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/
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.
Jason Bardi | EurekAlert!
New biomaterial could replace plastic laminates, greatly reduce pollution
21.09.2017 | Penn State
Stopping problem ice -- by cracking it
21.09.2017 | Norwegian University of Science and Technology
Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
26.09.2017 | Life Sciences
26.09.2017 | Physics and Astronomy
26.09.2017 | Information Technology