Research Description
He employs time-resolved Femtosecond Stimulated Raman Spectroscopy (FSRS) to study the role of structural dynamics in interfacial electron transfer in semiconducting quantum dots (QDs). Recent reports of multiple exciton generation in these systems suggest that QD-based solar cells could achieve quantum efficiencies far greater than organic dye-sensitized solar cells in which only one electron-hole pair per molecule can be generated. Sensitization of QDs with organic ligands can alter the dynamics by quenching the exciton(s), however the molecular motions involved in these processes are not well understood. He uses FSRS to examine the role of ligand conformation effects on exciton dynamics in sensitized hybrid QD systems such as CdSe, PbSe, and PbS QDs coupled with methyl viologen (MV2+) or methylene blue (MB+), where quenching of as many as four excitons per QD have been reported. By understanding the particular molecular motions mediating electron transfer in sensistized quantum dots, he can design more efficient QD-based solar devices.