CCST Seminar: Yi Rao
Dr. Yi Rao obtained his Ph.D. from Chinese Academy of Sciences, Institute of Chemistry, in 2004. After completing three years of postdoctoral research, he was appointed an associate research scientist in 2007 jointly supported by Drs. Nicholas J. Turro and Kenneth B. Eisenthal at Columbia University. After working with Dr. Tony F. Heinz for one year in the field of materials science at Columbia University, Dr. Rao moved to Temple University in 2014 as a research associate professor, where he is now advising 5 Ph.D. graduate students and one research staff. As of July 2017, Dr. Rao is going to join a faculty position in the Department of Chemistry and Biochemistry in Utah State University. Over the years, Dr. Rao has been actively involved in diversified research areas including ultrafast optical spectroscopy, materials science, surface science, photochemistry, environmental chemistry, and biophysical chemistry.
"Ultrafast Sum Frequency Generation (SFG) Spectroscopy for Materials and Environmental Applications"
Sum frequency generation (SFG) is a proven interface-specific technique and widely used for determining vibrational and electronic structures of materials, environmental, and biological interfaces. However, it is barely known that SFG could act as a probe to examine structural dynamics occurred at interfaces. In this talk, I discuss basic principles of SFG and show our recent efforts in developing ultrafast interface-specific sum frequency generation for the applications of materials and environmental sciences. In the first example, I will investigate ultrafast intermolecular electron transfer at the air/water interface by employing our recently-developed transient sum frequency generation (SFG) spectroscopy. The electron transfer between photoexcited coumarin 314 and Dimethylaniline at the air/water interface includes both forward electron transfer (charge separation) and back electron transfer (charge recombination). The rates for both the processes are much faster than those in bulk. I will explain this phenomenon in terms of static and dynamical solvent effects as well as molecular orientational order at the interface. It was found that the weak polarity and highly orientational ordering of molecules at the interface account for the fast rates of the charge separation and charge recombination. The second example is interfacial charge transfer in hybrid solar cells. We take GaAs/C60 as an example. I will show you how surface states play a vital role in charge injection and interfacial electron transfer by developing ultrafast electronic sum frequency generation.
Thursday, June 22, 2017 at 11:00am to 12:00pm
Colburn Lab, 366 CLB
University of Delaware- Colburn Lab, University of Delaware, 150 Academy St, Newark, DE 19716-3196, USA