Highly Sensitive NO2 Detection and DMP Sensing at Room Temperature using Flexible SWNT Thick Film Sensor

Abstract

 Low cost; easy to fabricate and flexible single wall carbon nanotubes thick film resistor (SWNT-TFR) for detailed study of NO2 detection is reported. SWNT-TFR was fabricated by vacuum filtration technique on flexible polycarbonate membrane. SWNT-TFR sensor shows selective response to NO2. The response increases from 1.47 per cent to 17.34 per cent with increasing the NO2 concentration from 0.2 ppm to 10 ppm, respectively. Different energy sources, IR, thermal and UV were explored for achieving fast recovery of the SWNT-TFR sensor. The results showed that the gas sensor gives immediate and fast recovery in the presence of UVC light. The calculated detection limit is less than 764 ppt for NO2. We are also presenting sensing of dimethyl methylphosphonate (DMMP) as a simulant of sarin. SWNT-TFR gives repeatable response of ~2.7 per cent for 500 ppm of DMMP. This work suggests the possibility to utilise SWNTs-TFR as NO2 sensors for air-quality monitoring.