A study on the microstructure and gas sensing properties of ITO nanocrystals

The effect of different SnO2 loading (0–25 wt.%) on the microstructural, electrical and gas sensing properties of ITO (indium tin oxide) nanocrystals synthesized by a non-aqueous sol–gel technique was evaluated. TEM, HRTEM and XRD characterization has shown that all samples have a uniform grain morphology and narrow particle size distribution, while a remarkable size reduction was observed with the increase of tin loading in the mixed oxide formulation. Redox properties of the samples were also characterized by H2–TPR. The gas sensing properties of ITO films towards CO (100–1000 ppm) and ethanol (50–400 ppm) have been investigated. On the basis of the characterization data, explanations of the observed sensing behaviour of ITO films are given.