Graphene

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Graphene

  1. 1. GRAPHENE STRUCTURE AND APPLICATIONS SEMINAR BY : MR. PRAFULLA D. KAMBADE MIS NO. 141110024
  2. 2. i. WHAT IS GRAPHENE? ii. PROPERTIES OF GRAPHENE. iii. SOME PRODUCTION METHODS iv. APPLICATIONS v. MAJOR CHALLENGES vi. REFERENCES CONTENTS
  3. 3. It’s Story…. WHAT GRAPHENE IS? • It is all started with structure of graphite solved in 1916 –powder diffraction. • In 1924 -single crystal diffraction. •Comes in focus in 2010 when ‘For the Groundbreaking experiments regarding two dimensional material Graphene’
  4. 4. • It is almost completely transparent, yet so dense that not even helium can pass through it. • It is the one-atom thick planar sheet of carbon atoms (graphite), which makes it the thinnest material ever discovered. • 2-dimentional crystalline allotrope of carbon. • C-C Bond length is 0.142 nm. • Graphene Sheets interplanar spacing is of 0.335 nm. STRUCTURE
  5. 5. • Andre Geim and Kostya Novoselov pulled graphene layers from graphite and transferred them onto thin SiO2 on a silicon wafer in a process called either micromechanical cleavage or the Scotch tape technique. Graphene can be seen with help of 1.Transmission electron microscopy. 2.Electron microscopy 3.Optical microscope STRUCTURE……
  6. 6. Graphene can self-repair holes in its sheets, when exposed to molecules containing carbon, such as hydrocarbons. Bombarded with pure carbon atoms, the atoms perfectly align into hexagons, completely filling the holes. STRUCTURAL PROPERTIES OF GRAPHENE.
  7. 7. • Graphene one atom thick are a hundred times more chemically reactive than thicker sheets. (Stanford university) • Graphene is chemically the most reactive form of carbon. CHEMICAL ELECTRONIC • Intrinsic graphene is a semi-metal or zero-gap semiconductor. ELECTRICAL •Graphene has a remarkably high electron mobility at room temperature, with reported values in excess of 15000 cm2·V−1·s−1 •It conducts electricity as efficiently as copper and outperforms all other materials as a conductor of heat.
  8. 8. • one-atom-thick crystal can be seen with the naked eye because it absorbs approximately 2.3% of white light. see FIG. • Graphene's unique optical properties produce an unexpectedly high opacity for an atomic monolayer in vacuum OPTICAL FIG; 4 inch scale graphene film on Stretchable Substrate THERMAL • A graphene sheet is thermodynamically most stable 1.only for molecules larger than 24,000 atoms 2.Size greater than 20 nm • Thermal conductivity is measured to be between (4.84±0.44) × 103 to (5.30±0.48) × 103 W·m−1·K−1
  9. 9. • The flat graphene sheet is unstable with respect to scrolling i.e. bending into a cylindrical shape • As of 2009, graphene appeared to be one of the strongest materials known with a breaking strength over 100 times greater than a hypothetical steel film of the same (thin) thickness, with a Young's modulus (stiffness) of 1 TPa (150000000 psi). • 1 square meter graphene hammock would support a 4 kg cat but would weigh only as much as one of the cat's whiskers, at 0.77 mg (about 0.001% of the weight of 1 m2 of paper) MECHANICAL
  10. 10. 1. NANOSTRIPES- APPLICATION IN NEW FIELD OF SPINTRONICS 2. GRAPHENE OXIDE (GO)- USED IN WATER REMEDIATION AND REACTIVE GAS ADSORPTION (ENVIRONMENTAL APPLICATION) 3. SOLUBLE FRAGMENTS OF GRAPHENE- (THROUGH CHEMICAL MODIFICATION) 4. 3D GRAPHENE (self-supporting 3D graphene has not yet been produced) 5. BILAYER GRAPHENE - Bilayer graphene typically can be found either in twisted configurations where the two layers are rotated relative to each other. OTHER FORMS OF GRAPHENE
