Luminescence properties of Tb3+ and Eu3+-doped alumina films prepared by sol-gel method under various conditions and sensitized luminescence

Rare earth ion (Tb3+ and Eu3+)-doped alumina films were prepared by the aqueous sot-gel method under various conditions. The influences of the OH groups (phonon relaxation) and rare earth ion concentration (cross-relaxation) on luminescence were examined. In regard to the former relaxation, at treatment temperature above 600degreesC, reciprocal lifetime decreased with OH concentration, and below 500degreesC, decreased markedly and nonlinearly. On the other hand,! in regard to the latter relaxation, there was negligible effect on luminescence for these doped films. The quantitative treatment was tried to lifetime considering these influences. Tb3+ and Eu3+ co-doped alumina films showed enhanced Eu3+ luminescence by the energy transfer from Tb3+ to Eu3+. Eu3+ luminescence intensity increased with a greater Tb3+ concentration. (C) 2002 Elsevier Science Ltd. All rights reserved.