The printing method is fast and works with a variety of organic materials to produce semiconductors of strikingly higher quality than what has so far been achieved with similar methods.
This photo shows an array of 1-mm-wide by 2-cm-long single-crystal organic semiconductors. The neatly-aligned blue strips are what provide greater electric charge mobility. The Stanford logo shown here is the same size as a dime.
Credit: (Credit: Y. Diao et al.)
Organic electronics have great promise for a variety of applications, but even the highest quality films available today fall short in how well they conduct electrical current. The team from the U.S. Department of Energy's (DOE) SLAC National Accelerator Laboratory and Stanford University have developed a printing process they call FLUENCE—fluid-enhanced crystal engineering—that for some materials results in thin films capable of conducting electricity 10 times more efficiently than those created using conventional methods.
"Even better, most of the concepts behind FLUENCE can scale up to meet industry requirements," said Ying Diao, a SLAC/Stanford postdoctoral researcher and lead author of the study, which appeared today in Nature Materials.
Stefan Mannsfeld, a SLAC materials physicist and one of the principal investigators of the experiment, said the key was to focus on the physics of the printing process rather than the chemical makeup of the semiconductor. Diao engineered the process to produce strips of big, neatly aligned crystals that electrical charge can flow through easily, while preserving the benefits of the "strained lattice" structure and "solution shearing" printing technique previously developed in the lab of Mannsfeld's co-principal investigator, Professor Zhenan Bao of the Stanford Institute for Materials and Energy Sciences, a joint SLAC-Stanford institute.
To make the advance, Diao focused on controlling the flow of the liquid in which the organic material is dissolved. "It's a vital piece of the puzzle," she said. If the ink flow does not distribute evenly, as is often the case during fast printing, the semiconducting crystals will be riddled with defects. "But in this field there's been little research done on controlling fluid flow."
Diao designed a printing blade with tiny pillars embedded in it that mix the ink so it forms a uniform film. She also engineered a way around another problem: the tendency of crystals to randomly form across the substrate. A series of cleverly designed chemical patterns on the substrate suppress the formation of unruly crystals that would otherwise grow out of alignment with the printing direction. The result is a film of large, well-aligned crystals.
X-ray studies of the group's organic semiconductors at the Stanford Synchrotron Radiation Lightsource (SSRL) allowed them to inspect their progress and continue to make improvements, eventually showing neatly arranged crystals at least 10 times longer than crystals created with other solution-based techniques, and of much greater structural perfection.
The group also repeated the experiment using a second organic semiconductor material with a significantly different molecular structure, and again they saw a notable improvement in the quality of the film. They believe this is a sign the techniques will work across a variety of materials.
Principal investigators Bao and Mannsfeld say the next step for the group is pinning down the underlying relationship between the material and the process that enabled such a stellar result. Such a discovery could provide an unprecedented degree of control over the electronic properties of printed films, optimizing them for the devices that will use them.
"That could lead to a revolutionary advance in organic electronics," Bao said. "We've been making excellent progress, but I think we're only just scratching the surface."
Other study co-authors included researchers from Stanford University's departments of chemistry and chemical and electrical engineering and Nanjing University. The research was supported by the SLAC's Laboratory Directed Research and Development program. SSRL is a national user facility operated by Stanford University on behalf of the DOE's Office of Science.
SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit http://www.slac.stanford.edu.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Citation: Y. Diao et al., Nature Materials, 02 June 2013 (10.1038/NMAT3650)Press Office Contact:
Bronwyn Barnett | EurekAlert!
New design improves performance of flexible wearable electronics
23.06.2017 | North Carolina State University
Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology