<p>The pore-size dependence of liquid diffusivity in mesopores has been a controversial topic. It is especially meaningful in dye-sensitized solar cells (DSSCs) because the triiodide ion diffusivity is closely related to the cell performance. By applying electrochemical measurements, the pore-size dependence of ion diffusivity in DSSCs was investigated based on TiO<sub>2</sub> thin films of variable pore diameters. The alternation of pore-size was achieved by the epitaxial growth of TiO<sub>2</sub> after TiCl<sub>4</sub> post-treatments. From the trend of normalized diffusivities, the respective valid regimes of pore-size dependent and independent diffusion were determined, which were separated by the transition point located at 5-7 nm. In addition, my results have showed that the DSSC fabrication processes, e.g., dye loading, TiCl<sub>4</sub> post-treatment will not lead to the transition of diffusion behaviors. Furthermore, the unexpected drop of diffusivity after one TiCl<sub>4</sub> treatment is attributed to the involvement of surface diffusion in untreated TiO<sub>2</sub> matrix.</p> / Master of Applied Science (MASc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/12916 |
| Date | 04 1900 |
| Creators | Ma, Yiqun |
| Contributors | Xu, Gu, Materials Science and Engineering |
| Source Sets | McMaster University |
| Detected Language | English |
| Type | thesis |
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