Fluoride Action Network

Graphite fluorides: New Material Could Enable Faster Chips

Source: The Korea Times | Staff Reporter
Posted on September 4th, 2009
Industry type: Electronics Industry

A team of multinational scientists said they discovered an easier technique for producing graphene, a new material that could be used to make superfast microchips.

In a study published by peer-review journal, Advanced Materials, South Korean researchers led by Sungkyunkwan University’s Yoo Ji-beom and their collaborators from the Russian Academy of Sciences described a “one-stop” method that they claim as a key piece of the puzzle for mass-producing graphene.

Graphene, a pure form of carbon that was first discovered in 2004, has been garnering attention for its remarkable mechanical and electrical properties. Researchers believe that the material could be used to develop microchips that operate at much higher speeds compared to the conventional silicon chips used today, which may eventually enhance the data capabilities of mobile phones and other digital devices.

Similar to its close cousin, carbon nano-tubes, graphene is made of one-atom-thick layers of carbon atoms that are densely arranged in honeycomb shape. The name is derived from graphite, the same material used in pencil lead, which is basically comprised of graphene sheets stacked together.

Graphene-made transistors can theoretically operate near terahertz frequencies, or about a hundred times faster than gigahertz frequencies that are comparable to the speed of computers today. And since graphene sheets are practically transparent, the material may also be used to produce transparent and flexible displays and solar cells, scientists say.

However, developing methods to effectively produce graphene in bulk has been a major challenge, and researchers have been trying to come up with new ways to produce it in larger sheets without compromising its qualities.

One of the previous methods discussed was putting graphite oxide, often used to make graphene, in water. Dispersed in water, graphite oxide forms large, visible flakes, mostly one-layer thick. These flakes are then used to yield graphene through chemical reduction.

Although the use of graphite oxide offers a possible route for mass production, lab tests have confirmed that graphene obtained this way shows lesser conductivity and mobility compared to the material’s pristine form.

Yoo’s team preferred to start with fluorine-graphite intercalation compounds, a complex form of materials that are the precursor of graphite fluorides that are formed by the high temperature reaction of fluorine gas with carbon.

The researchers synthesized the materials by firing them up over a short period of time, which resulted in the production of “expanded” graphite with more room between the layers of carbon atoms. Expanded graphite is then dispersed in organic solvents, which could be used to produce larger sheets of graphene, Yoo said.

“The previous method required a lot of time, but we have found a simpler and quicker way to produce graphene without oxidizing graphite, Yoo said.