Carbon Nanotubes Nanotubes Carbon A New New Era Era A By By - - PowerPoint PPT Presentation
Low Dimensional System & Nanostructures Angel Rubio & Nerea Zabala Carbon Nanotubes Nanotubes Carbon A New New Era Era A By By Afaf El El- -Sayed Sayed Afaf 2009 2009 Outline Outline World of of Carbon Carbon World -
sp sp2 s p3
In graphite, The In graphite, The sp sp2
2 orbital
form the strong form the strong σ σ-
bonds between carbon atoms in between carbon atoms in the graphite planes, while the graphite planes, while the the p pz
z, or
, or π π, orbital provide , orbital provide the weak Van the weak Van der der waals waals bonds between the bonds between the planes. planes.
In diamond, each In diamond, each carbon atom has four carbon atom has four nearest neighbors. nearest neighbors. The The sp sp3
3 orbital form
the strong the strong σ σ-
bonds between carbon between carbon atoms. atoms.
In the In the C C60
60 molecule, the carbon atoms are
molecule, the carbon atoms are bonded in a structure made up of bonded in a structure made up of 20 20 hexagons hexagons and and 12 pentagons 12 pentagons. Each of the . Each of the carbon atoms in C carbon atoms in C60
60 is joined to three
is joined to three neighbors, so the bonding is the bonding is neighbors, so the bonding is the bonding is essentially essentially sp sp2
2, although there may be a
, although there may be a small a mount of small a mount of sp sp3
3 character due to the
character due to the curvature curvature. . The carbon 60 atoms are bonded The carbon 60 atoms are bonded together in an array of hexagons and together in an array of hexagons and pentagons, like a soccer ball. These pentagons, like a soccer ball. These molecules are called molecules are called Buckminster Buckminster fullerenes in honor of Buckminster Fuller fullerenes in honor of Buckminster Fuller who first designed similarly shaped who first designed similarly shaped geodesic domes. geodesic domes.
Since the early Since the early 1960s 1960s, , Harry Harry Kroto Kroto, of the , of the University of Sussex University of Sussex, had been , had been fascinated in the processes occurring on the surfaces of stars, fascinated in the processes occurring on the surfaces of stars, and and believed that experiments on the vaporization of graphite might believed that experiments on the vaporization of graphite might provide key provide key insights into these processes. insights into these processes. On the other hand, On the other hand, Richard Smalley Richard Smalley, of , of Rice University Rice University, Houston, had , Houston, had different reasons for being interested in what might happen when different reasons for being interested in what might happen when one
vaporizes carbon. vaporizes carbon. In August In August 1985 1985, the two scientists began the now famous series of , the two scientists began the now famous series of experiments on the experiments on the vaporization of graphite vaporization of graphite. They were immediately struck . They were immediately struck by the formation of by the formation of C C60
. The discovery of C60
60, published in nature in
, published in nature in November 1985, had an impact which extended way beyond the confi November 1985, had an impact which extended way beyond the confines nes
era in carbon science. carbon science. Perhaps, Perhaps, Carbon nanotubes Carbon nanotubes are the most important fruits of this research. are the most important fruits of this research. Discovered by the electron Discovered by the electron microscopist microscopist Sumio Sumio Iijima Iijima, of the , of the NEC NEC laboratories laboratories in Japan, in in Japan, in 1991 1991, these , these ‘ ‘molecular carbon fibers molecular carbon fibers’ ’ consist of consist of tiny cylinders of graphite, closed at each end with caps which c tiny cylinders of graphite, closed at each end with caps which contain
precisely six pentagonal rings. precisely six pentagonal rings.
2 1
ma na R + =
0 ≤ |m| ≤ n & Φ<30o
ϕ
ϕ
Neural Tree
π* anti-bonding
π bonding
Unit cell Brillouin Zone
2 1
ma na Ch + =
2 2 1 1
a t a t T + =
( ) ( )
2 1 2 2 1 1 2 1
1 1 b n b m N K b t b t N K r r r r − = + − =
~ ~ 200 200 GPa GPa for steel for steel ~ ~ 0.8 0.8 GPa GPa for steel for steel Elastic modulus ~ Elastic modulus ~ 10 103
3 GPa
GPa Yield Strength ~ Yield Strength ~ 65 65 GPa GPa
Elasticity
Metal wires in microchips Metal wires in microchips melt at melt at 600 600 – – 1,000 1,000 o
C Stable up to Stable up to 2,800 2,800 o
C in in vacuum, vacuum, 750 750 o
C in air in air
Temperature Stability
Nearly pure diamond Nearly pure diamond transmits heat at transmits heat at 3,320 3,320 W/ W/m.K m.K Predicted to be as high as Predicted to be as high as 6,000 6,000 W/ W/m.K m.K at room at room temperature temperature
Heat Transmission
Molybdenum tips require Molybdenum tips require fields of fields of 50 50 – – 100 100 V/m and V/m and have very limited lifetimes have very limited lifetimes Can activate phosphors at Can activate phosphors at 1 1– – 3 3 volts if electrodes are volts if electrodes are spaced spaced 1 micron 1 micron apart apart
Field Emission
Copper wires Copper wires burn burn out at
about 1X about 1X 10 106
6 A/cm
A/cm2
2
Estimated at 1 X Estimated at 1 X 10 109
9A/cm
A/cm2
2
for MWCNT: for MWCNT: 20 20 – – 50 nm 50 nm
Current carrying capacity By Comparison Nanotubes Properties
CNT- Flexible Displays
CNT-FETs
CNT scanning tip
CNT interconnects Neural Tree CNT-Solar Cells Glucose sensors
Faster, Better and Cheaper Space Aircrafts Space Platform Space Elevator
Peter Morgan, “Carbon Fibers and their composites”, CRC press, 2005. Michael J.O’Connell, “Carbon Nanotubes: Properties and Applications”, CRC press, 2006. Charles Kittle, “Introduction to Solid State Physics”, John Wiley & Sons, Inc., 8th Edition, 2005. Karl M. Kadish and Rodney S.Ruoff, “Fullerenes: Chemistry, Physics and Technology”, Wiley- IEEE, 2000. Peter J.F. Harris, "Carbon Nanotubes and Related Structure: New Materials for the Twenty First Century", Cambridge University Press, 1999. The nanotube Sites: http://nanotube.msu.edu/ http://www.pa.msu.edu/cmp/csc/nanotube.html http://cobweb.ecn.purdue.edu/~mdasilva/Structure.shtml
and Information Technology,” Wiley- VCH (2003).
http://www.pa.msu.edu/cmp/csc/ntproperties/electricaltransport.html Thomas A. Adams, "Physical Properties of Carbon Nanotubes", as a part of the honours chemistry research project, 2000. http://www.pa.msu.edu/cmp/csc/ntproperties/opticalproperties.html
Christina Guice, Henry C. Foley, Head and Robb Chair and Bo Yi, "Dynamics of Nanotube Synthesis", McNair Scholar, Pennsylvania State University, 2003. http://www.nanowerk.com/nanotechnology/introduction/introduction_to_nanotechnology_23.html NASA web site; http://www.nasa.gov/vision/space/gettingtospace/16sep_rightstuff_prt.htm NASA web site; http://science.nasa.gov/headlines/y2000/ast07sep_1.htm SPACE.com -- Russians Plan New Space Platform. http://www.space.com/businesstechnology/080115-technov-russia-platform.html http://en.wikipedia.org/wiki/Potential_applications_of_carbon_nanotubes