Nanomaths 2012
“TEXT-BOOK EXAMPLES”!
Overview of carbon nanoforms!
(PART I)
Irene Suarez-Martinez!
[email protected]!
Nanochemistry Research Institute, Curtin University, Perth, Western Australia!
6
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“every element says something to someone (something different to each) […] one
must perhaps make an exception for carbon, because it says everything to
everyone.”
Primo Levi in “The periodic table”
Carbon chemistry!
1s2, 2s2, 2p2 : 4 valence electrons for bonding
- 
- 
Possible hybridisation of s and p orbitals : spn, n = 1, 2, 3
C—C
sp3 hybridisation: tetrahedral with angle 109.5°
C=C
sp! hybridisation: trigonal with angle 120°
C!C
sp hybridisation: linear with angle 180°
Bond
Hybridation
Coordination
Length (A) Energy (KJ/mol)
Allotropes of Carbon (bulk carbons)!
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Allotropes of Carbon!
Carbon
Nanoforms
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Carbon Nanotubes
Fullerenes
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Graphene
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Carbon Nanotubes
Fullerenes
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Graphene
Fullerenes!
DEFINITION: Family of closed cage molecules exclusively made of carbon atoms.
• 
• 
Fullerenes were discovered in
1985 and their discover was
awarded the Nobel prize in
Chemistry to Robert Curl, Harry
Kroto and Richard Smalley in
1996
Fullerenes are considered as
the launch of the revolution in
carbon nanomaterials and the
birth of a whole new area of
chemistry.
Fullerenes!
DEFINITION: Family of closed cage molecules exclusively made of carbon atoms.
C60 is the Buckminsterfullerene
IUPAC name: (C60-Ih) [5,6] fullerene
Richard Buckminster Fuller
R. Buckminster Fuller’s patent for the “geodesic dome”.
R. Buckminster Fuller’s patent for the “geodesic dome”.
The Eden Project, Cornwall, UK
Buckminster Fuller
On the cover of “Time” magazine
..look at his head…
Fullerenes!
DEFINITION: Family of closed cage molecules exclusively made of carbon atoms.
C60 is the Buckminsterfullerene
12 pentagons + variable number hexagons
IUPAC name: (C60-Ih) [5,6] fullerene
Leonhard Euler's theorem on the relation
between the numbers of faces, vertices and
edges in polyhedra.
V-E+F=2 (condition for closed cage)
V = vertices
E = edges
F = faces
If only all pentagons and hexagons: 12 pentagons
C60 = 12 pentagons + 20 hexagons
C70 = 12 pentagons + 25 hexagons
Isolated pentagon rule
Fullerenes!
DEFINITION: Family of closed cage molecules exclusively made of carbon atoms.
C60 is the Buckminsterfullerene
IUPAC name: (C60-Ih) [5,6] fullerene
All atoms are equivalent (quasi-sp2)
Two types of bonds:
1) pentagon-hexagon: single-character (1.458 A)
2) hexagon-hexagon: double-character (1.401 A)
Schlegel representation
Fullerenes!
DEFINITION: Family of closed cage molecules exclusively made of carbon atoms.
C60 is the Buckminsterfullerene
IUPAC name: (C60-Ih) [5,6] fullerene
All atoms are equivalent (quasi-sp2)
Two types of bonds:
1) pentagon-hexagon: single-character (1.458 A)
2) hexagon-hexagon: double-character (1.401 A)
Schlegel representation
Fullerenes!
DEFINITION: Family of closed cage molecules exclusively made of carbon atoms.
C60 is the Buckminsterfullerene
IUPAC name: (C60-Ih) [5,6] fullerene
All atoms are equivalent (quasi-sp2)
Two types of bonds:
1) pentagon-hexagon: single-character (1.458 A)
2) hexagon-hexagon: double-character (1.401 A)
Fullerene Synthesis!
! 
! 
! 
Arc-electric (two graphite rods,
sharpened, electric
spark between tips)!
Laser ablation of a graphite powder
target under flowing Ar
gas!
Direct formation from
graphene!
Cuvilin et al. Nature
Chemistry vol 2, Pages:
450–453 (2010)
Applications of fullerene!
• 
Organic solar cells
D. Guldi, Pure Appl. Chem. 75, 1069 (2003)
• 
Skin creams
The company claims that Fullerene C-60 is 100 times more effective than Vitamin E
in the same concentration for neutralizing free radicals
Some genuine medical ʻproʼs!
! 
Water soluble fullerenes (functionalised) have shown promise
as:!
! Anti-cancer
! Anti-HIV
agents!
agents!
! Protective
agents against free-radical induced liver
damage!
! They
are good free radical scavangers and antioxidants!
“The exponential increase in patent filing and publications [in medicine / pharmaceuticals]
indicate growing industrial interest that parallels academic interest. The discovery of
fullerenes has been compared to the discovery of benzene by many researchers.”
T. Seema, R. Mehta, Ind. J. Pharm. Sciences, 68 (1), 13 (2006).
.. But, excited states…!
