Sub-ppm sensitivity towards carbon monoxide by means of pulsed laser deposited SnO2:Pt based sensors

The gas-sensing properties of nanoporous SnO2, SnO2:Pt, and multilayered SnO2:Pt thin films, deposited by pulsed laser deposition, have been investigated towards low concentrations of CO, in dry air. It is shown that SnO2:Pt films presenting an optimal thickness of similar to 400 nm and suitably doped with Pt nanoparticle catalyst are able to detect CO concentrations (C) as low as 100 ppb (parts per 10(9)). Interestingly, the response of the sensor is found to follow a [C](0.75) law over a CO concentration range as wide as 0.1-500 ppm. The multilayered approach developed here is shown to be effective in further improving the sensitivity of the sensors. (c) 2007 American Institute of Physics.