Synthesis and luminescent properties of gadolinium aluminates phosphors

In this work, aluminum–gadolinium oxides with different phases were prepared by the non-hydrolytic sol–gel route, using lower temperatures than those employed in methods such as solid-state reaction and Pechini method. The influence of heating treatment on sample structure was investigated. The formation process and the local structure of the samples are discussed on the basis of thermal, X-ray diffraction, photoluminescence (PL) spectroscopy, and infrared spectroscopy analyses. The quantum efficiency of Eu3+ in the different phases obtained in this studied was evaluated. Initial crystallization and the GdAlO3 phase were observed at temperatures around 400 °C. PL data of all the samples revealed the characteristic transition bands arising from the 5D0 → 5FJ (J = 0, 1, 2, 3, and 4) manifolds under maximum excitation at 275, 393, and 467 nm in all cases. The 5D0 → 7F2 transition often dominates the emission spectra, indicating that the Eu3+ ion occupies a site without inversion center.