Introduction Graphene has received great mass media coverage since Geim and Novoselov published their foundlings about monocrystalline graphitic films in 2004, which won them the Nobel Prize in Physics in 2010. (Novoselov et al, 2004) It has been described as the wonder substance or super material by the mass media, not only because it is the thinnest material ever known and the strongest ever measured, but also due to its excellent electrical, thermal, mechanical, electronic, and optical properties. It has high specific surface area, high chemical stability, high optical transmittance, high elasticity, high porosity, tunable band gap, and ease of chemical functionalization which helps in tuning its properties (Geim et al, 2007) Moreover, graphene has a multitude of amazing properties such as half-integer room-temperature quantum Hall effect (Novoselov et al, 2007), long-range ballistic transport with almost ten times greater electron mobility than that of silicon, and availability of charge carriers that behave as massless relativistic quasi particle, known as Dirac fermions. (Geim et al, 2007) The outstanding electrical conductivity and the transparency and flexibility of graphene-based material have led to research and development of some future technologies, such as flexible and wearable electronics. In addition, graphene can also be used for efficient energy storage materials, polymer composites, and transparent electrodes. (Geim et al, 2007) This paper presents a 2 brief overview on the structure and some properties of graphene, along with a presentation of graphene synthesis method and various applications. Structure Graphene refers to a single layer of graphite, with sp2 hybridized carbon atoms arranged in a hexagonal... ... middle of paper ... ...structure constant defines visual transparency of graphene." Science 320.5881 (2008): 1308-1308. 19. Novoselov, Kostya S., et al. "Electric field effect in atomically thin carbon films." science 306.5696 (2004): 666-669. 20. P. Sutter, Nat. Mater., 2009, 8, 171–172 21. Partoens, B., and F. M. Peeters. "From graphene to graphite: Electronic structure around the K point." Physical Review B 74.7 (2006): 075404. 22. Rao, C. emsp14N emsp14R, et al. "Graphene: The New Two‐Dimensional Nanomaterial." Angewandte Chemie International Edition 48.42 (2009): 7752-7777. 23. S. Alwarappan, S. Boyapalle, A. Kumar, C.-Z. Li and S. Mohapatra, J. Phys. Chem. C, 2012, 116, 6556–6559 24. Ujjal Kumar Sur, “Graphene: A Rising Star on the Horizon of Materials Science,” International Journal of Electrochemistry, vol. 2012, Article ID 237689, 12 pages, 2012. doi:10.1155/2012/237689
2. Liang Chi Shen and Jin Au Kong, Applied Electromagnetism, 3rd ed. PWS Publishing Company, 1995.
Current collectors are made of graphitic materials due to its good conduction. GDL gas diffusion layers are made of carbon paper, which has low electronic resistance in order to provide maximum electronic contact and prevent water flooding. Bipolar plates are made of either graphite sot thermosets materials. [Lister & McLean ]
By using strong oxidizing agent, oxygenated functionalities are introduced in the graphite structure which not only expand the layer separation, but also makes the material hydrophilic. Hydrophilic mean that they can be dispersed in water. This properties has enable graphite oxide to be exfoliated in water by using sonification, ultimately producing single and few layer of graphene that has been known as graphene oxide. The properties of graphene oxide is its easy dispersability in water and other organic solvents, as well as in the different matrixes due to the presence of the oxygen functionality (Jesus de La Fuente., 2011).
They can be seen as a collection of rolled sheets of graphene. CNTs demonstrate superconductivity with very large temperature transition. Electrons transport and resistance of CNTs do not depend on the sizes of CNTs. Carbon nanotubes electrodes are constructed by combining graphite powder and multiwall carbon nanotubes in a pestle and a mortar. Then, paraffin is added to the mixture by a syringe before the mixture is packed in a glass tube. After the construction, its electrochemistry is tested to verify its electro-activity by using standard solution of Fe(CN)63-/Fe(CN)64. Care is taken on information about electrode interfaces; mass transiport needs to be minimized in order to be used in catalysis, sensing and electrodeposition (Elrouby, 2013).
The advancement of material science over the past decade has allowed the scientists to create two structures of carbon namely carbon nanotubes and carbon nanowires. Nanowires are small wires with a diameter as small as 1 nanometre. These are being used to build tiny transistors with higher efficiency for computer chips and other electronic devices. In the last couple of years the carbon nanotubes have somewhat overshadowed the nanowires. A carbon nanotube is a cylinder full of carbon atoms. To put it into simpler words, nanotubes are simply sheet of carbon atoms in hexagonal shape. If this sheet is rolled into a form of a cylinder, you have a carbon nanotube. The properties of this carbon nanotube are based on how the sheet is rolled. Although they are formed from the same graphite sheet, their properties are dependent on the variations in length, thickness, type of helical structure and number of layers.
Liao, K., Ting, J. (2006). Characteristics of aligned carbon nanotubes synthesized usin a high-rate low-temperature process. Diamond and Related Materials, 2006, 1210-1216.
