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ECE 480 – Introduction to Nanotechnology

ECE 480 – Introduction to Nanotechnology. Emre Yengel Department of Electrical and Communication Engineering Fall 2013. Carbon; Basics. Carbon belongs to the group IV of the periodic table. It has four electrons in its outermost orbit, so its valency is four.

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ECE 480 – Introduction to Nanotechnology

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  1. ECE 480 – Introduction to Nanotechnology Emre Yengel Department of Electrical and Communication Engineering Fall 2013

  2. Carbon; Basics • Carbon belongs to the group IV of the periodic table. • It has four electrons in its outermost orbit, so its valency is four. • Carbon is a non-metal with melting point: ~ 3500oC and atomic radius: 0.077 nm

  3. Carbon; Basics • The number of carbon compounds is larger than that of all other elements put together.

  4. Carbon; Basics • Living organisms consist mostly of carbon-based compounds • Carbon is unparalleled in its ability to form large, complex, and diverse molecules • Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds

  5. Carbon; Basics • Electron configuration is the key to an atom’s characteristics • Electron configuration determines the kinds and number of bonds an atom will form with other atoms • With four valence electrons, carbon can form four covalent bonds with a variety of atoms • This ability makes large, complex molecules possible

  6. Carbon; Bonding • In molecules with multiple carbons, each carbon bonded to four other atoms has a tetrahedral shape • However, when two carbon atoms are joined by a double bond, the atoms joined to the carbons are in the same plane as the carbons

  7. Name andComment Structural Formula Space-Filling Model Molecular Formula Ball-and- Stick Model Carbon; Compounds (a) Methane (b) Ethane (c) Ethene (ethylene)

  8. Carbon; Compounds • The electron configuration of carbon gives it covalent compatibility with many different elements • The valences of carbon and its most frequent partners (hydrogen, oxygen, and nitrogen) are the “building code” that governs the architecture of living molecules

  9. Carbon; Bonding

  10. Carbon; Allotropes • In nature, pure carbon occur in two forms- • Diamond • Graphite

  11. Carbon; Allotropes • Allotropes are elements which are chemically identical, but they differ markedly in their physical properties. • Diamond and Graphite – two allotropes of carbon differ in their physical properties. • Why?

  12. Carbon; Bonding of Allotropes • Due to the difference in the arrangement of carbon atoms in diamond and graphite Graphite – sp2 Diamond – sp3

  13. Carbon; Physical Properties

  14. Carbon; Hydrocarbons • Hydrocarbons are compounds of carbon and hydrogen. The natural source of hydrocarbons is petroleum (crude oil)

  15. Carbon; The Simplest Hydrocarbon Methane CH4 • A molecule of methane has four hydrogen atoms linked to one central atom of carbon.

  16. Hydrocarbons Carbon; Hydrocarbons Saturated Alkanes

  17. Carbon; Alkanes • The hydrocarbons methane, ethane propane and butane form a series of carbon compounds known as alkanes • The alkane series can be represented by the general formula

  18. Carbon; Alkenes • Unsaturated hydrocarbons contain a double or triple bond between two carbon atoms. • The one with double bond are called alkenes

  19. Nanocarbon • Fullerene • Tubes • Cones • Carbon black • Horns • Rods • Foams • Nanodiamonds

  20. Nanocarbon • Fullerene • Tubes • Cones • Carbon black • Properties & Application • Electrical • Mechanical • Thermal • Storage

  21. Nanocarbon Shenderova et al. Nanotechnology 12 (2001) 191.

  22. Nanocarbon 6 + 6 pentagons 1 – 5 pentagons 12 pentagons

  23. Nanocarbon; Fullerene ”The most symmetrical large molecule” • Discovered in 1985 - Nobel prize Chemistry 1996, Curl, Kroto, and Smalley • C60, also 70, 76 and 84. • - 32 facets (12 pentagons and 20 hexagons) • - prototype Epcot center, Paris ~1 nm Architect: R. Buckminster Fuller

  24. Nanocarbon; Fullerene • Symmetric shape → lubricant • Large surface area → catalyst • High temperature (~500oC) • High pressure • Hollow → caging particles • Ferromagnet? - polymerized C60 - up to 220oC

  25. Nanocarbon; Fullerene • Chemically stable as graphite - most reactive at pentagons • Crystal by weak van der Waals force • Superconductivity - K3C60: 19.2 K - RbCs2C60: 33 K Kittel, Introduction to Solid State Physics, 7the ed. 1996.

  26. Nanocarbon; Nanotube • Discovered 1991, Iijima Roll-up vector:

  27. Nanocarbon; Nanotube Electrical conductanse depending on helicity If , then metallic else semiconductor • Current capacity • Carbon nanotube 1 GAmps / cm2 • Copper wire 1 MAmps / cm2 • Heat transmission • Comparable to pure diamond (3320 W / m.K) • Temperature stability • Carbon nanotube 750 oC (in air) • Metal wires in microchips 600 – 1000 oC • Caging • May change electrical properties • → sensor

  28. Nanocarbon; Nanotube High aspect ratio: Length: typical few μm → quasi 1D solid Diameter: as low as 1 nm SWCNT – 1.9 nm Zheng et al. Nature Materials 3 (2004) 673.

