Printable electronics are created by spraying or printing inks containing conductive organic molecules onto a surface. The process is fast and much less expensive than current production techniques for items like solar cells or computer and television displays.
Additionally, it holds potential for amazing new applications: picture a wearable interactive display that needs no batteries. In the solar industry, the ability to print solar cells on giant roll-to-roll printing presses – like printing a newspaper – could make the technology much more affordable and mass marketable.
NC State physicists Dr. Harald Ade and Dr. Brian Collins, in collaboration with Dr. Michael Chabinyc at the University of California Santa Barbara, wanted to know why some processing steps resulted in better and more efficient devices than others. "Manufacturers know that some materials work better than others in these devices, but it's essentially still a process of trial and error," Ade says. "We wanted to give them a way to characterize these materials so that they could see what they had and why it was working."
To do that, Collins and Ade went to Lawrence Berkeley National Laboratory's Advanced Light Source (ALS). They developed a new technique which used the powerful X-rays from the ALS to look at how individual molecules within these materials organize. They found that the best performing devices were characterized by particular molecular alignments within the materials.
"In transistors, we found that as the alignment between molecules increased, so did the performance," Collins says. "In the case of the solar cells, we discovered alignment of molecules at interfaces in the device, which may be the key to more efficient harvesting of light. For both, this was the first time anyone had been able to really look at what was happening at the molecular level."
The researchers' results appear in the journal Nature Materials. Led by NC State and UCSB, an international collaboration of researchers from Lawrence Berkeley National Laboratory, Monash University in Australia, and University Erlangen-Nuremberg in Germany contributed to the work.
"We're hoping that this technique will give researchers and manufacturers greater insight into the fundamentals of these materials," Collins says. "Understanding how these materials work can only lead to improved performance and better commercial viability."
The research was funded by the Department of Energy, National Science Foundation through the American Reinvestment and Recovery Act, and Department of Education. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy.
Note to editors: Abstract follows.
"Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films"
Authors: B. A. Collins, H. Yan, E. Gann, H. Ade, North Carolina State University; J. E. Cochran, M. L. Chabinyc, University of California, Santa Barbara; C. Hub, R. Fink, Physikalische Chemie and ICMM, University Erlangen-Nuremberg, Erlangen, Germany; C.Wang, Advanced Light Source, Lawrence Berkeley National Laboratory; T. Schuettfort, University of Cambridge, U.K.; C. R. McNeill, Monash University, Victoria, Australia
Published: April 15th 2012 in Nature Materials
Abstract: Molecular orientation critically influences the mechanical, chemical, optical and electronic properties of organic materials. So far, molecular-scale ordering in soft matter could be characterized with X-ray or electron microscopy techniques only if the sample exhibited sufficient crystallinity. Here, we show that the resonant scattering of polarized soft X-rays (P-SoXS) by molecular orbitals is not limited by crystallinity and that it can be used to probe molecular orientation down to size scales of 10 nm. We first apply the technique on highly crystalline small-molecule thin films and subsequently use its high sensitivity to probe the impact of liquid-crystalline ordering on charge mobility in polymeric transistors. P-SoXS also reveals scattering anisotropy in amorphous domains of all-polymer organic solar cells where interfacial interactions pattern orientational alignment in the matrix phase, which probably plays an important role in the photophysics. The energy and q-dependence of the scattering anisotropy allows the identification of the composition and the degree of orientational order in the domains.
Tracey Peake | EurekAlert!
Decoding cement's shape promises greener concrete
08.12.2016 | Rice University
Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D
08.12.2016 | DOE/Brookhaven National Laboratory
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine