Center for Excitonics
Seminar Series Announcement
The Center for Excitonics is an Energy Frontier Research Center funded by
the
U.S. Department of Energy, Office of Science and Office of Basic Energy
Sciences
The Center for Excitonics (
http://www.rle.mit.edu/excitonics) invites you
to join us at the
next seminar of the Fall 2009 series. Please forward this information on
to others who might be interested
in attending this seminar.
Title: "Plastic" Solar Cells: Self-Assembly of
Bulk Heterojunction Nano-Materials by
Spontaneous Phase Separation
Presenter: Professor Alan J. Heeger
Organization: University of California, Santa Barbara
Department of Chemistry
Date: October 20, 2009
Time: 3:00 - 4:00pm
Place: 36-428
Refreshments: Yes
URL:
http://www.rle.mit.edu/excitonics/heeger-102009.html
abstract
Solar cells --- Power from the Sun --- can provide and must provide --- a
significant contribution to our future energy needs. The challenge is
clear; we must create the scientific foundation and the technology to
enable fabrication of high efficiency solar cells at low cost.
I will describe the discovery of ultrafast photoinduced electron transfer
as the scientific foundation for the creation of a technology for low cost
“plastic” solar cells. This initial charge separation occurs at a time
scale two orders of magnitude faster than the first step in
photo-synthesis in green plants. Charge collection at the electrodes is
accomplished through self-assembly of bulk heterojunction (BHJ)
nano-materials by spontaneous phase separation.
Recent results include the achievement of 6% power conversion efficiency
and the demonstration of quantum efficiencies approaching 100%: Each
photon absorbed leads to a (positive and negative) pair of mobile charge
carriers, and all the photo-generated charge carriers are collected at the
electrodes. Higher efficiencies will come from improved harvesting of the
photons from the solar spectrum using new semiconducting polymers designed
and synthesized for use in “plastic” solar cells.
We see a clear technology pathway to high efficiency “plastic” solar cells
with lifetimes sufficient for a wide range of applications including
portable electronics, semi-transparent solar cells for windows in homes
and buildings, and rooftop installation. I will discuss lifetime issues
and progress toward manufacturing plastic solar cells by printing/coating
technology. I will demonstrate that the dream of low cost plastic solar
cells is becoming reality.
bio
Widely known for his pioneering research in and the co-founding of the
field of semiconducting and metallic polymers, Professor Heeger is also
the recipient of numerous awards, including the Nobel Prize in Chemistry
(2000), the Oliver E. Buckley Prize for Condensed Matter Physics, the
Balzan Prize for the Science of New Materials, the Eni Italgas Prize for
Energy and the Environment, the President’s Medal for Distinguished
Achievement from the University of Pennsylvania, the Chancellor’s Medal
from the University of California, Santa Barbara, and honorary doctorates
from more than a dozen universities in the United States, Europe and
Asia. He is a member of the National Academy of Science (USA), the
National Academy of Engineering (USA) and a foreign member of the Korean
Academy of Science. Prof. Heeger founded UNIAX Corporation in 1990; UNIAX
was acquired by DuPont in 2000. Prof. Heeger is Chairman and Co-founder of
CBrite Inc. in Santa Barbara.
Barbara.