The world’s energy requirements are always increasing, but sunlight provides more than sufficient energy to sustain humanity’s energetic needs for decades to come. In developing future generations of light harvesting materials, scientists can turn to biology to provide design rules for efficient and robust methods of converting sunlight to address these requirements. Photosynthetic antenna complexes demonstrate remarkable efficiency and resilience, including capabilities to regulate light harvesting activity in the presence of hazards such as oxidizing agents. Through control of the environment surrounding chromophores, these complexes exercise incredible control of electronic dynamics to a level not yet achievable in manmade systems. In this dissertation I investigate biological and manmade approaches to controlling electronic dynamics via external processes on the scaffolds that hold chromophores in place. These investigations use two-dimensional electronic spectroscopy to correlate excitation energy with emission and absorption at later times as a probe of electronic couplings and dynamics on the femtosecond to nanosecond timescale. In the course of this study, I identify a potential redox protection mechanism in the Fenna-Matthews-Olson light harvesting complex arising from a structural motif repurposed from redox enzymes. Moving to synthetic light harvesting structures, I observe how nuclear motion can limit energy transfer outside the bounds predicted by Förster theory in a temperature-controlled resorcin[4]arene molecular switch. In a study of vibronically coupled cyanine dimers bound to DNA, I found evidence for multi-mode vibrational coupling that may lead to new paths for efficient energy transfer, and I propose new experiments making use of DNA nanostructures to explore this area further. Combined, these observations will lead to new designs for light harvesting materials that can help to meet future energy generation requirements.




Downloads Statistics

Download Full History