Spectroscopic investigation of novel yellow-emitting Li3Bi3Te2O12:Dy3+ phosphors with high thermal stability for w-LEDs applications.

A series of Li₃Bi₃Te₂O₁₂:xDy³⁺ (x = 0.01, 0.02, 0.05, 0.10, 0.15, 0.20, and 0.30 mol) samples were successfully prepared by high-temperature sintering method. The phase purities of the Li₃Bi₃Te₂O₁₂:Dy³⁺ phosphors were verified by powder X-ray diffraction (XRD) and revealed as single-phase structure. Under 386-nm excitation, the Dy³⁺-doped Li₃Bi₃Te₂O₁₂ phosphors show three emission peaks are located at 488, 579, and 673 nm, which are ascribed to the typical transitions from ⁴F_9/2 to ⁶H_J/2 (J = 15, 13, and 11), respectively. The effects of concentration on luminescence properties indicate that the optimal doping concentration was x = 0.02 mol. The prepared Li₃Bi₃Te₂O₁₂:0.02Dy³⁺ phosphor has the excellent thermal stability with high-temperature quenching temperature (T_0.5 > 480 K) and high activation energy (E_a = 0.38 eV). The shift of CIE chromaticity coordinates of Li₃Bi₃Te₂O₁₂:0.02Dy³⁺ phosphor with concentrations are Δx = 0.018 and Δy = 0.020. Thus, Li₃Bi₃Te₂O₁₂:Dy³⁺ phosphors have potential application for white light-emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]