Nanotechnology-based ozone sensors exploiting low-frequency impedance changes for detection

Scientific studies on pollutants and their health effects indicate that real-time monitoring of environmental triggers can improve public health and reduce healthcare costs. This paper introduces sensitive detectors based on functionalized single-walled carbon nanotubes (CNTs) to monitor ozone concentration at sub-ppm level. The CNTs were dispersed and sonicated into an ink formulation which was spray-coated onto interdigitated electrodes on a low-cost commercial substrate. The complex impedance of the sensor signal is measured in the laboratory at frequency between 1 kHz and 200 kHz using a benchtop Impedance Meter. Shunt conductance and capacitance extracted from these measurements on several ozone sensors reveal sensitivity of over 60% at room temperature below 50 kHz, and sensor retractability during desorption.