Eu(III) incorporation in sol–gel aluminum–yttrium matrix by non-hydrolytic route

The sol–gel method using metal alkoxide has been investigated to prepare aluminum–yttrium oxide as yttrium–aluminum garnet (YAG) matrix composite fiber. In this paper we investigate the influence of yttrium content and temperature in the synthesis of Eu(III)-doped aluminum–yttrium oxide by non-hydrolytic sol–gel route. The formation process and the local structure of the samples were discussed by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. For temperatures around 800 °C, initial crystallization was observed and the phases Y4Al2O9 (YAM) and Y3Al5O12 (YAG) appear. For samples treated at 800 and 1500 °C the emission spectra display preferentially the f–f transitions characteristic of the YAM monoclinic phase, whereas the YAG cubic appears as the favored phase at 1100 °C, in accordance with the Eu(III) centrosymmetrical local site.