Traditional plastics, or polymers, are electrical insulators. In the seventies a new class of polymers that conduct electricity like semiconductors and metals was discovered by Alan J.Heeger, Alan G. MacDiarmid and Hideki Shirakawa.
Photo: Ida Ling Flanagan
This was the motivation for their Nobel Prize in Chemistry year 2000. Now Xavier Crispin, Docent in organic electronics at Linköping University’s Department of Science and Technology, has led a project where no fewer than twenty researchers from five universities worldwide have collaborated to prove that polymers can also be semimetals.
The results are published in an article in the prestigious journal Nature Materials, with Dr Crispin as principal author.
A few years ago Xavier Crispin discovered that conductive polymers can be thermoelectric. A thermoelectric material undergoes a diffusion of electronic charge carriers to the cold region when the material is submitted to a temperature gradient. As a result an electric potential is created between the cold and hot side of the material. This thermo-voltage is the basis of thermo-couples used for instance in an everyday oven thermometer.
Xavier Crispin“Our experiments yielded a high thermoelectric effect, a Seebeck effect, which indicated that we were dealing with semimetals. But we needed proof,” says Dr Crispin.
This required talented people from various locations to gain an in-depth understanding of the phenomenon.
No less than twenty researchers from Sweden, Australia, Belgium, Norway and Denmark are co-authors of the article in Nature Materials. Ten of them are from Linköping University, including Xavier Crispin, Professor Magnus Berggren and Igor Zozoulenko from the Laboratory of Organic Electronics, Department of Science and Technology, Campus Norrköping, as well as Professor Mats Fahlman, Division of Surface Physics and Chemistry, and Professor Weimin Chen, Division of Functional Electronic Materials, both at the Department of Physics, Chemistry and Biology.
“It has been very impressive to see how Xavier Crispin has led this. We have a fantastic environment for materials research at Linköping University, with world-leading expertise. We are all friends and we’ve been able to produce this article without joint funding,” says Magnus Berggren, professor or organic electronics.
The theoretical input of Igor Zozoulenko, advanced spectroscopic analysis by Mats Fahlman and Weimin Chen at Linköping University, as well as state-of-the-art polymer samples and morphology studies by research colleagues in Australia, Belgium, Norway and Denmark showed the exact same thing: the polymer, in this case a doped variant of the plastic PEDOT, behaves exactly like a semimetal, which also explains the high Seebeck effect.
Thermoelectric generators are available on the market today, but these are made from alloys of bismuth and the semimetal tellurium. Unlike the polymers, these elements are both rare and expensive.
“These polymers are both easy and inexpensive to produce. That we now have an understanding of these phenomena will really drive developments forward, and will open up a new research field in organic electronics,” says Prof Berggren.
The research was financed primarily by ERC, the European Research Council. In 2012 Dr Crispin was awarded an ERC Starting Grant of SEK 13 million.
Photo: Ida Ling Flanagan
Related linksLaboratory of Organic Electronics, ITN
Slawomir Braun, Daniel Dagnelund, Weimin M. Chen and Mats Fahlman, Department of Physics, Chemistry and Biology, Linköping University, Sweden.
Drew R. Evans, Manrico Fabretto, Pejman Hojati-Talemi, Peter J. Murphy, University of South Australia, Mawson Lakes, Australia.
Jean-Baptiste Arlin, Yves Geerts, Free University of Brussels, Bryssel, Belgium.
Simon Desbief, Roberto Lazzaroni, University of Mons, Mons, Belgium.
Dag W Breiby, Norwegian University of Science and Technology, Trondheim, Norway.
Jens W Andreasen, Technical University of Denmark, Roskilde, Denmark.Nature Materials 2013-12-08
Xavier Crispin | EurekAlert!
The stacked colour sensor
16.11.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Counterfeits and product piracy can be prevented by security features, such as printed 3-D microstructures
16.11.2017 | Karlsruher Institut für Technologie (KIT)
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
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses