Presenter: Laura Leibfried – Chemistry, Physics
Faculty Mentor(s): Cathy Wong
Session: (In-Person) Poster Presentation
Using organic photovoltaic (OPV) devices to harvest solar energy is uniquely enticing as they allow for mass manufacture, greater accessibility, and extraordinary chemical tunability. This study aimed to investigate a class of organic dyes called squaraines (SQs) which are potential donor molecules in OPVs and form molecular aggregates, affecting their electronic structure and energy transfer dynamics. Spatially encoded transient absorption was used to study restructuring SQ films during thermal annealing to reveal how the extent of aggregation affects exciton dynamics. Rapid and verging on total energy transfer from the targeted excitation of monomer molecules to aggregates is observed and dynamics are replicated by a kinetic model that evolves as a function of annealing temperature and the consequent extent of aggregation. Results indicate potential exciton trapping as a consequence of rapid energy transfer to optically darker states, which could imply less effective exciton diffusion in OPVs with only partially aggregated SQ donor domains.