Charge transfer porphyrin functionalized titanium dioxide interfaces

The work presented in this thesis is aimed at understanding charge transfer at porphyrin functionalized TiO2 interfaces. Chapter 1 presents a brief overview of molecular approached to solar energy conversion and introduces the reader to the components, mechanisms and characterization techniques relevant to dye-sensitized solar cells (DSSC) and reductive dehalogenation of organohalide pollutants in groundwater. Chapter 2 describes theoretical considerations for supramolecular sensitization of planar semiconductors utilizing porphyrin arrays. In Chapter 3 we examine the potential of utilizing trans Ru polypyridyl compounds for sensitization of nanocrystalline TiO 2. In Chapter 4 the performance of five tetrapyrrole molecules as sensitizers in regenerative solar cells was evaluated. In Chapter 5 the preparation of a new porphyrin sensitizer with all four of the pyrrole nitrogens protonated has been achieved. This molecule, due to the increased spectral overlap and high conversion efficiencies, represents a new direction for the design of organic sensitizers for use in efficient photovoltaic cells. Chapter 6 examines the effect surface functionalization had on carbon monoxide (CO) equilibrium coordination kinetics. In Chapter 7 we examine the reactivity of hemin, (chloro(protoporhyrinato)iron(III)), on the surface of TiO2 with organohalides in the presence of methanol.