Preparation and study on the spectral properties of garnet-type Li₃Gd₃Te₂O₁₂:Dy³⁺ single-phase full-color phosphor

Novel single-phased white-light-emitting Li₃Gd₃Te₂O₁₂:xDy³⁺ (x = 0.005, 0.01, 0.02, 0.05, 0.08, 0.10, and 0.15) garnet-type tellurate phosphors were firstly synthesized. The X-ray powder diffraction analysis, photoluminescence excitation and emission spectra, thermal quenching, and decay curves were applied to investigate the phase structure, luminescence, and thermal stability properties. Under the excitation of 351 nm, the emission of Li₃Gd₃Te₂O₁₂:0.02Dy³⁺ sample centered at blue (488 nm) and yellow (580 nm), corresponding to ⁴F_9/2–⁶H_15/2 transition and ⁴F_9/2–⁶H_13/2 transition, respectively. The optimum dopant concentration of Dy³⁺ ions in Li₃Gd₃Te₂O₁₂:xDy³⁺ was around 2 mol%. The thermal-quenching temperature was above 500 K for Li₃Gd₃Te₂O₁₂:0.02Dy³⁺. The tunable white light and correlated color temperature can be achieved in the present Li₃Gd₃Te₂O₁₂:xDy³⁺ phosphors by adjusting the yellow to blue intensity ratio based on the concentration of Dy³⁺ ions. The fabricated warm white LED indicates the phosphor could be a single-component white light-emitting phosphor for UV light-emitting diodes.