*FYI--The date has been changed to May 17th, 2013.* On 3/15/2013 9:15 AM, Jennifer Keddle wrote: > > MichiganState University > > Science at the Edge > > Engineering Seminar > > *May 17, 2013* > > 11:30 a.m. > > Room1400 Biomedical and Physical Sciences Building > > Refreshments served at 11:15 a.m. > > Mark E. Thompson > > Department of Chemistry > > University of Southern California > > > Exciton Management in Organic Solar Cells > > ** > > Abstract > > The exciton is a critical part of each of the processes leading to > photocurrents in Organic PhotoVoltaics (OPVs), and being able to > control the location, lifetime and energy of the exciton is essential > to achieving high efficiency.We have investigated methods for tuning > exciton energies and controlling their migration paths, both > intramolecularly and within a thin film.I will discuss our most recent > work with both organic dyes, such as squaraines and dipyrrins as well > as porphyrinic materials for OPVs.This involves a careful materials > design study that leads to both low energy absorption (into the > nearIR) and the efficient use of multiple absorbers to efficiently > harvest photons through the entire visible spectrum.To that end we > have used transient absorption spectroscopy and measured the rates of > singlet and triplet energy transfers between organic dyes (BODIPY and > tetracenes).Both intra- and inter-molecular energy transfers take > place on the picoseconds time scale.Thus, the systems are fully > equilibrated into the lowest energy triplet state(s) before > nonradiative decay.Using this approach we can efficiently harvest > energy across the visible and into the NIR. I will also discuss our > latest results with new singlet fission materials for efficient light > harvesting in OPVs. Our control of singlet and triplet excitons has > been important in exploring the use of singlet fission to enhance the > efficiencies of OPVs. > > Bio > > */Dr. Mark E. Thompson/*is Professor of Chemistry and Materials > Science at the University of Southern California. He received his B.S. > degree in Chemistry in 1980 (U.C. Berkeley) and his Ph.D. in chemistry > in 1985 (California Institute of Technology).He spent 2 years as a > postdoctoral fellow in the Inorganic Chemistry laboratory at Oxford > University.Prof. Thompson took a position in the chemistry department > at Princeton University in 1987, as an assistant professor.In 1995 he > moved his research team to the University of Southern California, > where he is currently a Professor of Chemistry.He has won a number of > awards, including the MRS Medal in 2006, given by the Materials > Research Society, and the Jan Rachman Prize for Outstanding > Achievement in Flat Panel Displays, also in 2006, given by the Society > for Information Display. In 2011 he was named the 12 of the top 100 > most influential chemists in the world by Thomson-Rueters.In 2012 he > was received the Alexander von Humboldt Research Award.He currently > has over 250 papers in print and over 125 US patents.His research > interests involve the optical and optoelectronic properties of > molecular materials and devices, particularly organic LEDs and solar > cells, as well as nanoscale materials, catalysis and biosensors. > > For further information please contact Prof. Christina Chan, > Department of Chemical Engineering and Materials Science at > [log in to unmask] <mailto:[log in to unmask]> > > Persons with disabilities have the right to request and receive > reasonable accommodation. Please call the Department of Chemical > Engineering and Materials Science at 355-5135 at least one day prior > to the seminar; requests received after this date will be met when > possible. >