A Dye-Sensitized Sensor for Oxygen Detection under Visible Light

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.