luminescence quenching is confirmed by the nearest-neighbor ions interaction. The commission international de l'Eclairage (CIE) chromaticity coordinates (0.655, 0.344) of Li₃Bi₃Te₂O₆:0.40Eu³⁺ phosphors are in the red region. The values of decay time are calculated in the millisecond time range from 0.878 to 0.493 ms. Phosphors show common thermal stability with activation energy (0.25 eV). All the properties indicate that Li₃Bi₃Te₂O₆:Eu³⁺ phosphors have potential applications in displays and photonic devices.