Carbon nanomaterials DCMST June 2 nd, 2011 Gavin Lawes Wayne State University

DCMST June 2 nd, Carbon structures 2. Carbon nanostructures 3. Potential applications for Carbon nanostructures Outline

DCMST June 2 nd, 2011 from bpc.edu Periodic table

DCMST June 2 nd, 2011 Electron (-) Proton (+) Neutron Carbon atom

DCMST June 2 nd, 2011 from msu.edu/gallego amino group carboxylic acid group Carbon-based molecules are somewhat important for life on Earth… Amino acids

DCMST June 2 nd, 2011 Lecithin from indiana.edu/oso Phospholipids

DCMST June 2 nd, 2011 Pentane from wikimedia.org …and are also important for all industrial activity

DCMST June 2 nd, 2011 from britannica.com s orbital p orbital Electron orbitals

DCMST June 2 nd, 2011 from ASDN.net Hybridization

DCMST June 2 nd, 2011 from cnx.org from diamonds.net sp 3 hybridized C crystals

DCMST June 2 nd, 2011 from cochise.edu/wellerr sp 2 hybridized C crystals

DCMST June 2 nd, 2011 from chem.wisc.edu Graphite consists of layers of hexagonal Carbon sheets.

DCMST June 2 nd, 2011 DiamondGraphite Electrical insulatorElectrical conductor* Very hardVery soft* TransparentOpaque ExpensiveCheap

DCMST June 2 nd, 2011 Nanoscale carbon structures

DCMST June 2 nd, 2011 from sciencedaily.com Buckminsterfullerene Molecule consisting of 60 C atoms sp 2 hybridized bonds Has 20 hexagons, 12 pentagons Other related structures have 70 or 84 C atoms

DCMST June 2 nd, 2011 from unusualife.com C 60 is named for Buckminster Fuller who designed geodesic domes.

DCMST June 2 nd, 2011 Original report of C 60

DCMST June 2 nd, Nobel Prize in Chemistry Robert Curl, Sir Harold Kroto, Richard Smalley “for their discovery of fullerenes”. from Nobelprize.org

DCMST June 2 nd, 2011 from informaworld.com Carbon nanotubes Rolled up sheet of sp 2 bonded carbon atoms

DCMST June 2 nd, 2011 from rice.edu Single walled carbon nanotube (single sheet of carbon atoms) Multiwalled carbon nanotube (several sheets of carbon atoms) Carbon nanotubes can be formed from a single sheet of C atoms or several sheets

DCMST June 2 nd, 2011 Carbon sheets can also be rolled up in different directions to give different types of nanotubes.

DCMST June 2 nd, 2011 from phycomp.technion.ac.il Electrical conductor Electrical insulator The properties of nanotubes depend on how they are rolled up

DCMST June 2 nd, 2011 Nanotube sizes also depend on how they are rolled up

DCMST June 2 nd, 2011 Graphene (single sp 2 bonded carbon sheet)

DCMST June 2 nd, 2011 from cnx.org C atoms in hexagonal array

DCMST June 2 nd, 2011 From ncem.lbl.gov Scale bar 0.2 nm

DCMST June 2 nd, 2011 Nobel Prize in Physics 2010 Andre Geim and Konstantin Novoselov “for groundbreaking experiments regarding the two-dimensional material graphene”. from Nobelprize.org

DCMST June 2 nd, 2011 Carbon nanostructures

DCMST June 2 nd, 2011 Why are carbon nanostructures interesting?

DCMST June 2 nd, 2011 Multiwall carbon nanotube breaking They are strong

DCMST June 2 nd, 2011 Silica fibres+MWCNT Multiwall carbon nanotube composite Mechanical properties can improve by 50% or more by adding carbon nanotubes.

DCMST June 2 nd, nm Damascus sabre steel contains nanotubes Multiwalled carbon nanotubes found in 17 th century sword. These are formed during the synthesis and may have produced the very good mechanical properties.

DCMST June 2 nd, 2011 from bpc.edu They have good electrical properties

DCMST June 2 nd, 2011 from nanotechweb.org Carbon nanostructures may be used in new electronic devices

DCMST June 2 nd, 2011 Devices made with carbon nanotubes

DCMST June 2 nd, 2011 Carbon Nanotubes. Advanced Topics in the Synthesis, Structure, Properties and Applications, , 2008 Carbon nanotubes can be used for making electronic devices

DCMST June 2 nd, 2011 from als.lbl.gov Properties of graphene depend on the subtrate

DCMST June 2 nd, 2011 From nanotechweb.org Geometry of graphene may also affect the properties

DCMST June 2 nd, 2011 Graphene may be used as a transparent electrode

DCMST June 2 nd, 2011 Carbon nanotube mechanical oscillator Force sensitivity of 1 fN Hz -1/2

DCMST June 2 nd, 2011 Graphene mechanical oscillator

DCMST June 2 nd, 2011 Carbon nanotubes may have biomedical applications Carbon nanotubes can be functionalized with different biologically relevant molecules.

DCMST June 2 nd, 2011 Cells incubated with functionalized carbon nanotubes

DCMST June 2 nd, 2011 Metal Semiconductor Energy Momentum Electronic bandgap

DCMST June 2 nd, 2011 from wikipedia.com The electronic bandgap for graphene looks like a pair of cones touching at their tips for certain positions (in momentum space). This leads to interesting electronic properties.

DCMST June 2 nd, 2011 Schrodinger Equation Dirac Equation (for massive particles) (for relativistic particles) E~p 2 E~p Appropriate for electrons in graphene

DCMST June 2 nd, 2011 How do you make carbon nanotubes? 1. Carbon arc discharge. Hold two carbon (graphite) electrodes at some potential difference in a Helium atmosphere and bring the electrodes together. At some separation and arc will be produced, and carbon nanotubes will grow on the cathode. These will normally be multiwalled nanotubes, but single walled nanotubes can be grown by adding Ni, Fe, or Co to the cathode.

DCMST June 2 nd, Laser ablation. Heat up a lump of graphite to ~1200 C in an Ar atmosphere, and then blast it with a laser. This can make single walled nanotubes if the graphite has a catalyst like Co or Ni included. 3. Catalytic growth. Heat up hydrocarbons (e.g. acetylene) to high temperatures and then let them settle on a substrate coated with a catalyst (Fe, Co, Ni). This will form either multiwalled nanotubes or single walled nanotubes depending on the growth conditions. How do you make graphene? Graphite and scotch tape.

DCMST June 2 nd, 2011 Open problems 1. To be useful for devices, these carbon nanomaterials need to be prepared on and/or connected reliably to electrodes. 2. Since the properties of these nanomaterials depend strongly on structure (e.g. armchair vs zig-zag nanotubes), we need to have good control over these structural details. 3. Many unanswered physics questions remain, including the magnetism, superconductivity, and optical properties of these materials.

DCMST June 2 nd, A number of carbon allotropes naturally form interesting nanostructures 2. These nanostructures have enormous potential in developing new electronic, optical, and nano-mechanical devices. Summary

DCMST June 2 nd, 2011 End