The chemistry of diamonds is very interesting. Diamonds are composed mainly of carbon. Carbon can also exist as graphite, in a carbon chain or as buckminsterfullerene. It never forms bonds and leaves unshared electron pairs. In graphite the carbon atoms form an sp2 bonds. In this type of bonding an electron of the s orbital jumps to the p orbital to complete the octet with the other carbon atoms. When this happens it causes the orbital to flatten and the result is one big lattice in a two dimensional plane (Oxtoby). These lattices are attracted to each other not bonded to each other in compounds of graphite. Although they are made of the same carbon the diamond compound is different because of the type of bonds. Each atom forms four directional sp3 bonds instead of the three resonating bonds in graphite. This allows the diamond to keep its tetrahedral shape. It is also what makes the diamond so hard. The tetrahedral sh...
In 2010 two Russian-born scientists pioneered and synthesized a form of “wonder material” that generates heat and electricity at faster speeds, copes with high temperatures, and is almost transparent. Graphene is arranged in a flat hexagon lattice (like microscopic chicken wire) and is one atom thick two-dimensional 〖sp〗^2 bonded carbon. It is the world’s thinnest and strongest material, which can be manufactured into a plethora of provisions that can be used for next generation technology, such as planes, satellites, cars, and computers. However, uses of the material can be expensive and difficult to manufacture for mass production, which is why many of us today do not have access to graphene or use it for various applications in technology in day-to-day life. Graphene is a newly developing material, which is under scrutiny and scientific study in order to integrate it simply and effectively into everyday life.
In the individual layer of graphite , the carbon atoms are assembled to form an honeycomb lattice with a gap of about 0.142 mm, and the average distance between planes is 0.335 NM. Graphite are found in two forms, alpha (hexagonal) and beta (rhombohedra), which share a very similar physical properties. The hexagonal graphite form which can either be flat or distorted. The alpha form can be changed to the beta form through mechanical processing and the beta form regresses to the alpha form when it is subjected to heat above 1300 °C. “7”
Fullerenes are accepted as the fourth for of solid carbon after amorphous, graphite and diamond forms. Fullerene chemistry has provided a new dimension of aromatic and a new platform for discussion of mathematical techniques pertinent to large cages. They are basically, large carbon cage molecules. These fullerenes have attracted great interest a large number of physical and chemical properties. These properties of nanostructures strongly depend on this size, shape and chemical compositions. This property leads to very interesting and recent applications in medicinal chemistry, material science and nanotechnology. Functionalization, intercalation and doping by the addition of electron acceptors or donors are the way of modifying the properties of these nanostructures. Among these nanostructures carbon based nanomaterials such as nanotubes, nanocages, nanoshells,
Graphene is a two-dimensional matrix of carbon atoms, arranged in a honeycomb lattice structure. Graphene has incredible strength to weight ratio, according to (Graphene Composites: Introduction And Market Status | Graphene-Info, 2017), “a single square-meter sheet of graphene would weigh just 0.0077 grams but could easily sustain up to four kilograms”. Graphene has a variety of amazing qualities a few examples are, it has a large surface area and great electrical and heat conductivity. (Graphene Composites: Introduction And Market Status | Graphene-Info, 2017) also states that “scientists and researchers are calling graphene “a miracle material” and expect it to revolutionize just about every industry known to
As transistors get smaller and smaller, silicone transistors are shrinking rapidly to nearly atomic scale. As silicone transistors reach that size, it starts to become ineffective. Transistors has reached a saturation limit, where if made smaller electrons cannot be stopped from source to drain. Graphene now comes into the pictures. Graphene, is the hot topic that every physicists, material scientists, and electrical engineers have been talking about. Why did it garner such popularity in the scientific world, and deserve a Nobel Prize? One, out of many great future application of Graphene is further the shrinkage of transistors. Dominated in a world of silicone transistors, as it is being shrunk to near atomic sizes there emerges many limitations; one of which is the halt of further improvement in transistor speed. Graphene is composed of single carbon atoms bounded together to form a flat hexagonal plane, where one carbon is at each of the six corners. Multiple hexagonal shapes are connected together to form a plane. The “miraculous” physical aspect of this composition allows the e...
Expo 2020 in Dubai, is set to be a very impactful event that will bring minds together to find solutions to global issues. The miraculous multi-functional material graphene will surely be featured in this world fair and it will definitely play a huge role in the future of not only the UAE, but also the entire world.
A schematic configuration of the problem is illustrated in Figure 1. As can be seen in this figure, a double layer graphene sheet is covered by two ZnO piezoelectric layers. The thicknesses of graphene and piezoelectric layer are distinct and denoted by and , respectively. The interaction between graphene layers is modeled by Vdw force. The whole system surrounded by Pasternak foundation. Magnetic and electric field are applied to graphene and piezoelectric layers, respectively. Moreover, a biaxial force applied to the GSs. Before keeping on, it must be noted that the system shown in Figure 1 is divided into two systems. System 1 is considered upper piezoelectric and graphene layers, and system 2 is considered the lower ones.
The ultra-small thickness of graphene could significantly improve the pressure sensitivity of the FPI sensors. In addition, graphene has much better mechanical strength than other thin film materials including metal and silica and could bear a static pressure up to MPa.