| dc.description.abstract | Dye-sensitized solar cells (DSSCs) are cheaper alternatives to conventional, silicon-based photovoltaic cells for the conversion of solar energy into electricity. In this work, the use of mixed valence tin oxide (Sn3O4) as photoanode semiconductor, with N3 molecular dye, is described for the first time in literature. Results demonstrate an increase in photoconversion efficiency with Sn3O4 compared to a conventional SnO2 photoanode, with an average of 1.8 mA cm-2 photocurrent obtained. The effect of the incorporation of SnO2 blocking layers is also investigated, and a slight decrease in the conversion efficiency is found. The generation of hydrogen as an alternative fuel with the concomitant production of a value-added chemical using solar energy is a promising clean energy approach as well. In this work, a dye-sensitized photoelectrochemical cell (DSPEC) is used to drive the oxidation of benzyl alcohol to produce benzaldehyde and hydrogen gas. A photoanode composed of a mesoporous TiO2 semiconductor layer and a monolayer of a ruthenium-trisbipyridine-based dye, RuC, serves as the reference photoanode for this work. Incorporation of a compact, thin layer of TiO2 significantly alters the resulting photocurrent of the system. The location of the thin TiO2 layer—either under, above, or both under and above the mesoporous TiO2 layer also impacts the observed photocurrents. Investigation of numerous different photoanode configurations, obtained by varying the length of the thin TiO2 layer deposition and the use of sintering, has guided optimization of the electrode surface. The highest photocurrents, with a five-fold increase compared to a reference photoanode, was obtained for electrodes composed of a TiO2 blocking layer both under and above the mesoporous TiO2 layer, with deposition time optimized for each layer. The production of H2 gas via light-driven water splitting is another promising approach for a carbon-neutral economy. To improve the solar energy conversion efficiency of a water splitting DSPEC, electropolymerization has been investigated as a new means of fabricating the photoanode. Synthesis of iridium oxide nanoparticle water oxidation catalyst (IrOx·nH2O), functionalized with capping groups that contain terminal double bonds to enable electrochemical polymerization to form a surface polymer film, was first performed. Using acrylic acid and acrylamide as small molecule precursors, electropolymer coatings have been prepared on fluorine-doped tin oxide (FTO) surfaces, which served as a foundational layer for the electrochemical deposition of surface coated IrOx·nH2O. | |
