Sensitivity enhancement towards ethanol and methanol of TiO2 films doped with Pt and Nb

This paper presents a possibility to improve the sensitivity towards ethanol and methanol of nanocrystalline TiO2 thin films by doping with Nb and Pt. The thin films were prepared using the sol–gel process by the spin coating technique on alumina substrates. The microstructure and the chemical composition of the thin films were characterised using XRD, SEM, RBS and XPS techniques. The experimental results of the alcohol sensing characteristics indicated that the doped TiO2 thin film has an enhanced sensitivity with respect to the undoped ones. The relative change of the conductance of the thin films due to the introduction of 500 ppm of ethanol is as high as 2370% at an operating temperature of 300°C, making them feasible for development of breath analysers (detection limit is 200 ppm).