Enhanced Dy³⁺ white emission via energy transfer in spherical (Lu,Gd)₃Al₅O₁₂ garnet phosphors

The Dy³⁺ doped (Lu,Gd)₃Al₅O₁₂ garnet phosphors with spherical morphology were obtained via homogeneous precipitation method, followed by calcination at 1100 °C. The particle morphology does not change significantly, but can be controlled by adjusting the urea content. The synthesis, structure, luminescent properties of precursor and resultant particles were analyzed by the combined technologies of XRD, FE-SEM, PLE/PL decay behavior. The (Lu_0.975Dy_0.025)AG phosphors display strong blue and yellow emission at ~481 nm (⁴F_9/2 → ⁶H_15/2 transition of Dy³⁺) and ~582 nm ⁴F_9/2 → ⁶H_13/2 transition of Dy³⁺), respectively. The phosphors have similar color coordinate and temperature of (~0.33, ~0.34), ~5517 K, respectively, which are closed to the white emission. The particle size and luminescent intensity decreased while the lifetime increased with the urea concentration increasing. The Gd³⁺ addition does not alter the shape/position of emission peaks, but enhance the blue and yellow emission of Dy³⁺ owing to the efficient Gd³⁺ → Dy³⁺ energy transfer. The [(Lu_1-xGd_x)_0.975Dy_0.025]₃Al₅O₁₂ phosphors are expected to be widely used in the lighting and display areas.