CO gas sensing properties of direct-patternable TiO2 thin films containing multi-wall carbon nanotubes

Abstract The sensing properties of direct-patternable TiO 2 thin films prepared by photochemical solution deposition were improved by the incorporation of multi-wall carbon nanotubes (MWCNTs). Upon incorporation of the MWCNTs, the crystallinity of the TiO 2 thin films containing MWCNTs did not change. However, the electron conductivity was improved due to the π-bond nature of the MWCNT surface. In addition, an increase in the oxidation ratio on the surface of the TiO 2 thin films upon MWCNT incorporation caused an increase in surface area. Because of the high electron conductivity and surface area of the MWCNT-incorporated TiO 2 sensor, the sensitivity of the sensor was enhanced from 2.19 to 89.2. Direct-patterning of MWCNT-incorporated TiO 2 thin films can be performed without a photoresist or etching process. These results suggest that a micro-patterned sensor can be simply fabricated at a low cost and the sensitivity of TiO 2 thin films can be improved by incorporating MWCNTs.