Events
Molecular Engineering of Conjugated Polymers to Reach Higher Efficiency “Plastic” Solar Cells
November 12, 2010 at 3pm/36-428
Wei You
University of North Carolina
abstract:
The bulk heterojunction (BHJ) organic photovoltaic cells of regioregular poly(3-hexylthiophene) (RR-P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) represent one of the most successful systems with reproducible efficiencies approaching 5% after careful optimization. However, with a fixed band gap of 1.9 eV, P3HT can only harvest a small portion of the solar spectrum (maximum 22.4%). Therefore low band gap polymers for better light harvesting have been intensively pursued in recent years. Though impressive progresses have been made, the outstanding question remains: how to rationally design ideal polymers to approach 10% efficiency and beyond?
I will summarize the design criteria for “ideal” polymers to be used with PCBM to further improve the efficiency of BHJ photovoltaic devices. Specifically, I will focus on three main topics: (a) design of new conjugated backbone to control the band gap and energy levels; (b) the significant influence of “trivial” side chains; (c) the impact of substituents such as F. A number of new polymers will be discussed in detail to elaborate these topics. A design motif has been proposed, which successfully produced polymers that demonstrated over 7% efficiency in BHJ devices
bio:
Dr. Wei You obtained his BS from University of Science and Technology of China in 1999. He graduated with his PhD from the University of Chicago in 2004 with Luping Yu, and finished his postdoctoral training at Stanford University in 2006 with Zhenan Bao. In July 2006, Dr. You joined the University of North Carolina at Chapel Hill as an Assistant Professor in Chemistry. He has been awarded the DuPont Young Professor Award (2008) and the NSF CAREER Award (2010). His group is currently investigating organic solar cells, molecular spintronics/electronics and devices, new methods for nanofabrication (microfabrication), and new materials for dental applications.
