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Carbon Nanosheets
as Nanostructured Electrodes in Organic Photovoltaic
Devices--Luna
Innovations Incorporated, 1 Riverside Circle, Suite 400, Roanoke, VA 24016; 540‑552‑5128; www.lunainnovations.com
Mr. Martin Drees,
PhD, Principal Investigator, submissions307@lunainnovations.com
Ms. Angela Keen, Business Official, submissions307@lunainnovations.com
DOE Grant No. DE‑FG02‑07ER84806
Amount:
$749,935
Photovoltaics, the direct conversion of sunlight into
electric energy, is a promising clean-tech approach to energy production. Organic solar cells show particular promise
because they have the potential for light-weight flexible devices with low
material and production costs. Yet,
despite significant improvements over the last couple of years, the maximum
power conversion efficiency of organic photovoltaic devices is still about 5%,
largely due to the low charge-carrier mobility in the organic materials. Low mobility increases resistance in the film,
thereby reducing the photocurrent and the efficiency of the devices. This
project aims to develop high efficiency, low-cost organic solar cells using
novel nanostructured carbon electrodes consisting of
free-standing carbon nanosheets. The volume between the sheets will be filled
with photoactive material, thereby reducing the distance that charges have to
travel to the collecting electrode. In Phase
I, growth conditions for the carbon nanosheets were
optimized for the organic photovoltaic application. An advanced spray coating technique was used
to fill the nanosheets with photoactive material, and
photovoltaic devices were built and tested. In addition, a technique was developed to
transfer the nanosheets to a zero-thermal-budget
substrate. Lastly, an atomic-layer-deposition
process was developed to conformally coat the nanosheets with a dielectric interface layer. In Phase II, carbon nanosheet
devices with superior photovoltaic performance will be demonstrated. A prototype device – which will be compatible
with a large-scale, roll-to-roll manufacturing process – with commercially
viable conversion efficiency will be built and characterized.
Commercial Applications and Other Benefits as described by
the awardee: Applications for the technology should range
from rooftop photovoltaic systems to light weight, flexible solar cells
integrated into tents, textiles, and small electronic devices (i.e. cell
phones, PDAs, etc.). A successful commercialization also would help
the economically challenged region of