Event time:
January 18, 2024 - 10:30am
Location:
SCL 160
Event description:
Join Yale Chemistry for a Experimental Physical Chemistry Seminar with Dr Yifan Dong, Postdoctoral researcher, National Renewable Energy Laboratory. A remote option is available here.
Title: Unraveling Charge Transfer Mechanisms in Optoelectronic Materials with Ultrafast Optical Spectroscopy
Controlling charge, spin, and lattice degrees of freedom in semiconductor systems has broad implications towards affordable, efficient, and sustainable energy and information technologies. For example, charge transfer mechanisms are central to solar energy conversion processes such as photosynthesis and photovoltaics, while charge and spin current interconversion mechanisms underpin processes such as chiral-induced spin selectivity (CISS). In this talk, I will discuss three recent studies on charge transfer at organic heterojunctions and spin to charge conversion in hybrid organic-inorganic perovskite semiconductors with ultrafast spectroscopy. Firstly, I will discuss the phenomenon of barrierless charge photogeneration in Donor:Acceptor heterojunction organic solar cells. Temperature-dependent broadband transient absorption spectroscopy results show barrierless charge generation is universal even when the driving force for charge generation is suppressed. Secondly, I will discuss the binding energy of interfacial charge-transfer states determined using pump push photocurrent spectroscopy. Coupled with transient absorption studies on the lifetimes of such charge-transfer states, I will discuss the design rules for controlling charge dynamics, enhancing charge generation efficiency, and reducing loss pathways. Finally, I will discuss recent advancements in using ultrafast Terahertz (THz) emission spectroscopy to study spin to charge conversion and charge transfer in various chemical systems, specifically on revealing the underlying mechanisms for CISS. These three studies demonstrate capabilities of ultrafast optical and THz spectroscopy to uncover fundamental mechanisms driving quantum processes in next-generation energy and information technologies.
Faculty Host: Mark Johnson, Arthur T. Kemp Professor of Chemistry
This seminar is generously sponsored by the Yale Department of Chemsitry
Event contact name:
Chemistry Events