Optical characteristics of a ruthenium(II) complex immobilized in a silicone rubber film for oxygen measurement

Abstract

The optical characteristics of tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) perchlorate immobilized in a silicone rubber film were studied for its application to the measurement of oxygen. The luminescence intensity and the degree of quenching of the ruthenium complex by oxygen were shown to be affected by the concentration of the complex in the silicone rubber film. The optimum concentration was found to be about 0.2 mmol dm–3. At this concentration, the silicone rubber film containing the immobilized ruthenium complex emits the highest luminescence intensity and is able to undergo a high degree of quenching of the luminescence by oxygen. The quenching curves for 20 samples containing various concentrations of the ruthenium complex were correlated with high accuracy by using a modified form of the Stern–Volmer equation. The film preparation procedure and the solvent used were found to be critical for performance. The effect of the film thickness on the luminescence intensity and the dynamic response was also studied.