Preparation and characterization of nano-sized Y₃Al ₅O₁₂:Ce³⁺ phosphor by high-energy milling process

Nano-sized Ce-doped Y₃Al₅O₁₂ (YAG:Ce) phosphors were prepared by high-energy milling process which utilizes a top-down synthesizing method. The beads-milling process was performed by a Laboratory Mill MINICER with ZrO₂ beads. Nano-sized YAG:Ce can be produced by a mechanical collision between ZrO₂ beads and YAG:Ce particles. After processing via beads milling, uniform nano-sized YAG:Ce particles sized below 100 nm were produced. By controlling the bead size, milling time and milling steps, we synthesized size-tunable and uniform nano-sized YAG:Ce phosphors with average diameters of 100, 70 and 40 nm, respectively. As the bead-milling process proceeded, the luminescent efficiency was degraded owing to the low crystallinity of the surface of the nano YAG:Ce. The phase and crystallinity of the nano-sized YAG:Ce were characterized by X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The particle size was identified using field-emission scanning electron microscope (FESEM). The luminescence and quantum efficiency (QE) of the nano-sized YAG:Ce were measured using a fluorescence spectrometer and a QE measuring instrument, respectively.