First transparent OLED display with graphene electrodes created
Flexible, clear, and extremely robust, graphene is also an exceptional conductor of both heat and electrical current, all of which makes it a clear front-runner for the next generation of electronic devices. In this vein, researchers have, for the first time, produced OLED electrodes from graphene. This could lead the way to a range of new components, including better touchscreens and much more efficient solar cells.
The electrodes attached to the OLED (organic light-emitting display) have an area of around 2 cm by 1 cm (1/2 in by 1/4 in), and were created using a process of chemical vapor deposition (CVD), where methane and hydrogen are pumped into a vacuum chamber where a copper plate has been heated to 800° C (1,472° F).
A chemical reaction occurs between the two gases and, as the methane dissolves into the copper, it forms graphene atoms on the surface. Once the layer is sufficiently formed, the whole set up is allowed to cool, a protective polymer sheet is applied, and the copper is then chemically etched away to reveal a single-atom layer of pure graphene.
"This was a real breakthrough in research and integration of extremely demanding materials," said Dr. Beatrice Beyer, project leader at the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP.
Though this is not the first flexible display to use graphene in its construction, it is the first to incorporate OLED technology, which is a large step toward full-color screens and fast response times.
With graphene used in everything from conductors, through to supercapacitors, solar cells and a raft of other electronic devices, displays made from this material are a logical choice for improving the longevity, robustness, and usability of photovoltaic cells, wearable, flexible textiles and medical devices. This research may lead to developments in these areas in the very near future.
"The first products could already be launched in two to three years," said Beyer.
The Fraunhofer Institute partnered with the Spanish company Graphenea S.A., for the production of the graphene electrodes, and with the British company Aixtron Ltd., who built the production CVD reactors.