A Dye‐Sensitized Sensor for Oxygen Detection under Visible Light

Abstract Sensors that can accurately assess oxygen (O₂) concentrations in real time are crucial for a wide range of applications spanning personal health monitoring, environmental protection, and industrial process development. Here a high‐performance chemiresistive sensor that allows for the rapid detection of O₂ at room temperature under visible light illumination is described. Inspired by the operating principles of dye‐sensitized solar cells, the chemiresistor is based on a single‐walled carbon nanotube‐titania hybrid (SWCNT‐TiO₂) bearing a molecular Re‐based photosensitizer [(^Pbpy)(CO)₃ReBr] (^Pbpy = 4,4′‐[P(O)(OH)₂]₂‐2,2′‐bipyridine). The resulting SWCNT‐TiO₂‐Re composite undergoes photoinduced charge transfer that is sensitive to ppb levels of O₂, thereby yielding a rapid and reversible chemiresistive response. Owing to its unique mode of operation and robust components, the sensor shows a high degree of selectivity for O₂ over a range of interferants, humidity tolerance, and multimonth benchtop stability. The approach presented herein demonstrates the translatability of concepts in light harvesting to the development of robust, rapid, and low‐power sensing technologies.