MAFO researchers are active in the production and research on GRAPHENE, the newest and most promising of carbon-based materials.
Graphene sheets are monoatomic layers of carbon forming a perfect, completely aromatic network.
Graphene sheets have very good mechanical properties, high electrical and thermal conductivity and excellent stability in air. The MAFO group at ISOF works on the production of graphene and graphene oxide by low-cost chemical exfoliation of graphite, to obtain stable solutions which can be easily processed and deposited on different substrates.
Sheets of graphene oxide having size up to 100 microns and thickness below 1 nanometer can be produced in water solutions in large scale, and functionalized with different molecules to modify their chemical and optical properties.
Composites of graphene with other organic materials (polymers, organic semiconductors, etc.) are produced by supramolecular self-assembly and characterized for applications in the field of electronics, composites, photovoltaics, etc.
We shall produce and characterize different kinds of graphene-based materials:
- Graphene exfoliated in organic solvents.
- Graphene exfoliated in water with surfactants.
- Graphene oxide solutions in water.
- Large sheets of graphene oxide on different substrates.
- Graphene polymer composites for bulk applications.
V. Palermo of ISOF is Work package leader of the GRAPHENE FLAGSHIP pilot, a large-scale European initiative on graphene research and industrial development.
POTENTIAL APPLICATIONS OF GRAPHENE
Electrons in graphene don't simply go faster than in silicon, they also obey a completely different physics, which will allow technology applications significantly different form the actual ones; and, in the past, new technology have always had a big impact on society.
Graphene properties can be tuned from highly conductive (metallic), to semiconducting, to insulating, as represented in the scheme here below.Graphene monolayers have a very high charge mobility, much better than the one of silicon, and can be used to transport charges and to make highly conductive electrodes and interconnect. Though, simple graphene has a zero-bandgap, and thus does not allow efficient current modulation (graphene transistors are always "ON").
This issue can be solved using bilayer graphene, or laterally confined graphene nanoribbons, which have a finite bandgap, or modulating charge transport with organic molecules and dopants interacting with the graphene layer.
Finally, chemically modified, insulating graphene could be in principle used to have insulating layers, using as example graphene oxide (GO) or hydrogenated graphene (named "graphane").
Even if we cannot foresee which will be most important effects of such a new technology on every days life, we can try to envision them using our experience of the past.
As example, there has been another technological revolution based on carbon in 20th century, when the first polymers moved from scientific research, to technological application, to every days products, under the name of plastic.
The use of plastic tools or even clothes rapidly displaced metal, wood or leather for many applications. This was not due to better performance in absolute value of plastic respect to more conventional materials; plastic was not stronger than steel, or warmer than wool; even today people prefer to buy wooden furniture in their homes respect to plastic ones. Plastics success was not due to pure performance, but rather to cost and versatility advantages.
As we now use plenty of plastic tools, but still build airplanes of metal and tables of wood, graphene electronics will not displace silicon one; probably, silicon will still be at the heart of computers and microprocessors, but graphene will allow information processing and communication to reach a new level of diffusion in our life; using low cost devices, transparent flexible displays and touch screens (based on graphene seamlessly integrated with plastic materials) we will have the possibility to include data and information in virtually any aspect of everyday life.
The possibility to have high-performing electronics, displays and touch screens, obtained on plastic substrates from solution processing or roll-to-roll printing, will allow the widespread use of smart tags, smart windows, flexible displays, and in general the encoding of information on objects actually not compatible with conventional silicon technology.
1. M. Melucci, E. Treossi, L. Ortolani, G. Giambastiani, V. Morandi, P. Klar, C. Casiraghi, P. Samori, and V. Palermo,Facile covalent functionalization of graphene oxide using microwaves: bottom-up development of functional graphitic materials, Journal of Materials Chemistry, 2010, 20, 9052.
2. J.M. Mativetsky, E. Treossi, E. Orgiu, M. Melucci, G.P. Veronese, P. Samorì, and V. Palermo,Local Current Mapping and Patterning of Reduced Graphene Oxide, Journal of the American Chemical Society, 2010, 132, 14130.
3. E. Treossi, M. Melucci, A. Liscio, M. Gazzano, P. Samori, and V. Palermo,High-Contrast Visualization of Graphene Oxide on Dye-Sensitized Glass, Quartz, and Silicon by Fluorescence Quenching, Journal of the American Chemical Society, 2009, 131, 15576.