A European project to make large area, high quality graphene sheets for transparent electrodes has kicked off at the beginning of this month. Project Gladiator (Graphene Layers: Production, Characterization and Integration), worth a total of 12.4 million euros, includes 16 partners from 7 countries. Graphenea is the leading industrial expert on CVD growth of large graphene sheets in the consortium, which includes Aixtron, the Technical University of Denmark, and others, and is led by Fraunhofer COMEDD.
GLADIATOR directly targets the global market for transparent electrodes (estimated to be worth over 11,000 million USD in 2016) and will demonstrate that the performance and price of indium tin oxide (ITO) can be matched by graphene (transparency > 90%, sheet resistance < 10 W/sq, cost < 30 Eur/m2). New production technologies will be demonstrated by making ultraviolet organic photodiodes (with possible application as flame detectors) and large area flexible OLEDs.
The project will achieve this by
- optimizing the performance of CVD graphene (using doping)
- increasing the throughput and size of CVD batch reactors
- improving the process by which graphene is transferred from the CVD catalysts to the application substrate.
CVD graphene production will be optimized using new diagnostic and process control instrumentation based on Raman spectroscopy and spectrometric ellipsometry; the quality of graphene layers post-transfer will be assured using new non-contact in-line eddy current measurements and THz imaging. CVD production costs per unit area will be reduced not only by process parameter optimization, but also by developing methods to re-use the catalysts and by increasing the size of the reactor chamber. Process safety will also be addressed.
A critical issue for graphene, especially as a transparent electrode, is how to achieve homogenous large area coverage. GLADIATOR will extend the size of graphene layers beyond that of the CVD tools by implementing a novel patchwork process using a transfer process with high yields and negligible impact upon the properties of the graphene. Transfer processes will be developed for rigid and flexible substrates appropriate for organic large area electronics (OLAE), and substrate and barrier properties will be optimized for use with graphene.
The GLADIATOR project (FP7 grant agreement number 604000) began on 1st November 2013 and will finish in April 2017 after 42 months. Graphene has long been considered as an alternative to ITO as a material of choice for transparent conducting electrodes, the most imminent use being touchscreens. Compared to the brittle ITO, graphene has the advantage of being flexible, leading to visions of future bendable touchscreens. Gladiator aims to address the main barriers to fulfilling this vision.