T. Seema, R. Mehta, Ind. J. Pharm. Sciences, 68 (1), 13 (2006).
Bethany Halford, Chem. Eng. News 84, 13, p.47 Oct (2006)
Medical Summary!
! 
Seem to have great potential in medicine!
! 
Exposed to light or not –!
!  Anti-oxidants
!  Generate
! 
in general!
radicals via triplet state on light exposure!
Water soluble or not –!
!  Tissue
take-up!
!  Absorption
in lipid bi-layers (can cause cell death, e.g. anti-bacterial)!
!  Clustering
! 
behaviour!
Medical use – toxic or not? !
!  Need
very specific testing for the exposure conditions.!
Filled Fullerenes!
Filled fullerenes for MRI (magnetic resonance imaging)
Sc3N @ C80
Also with scandium, yttrium, and lanthanum
• 
more effective contrast agent in MRI
• 
currently inject Gd
• 
Gd toxic, so wrapped in an organic compound
• 
toxicity not completely removed, limits dose
• 
40x better contrast than agents
currently on the market
• 
Stay in body ~1 hour
Robert Lenk, Luna nanoWorks
Yet to go through drug trials
Similar idea for X-ray contrast agents (Ho3+) and
Radiopharmaceuticals (Ho3+ and Tm2+)
• 
Filled fullerenes for quantum computing
N @ C60
• 
The electron spin in 14N@C60 can be used as a resource for
the nuclear spin qubit.
Fullerene based solids : Fullerites!
Polymerised fullerenes give fullerites, new ultra-hard materials.
Ultrahard fullerite has hardness of 310 GPa, greater than diamond (167GPa)…
- Fullerite tip scratch on the (111) diamond surface
– plastic deformation of the diamond…
Bulk modulus K ~600-900GPa measured, cf. 440-490GPa for diamond
Synthesis difficult – HPHT (15GPa, 670-1820K)
Berber et al, PRB70, 085417 (2004)
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Carbon Nanotubes
Fullerenes
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Graphene
Graphene!
DEFINITION: One atom thick hexagonal layer made exclusively of carbon atoms.
• 
• 
Graphene was first produced in
2004 and Andre Geim and
Konstantin Novoselov were
awarded the Nobel prize in
Physics for their experiments in
2010.
Graphene is the ultimate twodimensional material, it has
open a new venues in physics.
Graphene
The suffix “-ene” = related to fused polycyclic aromatic hydrocarbons.
Graphene may be considered as the final member of this series, the largest member with quasi-infinite size.
Benzene
Naphthalene
Anthracene
Phenanthrene
…
Graphene
Graphene is an aromatic system
(resonant bonds)
« Ideal » graphene is not very
chemically reactive
F-Graphene*
F2-Graphene* Single Au atom on Graphene**
B.E.=0.81 eV/F B.E. = 1.10 eV/FB.E =0.66 eV
DFT/LDA, 4x4x1 unitcell
*C.Bittencourt, G.Van Lier, X.Ke, I.Suarez-Martinez, A.Felten, et al ChemPhysChem 2009, 10, 920 – 925
** I. Suarez-Martinez, C Bittencourt, X Ke , A. Felten et al. Carbon 47 (2009) 1549-1554
Two-dimensional solid!
• 
Infinite layer of graphene: supercell 128C (8x8x1)
Two-dimensional solid!
• 
Infinite layer of graphene: supercell 128C (8x8x1)
Graphene
K
A. K. Geim, A. H.
MacDonald,
Physics Today 60 (8), 35
(2007)
Andrea Ferrari (2011)
Micromechanical Cleavage (scotch tape)!
Andre Geim (2011)
Liquid Phase Exfoliation : Graphene Oxide (GO)!
! 
! 
! 
! 
! 
Acid treat (e.g. HNO3) graphite and
sonicate!
Graphene layers become oxygen
functionalised and peel off the
graphite!
Good cheap way to produce
graphene solutions!
Graphene Oxide (GO) is NOT
graphene (e.g. non-conductive, water soluble))!
Good for composites and chemical
functionalisation!
Rod Ruoff (2011)
Graphene Oxide (GO) /Reduced Graphene Oxide (RGO)!
Hydrazine
Treatment
RGO is NOT
graphene!
Functionalised graphene
produced in tonne quantities
• 
M. Segal, Nature Nanotechnology 4, 612 - 614 (2009)
doi:10.1038/nnano.2009.279
Vorbeck.com
Graphene
DEFINITION: One atom thick hexagonal layer made exclusively of carbon atoms.
PROPERTIES
! 
Thinnest imagineable material
A. K. Geim, A. H.
! 
Largest surface area (~2700m2 / g)
K
MacDonald,
! 
Strongest material (Modulus ~1100 GPa,
Physics Today 60 (8),
35 (2007)
Fracture strength ~130GPa)
! 
Low density ~2g/cm3 (light)
! 
Stiffest material (stiffer than diamond)
! 
Most stretchable (up to 20% elasticity)
! 
Record thermal conductivity (beats diamond) ~3000W/m-K in plane, ~2 W/m-K out of plane
! 
Highest current density at room T (106 x Cu)
! 
