Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Graphene? From any lab!

21.06.2012
Considered by many as the most promising material of the future, graphene still remains an expensive and hard-to-fabricate substance.

Researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw, and the Interdisciplinary Research Institute in Lille developed a low cost method for manufacturing multilayered graphene sheets. The new method does not require any specialized equipment and can be implemented in any laboratory.


This is a visualization of a graphene oxide sheet (left top) and a graphene surface with attached tertathiafulvalene (TTF) molecules (right bottom). Graphene rings are composed of six carbon atoms, TTF rings – of three carbon and two sulphur atoms. Credit: IPC PAS, Piotr Gdziorowski

A low cost method for producing graphene sheets has been developed in cooperation within research project by teams from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw and the Interdisciplinary Research Institute (IRI) in Lille, France. The method is simple enough to be provided in almost any laboratory throughout the world.

Graphene was discovered in 2004, by peeling off carbon layers from graphite using an ordinary scotch tape. "In what had been peeled off the researchers were able to find one-atom-thick sheets. And that was graphene. If we are thinking about industrial applications of graphene, we have to find better controlled methods for producing this material in a large scale, without using an expensive, specialized equipment", says Izabela Kamiñska, a PhD student from the IPC PAS, a scholarship holder of the Foundation for Polish Science within the International PhD Projects Programme. Kamiñska has carried out her experiments at the International Research Institute.

Considering the structure, graphene is a two dimensional system composed of six-membered carbon rings. The hexagonal graphene lattice resembles a honeycomb, with the difference that the graphene sheet has the lowest possible thickness: of one atom only.

Unusual properties of graphene are closely related to the unique structure. Graphene is almost entirely transparent, more than hundred times stronger than steel and very flexible. At the same time it shows excellent thermal and electric conductivity, which makes it a good material for applications in electronics, e.g. for manufacturing thin, flexible and strong displays or fast processing circuits. It is also suitable as a material for various sensors.

The existing methods for fabricating graphene – including deposition of epitaxial layer on a metallic substrate or silicon carbide, or chemical or physical vapour deposition – require expensive, specialized equipment and complex manufacturing procedures. Meanwhile, the only more complex apparatus used in the method for producing graphene sheets developed at the IPC PAS and the IRI is an ultrasonic cleaner, an equipment common in many laboratories.

The new process for producing graphene sheets starts with graphite, one of carbon allotrope, on the molecular level resembling a sandwich composed of many graphene planes. These sheets are hardly separable. To weaken interactions between them, graphite must be oxidized, which is usually accomplished with the Hummers method. A powder obtained in that way – graphite oxide – is subsequently suspended in water and placed in an ultrasonic cleaner. The ultrasounds exfoliate oxidized graphene sheets from each other and the resulting colloid contains single graphene oxide flakes with diameter of about 300 nanometers.

The researchers from the IPC PAS and the IRI used graphene oxide manufactured at Materials Science Division in North East Institute of Science and Technology (NEIST) in Dispur, India. "One-atom-thick graphene oxide colloids were a good starting material, but numerous oxygen-containing functional groups became a real difficulty. The problem was that they changed dramatically the physico-chemical properties of the material. Instead of an excellent conductor we had... an insulator", explains Kamiñska.

To remove oxygen from graphene flakes, the researchers from the IPC PAS and the IRI decided to use non-covalent pi-pi stacking interactions between the carbon rings of graphene oxide and the aromatic rings of a compound called tertathiafulvalene (TTF). A TTF molecule is composed of two rings containing three carbon and two sulphur atoms each. "Practically, it was sufficient to mix graphene oxide with tertathiafulvalene, and then put the whole in an ultrasonic cleaner. The interactions between the TTF rings and the graphene oxide rings resulted in a reduction of graphene oxide to graphene with a simultaneous oxidation of the TTF molecules", describes Kamiñska.

As a result, the obtained composite contained graphene flakes with TTF molecules intercalated into them. A droplet of the composite solution was subsequently deposited onto an electrode and dried. Graphene flakes formed on the surface a smooth coating with controllable thickness from 100 to 500 nm that was composed of a few dozen to a few hundreds alternate graphene sheets and TTF molecules.

The final stage in the production of graphene coating was to expel tertathiafulvalene molecules, which was attained by a simple chemical reaction with an appropriately selected compound.

"One of our motivations for the research was to look for new methods for detecting biological substances. That's why after expelling TTF from the graphene coating we checked immediately if we could reincorporate the chemical into the matrix. It turned out that yes. Therefore it is possible to develop a process allowing one to bind a selected compound to a TTF molecule, and then to incorporate the entire complex into a graphene sheet on an electrode and monitor the electric current flow", sums up Prof. Marcin Opa³³o (IPC PAS).

A publication describing the new method appeared early this year in the prestigious journal Chemical Communications, with the cover showing computer visualisation of the graphene sheets with TTF. At present, the researchers from the IPC PAS and the IRI continue their work on further decrease of graphene matrix thickness. The final stage reached also the experiments which show that it is possible to incorporate into the graphene sheet TTF molecules with attached mannose (one of the monosaccharides).

This press release was prepared thanks to the NOBLESSE grant under the activity "Research potential" of the 7th Framework Programme of the European Union.

The Institute of Physical Chemistry of the Polish Academy of Sciences (http://www.ichf.edu.pl/) was established in 1955 as one of the first chemical institutes of the PAS. The Institute's scientific profile is strongly related to the newest global trends in the development of physical chemistry and chemical physics. Scientific research is conducted in nine scientific departments. CHEMIPAN R&D Laboratories, operating as part of the Institute, implement, produce and commercialise specialist chemicals to be used, in particular, in agriculture and pharmaceutical industry. The Institute publishes approximately 200 original research papers annually.

Marcin Opallo | EurekAlert!
Further information:
http://www.ichf.edu.pl

Further reports about: CHEMISTRY IPC IRI Interdisciplinary PAS TTF graphene graphene oxide graphene sheet industrial application

More articles from Physics and Astronomy:

nachricht Transportable laser
23.01.2018 | Physikalisch-Technische Bundesanstalt (PTB)

nachricht New for three types of extreme-energy space particles: Theory shows unified origin
23.01.2018 | Penn State

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Rutgers scientists discover 'Legos of life'

23.01.2018 | Life Sciences

Seabed mining could destroy ecosystems

23.01.2018 | Earth Sciences

Transportable laser

23.01.2018 | Physics and Astronomy

VideoLinks Science & Research
Overview of more VideoLinks >>>