TiO2 thin film capacitive humidity sensor based on sol-gel technique

A new approach for humidity sensing is reported. The sensor is based on ordered nanoporous titanium dioxide (TiO 2) thin film over silver palladium coated nonporous alumina substrate. Porous TiO 2 thin films were prepared by emulsification-gelation technology using hydrolysis and reflux process. Coating optimization was achieved and hydrophilicity of the TiO 2 thin film was determined. SEM results revealed that pores were distributed uniformly throughout the sample, which enhanced the adsorption of water molecule over the film. Raman study clearly confirmed the anatase and rutile phase of TiO 2 thin film. Electrical sensing response was calculated using impedance measurement. It was found that at an optimized coating thickness the sensitivity of our humidity sensor was suitable for commercial applications. © 2012 IFSA