PCBM (fullerene) P3HT (polymer)

Power From Plastics
Lightweight, flexible, inexpensive solar panels made with conductive
polymers can help access clean, renewable solar energy.
More energy from the sun reaches the earth’s
PCBM
(fullerene)
surface in one hour than the world uses in a year.
However, less than 0.01% of all power generation
P3HT
(polymer)
comes from solar power.
Why? Because the current technologies are expensive,
heavy, and slow to manufacture.
Now imagine a solar panel that can charge your laptop
and is so lightweight and flexible that it can be rolled up and
stored in your bag.
Or specially designed windows that absorb light to generate
electricity and at the same time reduce air conditioning costs
on hot summer days.
Here at UC Davis, in the lab of Dr. Adam J. Moulé, researchers
are gaining new understanding of how molecular interac-
s This diagram shows the architecture of an organic photovoltaic cell. The active layer is a mixture of polymer (P3HT) and
tions used in these organic photovoltaic devices affect
fullerene (PCBM). When light is absorbed it creates separated charges called holes and electrons. These charges are collected by the electrodes (anode and cathode) to produce electricity. The structure of the active layer on the atomic, nanoscopic
and microscopic length scales directly affects the electrical properties and efficiency of these devices.
metrics like efficiency and stability.
(a)
a)
(b)
b)
50μm
energy
(c)
s Using transmission electron microscopy we can
s Using supercomputers we can simulate atomic scale behavior of individual
molecules within the solar cell devices. Figure a shows a snapshot of a polymer and
fullerene molecule. Figure b shows a cluster of fullerene molecules that have phase
separated from the polymer. It is important to understand how these molecules fit
together so that we can better understand charge separation at the interfaces.
(Image source: DM Huang et al., J. Chem. Theory. Comput. 6, 526 (2010))
CREDITS:
Scott A. Mauger, Lilian Chang,
John D. Roehling, and
Christopher W. Rochester
Graduate Students
Dept. of Chemical Engineering
and Materials Science
Dr. Sook Yoon
Postdoctoral Scholar
Dept. of Chemical Engineering
and Materials Science
Contact:
Adam J. Moulé, Ph.D.
amoule@ucdavis.edu
(530) 754-8669
chms.engineering.ucdavis.edu/faculty/moule.html
image the structure of a polymer-fullerene film on
the nanoscopic scale. In this image metal atoms
have been added to the fullerene molecule to
increase contrast. It shows that the polymers
(dark areas) and fullerenes (bright areas) form
distinct domains.
Dr. David M. Huang
Lecturer in Chemistry
School of Chemistry & Physics,
University of Adelaide, Australia
50μm
(d)
50μm
50μm
s Our research has also shown that using different solvent additives
affects the size of microscopic fullerene domains (dark areas). Figure a
shows fullerene domains in a film cast without additives. Relative to
no additives, using a bad solvent additive (b) causes the domains to
be smaller while good solvents (c, d) results in much larger domains.
Dr. Adam J. Moulé
Assistant Professor
Dept. of Chemical Engineering
and Materials Science
Technical Director, California
Solar Energy Collaborative