Fabrication of SWCNTs Based Flexible, Trace Level NO2 Gas Sensor Using Spray Coating Technique
Flexible nitrogen dioxide (NO2) sensor using thin-film single-walled carbon nanotubes (SWCNTs) was fabricated by spray coating on Polyethylene terephthalate (PET) substrate. The SWCNTs dispersed in deionized water using sodium dodecyl sulphate (SDS) as the surfactant. The uniformly dispersed SWCNTs were deposited on the PET film by using spray gun, and then SDS surfactant was removed from the sample for its proper gas sensing. This was done by dipping the sample into the HNO3 and then washing with the deionized water followed by heat treatment at 110 °C for 1 h. The resultant devices were tested for sensing NO2 molecules and a trace level NO2 sensing was detected. The sensing mechanism was attributed by the electron transfer to the SWCNTs, as a result, the NO2 reduced on the nanotube surface.