Embossed TiO 2 thin films with high surface areas were achieved using soft templates composed of monolayer polystyrene beads. The structure of links between beads in the templates could be controlled by varying O 2 plasma etching time, resulting in a variety of templates with close-linked, nanolinked, or isolated beads. Room-temperature deposition of TiO 2 on the plasma-treated templates and calcination at 550 °C resulted in embossed films with tailored links between anatase TiO 2 hollow hemispheres. Although all embossed TiO 2 films displayed a similar increase in the surface-to-volume ratio compared with a plain TiO 2 thin film, the response of embossed TiO 2 films with nanolinked hollow hemispheres to CO or ethanol gases was much higher than the response of films with close-linked or isolated hollow hemispheres. The strong correlation between gas sensitivity and the structure of links between the TiO 2 hollow hemispheres revealed the critical importance of tailoring links between individual oxide nanostructures for enhancing gas-sensing properties of the ensemble of the individual nanostructures. The facile and large-scale synthesis of embossed TiO 2 films with nanolinked hollow hemispheres on Si substrates and the high sensitivity that is achieved without the aid of additives provide a sustainable competitive advantage over other methods for fabricating highly sensitive metal oxide gas sensors.
No takes yet. Share an insight, caveat, or question.
Moon et al. (2011) studied this question.