Gas impermeable (blocks all gases when defect free)
! 
Highest intrinsic mobility (100x Si)
! 
Lightest charge carriers (zero rest mass!)
! 
Longest mean free path at room T (micron range)
Potential applications!
Watches
/ calendars
Thin flexible
light panel
Mobile
phones
Electronic
payment
Touch screens,
Microelectronics
Composite
materials
Tablet
computers
Solar
cells
Royal Swedish Academy of Sciences http://kva.se
SungKyunKwan University /
Samsung!
S. Bae et al, Nature Nanotechnology
5, 574–578 (2010)
Replacement for ITO?!
Transparent conducting electrode
•  Cheaper, more available source
•  Stronger, flexible
• 
S. Bae et al, Nature Nanotechnology
5, 574–578 (2010)
http://chem.skku.edu/graphene/
Gas Barrier!
Graphene related forms!
• 
Carbon Nanowalls: vertically oriented graphenes on a substrate
• 
Multiple stacked graphenes
• 
Similar growth method as for multi-walled carbon nanotube (MWCNT) growth.
• 
The “walls” are typically less than 10 nm and typically a micron long.
• 
This material is expected to be of interest for field emission.
Graphene related forms!
Carbon Nanoribbons:
• 
Armchair, zigzag and (chiral)
• 
SYNTHESIS OF NANORIBBONS!
! 
Lithography of graphenes!
! 
Bottom-up synthesis !
!  Klaus
Müllen and colleagues!
!  Possibility
! 
also for 3D structures!
Plasma opening nanotubes!
« Unzipping » carbon nanotubes!
Materials science: Nanotubes unzipped
M.Terrones, Nature 458, 845 (2009)
doi:10.1038/458845a
C. Soldano, A. Mahmood, E. Dujardin
http://arxiv.org/abs/1002.0370
Vol 466|22 July 2010| doi:10.1038/nature09211
Graphene nanoribbons!
!"
!"
Ph. Wagner et al, PRB, submitted (2011)
Graphene nanoribbons!
M. Baldoni, A. Sgamellotti, F. Mercuri, Chem. Phys. Lett. (2008), 464, 202
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Carbon Nanotubes
Fullerenes
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Graphene
Carbon Nanotubes!
DEFINITION: Tubular hollow-core sp2 bonded carbon nanostructure with no axially oriented
edges, where the tube walls are approximately parallel to the tube axis at all times.
• 
Iijima first identified carbon
nanotubes as a by-product ofa
fullerene experiment.
Transmission Electron microscopy image of a
single-wall carbon nanotube
• 
Sumio Iijima, Japan, 1991
They are often defined as “wrapped
graphene” but they are not made that way!
Single Walled carbon nanotubes!
• 
• 
They are often defined as “wrapped graphene” but they are not made that way!
Hoewer, this “definition” helps to undestand their nomenclature
CHIRAL VECTOR: Hamada indices (n,m) define the diameter and electrical
properties of single-wall nanotubes
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Modelling
capping not
always easy!
Semiconducting or METALLIC
METALLIC
Electronic properties of SWNT
When n-m is a multiple of 3
the tube is metallic
Nanotube Synthesis!
! 
Arc-electric : two graphite
rods, sharpened, electric
spark between tips!
! Metal
catalyst for single-walled
nanotube!
! 
! 
Laser ablation of a graphite
powder target !
Chemical Vapor
Deposition :from an organic
molecule!
Nanotube Forests!
Bundling!
SWNT are generally in bundles
- 
size of bundles : typically 10 to 200 nanotubes
- 
orthorhombic-like structure
- 
inter-tube distance dvdw ~ 3.15 Å
Bundle of SWNT
(TEM - ONERA)
Bundle of SWNT
(GDPC - Montpellier)
2 Chiral SWNT
(STM image - U. Illinois, Urbana, USA)
c)
d)
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« Dogbone » tubes!
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Unique properties for many potential applications
- 
- 
- 
high aspect ratio length/diameter, small diameters, metallic NTC
=> field emission, composites with conductive behavior
very high current density (the higher ! 109 A/cm!)
=> vias (interconnexion between 2 levels of transistor in a chip)
field emission
balistic electronic transport
=> Field-effect-transistor (FET)
elastic (Young) modulus (the higher ! 1 Tpa : 1012 Pa)
=> composites with mechanical behavior
-  thermal conductivity (the higher ! 4000 W/m.K)
=> composites, components
-  very high surface/volume ratio, broad potential range of electrodes
=> sensors, supercapacity, biologic applications
- 
(b) Field-emission properties and applications
Benefits from CNT for field-emission
- High aspect ratio => smaller voltages to emit electrons
-  high current values (0,1-0,2 mA) => more light
-  stable light emission
Bonard et al., Appl. Phys. A 69, 245, 1999
Fibres made with
lots of
nanotubes:
ultra-strong,
ultra-resistant
How to purify water?!
VIDEO
nano
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Carbon Nanotubes
Fullerenes
COMING UP….
MORE “EXOTIC FORMS”
12.0107
Graphene