Researchers from the Korea-based ETRI (Electronics and Telecommunications Research Institute) produced the largest OLED panel to date (370 x 470 mm) that use graphene electrodes.

ETRI graphene-electrode OLED prototype, Apr 2017

From the photo above (and image below) it seems that this panel is actually made from 12 small OLEDs - but it seems that the graphene deposition itself was done on the whole substrate.

We have seen several OLED prototypes with graphene electrodes before - graphene may prove to be a low-cost, highly flexible and efficient transparent electrode material. Earlier this year the European GLADIATOR project, led by the Fraunhofer Institute, developed a functional 2x1 cm flexible OLED lighting panel based on graphene electrodes.

In June 2016 researchers from ETRI demonstrated the world's first transparent OLED prototype that uses graphene transparent electrodes. The prototype display was 26x26 in size with a resolution of 155 x 60 (121 PPI).

Merck - Advancing Display, Advancing LifeMerck - Advancing Display, Advancing Life