TCOs are normally produced on solid substrates using vacuum coating such as sputtering, but can also be applied to flexible substrates such as plastic film using special TCO inks.
To do this, developers at the INM use TCO inks containing TCO nanoparticles and produced using wet chemistry processes. This method enables not only application to plastics and films but also, for the first time, direct printing of transparent conductor structures.
The INM will be exhibiting these and other developments from 15 to 17 October at Materialica 2013 in Munich and from 23 to 24 October at Eurofinish 2013 in Ghent (Belgium).
“We produce special nanoparticles from the transparent conducting oxides”, explains Peter William de Oliveira, Head of the Optical Materials Program Division. “By adding a solvent and a special binder, these modified TCO nanoparticles can be applied to the film directly by gravure printing as an “ink” using a printing plate”, he adds.
This process has a number of advantages. Gravure printing enables TCO layers to be printed cost-effectively in just one process step. As a result of UV curing at temperatures below 150°C, it is also possible to coat thin plastic films. The binder fulfills a number of tasks here. It produces good adhesion of the TCO nanoparticles to the substrate and also increases the flexibility of the TCO layers. This means that the conductivity remains the same, even if the films become distorted - a clear advantage over current high-vacuum techniques such as sputtering. “There is still potential here for further development”, explains physicist de Oliveira. “If we succeed in also making the binder conductive, conductivity as a whole will increase and the surface resistance will be further reduced.”
Coating on flexible film substrates is possible using the classic roll-to-roll process. Initial experiments on this at the INM are promising, and researchers are agreed that the use of structured rolls in future will mean that large, structured, conductive surfaces can also be printed cost-effectively and with a high output.
In addition to using TCO nanoparticles, developers at the INM are also working with the wet chemistry sol-gel process which is particularly suitable for temperature-stable substrates such as glass or ceramic. In this process, curing takes place at temperatures above 450°C. In addition to large-area substrates, more complex geometries such as pipes and moldings can also be coated. “Here again, the advantage lies in the costs”, says the Head of the Program Division.
With vacuum coating processes such as the sputter method, expensive high-vacuum apparatus and large TCO targets are needed for coating large areas; there is also the limited possibility of evenly coating curved substrates using this technique.
At the INM, too, the material of choice is predominantly indium tin oxide (ITO). Because of dwindling resources and the high price of the raw material indium, researchers at the INM are also increasingly testing alternative transparent oxides such as aluminum zinc oxide (AZO).
Dr. Peter William de Oliveira
INM – Leibniz Institute for New Materials
Programme Division Optical Materials
INM conducts research and development to create new materials – for today, tomorrow and beyond. Chemists, physicists, biologists, materials scientists and engineers team up to focus on these essential questions: Which material properties are new, how can they be investigated and how can they be tailored for industrial applications in the future? Four research thrusts determine the current developments at INM: New materials for energy application, new concepts for implant surfaces, new surfaces for tribological applications and nanosafety/nanobio interaction. Research at INM is performed in three fields: Chemical Nanotechnology, Interface Materials, and Materials in Biology.
INM – Leibniz Institute for New Materials, situated in Saarbruecken, is an internationally leading centre for materials research. It is an institute of the Leibniz Association and has about 190 employees.
More articles from Trade Fair News:
Siemens launches Artis one angiography system for universal use
02.12.2013 | Siemens AG
COMPAMED is holding on to its position as international leading market place for medical devices
02.12.2013 | IVAM Fachverband für Mikrotechnik
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
A star is formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball of gas, where the pressure heats the matter, creating a glowing gas ball – a star is born.
New research from the Niels Bohr Institute, among others, shows that a young, newly formed star in the Milky Way had such an explosive growth, that it was initially about 100 times brighter than it is now. The results are published in the scientific journal, Astrophysical Journal Letters.
The young ...
EPFL scientists have shown how to achieve a dramatic increase in the capacity of optical fibers; Their simple, innovative solution reduces the amount of space required between the pulses of light that transport data
Optical fibers carry data in the form of pulses of light over distances of thousands of miles at amazing speeds. They are one of the glories of modern telecommunications technology.
However, their capacity is limited, because the pulses of light need to be lined up one after the other in ...
NASA's Hurricane and Severe Storms Sentinel airborne mission known as HS3 wrapped up for the 2013 Atlantic Ocean hurricane season at the end of September, and had several highlights. HS3 will return to NASA’s Wallops Flight Facility in Wallops Island, Va., for the 2014 Atlantic hurricane season.
During the 2013 mission, two unmanned Global Hawks flew from Wallops for the first time. The mission highlights included studying the Saharan Air Layer, following the genesis of a tropical storm, finding a unique hybrid core or center circulation in a redeveloped storm, obtaining measurements on the strongest side of ...
05.12.2013 | Health and Medicine
05.12.2013 | Ecology, The Environment and Conservation
05.12.2013 | Information Technology
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News