Metal oxide nanocrystals for gas sensing

Quasi-one-dimensional nanostructures (so-called nanobelts or nanowires) of tin dioxide, obtained by vapour phase deposition, have been investigated for gas sensing. The physical quantity for signal transduction could be either electrical conductance or photoluminescence. Tin dioxide nanobelts/nanowires could be used as conductometric gas sensors for oxygen and environmental polluting species like CO and NO2 as well as ethanol. The visible photoluminescence is quenched by nitrogen dioxide at hundreds of ppb in a fast (time scale order of seconds) and reversible way. The response is highly selective towards humidity and other polluting species like CO and NH3. The differences between conductometric and optical sensor are discussed. (c) 2005 Elsevier B.V. All rights reserved.