Currently, virtually all touchscreen displays found in our electronic devices rely on a coating of indium tin oxide (ITO). It is used because of its electrical conductivity, its optical transparency, and the ease with which it can be deposited onto a display as a thin film. Using graphene, researchers at the University of Exeter have developed a viable alternative to increasingly expensive ITO that they claim is the “most transparent, lightweight and flexible material ever for conducting electricity.”
The popularity of touchscreen displays has resulted in high demand for ITO, leading to indium becoming increasing rare, with supplies expected to run out within the decade. ITO layers are also fragile and lack flexibility, making them unsuitable for use in flexible displays.
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In the search for an alternative to ITO with none of its shortfalls, a team from the University of Exeter’s Centre for Graphene Science turned to graphene, the thinnest material capable of conducting electricity that is also flexible and one of the strongest known materials. However, like other researchers looking to develop graphene-based flexible electronics, they ran into the problem if graphene’s sheet resistance, which limits its conductivity.
To overcome this hurdle the team sandwiched a layer of ferric chloride molecules between two sheets of graphene to enhance the graphene’s electrical conductivity, without affecting its transparency. They claim the resulting material, which they have dubbed “GraphExeter,” is the most transparent, lightweight and flexible material for conducting electricity that has ever been created.
With such properties, the team says GraphExeter could be used not only in flexible touchscreens, but also in wearable electronics (an MP3 player embedded in a t-shirt, for example) and “smart” mirrors or windows with computerized interactive features. They add that, because it is transparent over a wide light spectrum, the material could also be used to enhance the efficiency of solar panels by more than 30 percent.
“GraphExeter could revolutionize the electronics industry. It outperforms any other carbon-based transparent conductor used in electronics and could be used for a range of applications, from solar panels to ‘smart’ t-shirts,” says lead researcher, Dr Monica Craciun.
The research team is now working on developing a spray-on version of the material for use in such applications.
A paper detailing GraphExeter appears in the journal Advanced Materials.
Source: University of Exeter