Researchers from Philips, Graphenea and the University of Cambridge developed a monochrome OLED device that uses graphene as the transparent conductor layer. They report that the graphene-based TC outperforms that state-of-the-art ITO solutions currently used for OLED panels.
ITO is the most popular material for transparent conductors in displays and solar cells, but it is expensive, rare and brittle, and a lot of companies are developing alternatives - based on silver, carbon or other materials.
Graphene by itself is not a good electrode material because the concentration of the charge carriers is low - which means that you need to dope it with excess carriers - while leaving it flexible and transparent. To achieve that, the team used a metal oxide film (molybdenum trioxide, MoO3) as an intermediate layer between the graphene and the OLED layers. The graphene was produced using a CVD process. By optimizing the MoO3 thickness, the researchers were able to achieve excellent power efficiency - better than the ITO reference device.
The work was performed as part of the EU project GRAFOL, aimed at roll-to-roll mass production of graphene.
Excellent news
This is exciting news, as Graphene now seems to be at the entrance towards commercial use, when companies like Philips combine it with OLEDs. Is there any information, when it is expected to demonstrate roll-to-roll production of graphene-based OLEDs? Was the OLED efficiency so high because of the superior conductivity and transparency of Graphene vs. ITO?
Really has a competitive Graphene to replace the ITO?
I am also interested in Graphene transparent conductor.
However many researcher have a skepticism for replace-ability to ITO.
ITO transparent conductor price was reduced almost one third and Nitto Denko has also decreased resistance.