Luminescence properties of Tb3+:Y3Al5O12 nanocrystallites prepared by the sol-gel method

Tb3+:YAG nanocrystalline powders have been prepared by the sot-gel route. Structure and morphology of the obtained materials have been studied. The average grain sizes have been determined by X-ray powder diffraction measurements. Photo- and cathodoluminescence spectra of the Tb3+:Y3Al5O12 powders have been measured. It has been found that the samples at low concentration demonstrate emission ascribable to the D-5(3) --> F-7(J) and D-5(4) --> F-7(J) transitions. In particular, the concentration dependence of the luminescence spectra and lifetimes have been investigated as a function of the YAG grains sizes. It has been shown that the cross-relaxation responsible for the quenching of the D-5(3) state depends on the nanocrystalline grains size. (C) 2003 Elsevier B.V. All rights reserved.