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

The sensing properties of direct-patternable TiO2 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 TiO2 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 TiO2 thin films upon MWCNT incorporation caused an increase in surface area. Because of the high electron conductivity and surface area of the MWCNT-incorporated TiO2 sensor, the sensitivity of the sensor was enhanced from 2.19 to 89.2. Direct-patterning of MWCNT-incorporated TiO2 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 TiO2 thin films can be improved by incorporating MWCNTs.

► Directly patternable TiO2 thin films ► Incorporation of multi-wall carbon nanotubes (MWCNTs) in the thin films ► Electrical conductivity and surface area increased by incorporation of MWCNTs. ► Sensitivity of TiO2 sensor enhanced by MWCNT incorporation.