The synthesis of a conjugated organic polymer--widely used as a conductive material in devices like light-emitting diodes, televisions and solar cells--could mean more efficient, cheaper electronics.
In a paper published in the Proceedings of the National Academy of Sciences, the group of scientists from ORNL and two Canadian universities outlined their success in growing highly structured short chains of polymer poly(3,4-ethylenedioxythiophene), or PEDOT. Analysis and understanding of the polymerization process and results were provided with the help of ORNL supercomputers.
The theoretical expertise provided by ORNL scientists Bobby Sumpter and Vincent Meunier in synthesizing the PEDOT polymer could potentially have an impact on everyday electronic products. PEDOT is valued in electronic applications for the transparency, ductility and stability of its conducting, or doped, state. Because of its role as conductive material in organic light-emitting diodes, PEDOT is found in many electronic devices such as televisions and computer monitors.
The polymer is also used in many solar panel cells as a hole-filling material. "It's one of the most successfully used semiconducting polymers on the planet," Sumpter said.
Improving and controlling the molecular order of a nanostructured PEDOT material is critical to the polymer's performance in electronic applications. The highly ordered polymer arrays such as those constructed by the researchers could lead to increased efficiencies in a multitude of electronic devices.
To create ordered arrays of the PEDOT polymer, the team placed a precursor molecule onto a copper crystalline surface, which helped to guide and initiate the polymerization reaction. Team member Meunier of ORNL compared the process to placing eggs in an egg carton, where the free energy minima, or "indentations," in the copper surface allow the molecules to neatly stack next to each other to form a compact and organized polymer structure.
"The chemistry and resulting stereochemical structure on the surface are very unusual," said Sumpter. "Most attempts to synthesize polymers usually result in imperfect polymer arrays with a very different prominent structure."
Sumpter and Meunier from ORNL's Center for Nanophase Materials Sciences with appointments in the Computer Science and Mathematics Division collaborated in the project by analyzing the results through a "virtual microscope." Based on density functional theory calculations and simulations performed on ORNL supercomputers, the "virtual microscopy" revealed the highly organized structure of the polymer arrays. By examining the polymer formation with the conventional means of scanning tunneling microscopy combined with the virtual microscopy, the team was able to clearly illustrate the construction and bonding of PEDOT arrays.
"This experiment defines what nanoscience is about--a mixture of experimental techniques combined with theoretical knowledge," Meunier said. "It was an excellent opportunity to interface directly with experimentalists and establish new international collaborations."
Although the team focused its research on the PEDOT polymer, the researchers believe the same approach could potentially be used to construct other well-defined polymers.
These findings are published as "Step-by-step growth of epitaxially aligned polythiophene by surface-confined reaction" (Lipton-Duffin et al.) in the Proceedings of the National Academy of Sciences. The research team included scientists from Université du Québec and McGill University in Canada.
This research was funded by Natural Sciences and Engineering Research Council of Canada, Air Force Office of Scientific Research and Asian Office of Aerospace Research and Development of the USA, the Petroleum Research Fund of the American Chemical Society, the Ministère du Développement économique, de l'Innovation et de l'Exportation of Quebec, the Fonds québécois de la rescherche sur la nature e les technologies Centre for Self-Assembled Chemical Structures, a DuPont Young Professor Award, and the Canada Research Chairs Program. Additional support was provided by the DOE Office of Science through the Center for Nanophase Materials Sciences and the Polymer-Based Materials for Harvesting Solar Energy center, an Energy Frontier Research Center.
The Center for Nanophase Materials Sciences at ORNL is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://nano.energy.gov.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.
Researchers take next step toward fusion energy
16.11.2017 | Texas A&M University
Desert solar to fuel centuries of air travel
16.11.2017 | SolarPACES
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
20.11.2017 | Earth Sciences
20.11.2017 | Earth Sciences
20.11.2017 | Life Sciences