The 2nd QLC seminar

Date&Time: 2019/08/02 (Fri) 14:00-16:00
Place: IMRAM West 1st Building Seminar Room (2F), Katahira campus, Tohoku University (B06)
Title: Role of Organic Molecules in the Physics of Organic-Inorganic
Lead Iodide Perovskites
Speaker: Prof. Seung-Hun Lee
Affiliation: Department of Physics, University of Virginia

The realization of economical renewable energy technologies is critical for securing long term prosperity of mankind and mitigating the threat of climate change. Power from the Sun is the most abundant source of renewable energy. In just one hour, more solar energy hits the Earth’s surface than humanity uses in an entire year. Therefore, development of solar cells that can produce electrical power at a cheaper rate than fossil fuel based electricity is highly desirable. However, only about 1 percent of the world’s energy production currently comes from solar cells. This is because the conventional technologies, mostly based on silicon solar cells, are too expensive to be competitive with energy generated by burning fossil fuels. What is needed is research on new solar cell materials that can be fabricated into solar cells with high-efficiency and low-cost simultaneously.

Hybrid Organic-Inorganic perovskites (HOIPs) have recently been discovered as one of the most promising next generation solar cell materials. Solar cells based on HOIPs have achieved high efficiency that rivals that of the conventional silicon solar cells. At the same time, HOIPs can be deposited on surfaces from ink solutions which enable low-cost and high-throughput manufacturing of solar cells as if printing out newspapers. In this talk, I will present our recent research that revealed microscopic mechanism of the photovoltaic properties of HOIPs.[1-3]

1. Origin of Long Lifetime of Band-Edge Charge Carriers in Organic-Inorganic Lead Iodide Perovskites, Tianran Chen, Wei-Liang Chen, Benjamin J. Foley, Jooseop Lee, Jacob Ruff, J. Y. Peter Ko, Craig M. Brown, Leland W. Harriger, Depei Zhang, Changwon Park, Mina Yoon, Yu-Ming Chang, Joshua J. Choi, and Seung-Hun Lee, Proc. Natl. Acad. Sci. 114, 7519-7524 (2017).
2. Entropy Driven Structural Transition and Kinetic Trapping in Formamidinium Lead Iodide Perovskite, Tianran Chen, Benjamin J. Foley, Changwon Park, Craig M. Brown, Leland W. Harriger, Jooseop Lee, Jacob Ruff, Mina Yoon, Joshua J. Choi, and Seung-Hun Lee, Science Advances 2, e1601650 (2016).
3. Rotational dynamics of organic cations in CH3NH3PbI3, T. Chen, B. J. Foley, B. Ipek, M. Tyagi, J.R.D. Copley, C. M. Brown, J. J. Choi, S.-H. Lee, Phys. Chem. Chem. Phys. 17, 31278-31286 (2015).