Presenter(s): Rima Pandit
Faculty Mentor(s): Kelly Wilson & Cathy Wong
Poster 12
Session: Sciences
Electronic coupling between organic molecules in an aggregate gives rise to distinct features in the measured linear absorption spectra. Electronic coupling is determined by the physical arrangement of the molecules within the aggregate packing structure, and this results in specific photophysical properties of the aggregate. In dropcasted thin films of pseudoisocyanine (PIC), in situ absorption spectra reveal a distinct intermediate aggregation stage with potentially useful photophysical properties. Single-shot transient absorption (SSTA) spectroscopy can measure the exciton dynamics of the intermediate aggregation stage and of the entire aggregation process. This work describes improvements to a novel SSTA spectrometer that can concurrently measure exciton dynamics, absorption, and fluorescence during the PIC aggregation process. These measured photophysical properties are correlated with aggregate packing structure and composition inferred from fitting in situ absorption spectra with a Holstein-Hamiltonian. This strategy provides insight into the evolving composition and properties of aggregates during the process of aggregation, and can inform initiatives to tune aggregate packing structure to yield aggregates with desired electronic properties for photovoltaics and semiconductors.