Many systems within the energy sector necessitate high-temperature or chemically harsh conditions (e.g., solid oxide fuel cells, power plant boiler systems, post-combustion facilities). Significant economic and technological value can be added through the integration of in-situ sensor technology; unfortunately, harsh environments pose a major challenge to traditional sensor materials. Optical fiber-based sensors provide a robust solution to this problem and offer capability for spatially distributed sensing. Silica fiber, with cladding removed and coated with bare or metallic nanoparticle incorporated sensing layers, exhibits stability up to 800-900°C under a wide range of chemical environments. As sensing layers, complex perovskites oxides - studied extensively as anode and cathode materials within the solid oxide fuel cell (SOFC) community – provide ideal tunability, stability, and defect-dependent optical properties for high-temperature gas-sensing applications. Modeled defect chemistry kinetics are presented in the context of experimental high-temperature (600-800°C) optical gas sensor data at visible and NIR wavelengths, both on planar substrates and on optical fiber. Doped SrTiO3 is highlighted as a model sensing material, due to strong Drude response under chemically reducing conditions, and due to its well-documented material / chemical properties. Equilibrium calculations are performed for ionic and electronic motion within thin films on fiber – using a ray-based approach for guided optical modes.
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