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Graphene is a one-atom-thick planar sheet of
sp2-bonded carbon atoms. The arrangement forms a densely packed
honeycomb that can be visualized as an atomic-scale chicken
wire made of carbon atoms and their bonds. The
carbon-carbon bond length in graphene is about 1.42 Ĺ (angstroms)
which compares to a bond length of 1.50 Ĺ for C-C single bond
as found in the ethane
molecule. (Note: The angstrom (Ĺ) is an internationally
recognized unit of length equal to 0.1 nanometre or 1 × 10
-10 meters.
Graphene
is the basic structural element of some carbon allotropes
including graphite,
carbon
nanotubes, and fullerenes.
The Nobel Prize in Physics for 2010 was awarded to Andre Geim
and Konstantin Novoselov "for groundbreaking experiments regarding
the two-dimensional material graphene".
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Graphene
structure shown using Jsmol -The Graphene Molecule shown
above was created using ArgusLab
| Note
about 3D molecules -- Our files on this page now
use Jsmol instead of Jmol. These files make
use of Javascript which permits viewing of molecules
on tablets, phones and easier use on Macs. For the
graphene_jmol
file. -- Jsmol is best viewed with the Chrome
browser. |
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Rotate the Graphene molecule
(Hold
the left mouse button down over the image and move the
mouse to rotate the graphene molecule -- you can easily
see that graphene is only ONE molecule thick).
Notice
that each carbon atom is the same distance to each of
its neighboring carbon atom.
What
is the bond length for a Carbon-Carbon bond in Graphene
Molecule?
Click
right mouse button-->Style -->Scheme--> Ball
and Stick
Double
click left mouse bottom on any carbon atom, then drag
+ to nearby carbon atom and double click again to get
distance.
View
other 3-D allotropes of Carbon:
Graphite
molecule
Diamond
molecule
Fullerene
Carbon
Nanotube
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Potential
applications
New
Materials
As
of 2009, graphene appears to be one of the strongest materials
ever tested. Measurements have shown that graphene has a breaking
strength 200 times greater than steel.[1]
Graphene
transistors
In
2008 Dr Kostya Novoselov and Professor Andre Geim from The
School of Physics and Astronomy at The University of Manchester
reported in the journal Science that graphene can be carved
into tiny electronic circuits with individual transistors
having a size not much larger than that of a molecule. [2]
Single
molecule gas detection --Graphene makes an excellent sensor
due to its 2D structure. The fact that its entire volume is
exposed to its surrounding makes it very efficient to detect
adsorbed molecules. Researchers at the University of Manchester
--Centre for Mesoscience and Nanotechnology-- have used the
world's thinnest material to create sensors that can detect
just a single molecule of a toxic gas. [3] The operational
principle of such sensors is based on changes in electrical
conductance of a number of base materials when gas molecules
are adsorbed on their surface. The existing sensors can detect
gases in concentrations as small as 1 part per million or
less.
Integrated
circuits --The unique properties of thin layers of graphite
make the material attractive for a wide range of potential
electronic devices. Researchers have experimentally demonstrated
the potential to replace copper for interconnects in future
generations of integrated circuits. Because graphene can be
patterned using conventional microelectronics processes, the
transition from copper could be made without integrating a
new manufacturing technique into circuit fabrication.
Graphene
biodevices -Graphene's modifiable chemistry, large surface
area, atomic thickness and molecularly-gatable structure make
them excellent candidates for mammalian and microbial detection
and diagnosis devices [5]
One
of the most ambitious biological application of graphene is
for rapid, inexpensive DNA sequencing. [6]
References
and Readings
1 Lee,
C. et al. (2008). "Measurement of the Elastic Properties and
Intrinsic Strength of Monolayer Graphene". Science 321 (5887):
385. doi:10.1126/science.1157996.Abstract:
http://www.sciencemag.org/cgi/content/abstract/321/5887/385.
2 L. A.
Ponomarenko, F. Schedin,1 M. I. Katsnelson, R. Yang, E. W.
Hill, K. S. Novoselov,A. K. Geim "Chaotic Dirac Billiard
in Graphene Quantum Dots" Science 18 April 2008: Vol.
320. no. 5874, pp. 356 - 358. Abstract: http://www.sciencemag.org/cgi/content/abstract/320/5874/356
3 Schedin,
F. et al. (2007). "Detection of individual gas molecules adsorbed
on graphene". Nature Mater 6 (9): 652–655. Abstract: http://www.nature.com/nmat/journal/v6/n9/full/nmat1967.html
4 Murali,
R. Brenner, K. Yang, Y. Beck, T. Meindl, J. D. Resistivity
of Graphene Nanoribbon Interconnects. Electron Device Letters,
IEEE, June 2009 Volume: 30, Issue: 6: 611-613 Abstract: http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4968006
5 Mohanty,
Nihar; Vikas Berry (2008). "Graphene-based Single-Bacterium
Resolution Biodevice and DNA-Transistor— Interfacing Graphene-Derivatives
with Nano and Micro Scale Biocomponents". Nano Letters 8:
4469–76. Abstract: http://pubs.acs.org/doi/abs/10.1021/nl802412n
6 Xu,
M. S. Xu; D. Fujita and N. Hanagata (2009). "Perspectives
and Challenges of Emerging Single-Molecule DNA Sequencing
Technologies". Small 5 (23): 2638–49. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/19904762 |
