Carbon Nanotubes - CMT - fh-muenster.de · Carbon Nanotube Mr. Anurak Udomvech. Construction of...
Transcript of Carbon Nanotubes - CMT - fh-muenster.de · Carbon Nanotube Mr. Anurak Udomvech. Construction of...
Synthesis of nanotubesSynthesis of nanotubesSynthesis of nanotubes
Ewelina BrodaEwelina BrodaEwelina Broda
Presentation Overview
1. Introduction2. History3. Types and structures4. Properties5. Synthesis6. Applications7. References
Allotropes of Elemental Carbon
History
1985 Discoverey of the buckyball (C60) and other fullerenesR. E. Smalley (Nobel Prize winning in 1996)
1991 Discovery of multi-wall carbon nanotubesS. Iijima
1992 Conductivity of carbon nanotubesJ. W. Mintmire, B. I. Dunlap and C. T. White
1993 Structural rigidity of carbon nanotubesG. Overney, W. Zhong, and D. Tománek
1993 Synthesis of single-wall nanotubesS. Iijima and T. Ichihashi
1995 Nanotubes as field emitters A.G. Rinzler, J.H. Hafner, P. Nikolaev, L. Lou, S.G. Kim, D. Tománek, P. Nordlander, D.T. Colbert, and R.E. Smalley
1997 Hydrogen storage in nanotubesA. C. Dillon, K. M. Jones, T. A. Bekkendahl, C. H. Kiang, D. S. Bethune and M. J. Heben
1998 Synthesis of nanotube peapodsB.W. Smith, M. Monthioux, and D.E. Luzzi
2000 Thermal conductivity of nanotubes S. Berber, Y.K. Kwon, D. Tománek
2001 Integration of carbon nanotubes for logic circuitsP.C. Collins, M.S. Arnold, and P. Avouris
2001 Intrinsic superconductivity of carbon nanotubesM. Kociak, A. Yu. Kasumov, S. Guéron, B. Reulet, I. I. Khodos, Yu. B. Gorbatov, V. T. Volkov, L. Vaccarini, and H. Bouchiat
Classification
Non carbon nanotubesMX2 compounds (M=transition metal; X= chalogen), eg.: WS2 and MoS2;BxCyNz, eg.: BN, BC3 and BC2N
Carbon nanotubes
Classification
Multi - walled nanotubesSingle - walled nanotubes
Multi – Walled Nanotubes
Russian dollmodel
Parchmentmodel
Single – Walled Nanotubes
Graphene Types of SWNTCarbon Nanotube Mr. Anurak Udomvech
Construction of Nanotubes
a1 , a2 primitive lattice vectors of graphene
Chiral vector: Ch = n1 a1 + n2 a2 n1 , n2 integers: chiral numbers
T tube axis
Mirror lines: "zig-zag line” through the midpoint of bonds"armchair line” through the atoms
θ - chiral angle
Sixfold symmetry: 0 ≤ θ < 60°http://en.wikipedia.org/wiki/Carbon_nanotubes
Armchair(n,n)
Zigzag(n,0)
Chiral(n,m)
http://en.wikipedia.org/wiki/Carbon_nanotubes
Properties
• Extraordinary electric properties• Very high tensile strength • Highly flexible – can be bent considerably without damage• Very elastic ~18% elongation to failure• Twice the thermal conductivity of diamonds• Low thermal expansion coefficient• Good electron field emitters• High aspect ratio (length = ~1000 x diameter)• Reported to be thermally stable in a vacuum up to 2800 deg. Centigrade (and we fret over CPU temps over 50o C)
Properties
• Electrical conductivity
Properties
http://nanopedia.case.edu/NWPage.php?page=nanotube.strength
Synthesis
1.) Arc discharge2.) Laser ablation3.) Chemical vapor deposition (CVD)
Techniques differ in:Type of nanotubes (SWNT / MWNT )Catalyst usedYieldPurity
Growth Mechanism
Arc Discharge
Arc Discharge
Electrodes are composed of high purity graphite (>99.999%)~70 A at ~18 V DC is applied to the electrodesCarbon nanotubes are formed at atmospheric pressures from the electrodes
Information courtesy of: K. Anazawa, K. Shimotani, C. Manabe, H. Watanabe, and M. Shimizu. “High-purity…magnetic field”
Laser Ablation
Laser Ablation
A well mixed acetylene-air mixture is burned inside a tube furnaceA laser is used to vaporize a metal target (either Fe or Ni)The post-flame exhaust gas is mixed with the metallic vapor and allowed to coolDuring cooling, carbon nanotubes are formed
Chemical Vapor Deposition (CVD)
Chemical Vapor Deposition (CVD)
Source of carbon atoms usually comes from an organic compound
Mixed with a metal catalyst and inert gas
Atomized and sprayed into reactor with temperatures ranging from 600ºC to 1200ºC
Pyrolysis of organic compound deposits carbon (as soot) and carbon nanotubes on reactor wall (usually a tube constructed from quartz)
Sources of Carbon
Typical Organic/Catalyst MixturesXylene/ferrocene (Andrews et al.)Toluene, benzene, xylene, mesitylene, and n-hexane/ferrocene (Vivekchand et al.)Ethylene and ethanol/Fe, Co, and Mo alloys (K. Mizuno et al.)
Typical Carrier GasesArgonHydrogen
Purification
Contaminants:Catalyst particlesCarbon clustersSmaller fullerenes: C60 / C70
Impossibilities:Completely retain nanotube structureSingle-step purification
Only possible on very small scale:Isolation of either semi-conducting SWNTs
Purification: Techniques
Removal of catalyst:Acidic treatment (+ sonication)Thermal oxidationMagnetic separation (Fe)
Removal of small fullerenesMicro filtrationExtraction with CS2
Removal of other carbonaceous impuritiesThermal oxidationSelective functionalisation of nanotubesAnnealing
Synthesis
The Wondrous World of Carbon Nanotubes Eindhoven University of Technology
Applications
Carbon Nano-tubes are extending our ability to fabricate devices such as:Molecular probesPipesWiresBearings SpringsGearsPumps
Applications
Molecular transistors.Field emitters.Building blocks for bottom-up electronics.Smaller, lighter weight components for next generation spacecraft.
Possible Applications of CNTs
Thank You for Your Attention!
References
http://www.pa.msu.edu/cmp/csc/nanotube.htmlhttp://www.photon.t.u-tokyo.ac.jp/~maruyama/nanotube.htmlCarbon Nano-tubes: An Overview An Undergraduate Research Paper By Scott E. Wadley http://students.chem.tue.nl/ifp03/Steffen Weber's Crystallography Picture Book Nanotubes & Nanocones Structure and Properties of Carbon Nanotubes Jannik Meyerhttp://en.wikipedia.org/wiki/Carbon_nanotubesR. Andrews, D. Jacques, D. Quan, and T. Rantell. “Multiwall Carbon Nanotubes: Synthesis and Application.” Accounts of Chemical Research. Vol. 35, No. 12, 2002A. Zettl “Non-Carbon Nanotubes” Advanced Materials Vol. 8, No. 5, 1996S.R.C. Vivekchand, L.M. Cele, F.L. Deepak, A.R. Raju, and A. Govindaraj. “Carbon nanotubes by nebulized spray pyrolysis.” Chemical Physics Letters. 386 (2004) 313-318