Xinliang Feng Discusses the Composites of Graphene
New Hot Paper Commentary, January 2011
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Article: Composites of Graphene with Large Aromatic Molecules
Authors: Su, Q;Pang, SP;Alijani, V;Li, C;Feng,
XL;Mullen, K |
Xinliang Feng talks with ScienceWatch.com and answers a few questions about this month's New Hot Papers paper in the field of Materials Science.
Why do you think your paper is highly
cited?
Graphene is a material that has generated enormous research interest for its unique electrical properties and its potential for use in future electronics. Graphene dispersion, unlike graphene oxide, is easily aggregated in the solution for its strong pi–pi interactions. Although the post reduction of the graphene oxide film can restore the electronic properties by hydrazine and other reducing agents, the low reduction efficiency is not sufficient for a large-scale application.
Our paper is likely well-cited because it presents the fundamental study of how the aromatic surfactants stabilize the reduced graphene sheets in the aqueous solution, which therefore renders a possible way to fabricate graphene sheets and graphene film on a large scale. Thereby, this work is relevant to a wider audience to study other aromatic systems for the influence on the electronic properties of graphene by doping.
Moreover, our work provides deep insight into the improvement of electrical conductivity of graphene film fabricated by a cost-effective process which leads to future manufacture of transparent window electrode as indium tin oxide replacement. Along this line, the reasonable organic solar cell device performance has been achieved employing such conductive graphene film as a transparent electrode.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"Graphene holds great potential for future electronics and composite materials. Our work provides a simple method to make the reduced graphene oxide dispersion and is ready for fabrication of low-cost solar-cell devices employing graphene film as the transparent electrode..."
In this paper, we have presented an unprecedented approach to functionalize graphene with large aromatic donor and acceptor molecules, resulting in water-processable graphene dispersion. This is an important criterion in utilizing graphene for technological applications.
Our results also demonstrate that the different electronic characteristics of the large aromatic donor and acceptor molecules enable a rational modification of both the electronic structure and conductivity of graphene sheets.
Further, we find that the aromatic molecules can be dissociated into carbon radical species upon high-temperature treatment, which renders the defect restoration of graphene oxide for achieving highly conductive graphene electrode.
Would you summarize the significance of your paper
in layman's terms?
Graphene oxide is easy to synthesize but is an insulator, the reduction is required to restore its electronic property. Unfortunately, the reduced graphene oxide is apt to aggregate and precipitate from the solution. We found that some kind of large aromatic molecules can stabilize the reduced graphene oxide sheet very well in the aqueous solution as the result of non-covalent forces, such as pi-pi interaction and electrostatic repulsion. This eventually leads a potential application of graphene in electronic devices and composites in a cost-effective manner.
How did you become involved in this research, and
were there any problems along the way?
My group has been exploring organic electronic materials for a long time. In the meantime, we have also set foot in the synthesis of graphene molecules and graphene materials. We have successfully combined our knowledge of organic conjugated systems and graphene to generate various new materials. Along this line, we have developed the controlled pyrolysis of aromatic molecules and graphene in confined geometry, which leads to various unprecedented carbon and graphene-based nanomaterials for energy storage and conversion, for which the transparent graphene electrode is just one example to be highlighted.
The major challenges of this work include the design and synthesis of the proper organic donor and acceptor molecules which possess not only large aromatic cores but also charge moieties at the perimeter, enabling them to stabilize graphene sheets in water. The accurate position of aromatic molecules inside the defective sites of graphene oxide for achieving perfect graphene by thermal pyrolysis constitutes a biggest challenge task in our future research.
Where do you see your research leading in the
future?
Graphene holds great potential for future electronics and composite materials. Our work provides a simple method to make the reduced graphene oxide dispersion and is ready for fabrication of low-cost solar-cell devices employing graphene film as the transparent electrode.
Do you foresee any social or political
implications for your research?
While I do not expect to see any immediate social or political impact from
our research, I hope that this work may contribute new insight into the
electronics industry beyond the conventional materials, and potentially
generate applications in new energy industry based on high-performance
graphene-based materials.
Dr. Xinliang Feng
Max-Planck Institute for Polymer Research
Mainz, Germany
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KEYWORDS: CARBON NANOTUBE BUNDLES; ELECTRON-WITHDRAWING GROUPS; FIELD-EFFECT TRANSISTORS; TRANSPARENT CONDUCTORS; AQUEOUS DISPERSIONS; RAMAN-SCATTERING; OXIDE SHEETS; SOLAR-CELLS; FILMS; SEMICONDUCTORS.