Chemical Society Seminar: Kathy Wong - In situ transient absorption spectroscopy during materials formation

Zoom link: https://mcgill.zoom.us/j/86911341204

Abstract:

Molecules, polymers, and nanocrystals can form the active layer in electronic devices such as photovoltaics and light-emitting diodes. Their electronic structure and excited state dynamics dictate their function and suitability for these applications. Transient absorption (TA) spectroscopy is used to measure these properties, and has provided remarkable insights into the behavior and function of electronic materials. However, multiple minutes-to-hours are typically required to perform these measurements, making it difficult to accurately measure the excited state dynamics of unstable and evolving materials systems such as electronic materials during their synthesis or deposition into a thin film. In this seminar, I will introduce a novel implementation of TA spectroscopy that can measure transient spectra in 8 ms, with good signal-to-noise achieved in ~30 s. This new technique is applied to the study of organic molecules during their aggregation into a thin film, as well as lead-halide perovskite nanocrystals during their synthesis. These examples demonstrate that in addition to providing an understanding of how excited state dynamics change during materials formation, TA signals measured in situ can reveal new insights into the mechanisms of complex materials formation processes.

Bio:

Cathy received a BSc from McMaster University in Canada, and earned a PhD at the University of Toronto where she worked with Greg Scholes. After performing postdoctoral research in Naomi Ginsberg’s group at Berkeley, she started her independent career as an Assistant Professor at the Department of Chemistry and Biochemistry at the University of Oregon. She has received a Doctoral New Investigator award from the ACS Petroleum Research Fund, a CAREER award from the National Science Foundation, and was recently named an Emerging Scholar in Diverse: Issues In Higher Education magazine.