Engineered Sensitivity of Structured Tin Dioxide Chemical Sensors: Opaline Architectures with Controlled Necking


  • This research is part of a Canadian Institute for Advanced Research (CIAR Nanoelectronics Program) and University of Toronto (UOT Advanced Materials) sponsored collaborative research program involving the exchange of faculty and students between the University of Toronto, University College London, and The Royal Institution Great Britain. GAO is Government of Canada Research Chair in Materials Chemistry. He is deeply indebted to the Natural Sciences and Engineering Research Council of Canada for sustained financial support of the research of his materials chemistry group.


Structure–property relationships in tin dioxide materials have been studied utilizing a reverse templating strategy to synthesize opaline structures with controlled neck dimensions between spheres. The necking dimensions could be controlled by sintering the parent silica opals at temperatures between 700 and 1050 °C. Inverted polymer opals were synthesized by infiltrating the silica opals with styrene, followed by thermally induced polymerization, and removal of the silica with HF. Tin dioxide opals with controlled microstructures were then synthesized from these inverted polymer opals. The gas sensing response of these materials to carbon monoxide could be understood as a function of the necking diameter in the resulting tin dioxide opals.