Synthesis and luminescence properties of ZnO/Zn2SiO4/SiO2 composite based on nanosized zinc oxide-confined silica aerogels

Luminescence properties of crystalline Zn2SiO4 greatly depend on the method of elaboration. A new protocol of sol-gel processing technique was used to prepare zinc orthosilicate willemite crystals incorporated in silica host matrix containing ZnO nanoparticles (ZnO/ Zn2SiO4/SiO2). Hydrolysis and condensation of tetraethylorthosilicate have been achieved in the presence of 25 nm-sized nanocrystalline ZnO particles. Supercritical drying and annealing in the range 1423-1473 K in air atmosphere yielded a new photoluminescence band centred at around 760 nm and observed for the first time. Photoluminescence excitation measurements show different origins in the recombination mechanism of this emission band. Different possible attributions of the 760 nm emission band will be discussed. (c) 2006 Elsevier B.V. All rights reserved.