Titanate-PMMA composites in photoluminescence based oxygen sensing

Abstract Titanate MTiO3 (M = Ni, Co) composites have been investigated for the first time as optical sensing materials. The photoluminescence (PL) emission of MTiO3 nano-hybrid systems, consisting of nanorods dispersed in an organic (poly (methyl methacrylate)-PMMA) matrix exhibited a reversible modification in the presence of oxygen (O2). For the optical characterization and study of the photoluminescence, the MTiO3/PMMA specimens were excited with a pulsed laser source of 248 nm wavelength. The performance of this new optical sensing system has been systematically investigated with respect to response, reversibility, and dynamic characteristics. All experimental results confirmed that the photoluminescence emission of the MTiO3 nanocomposites is sensitive and directly related to the oxygen presence, at room temperature. The MTiO3 nanohybrids, subjected to successive low vacuum-oxygen cycles, exhibited a dynamic response towards different ranges of oxygen concentrations, with the limit of detection being about 1 mbar and 5 mbar for NiTiO3 and CoTiO3 respectively and response time of the order of 40s.