Single-wall carbon nanotube interaction with gases: sample contaminants and environmental monitoring

Here, we show that residual contaminants in purified single-wall carbon nanotube bundles may be responsible for the reported sensitivity of the electronic and transport properties to oxygen. Removal of these contaminants makes the electronic spectra insensitive to O2, CO, H2O, and N2, while a strong sensitivity to NO2, SO2, and NH3 is observed, confirming the possible application of single-wall nanotubes as powerful sensors capable of measuring environmentally significant levels of toxic gases.