Neutralized fluorine radical detection using single-walled carbon nanotube network

It is known that single-walled carbon nanotubes (SWCNTs) can be functionalized by fluorine gas. Here, we report neutralized fluorine radical detection using a matted sheet of SWCNTs, prepared by alternating current dielectrophoresis. Upon exposure to neutralized radicals containing fluorine atoms in a plasma, as model analytes, the conductance of the SWCNT matt showed fast modulation. The transduction mechanism was investigated by electrical transport measurements, X-ray photoelectron spectroscopy and Raman spectroscopy. Metallic nanotubes were shown to react covalently to the near exclusion of semiconducting species. The selectivity was promoted by the curvature-induced strain of the nanotubes. The results open new opportunities for the detection of fluorine radicals at specific locations inside the reaction zone using a simple, miniaturized carbon nanotube network.