Fine YAG:Ce3+ nanoparticles synthesised by supercritical hydrothermal reaction

Yttrium aluminium garnet (YAG):Ce³⁺ nanoparticles have been synthesised by the supercritical hydrothermal method at 390 °C in a series of reaction times of 2, 4, 6, 8, 10 and 12 h, respectively, and characterised by X-ray diffraction, a scanning electron microscope, (high resolution) transmission electron microscopy and several measurements of fluorescence properties. The single-phase YAG:Ce³⁺ can be obtained at much lower temperature (390 °C) by means of the supercritical hydrothermal method with inexpensive raw materials and simple processing conditions than by the conventional solid-state method and other wet-chemical methods. The YAG:Ce³⁺ phosphors synthesised by the supercritical hydrothermal method exhibit more uniform size distribution and stronger emission, compared with those synthesised at the 360 °C below the supercritical point of water. The reaction time also influences the luminescent properties, and the related mechanism is discussed.