Fraunhofer IWS Dresden scientists print electronic layers with polymer ink
Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed on pipes or other surfaces in order to convert waste heat into electricity. The experts at the Fraunhofer Institute for Material and Beam Technology IWS Dresden use ink based on conductive polymers for this purpose.
The engineers coated a glass plate with a particularly smooth and conductive polymer layer of “Poly(Kx[Ni-itto])” by rotation coating (“spin coating”).
Fraunhofer IWS Dresden
The IWS engineers have developed a new process for this project: Small molecules are synthesized into polymers which are able to transport negative charge carriers (electrons). The “trick” is that this polymer, unlike comparable polymers, is in a liquid state. This polymer enables the scientists to print or spray very thin and smooth organic functional coatings on surfaces.
“We want to construct thermoelectric generators that, for example, supply energy to sensors in places that are difficult to access, where battery replacement is not useful, not possible or very expensive,” reports Lukas Stepien, who, together with Dr. Roman Tkachov, manages this development project at Fraunhofer IWS Dresden. Warm pipes that do not get hotter than 100 degrees Celsius - this is the upper limit for the polymers investigated so far.
“Additionally, this technology might also benefit the 'Internet of Things': sensors and other electronic components using thermoelectric generators could cover their own electrical energy requirements. An external power supply will be no longer necessary,” adds Lukas Stepien.
Thermoelectric generators suffer from low efficiency so far
“Thermoelectric generators” have been known as concept for years. However, their efficiency is still far too low for large-scale use: on average, they convert only six percent of the heat energy received into electricity. “The fact that this technology has not yet been able to establish itself might probably be also due to the industry's excessively high expectations,” reports Lukas Stepien. “Today's polymer-based thermoelectric generators, unfortunately, usually deliver only a few milliwatts.
If, however, we succeed in significantly increasing this efficiency, far-reaching consequences for the German energy balance might result: Car manufacturers, for example, have long been dreaming of coating their engines with such thermoelectric generators.
Manufactures strive for electrical recycling of the waste heat from the drive units, which had previously been painstakingly cooled away. The fuel consumption of cars could thus be reduced by up to a tenth, according to estimates. However, solutions so far tested are not very effective.
Fraunhofer polymers also tolerate air contact
With Fraunhofer IWS polymer technology things could change in the future. Roman Tkachov and Lukas Stepien have already taken an important step: they have found a way to liquefy polymers of the so-called “n-conductor type” (where “n” stands for negative charge carriers) in order to further process them.
An important point here is that these polymer layers remain comparatively stable even after use under everyday conditions. That is not self-evident. Such long organic molecules tend to age and lose their special properties when they come into contact with air.
Dr. Roman Tkachov and Lukas Stepien have developed a multi-stage process to produce their inks based on conductive polymers. They initially modify the short elements for polymers, the so-called monomers, chemically. Subsequently they are dissolved in a liquid. Once the polymers have joined, the liquid material can be processed by print, spray or other coating methods.
“In principle, these polymers have already been printable,” emphasizes Lukas Stepien. “But as long as they are in a solid state dispersion, that is, a particle mixture is necessary.” The dissolved polymers, on the other hand, allow very high-quality smooth layer structures, which – depending on the process – are only a tenth to ten micrometers (thousandths of a millimeter) thick.
Potential also for organic solar cells
This in turn allows for more compact and effective components than previously used polymers. “In perspective, we also see great potential for the construction of organic transistors and solar cells,” emphasizes Dr. Roman Tkachov. Until then, however, some research work still needs to be done.
Next, the engineers will initially concentrate on further increasing the electrical conductivity of their polymers. They also aim at producing the first prototypes of thermoelectric generators from their new materials. “And of course we will have to work on further increasing the efficiency of these generators,” says Dr. Roman Tkachov.
Group Manager Printing
M.Sc. Lukas Stepien | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS | Phone +49 351 83391-3092 | Winterbergstraße 28 | 01277 Dresden | www.iws.fraunhofer.de | email@example.com
Markus Forytta | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS
More reliable operation offshore wind farms
23.08.2019 | Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration IZM
Scientists develop a metamaterial for applications in magnonics
22.08.2019 | Moscow Institute of Physics and Technology
Since their experimental discovery, magnetic skyrmions - tiny magnetic knots - have moved into the focus of research. Scientists from Hamburg and Kiel have now been able to show that individual magnetic skyrmions with a diameter of only a few nanometres can be stabilised in magnetic metal films even without an external magnetic field. They report on their discovery in the journal Nature Communications.
The existence of magnetic skyrmions as particle-like objects was predicted 30 years ago by theoretical physicists, but could only be proven experimentally in...
Theoretical physicists at Trinity College Dublin are among an international collaboration that has built the world's smallest engine - which, as a single calcium ion, is approximately ten billion times smaller than a car engine.
Work performed by Professor John Goold's QuSys group in Trinity's School of Physics describes the science behind this tiny motor.
Together with the University of Innsbruck, the ETH Zurich and Interactive Fully Electrical Vehicles SRL, Infineon Austria is researching specific questions on the commercial use of quantum computers. With new innovations in design and manufacturing, the partners from universities and industry want to develop affordable components for quantum computers.
Ion traps have proven to be a very successful technology for the control and manipulation of quantum particles. Today, they form the heart of the first...
Experimental progress towards engineering quantized gauge fields coupled to ultracold matter promises a versatile platform to tackle problems ranging from condensed-matter to high-energy physics
The interaction between fields and matter is a recurring theme throughout physics. Classical cases such as the trajectories of one celestial body moving in the...
Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.
Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...
16.08.2019 | Event News
14.08.2019 | Event News
12.08.2019 | Event News
23.08.2019 | Medical Engineering
23.08.2019 | Power and Electrical Engineering
23.08.2019 | Life Sciences