Electrical and spectroscopic properties of Ti0.2 Sn0.8O2 solid solution for gas sensing

In this work we report the synthesis, microstructure, electric and spectroscopic properties, and sensing performances of TixSn1-xO2 (x = 0.1, 0.2, 0.3, 0.5, 0.7, 0.9) nano-powders and of SnO2 and TiO2 reference samples, prepared via sol-gel route starting from metal-organic precursors working in hydro-alcoholic media. Actually, the attention is particularly focused on properties of the sample with x = 0.2, in comparison with ones of the other solid solutions and of the single oxides. Indeed, this solid solution showed a borderline behaviour between that of the solid solution with x = 0.1 and that of the other solid solutions with x >= 0.3. An abrupt change in the structural, electrical and spectroscopic properties has been observed, passing from sample with x = 0.1, showing a behaviour very similar to that of SnO2, to one x = 0.3 showing a behaviour very similar to that of TiO2. The borderline properties of the mixed oxide with x = 0.2 represent the expected continuous transition among the two behaviours. (C) 2009 Elsevier B.V. All rights reserved.