Synthesis and characterization of highly organized mesoporous palladium-doped tin dioxide thin films for gas sensing

Highly organized and transparent mesoporous palladium-doped tin dioxide thin films are obtained via spin-coating with a diluted sol–gel composed of tin tetrachloride as precursor and the triblock copolymer Pluronic F127 as structure director in combination with a high concentration of hydrochloric acid. The films do not exhibit ordered nanostructure after spin-coating. Upon exposure to water vapor at elevated temperatures (delayed humidity treatment) reorganization to highly ordered mesostructures is observed. The films are thermally stable and retain the ordered nanostructure after template removal at temperatures up to 400 °C. The thin films of some hundred nanometre thick show high sensitivity towards hydrogen at room temperature due to their crystallinity and high porosity.