| Summary: | 碩士 === 國立臺北科技大學 === 有機高分子研究所 === 102 === In this work, nanosheets (NS) and elongated slightly truncated tetragonal nanobipyramids (ETTB) shape TiO2 structures were synthesized via hydrolysis of titanium tetra-isopropoxide (TTIP) as a TiO2 precursor, followed by hydrothermal treatment under the acidic condition. Various kinds of TiO2 colloids were prepared by adding ionic liquids with different cations such as tetrabutylammonium hexafluorophosphate (TBAH), 1-ethylpyridinium hexafluorophosphate (EPH) and 1-hexylpyridinium hexafluorophosphate (HPH) before the hydrothermal reactions. The crystal phase, shape, and morphology of TiO2 NS and ETTB were studied by XRD, TEM, and SEM analysis. It was found that the morphology and aspect ratio of the anatase TiO2 NS and ETTB can be tuned by changing the composition parameters including the contents of ionic liquids, water, TTIP, trifluoroacetic acid (TFA) and acetic acid (HOAc) in the reaction solution. TFA was used as a stabilizing agent to reduce the surface energy of anatase TiO2, especially (001) facets. On the other hand, F atoms decreased the aggregation of titania nuclei due to its low bonding energy and restricting the formation of polycrystalline agglomerates. The above TiO2 NS and ETTB were applied as the scattering layer in DSSCs. A systematic comparison of different morphologies, concentration of the composition parameters and its effect on the photo-conversion efficiency of DSSCs is discussed in this work.
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