A Dye-Sensitized Sensor for Oxygen Detection under Visible Light.

Sensors that can accurately assess oxygen (O 2 ) 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 O 2 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-TiO 2 ) bearing a molecular Re-based photosensitizer [( P bpy)(CO) 3 ReBr] ( P bpy = 4,4'-[P(O)(OH) 2 ] 2 -2,2'-bipyridine). The resulting SWCNT-TiO 2 -Re composite undergoes photoinduced charge transfer that is sensitive to ppb levels of O 2 , 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 O 2 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.