Ruthenium-Doped Sol-Gel Derived Silica Films: Oxygen Sensitivity of Optical Decay Times

Sol-gel silica thin films, produced by a dip-coating process, were impregnated with the complexes Ru(bpy)(3)(2+) and Ru(Ph(2)phen)(3)(2+). For each complex ruthenium fluorescence was quenched in the presence of oxygen. Intensity and decay time Stern-Volmer plots were produced for both complexes. The optical decay times were analysed in terms of one quenched and one unquenched component, the latter arising from the fraction of complex molecules which are inaccessible to oxygen. All the data were consistent with the predominance of dynamic quenching in these systems. The feasibility of an oxygen sensor based on decay times was discussed.