Events
Steering and Separating Excitons in Organic Thin Films and Devices
October 26, 2010 at 3pm/36-428
Mark Thompson
University of Southern California (USC)
abstract:
We have taken a materials intensive approach to developing an understanding of the mechanism of photocurrent and photovoltage generation in organic photovoltaic devices (OPVs) and electroluminescence in organic LEDs (OLEDs). The exciton is a critical part of each of these processes, 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 porphyrinic materials for OPVs. This involves a careful materials design study that leads to both low energy absorption (into the nearIR) and the use of substituted porphyrins to efficiently harvest photons through the entire visible spectrum. Both long wavelength and broad absorption are achieved with high extinction (> 105 cm‑1). Time permitting, I will also discuss our recent results for white emitting OLEDs, and how we use materials with long triplet exciton diffusion lengths to selectively harvest singlet and triplet excitons onto separate emitters.
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 was an S.E.R.C. fellow in the Inorganic Chemistry Laboratory at Oxford University from 1985-87. 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 and Materials Science. 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.