  29. Nanocarbon; Nanotube Carbon nanotubes are the strongest ever known material. • Young Modulus (stiffness): • Carbon nanotubes 1250 GPa • Carbon fibers425 GPa (max.) • High strength steel 200 GPa • Tensile strength (breaking strength) • Carbon nanotubes 11- 63 GPa • Carbon fibers 3.5 - 6 GPa • High strength steel ~ 2 GPa • Elongation to failure : ~ 20-30 % • Density: • Carbon nanotube (SW) 1.33 – 1.40 gram / cm3 • Aluminium 2.7 gram / cm3

  30. Nanoscience Research Group University of North Carolina (USA) http://www.physics.unc.edu/~rsuper/research/ Nanocarbon; Nanotube • Carbon nanotubes are very flexible http://www.ipt.arc.nasa.gov/gallery.html

  31. Nanocarbon; Cones • Discovered 1994 (closed form) Ge & Sattler • 1997 (open form) Ebbesen et al. Li et al. Nature 407 (2000) 409. • Closed: same shape as HIV capsid • Possible scale-up production (open form) • Storage? • → Hydrogen 19.2 o 38.9 o 60.0 o 84.6 o 112.9 o Scale bar: 200 nm Krishnan, Ebbesen et al. Nature 388 (2001) 241.

  32. Nanocarbon; Carbon Black • Large industry • - mill. tons each year • Tires, black pigments, plastics, dry-cell batteries, UV-protection etc. • Size: 10 – 400 nm

  33. Nanocarbon; Applications Writing C60: 1000x better resolution than ink (Xerox) Carbon – graphite

  34. CNT / polymer composite Nanocarbon; Applications • Current technology - carbon black - 10 – 15 wt% loading - loss of mechanical properties • CNT composites - 0.1 – 1 wt% loading - low perculation treshold

  35. CNT / polymer composite Nanocarbon; Applications • Transparent electrical conductor • - Thickness: 50 – 150 nm • - High flexibility Wu et al. Science 305 (2004) 1273.

  36. Transistor Nanocarbon; Applications • Semiconductor, Si-based • - Nobel prize 1956, Shockley, Bardeen, and Brattain. • - 2000, Kilby. • Vacuum tubes - Nobel prize 1906, Thomson. IBM, 1952.

  37. Transistor Nanocarbon; Applications • SWCNT - 2.6 GHz, T = 4 K - Logical gates Bachtold, Dekker et al. Science 294 (2001) 1317. Li et al. Nano Lett. 4 (2004) 753.

  38. Antenna Nanocarbon; Applications • Dipole Radio wave: ~ 3/4 m • Nanotube Optical wave: L Dekker, Phys. Today May (1999) 22

  39. Flat screen displays Nanocarbon; Applications • Field emission Saito et al., Jpn. J. Appl. Phys. 37 (1998) L346.

  40. Atomic Force Microscopy Nanocarbon; Applications Eldrid Svåsand, IFE, Kjeller

  41. Atomic Force Microscopy Nanocarbon; Applications • Tube or cone • Chemical probe Wong, Lieber et al. Nature 394 (1998) 52.

  42. Yarn Nanocarbon; Applications Zhang, Atkinson and Baughman, Science 306 (2004) 1358.

  43. Yarn Nanocarbon; Applications • MWCNT • Operational -196oC < T < 450oC • Electrical conducting • Toughness comparable to Kevlar • No rapture in knot Zhang, Atkinson and Baughman, Science 306 (2004) 1358.

  44. Hydrogen storage Nanocarbon; Applications 2 H2(g) + O2(g) → 2 H2O (l) + energy H2 (200 bar) Mg2NiH LaNi5H6 H2 (liquid) 3.16 wt% 1.37 wt% Schlapbach & Züttel, Nature 414 (2001) 353

  45. Hydrogen storage Nanocarbon; Applications • Aim: 5 - 7 wt% H2 • SWCNT - Dillon et al. (1997) : 8 wt% (questionable) - Tarasov et al. (2003): 2.4 wt% reversible, 25 bar H2, -150oC. • Cones - Mealand & Skjeltorp, (2001) US Patent 6,290,753 Eldrid Svåsand, IFE Kjeller

  46. Nanocarbon; Conclusion • Nanocarbon - fullerene - ”most symmetrical” - tubes - ”strongest” - cones - ”one of the sharpest” - carbon black - ”large production” • Properties - electrical, mechanical, thermal, storage, caging • Applications - antenna, composite, writing, field emission, transistor, yarn, microscopy, storage

  47. Nanocarbon; Commercial • Companies: ~ 20 worldwide - Carbon Nanotechnologies Inc. (CNI) - SES Research - n-Tec • Prices: - Tubes: pure SWCNT $500 / gram (CNI) MWCNT € 20-50 / gram (n-Tec) - C60 : pure $100-200 / gram (SES Research) - Cones: Multi € 1 / gram (n-Tec) - Gold : $10 / gram

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