Acquired Electronics360

Aerospace

Method to Produce Low-Cost, Defect-Free Graphene

08 September 2016

Researchers in Germany have succeeded for the first time in producing defect-free graphene directly from graphite. They say the method is both low cost and efficient, and enables high-quality graphene to be cut without causing defects, making the material much more valuable to the semiconductor industry.

In the chemical production of graphene, benzonitrile (grey circle) removes the causes of possible defects and turns red, resulting in defect-free graphene (red circle). Source: Philipp Vecera/FAU In the chemical production of graphene, benzonitrile (grey circle) removes the causes of possible defects and turns red, resulting in defect-free graphene (red circle). Source: Philipp Vecera/FAU Graphene is two dimensional and consists of a single layer of carbon atoms. It is transparent and flexible, yet strong and particularly good at conducting electricity and heat. Graphene’s unique properties make it suitable for use in a wide range of pioneering applications, such as in transparent electrodes for flexible displays.

However its usefulness to the semiconductor industry will be limited until the material’s properties—such as size, area and number of defects, which influences its conductivity—can be improved during synthesis.

Now a team of chemists at Germany’s Friedrich-Alexander-Universität, FAU, has discovered a method to produce defect-free graphene directly from a solution using the additive benzonitrile.

A common way to synthesize graphene is through chemical exfoliation of graphite. In this process, as explained by researchers, metal ions are embedded in graphite, which is made of carbon, resulting in what is known as an intercalation compound. The individual layers of carbon—the graphene—are separated using solvents. The stabilized graphene then has to be separated from the solvent and re-oxidized. However, defects in the individual layers of carbon, such as hydration and oxidation of carbon atoms in the lattice, can occur during this process.

By adding the solvent benzonitrile, researchers discovered that the graphene can be removed without any additional functional groups forming—and it remains defect-free.

The method, they say, is low cost and efficient, and also comes with another advantage. The reduced benzonitrile molecule formed during the reaction turns red as long as it does not come into contact with oxygen or water. This change in color allows the number of charge carriers in the system to be easily determined through absorption measurements. Previously this could only be done by measuring voltage, and now it gives graphene and battery researchers a new way of measuring the charge state.



Powered by CR4, the Engineering Community

Discussion – 0 comments

By posting a comment you confirm that you have read and accept our Posting Rules and Terms of Use.
Engineering Newsletter Signup
Get the Engineering360
Stay up to date on:
Features the top stories, latest news, charts, insights and more on the end-to-end electronics value chain.
Advertisement
Weekly Newsletter
Get news, research, and analysis
on the Electronics industry in your
inbox every week - for FREE
Sign up for our FREE eNewsletter
Advertisement

CALENDAR OF EVENTS

Date Event Location
30 May-02 Jun 2017 Lake Buena Vista, Florida USA
04-09 Jun 2017 Honolulu, Hawaii, USA
Find Free Electronics Datasheets
Advertisement