Graphene- the wonder material
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This document discusses the properties and applications of graphene. Graphene is a single layer of carbon atoms arranged in a hexagonal lattice. It is the strongest and thinnest material known. Graphene was first isolated in 2004 by Geim and Novoselov at the University of Manchester. Graphene has high electrical conductivity, is very strong yet light, and is an excellent conductor of heat. Potential applications of graphene include use in bendable mobile device screens, drug delivery systems, batteries, solar cells, desalination, pollution removal, and aircraft design. Graphene derivatives also show promise as photocatalysts. The document concludes that graphene's potential applications are limited only by imagination.
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Graphene- the wonder material
- 1. GRAPHENE: THE WONDER MATERIAL SUBMITTED BY : SANSKRITA MADHUKAILYA M.Sc 1st SEM, DEPT. OF CHEMISTRY, DIBRUGARH UNIVERSITY
- 2. TOPICS TO BE COVERED 1. INTRODUCTION 2. HISTORY OF GRAPHENE 3. PROPERTIES THAT DISTINGUISHES GRAPHENE FROM OTHERS 4. APPLICATIONS TO DIFFERENT FIELDS 5. CONCLUSION 6. REFERENCE
- 3. INTRODUCTION A single layer of sp2 hybridized carbon atoms. allotrope of carbon Basic structural element of other allotropes. Strongest, thinnest material known to exist.
- 4. Layered structure of graphene
- 5. HISTORY OF GRAPHENE In 2004, Andre Geim and Konstantin Novoselov at University of Manchester extracted single atom thick crystallites. Received Nobel Prize in Physics,2010.
- 6. WHAT MAKES GRAPHENE SO SPECIAL?? Different fascinating properties makes Graphene a wonder material that could revolutionize the world…
- 7. Properties that distinguishes Graphene from others: have high electrical conductivity. extraordinarily strong & very light. contains elastic properties Can absorb a rather large 2.3% of white light, especially considering that it is only 1 atom thick. it is a perfect thermal conductor Most reactive form of carbon.
- 8. Applications to various fields Unbreakable & bendable mobile screens Graphene drug delivery system Fast chargeable batteries Solar cells Desalination of water Removal of organic pollutant from water Graphene based aircraft DNA sequencing
- 9. GRAPHENE DERIVATIVES AS PHOTOCATALYST Graphene oxide prepared from graphene (Hummer & Offeman method) functions as efficient photocatalyst due to presence of oxygen functionalised groups. These photocatalysts are used to remove organic pollutants (pesticides, dyes etc.) from water; a MAJOR environmental concern!
- 10. And this is only the start. These are only the first steps. The potential of graphene is limited only by our imagination. CONCLUSION The future in the trace of a pencil…
- 11. REFERENCES 1. W. Choi, I. Lahiri, R. Seelaboyina, Y. S. Kang, Synthesis of Graphene and its Applications: A Review, Critical Reviews in Solid State and Material Sciences, 35: 2010, 52-71. 2. S. P. Lonkar , A. A. Abdala, Application of Graphene in catalysis, J Thermodyn Catal., 5:2, 2014, 1-6. 3. P. K. Boruah, B. Sharma, I. Karbhal, M. V. Shelke, M. R. Das, Ammonia- modified graphene sheets decorated with magnetic Fe3O4 nanoparticles for photocatalytic and photo-Fenton degradation of phenolic compounds under sunlight irradiation, J. Hazard. Mater, 325, 2017, 90–100 4. Z. Terzopoulou, G. Z. Kyzas, D. N. Bikiaris, Recent advances in nanocomposite materials of Graphene derivatives of Polysachharides, Materials, 8, 2015, 652-683. 5. https://www.graphenea.com/pages/graphene-uses-applications 6. http://www.understandingnano.com/graphene-applications 7. http://youtu.be/eh3dA8xnZ4Y
Editor's Notes
- it was theoretically believed that two dimensional compounds could not exist due to thermal instability when separated. However, once graphene was isolated, it was clear that it was actually possible, and it took scientists some time to find out exactly how. After suspended graphene sheets were studied by transmission electron microscopy, scientists believed that they found the reason to be due to slight rippling in the graphene, modifying the structure of the material. However, later research suggests that it is actually due to the fact that the carbon to carbon bonds in graphene are so small and strong that they prevent thermal fluctuations from destabilizing it. The extraordinary characteristics of graphene originate from the 2p orbitals, which form the π state bands that delocalize over the sheet of carbons that constitute graphene. As a result, graphene is the extremely stiff, exhibits very high thermal conductivity, has zero effective mass, is impermeable to gases, displays high mobility of charge carriers, while it is optically transparent.
- Carbon atoms have a total of 6 electrons; 2 in the inner shell and 4 in the outer shell. The 4 outer shell electrons in an individual carbon atom are available for chemical bonding, but in graphene, each atom is connected to 3 other carbon atoms on the two dimensional plane, leaving 1 electron freely available in the third dimension for electronic conduction. Scientists have found that graphene remains capable of conducting electricity even at the limit of nominally zero carrier concentration because the electrons don't seem to slow down or localize. The electrons moving around carbon atoms interact with the periodic potential of graphene’s honeycomb lattice, which gives rise to new quasiparticles that have lost their mass, or rest mass(so-called massless Dirac fermions). That means that graphene never stops conducting. It was also found that they travel far faster than electrons in other semiconductors. It is often said that a single sheet of graphene (being only 1 atom thick), sufficient in size enough to cover a whole football field, would weigh under 1 single gram.
- . One of the earliest biomedical applications of graphene was for improved drug delivery. Graphene oxide, produced by the oxidation of graphite, was first reported as a suitable nanocarrier for drug delivery in 2008. The large, planar surface structure and enriched oxygen-containing groups provide biocompatibility and solubility, properties which are appropriate for delivering drugs within the body. Graphene oxide contains COOH and OH groups which will readily allow for the attachment to various biomolecules. Biosensors are utilized for the detection of biological molecules and events through the production of a measurable signal. Single-layer graphene sheets are particularly suitable for use as a biosensor material because its properties include high mechanical strength and thermal conductivity, along with a tunable electronic band gap. Graphene also has enormous potential in DNA sequencing. Imagine a sheet of graphene with a small gap, big enough to allow a strand of DNA to pass through, like thread through cloth. As the DNA passes through the sheet, the electrical properties of graphene change on exposure to each base pair. Because it is 2D, it can "read" one base at a time, making it much more accurate than anything used today. Even though the surface of graphene is planar and uniform, like any other material in existence it is subject to intrinsic defects. Catalysts in the form of metal ions can sit in these cavities and be supported. In addition to providing mechanical support, the excellent charge carrier ability of graphene assists the charge transfer reactions involving the catalyst. Graphene is also inert and does not interfere (in a negative way) with the interaction between the catalyst and the substrate materials. Graphene also provides an even dispersion of catalyst particles, so the catalyst-substate reaction is consistent across the whole support.