Enhancing the sensing performance of SnO2 inverse opal thin films by In and Au doping

SnO2 is an important n-type semiconductor sensing material. However, there are some drawbacks in the traditional SnO2 based gas sensors, such as high operating temperature, low gas response, long response/recovery time and poor selectivity. In this paper, In and Au doped SnO2 inverse opal thin films (IOFs) were prepared by employing a monolayer PMMA sphere template. The ordered macroporous strutture of IOFs with large surface areas benefited the enhancement of the sensing performance. The response of the SnO2 IOFs to 100 ppm ethanol had been enhanced from 6 to 308 by 5% In doping. Moreover, the optimum operating temperature was decreased from 350 degrees C to 250 degrees C, and the response/recovery time was shortened obviously by 0.25% Au doping. The 0.25%Au-SnO2:5%In IOFs based sensor exhibited high response, low operating temperature, high response speed, good selectivity and repeatability to ethanol, which had a promising application in ethanol detection. The XPS characterizations indicated that the doping of In and Au contributed to the increase of the adsorbed oxygen amounts which benefited the enhancement of the sensing performance. (C) 2017 Elsevier B.V. All rights reserved.