AEROGELS CONTAINING STRONGLY PHOTOLUMINESCING ZINC-OXIDE NANOCRYSTALS

Sol-gel processing was used to prepare ZnO-doped silica-aerogels by hy drolysis and condensation of tetramethoxysilane (TMOS) in the presence of 6 nm sized nanocrystalline ZnO particles. Supercritical drying yie lded strongly green-yellow fluorescing aerogels. Fluorescence excitati on and emission spectra of the resulting ZnO particles in a silica mat rix were preserved after the supercritical drying, in contrast to air sintering conditions under which the visible ZnO fluorescence is compl etely suppressed. Anomalous small angle X-ray scattering (ASAXS) was e mployed to evaluate the internal structure of these nanocrystalline pr ecursors as well as the resulting nearly transparent aerogel samples. (C) 1998 Published by Elsevier Science B.V. All rights reserved.