Events Calendar

Center for Energy Nanoscience and Technology Distinguished Speaker Series

Speaker: Garry Rumbles, National Renewable Energy Laboratory (NREL) Golden, Colorado and Department of Chemistry and Biochemistry University of Colorado, Boulder

Talk Title: Comparing the Primary Electron Transfer Process in Photosynthetic Reaction Centers with Organic Photovoltaic Heterojunctions

Abstract: Abstract:
This presentation will focus on some of the fundamental science associated with the rapidly emerging field of organic
photovoltaics (OPV). It will include a discussion of how the OPV field is evolving, examine some of the fundamental
scientific issues that underpin the subject, and will discuss how spectroscopy can help to understand these issues. The
goal is to enable both a better understanding of how these systems function and consequently help to advance solar
energy conversion efficiencies of future OPV devices.
So-called organic photovoltaic devices have seen certified power conversion efficiencies increase from 2.5% in 2001 to
~9% in 2011. Close inspection of the strategies employed to realize this impressive improvement in performance reveal
a common approach of synthesizing new donor polymers, fullerene acceptors and, in some cases, new device
architectures. It is questionable as to whether this approach will result in a similar four-fold level of improvement over the
next ten years. And it is this question that motivates the work that will be described.
At the heart of all OPV devices is the donor-acceptor interface, where photogenerated excitons are dissociated into
separated charge carriers. Using flash photolysis, timeresolved microwave conductivity as a tool for detecting mobile
carriers, a number of recently-studied systems will be demonstrated. These may include systems that contain new
conjugated polymers, novel derivatives of fullerenes, single-walled carbon nanotubes and colloidal quantum dots, to
name a few. These studies will serve to highlight a fundamental issue that we have yet fully understand: how are these
carriers created with such efficiency and yield, and in a system that does not immediately suggest that this is possible?
The talk will therefore include a speculative discussion about how we might better understand this process by looking at
the function of Nature’s photosynthetic reaction centers

Biography: Bio:
Dr. Garry Rumbles is a Research Fellow at the U.S. DOE National Renewable Energy Laboratory (NREL). Dr. Rumbles
joined NREL in 2000 and is widely recognized for his research in photochemistry and photophysics of conjugated
molecular systems, energy conversion in organic light emitting diodes and organic photovoltaic devices, and nanoscale
morphology. In May 2009, he became a Professor Adjoint in the Department of Chemistry and Biochemistry at CU
Boulder; and in October 2009 a Fellow of the joint CU/NREL adventure: Renewable and Sustainable Energy Institute
(RASEI). In 2004, he was made a Fellow of the Royal Society of Chemistry. Dr. Rumbles has published more than 130
journal articles and more than 10 book sections.

Host: P. Daniel Dapkus, Center Director

More Information: Rumbles.pdf

Location: Grace Ford Salvatori Hall Of Letters, Arts & Sciences (GFS) - 106

Audiences: Everyone Is Invited

Contact: Eliza Aceves