Functionalized Carbon Nanotube–Based Sensors for Detecting a Trace Quantity of 2,4-Dinitrotoluene Explosive Vapors, with Selectivity

V. Kayastha, C. Jones, C. Landorf
Brewer Science, Inc., US

Keywords: carbon nanotubes, interdigitated electrode sensor, thin-film-transistor sensor, 2, 4-dinitrotoluene, selectivity


We have developed a new sensing material that can selectively detect explosive molecules such as 2,4-dinitrotoluene and 2,4,6-trinitrotoluene; and have successfully demonstrated functional chemical sensors using this new material. The newly developed sensing material is a semiconducting carbon nanotube (SWCNT) ink; which is stable, surfactant-free and is printable. These SWCNTs are functionalized with receptor molecules to achieve selectivity toward DNT and TNT molecules. The interdigitated electrode (IDE) sensors that were fabricated using these functionalized CNT inks were able to repeatedly detect DNT levels as low as 0.5 ppb, with a response time of less than 10 seconds. In addition, these sensors showed a high degree of selectivity toward DNT over other chemically similar molecules such as nitrobenzene and nicotine. Further studies showed that sensor sensitivity increased with increase in receptor molecules in the CNTs. Preliminary results on a CNT thin film transistor sensor showed a response to DNT that was similar to that of the IDE sensors that used CNTs with the same level of functionalization. Preparation and testing of sensors using CNT inks with a higher level of functionalization, as well as new TNT sensing tests, are ongoing.