Effect of LiCl on the crystallization behavior and luminescence of Y3Al5O12:Tb

The single-phase cubic Y3Al5O12 : 1% Tb sol-gel-derived powders were prepared after firing at 650 degrees C for 2 h when a LiCl flux was used. The addition of the LiCl can increase the crystalline size of the powders at low temperatures. By using the broadening effect of X-ray patterns, the estimated crystalline size of the powder with 20 wt.% LiCl addition fired at 650 degrees C for 2 h was evaluated as 480 A. Both emission and excitation luminescent spectra of the samples were measured. Emission spectra of the synthesized powders mainly show D-5(4)-F-6 transition under 275 nm excitation. The excitation spectra of The Tb3+ ions are different between amorphous and crystalline phase because of the crystal field effect. The excitation spectra also help observing the degree of the crystallinity of the resulting YAG phase. (C) 1998 Elsevier Science S.A. All rights reserved.