Eu3+ entrapped in alumina matrix obtained by hydrolytic and non-hydrolytic sol-gel routes

The optimized conditions for the preparation of luminescent materials consisting of Eu3+ entrapped in an alumina matrix are described. Eu3+ ions in an alumina matrix have been prepared by sol-gel process using both non-hydrolytic (through the condensation of aluminum chloride with diisopropyl ether) and hydrolytic (by the reaction of aluminum chloride with aqueous NH3) methodologies. Luminescence spectra, X-ray diffraction, surface areas, thermogravimetric properties and differential thermal properties have been measured. Through the non-hydrolytic sol-gel route we prepared amorphous, non-hydrated material with greater luminescence efficiencies and longer decay times, than for Eu3+ in alumina prepared by other processes, even when heat treated at temperatures less than or equal to 750 degreesC. The conventional hydrolytic solgel process produces materials where the Eu3+ ions are imbedded in a crystalline alumina matrix containing water which increases quenching which reduces the luminescence efficiency of Eu3+. (C) 2002 Elsevier Science B.V. All rights reserved.