  11. 11. 1.MECHANICAL EXFOLIATION : This involves splitting single layers of graphene from multi-layered graphite. Achieving single layers typically requires multiple exfoliation steps, each producing a slice with fewer layers, until only one remains. Geim and Novosolev used adhesive tape to split the layers. SOME PRODUCTION METHODS 2. EPITAXY : Epitaxy refers to the deposition of a crystalline overlayer on a crystalline substrate and the graphene–substrate interaction can be further passivated •In some cases epitaxial graphene layers are coupled to surfaces weakly enough (by Van der Waals forces)
  12. 12. Sicilicon-based epitaxy technology for producing large pieces of graphene with the best quality to date EPITAXY EXAMPLES :  Silicon carbide  Metal substrates  Copper Vapor Deposition ( CVD) 3. REDUCTION OF GRAPHITE OXIDE 4. METAL CARBON MELT 5. SOLVENT EXFOLIATION 6. CARBON DIOXIDE REDUCTION 7. NANOTUBE SLICING FIG METAL CARBON MELT
  13. 13. 1 MEDICINE - Graphene is reported to have enhanced PCR by increasing the yield of DNA product 2. INTEGRATED CIRCUITS - For integrated circuits, graphene has a high carrier mobility 3. TRANSISTORS - Researchers demonstrated four different types of logic gates, each composed of a single graphene transistor. In 2013 researchers reported the creation of transistors printed on flexible plastic that operate at 25-gigahertz, sufficient for communications circuits and that can be fabricated at scale. They grow large graphene sheets on metal, then peel it off and transfer it to the plastic 4. TRANSPERENT CONDUCTING ELECTRODE APPLICATIONS FIG TRANSPERENT CONDUCTING ELECTRODE
  14. 14. APPLICATIONS 5.ETHANOL DISTILATION 6.DESALINATION 7. SOLAR CELLS 8.COOLANT ADDITIVE 9.FREQUENCY MULTIPLIER FIG. INDUSTRIAL APPLICATIONS OF GRAPHENE MEMBRANE
  15. 15. CHALLENGES TO UNLOCK  COST REDUCTION  HANDELING  GROWTH ON WAFER SCALE  CHALLENGES IN MAKING STRONGER COMPOSITE MATERIAL  APPLICATION IN AIRCRAFT PARTS  LOW COST- HIGH SENSITIVITY SENSORS  APPLICATION IN ELECTRICAL ENERGY STORAGE
  16. 16. REFERENCES 1. High Quality, Scalable Graphene Production Doug Speight, Ivan Vlassiouk US Department of energy, 2. Graphene Technology: Roadmap to Applications Andrea C. Ferrari Department of Engineering, Cambridge University, Cambridge, UK 3. Environmental applications of graphene-based materials Alina Catrinel Ion1, Ion Ion1, Florinela Sirbu2 1.Department of Analytical Chemistry and Environmental Engineering, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest 2.Institute of Physical Chemistry “I. Gh. Murgulescu” of the Romanian Academy 4. Adhesion mechanics of graphene membranes J.S. Bunch n, M.L.Dunn Department of Mechanical Engineering, University of Colorado,Boulder,CO80309USA
  17. 17. 5. Graphene Membranes And Greenhouse Gas Pollution : An Interview With Professor Scott Bunch Dr. Scott Bunch UNIVERSITY OF COLORADO, Colorado,Boulder,CO80309USA • 6. Large Arrays and Properties of 3-Terminal GrapheneNanoelectromechanical Switches • Xinghui Liu , Ji Won Suk , Narasimha G. Boddeti , Lauren Cantley , Luda Wang , • Jason M. Gray , Harris J. Hall , Victor M. Bright , Charles T. Rogers , Martin L. Dunn , • Rodney S. Ruoff , and J. Scott Bunch * REFERENCES…..
  18. 18. THANK YOU

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