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10 December 1996 Fiber optic oxygen sensors based on the sol-gel coating technique
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Two fiber optic oxygen sensor designs were demonstrated by sol-gel coatings doped with an organo-metallic complex, ruthenium (II) tris-4,7-diphenyl-1,10-phenanthroline. The first design implemented a porous optical fiber coated with sol-gel that showed high sensitivity (less than 1 ppm) towards oxygen gas and a dynamic range up to 1% oxygen. The second optical sensor was based on a collimator device which involved a sol-gel film that was spin coated onto a silica glass disk. Compared to the porous fiber approach, a faster response time and lower oxygen gas sensitivity were determined for this sensor configuration. According the lifetime decay behavior of a sol-gel spin coating, the luminescence decay of the ruthenium complex followed a single exponential decay in nitrogen and air. Also, the spin coated sample showed a greater degree of quenching according to the Stern-Volmer ratio, at greater oxygen concentrations than the ratio calculated for the monolithic film. Analysis of the lifetime decay behavior of the different forming methods revealed that the micro-structure of the gel was dependent upon the type of sol-gel deposition. In this case, spin coated gels resulted in a denser coating than the monolithic film. As a result, these differences in the sol- gel micro-structure were used to discuss the different behavior of the collimator sensor with respect to the porous fiber oxygen sensor.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael Krihak, Michael T. Murtagh, and Mahmoud R. Shahriari "Fiber optic oxygen sensors based on the sol-gel coating technique", Proc. SPIE 2836, Chemical, Biochemical, and Environmental Fiber Sensors VIII, (10 December 1996);


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