Synthesis and Annealing Effects on the Structure of Alumina by Polyol Mediated Process

Rare-earth ion (Eu3+ and Tb3+)-doped and undoped aluminum oxide powders have been prepared via polyol mediated synthesis. The precursors were aluminium nitrate, rare-earth (RE: Tb, Eu) nitrate and diethylene glycol. The powders were generated using low-temperature (Tmax ~ 200°C) and reaction time of 150 min. By controlling the acidity of the synthesis solution and the precursor concentration, sub-micrometric aggregates (about 300 nm) with spherical morphology were obtained. The powders of RE-doped Al2O3 were further investigated by photon correlation laser, X-ray diffraction, transmission electron microscope, scanning electron microscope, thermal analysis and photoluminescence emission spectra. The results showed that a-Al2O3 is formed at a temperature significantly lower than the solid sate reaction route. The luminescence of Al2O3 doped with 5 at.% Eu was observed with emission band in 614 nm and Al2O3 doped with 5 at.% Tb showed an emission band in 544 nm.