Synthesis and characteristics of fine crystalline LuAG:Ce phosphors by microwave-induced solution combustion method

A series of cerium-activated lutetium aluminum garnet (LuAG:Ce) phosphors were synthesized via a novel and fast microwave-induced solution combustion method. The influence of calcination temperature, metal ions/fuels ratio, content of active ions and LiF flux on microstructure, morphological feature and optical properties of prepared phosphors were investigated. The properties of phosphor samples were studied by means of X-ray diffraction technique, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and photoluminescence spectroscopy. Single-phase cubic crystalline LuAG:Ce formed at around 900 °C. The emission spectra displayed a characteristic broad green-yellow band of Ce3+ ions in the range of 460-700 nm. The phosphors exhibited optimal luminescent properties when the fuels /metal ions molar ratio was 0.5. The quenching concentration of Ce3+ in prepared LuAG:Ce powders was 1.0 mol% and the emission spectra showed a red shift at higher Ce3+ concentrations. The results also revealed that an appropriate amount of LiF significantly intensified the luminescence of LuAG:Ce phosphors, and it reached the maximum at 3 wt%.