Sol-gel synthesis and luminescence of Y4Al2O9:RE3+(RE=Eu,Tb)

Y4Al2O9 (YAM) was prepared by a sol-gel process, using yttrium and aluminum citrate complexes as precursors. The sol-gel process produced single-phase YAM at 900 C, as opposed to the conventional solid-slate reaction, which led to the formation of other phases, even if at 1600 C. The emission and excitation spectra of Eu3+ and Tb3+ in YAM showed the existence of two luminescence centers, agreeing with the crystal structure of YAM. The spectral properties of the samples are discussed. (orig.)