Luminescence of composites based on oxide aerogels incorporated in silica glass host matrix

This paper deals with the elaboration and photoluminescence (PL) examination of oxide powder (OP = ZnO, Al2O3, SnO2, TiO2) incorporated in silica host matrix. OP, in the first step, was prepared by a sol-gel method using supercritical drying of ethyl alcohol. The obtained powder, in a second step, was incorporated in silica aerogel monolith using tetraethylorthosilicate as SiO2 precursor and ethyl alcohol supercritical conditions for drying. In the third step, silica aerogel containing oxide powders were heated under natural atmosphere at 1200 deg. C for 2 h to form the composites that exhibited a strong PL bands at Vis-IR range. Photoluminescence excitation (PLE) measurements show different origins of the emission. It was suggested that OH-related radiative centres and non-bridging oxygen hole centres (NBOHCs) defects resulting from thermal treatment and crystallization at the interfaces between OP and silica host matrix, were responsible for the bands at 400-600 and 700-900 nm respectively