Photovoltaics is a method of converting solar radiation into electricity. Some semiconducting materials exhibit a property known as the photoelectric effect that causes them to absorb light and release electrons. In addition to the semiconductors,

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Organic Ferroelectric Photovoltaics
Jinsong Huang, Stephen Ducharme, and Alexei
Gruverman (Nebraska MRSEC)
Photovoltaics is a method of converting solar
radiation into electricity. Some semiconducting
materials exhibit a property known as the
photoelectric effect that causes them to absorb
light and release electrons. In addition to the
semiconductors, ferroelectric materials have been
employed to create ferroelectric-photovoltaic
devices. In these devices, a ferroelectric thin
film is used as a light absorbing layer and the
electric field created by ferroelectric
polarization is the driving force for the
photocurrent. However the efficiency of the
photovoltaic effect in these devices is low due
to the low solar light absorption efficiency, low
electric conductivity, and short lifetime of
photoinduced charge carriers. MRSEC
researchers at the University of Nebraska come up
with a method for overriding these constraints by
combining the strong polarization electric field
from a ferroelectric material with the strong
absorption and conduction capabilities of polymer
semiconductors (Nature Materials, 10, 296
(2011)). With rationale of their device design,
the efficiency of organic ferroelectric
photovoltaic can be higher than that of both
organic photovoltaic and ferroelectric
photovoltaic. The proposed device also shows
unique functions such as switchable polarity and
efficiency. This discovery may lead to a novel
approach to photovoltaics resulting in the
enhanced efficiency of converting solar radiation
into electricity.
The figure illustrates how the introduced
electric field by the ferroelectric polymer layer
facilitates the charge separation and extraction
in polymer solar cell.
These programs are supported by the National
Science Foundation, Division of Materials
Research, Materials Research Science and
Engineering Program, Grant 0820521.