Potential ITO replacement with graphene

Researchers from Paragraf Limited and Queen Mary University of London have demonstrated the successful fabrication of an organic light-emitting diode (OLED) that uses a single layer of graphene to replace the indium-tin oxide that has traditionally made touchscreens touchable.

Despite being one of the rarest elements in earth's crust, indium is found in almost all modern electronic devices with a touchscreen. Indium-tin oxide is used to create a thin and invisible layer lying just under the glass that senses incoming electrical data triggered by the touch of your fingertip and transforms it into an optical signal that makes taps and swipes possible.

The Innovate UK-funded research carried out by Paragraf and Queen Mary University opens the door to a radical change in the potential of high-tech devices of the future by replacing that limited ingredient, indium, with graphene.

"Because of its importance and scarcity there have been many attempts to replace ITO, but no material has been found to have a comparable performance in an electronic or optical device until now," said Colin Humphreys of Queen Mary and Paragraf.

Only an atom thick, the most electrically conductive material and strongest material known to exist, graphene is a natural choice for taking over indium-tin oxide's role in touchscreens.

However, organizations such as IBM, Intel, and Samsung have been unable to scale up the growth of graphene for use in electronic devices.

A spin-out from the Department of Materials Science at Cambridge University, Paragraph has resolved this dilemma with the development of a new way to produce large-area graphene suitable for electronic devices.

At its custom research, development, and production facility just outside of Cambridge, UK, the company produces the highest-quality large-area graphene, as well as step-change graphene-based technologies.

It was work on the latter that led to the successful fabrication of OLEDs with a graphene anode.

The finding of this work was published in the December 20, 2021, edition of Advanced Optical Materials.

"Our paper is the first paper in the world to demonstrate that graphene can replace ITO in an electronic/optical device," added Humphreys. "We have shown that a graphene-OLED has identical performance to an ITO-OLED."

Since Apple's iPhone entered the smartphone space in 2007, conductive multitouch screens changed the way the world held mobile devices – and this was made possible by the development of indium tin oxide.

Over a decade later, touchscreen handheld devices are quickly becoming the forefront of consumers' choice in computing technology, with more powerful processing having led many to opt for tablets instead of laptops.

Now, with foldable screens being introduced, indium-tin oxide-OLEDs have been practically stretched to their limits.

A screen made with the highly conductive, incredibly powerful, exceptionally lightweight, and impossibly thin single layer of carbon atoms, a mobile device with a screen made nearly indestructible could bring forth a contender for Nokia in durability and a shift in the paradigm once again for mobile technologies.