Lindsey Jamula

Titanium dioxide (TiO₂) based dye-sensitized solar cells (DSSCs) provide a promising alternative to high cost silicon-based solar cells. Though TiO₂ is inexpensive, the production of this type of cell can be costly since expensive materials are typically employed. Our research group is exploring the use of first row transition metal-based chromophores in order to achieve cost/efficiency ratios in DSSCs necessary for them to compete with fossil fuels. My research involves the design and synthesis of iron(II)-based chromophores for use as sensitizers in DSSCs.

A series of iron(II) polypyridyl complexes have been designed to gain a better understanding of the ultrafast dynamics of prospective chromophores in DSSCs. To be an effective sensitizer the lifetime of a metal to ligand charge transfer (MLCT) excited state of the chromophore must be sufficiently long lived for injection into the semiconductor to occur. However, iron(II) polypyridyl complexes intrinsically have short lived MLCT states due to ultrafast deactivation to lower lying ligand field states.

I have designed and prepared new terpyridyl ligands, in which steric hindrance has been introduced to impose strain along a torsional coordinate in the iron(II) adducts for the analysis of a proposed relaxation pathway of the charge-transfer excited state. The synthesis of another set of iron(II) polypyridyl complexes is currently underway. This series involves more flexible polypyridyl ligands with which a more octahedral structure around an iron(II) center may be achieved. The fundamental understanding that we hope to gain from the analysis of these complexes is pertinent toward the development of iron(II) based sensitizers in DSSCs.