Spray deposited carbon nanotubes for organic vapor sensors

• The behavior of Single and Multi Wall CNTs based sensors has been analyzed.
• The CNTs were deposited by means of a spray technique.
• The devices were exposed to CCl4 and 2-propanol at different concentrations.
• The Teflon-like layer on SWCNTs increases the sensitivity to the organic vapors.
• The Melanin layer on MWCNTs increases the sensitivity only for nonpolar 2-propanol.

In this article a study of chemiresistor sensors based on Single and Multi Wall Carbon Nanotube films deposited at low temperature by means of a spray technique is presented. A dispersion of nanotube powder in a non-polar 1,2-Dichloroethane solvent was used as starting solution. Electron Microscopy in Scanning and Transmission mode were used in order to verify the morphological properties of the deposited films. The conductivity of carbon nanotubes (CNTs) was measured in two organic solvent vapors environments: 2-propanol and carbon-tetrachloride. The solvents used are characterized by different polarities. The results show that the electrical resistance of the sensors increases when exposed to solvent vapors. Finally the effect of Teflon-like and Melanin coatings on the sensitivity yield is presented and discussed.