High-performance fiber-optic oxygen sensors based on fluorinated xerogels doped with Pt(II) complexes

This paper develops two high-performance quenchometric fiber-optic oxygen sensors based on platinum complexes and studies their temperature effects. The sensors are fabricated by coating the ends of optical fibers with a microporous film prepared using an n-propyltrimethoxysilane (n-propyl-TriMOS)/3,3,3-trifluoropropyltrimethoxysliane (TFP-TriMOS) composite xerogel doped with either platinum tetrakis pentrafluoropheny porphine (PtTFPP) or platinum octaethylporphine (PtOEP) luminophores. The sensitivities of the two sensors are quantified in terms of the ratio I-N2/I-O2, where I-N2 and I-O2 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental results reveal that the PtTFPP-doped and PtOEP-doped oxygen sensors have sensitivities of 68.7 and 82.5, respectively. Furthermore, both sensors yield linear Stern-Volmer plots. The response time of the PtTFPP-doped sensor is found to be 3.7 s when switching from a fully deoxygenated environment (i.e. 100% nitrogen) to a fully oxygenated environment, and 5.3 s when switching reversely. The corresponding response times of the PtOEP-doped sensor are 3.7 and 5.9 s, respectively. The experimental results confirm that the current oxygen sensors exhibit a better sensitive performance, a shorter response time than existing oxygen sensors based on ruthenium dye immobilized in various sol-gel matrixes. (c) 2007 Elsevier B.V. All rights reserved.