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

Abstract

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 ∼400nm and suitably doped with Pt nanoparticle catalyst are able to detect CO concentrations (C) as low as 100ppb (parts per 109). Interestingly, the response of the sensor is found to follow a [C]0.75 law over a CO concentration range as wide as 0.1–500ppm. The multilayered approach developed here is shown to be effective in further improving the sensitivity of the sensors.