Finding a buckyball in photovoltaic cell

One approach uses a light-absorbing polymer along with a derivative of a sixty-carbon fullerene molecule, commonly known as a buckyball. For maximum efficiency, the two materials must be present in thin layers near opposite electrodes but most analytical methods cannot distinguish between polymer and the buckyball well enough to characterize the plastic solar cell film.

New research reported in the Journal of Chemical Physics describes a technique that analyzes the reflection of neutrons to locate the buckyballs within the composite material.

“Neutron scattering is not a new technique but it has yet to be widely applied to this class of materials,” says researcher Brian Kirby of the National Institute of Standards and Technology. “With this paper, we are providing an instruction book for researchers who want to use neutrons to study polymer photovoltaics.”

He points out that while neutron scattering requires a reactor or particle accelerator – not typical lab equipment – scattering facilities are widely available to industrial and academic users.

Because both the polymer and the buckyball are composed mostly of carbon and their locations must be defined within a few nanometers, standard techniques have not provided sufficient resolution to describe the location of the buckyballs. As a result, much of the research on organic solar cells has been a trial and error process. Neutrons happen to interact with the polymer and the buckyball derivative very differently, leading to a sharp contrast.

“Our goal is more effective research on photovoltaic devices,” says researcher Jon Kiel of the University of Delaware. “Using this technique, we have confirmed that particles are not distributed in the ideal way and have shown how to evaluate the distribution in new materials.”

The article, “Phase-sensitive neutron reflectometry measurements applied in the study of photovoltaic films” by J. W. Kiel, M. E. Mackay, B. J. Kirby, B. B. Maranville and C. F. Majkrzak is published in The Journal of Chemical Physics. http://link.aip.org/link/jcpsa6/v133/i7/p074902/s1

ABOUT THE JOURNAL OF CHEMICAL PHYSICS

The Journal of Chemical Physics publishes concise and definitive reports of significant research in methods and applications of chemical physics. Innovative research in traditional areas of chemical physics such as spectroscopy, kinetics, statistical mechanics, and quantum mechanics continue to be areas of interest to readers of JCP. In addition, newer areas such as polymers, materials, surfaces/interfaces, information theory, and systems of biological relevance are of increasing importance. Routine applications of chemical physics techniques may not be appropriate for JCP. Content is published online daily, collected into four monthly online and printed issues (48 issues per year); the journal is published by the American Institute of Physics. See: http://jcp.aip.org/

ABOUT AIP

The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.