Carbon Nanotubes : Methods Of Preparation And Applications

The use of nano-materials and extreme precision micro-engineering has the potential for great improvement in the world of electronics and information technology by providing smaller, faster, and more powerful computers and this has been at the forefront of the nanotechnology commercialization . Great examples of how nanotechnology is currently being used in these fields are products such as processors, data storage, and memory components made with nano-materials, TVs, monitors and even smartphone screens that use organic light-emitting diodes (OLED), and waterproof electronics such as smartphones due to the application of nano-coatings

Carbon has six total electrons; two of the electrons it has are in its first electron shell while the other four are its valence electrons. Due to its four valence electrons, it rarely gains and/or loses electrons and/or form ionic bonds due to the fact it would have to give away or take four other electrons. In order to complete its outer shell, carbons shares its valence electrons with other atoms by having four separate covalent bonds. The carbon atom then becomes the crossing point where each molecule branches off into four separate directions.Carbon’s electron configuration allows it to bond frequently with oxygen, hydrogen, nitrogen, and phosphorus. If the carbon atom forms only a single covalent bond, The electrons form so that its bonds angle towards an imaginary tetrahedron.

2a) Many characteristics allows carbon to be the base of biological molecules. Due to the four valance electrons carbon can bond with up to four other electrons in covalent bonds. This allows carbon to become the central point for many macromolecules. Carbon is also relatively small in size and is readily available on Earth. Carbon can also bin to other carbon atoms and can make single, double, or triple bonds. Due to this, long strings of carbon atoms can be created with seemingly no limit. The carbon-carbon bonds easily allow similar macromolecules with different functional groups. The shape of carbon-based macromolecules also easily vary. Shapes such as chains, rings, and branches are commonplace. With variance of shape, carbon can be the base for isomers; molecules with the same formula but different structures. Carbon is the only element on the periodic table that uniquely has all these characteristics.

Recent advances in carbon nanotechnology have led to the discovery that single-walled carbon nanotubes (SWNT) fluoresce from 900 to 1600 nm1 a region that is particularly transparent to biological tissue and media. Single-walled carbon nanotubes have a particular advantage as sensing elements due to the fact that all atoms are surface atoms causing the nanotube to be especially sensitive to surface adsorption events (Paul W. Barone, 2005).

The goal of nanotechnology is to make nanostructures or nano arrays with special properties, which do not exist in their bulk or single particle types. Oxide nanoparticles can present unique physical and chemical properties, because of their limited size and a high density in their corner or edge surface sites (Fernandez-Garcia & Rodriguez 2009; Bhattacharjee et al. 2011).

Some examples of compounds formed by carbon include diamonds which are pure carbon and are the hardest substance known to man with no known other material that can cut them. Graphite which is also a pure carbon-based molecule can be found in your pencil as lead. The oil in our cars is made of carbon, and the plastic of your keypad is carbon-based. Additionally, Carbon nanotubes which can self assemble and provide not only incredible strength, but also electrical, optical, thermal and kinetic properties like no other materials (The Biochemical Essense of Life: Carbon, n.d.). Another key feature of carbon is that its bonds are strong enough to resist environmental stresses, but weak enough to be manipulated by our bodies with enzymes which is a requirement of any organism’s metabolism (The Biochemical Essense of Life: Carbon, n.d.).

One of the things that carbon has the ability to do is to form strongly linked chains, Impure carbon can be in the form of charcoal, to help build fires to keep people warm or to cook things. Some important information that is key to know about carbon is, the abbreviation is C. The atomic number is 6, classification is non-metal. Atomic mass 12.0107. Carbon is in group 14 of the Periodic Table of Elements, it is is period 2 in the table. The element Carbon has 6 protons, neutrons, and electrons. Carbons density is 2.25 grams per cubic centimeter, with a boiling point of 4,287 degrees celsius, and has a melting point of about 3,500 degrees celsius. Carbon can survive in several different forms like graphite and diamond. Carbon is black and has an ash kind of look to

The three forms of carbon found freely in nature are the amorphous, graphite, and diamond, and each form has vastly different properties.

Carbon is the fourth most abundant element on Earth. It has many practical uses in a variety of different areas of science. Due to the wide variety of structures, which all have different properties, there are a variety of uses. Carbon is an element with the most allotropes, next to sulfur. The allotropes greatly differ in structure but are all widely used in modern production. Graphite, diamond and fullerenes are the three allotropes of carbon. Graphite has lubricating properties which makes it useful in pencils. The lubricating property exists due to the six membered rings existing in planes that can easily slide past one another. Graphite is the most thermodynamically stable allotrope at ordinary conditions. In

This involves setting up an arc between two graphite electrodes and using a stream of inert gas, such as Helium. (1) This causes the Carbon to form vapors, which then condenses into the C60 Fullerene as well as additional types of Fullerenes.

Carbon is the 15th most abundant element in the Earth’s crust and is the 4th most abundant element by mass in the universe. It is found in a large majority of organic material on Earth and its ability to bond in many different ways allows for a large diversity of organic compounds. These organic compounds that are formed in different shapes and structures are called allotropes. Carbon is a special element that is the base for almost all organic compounds and since it can form many allotropes of itself, and its allotropes have many different uses that can be applied to modern science. The most common allotropes of carbon are: diamonds, amorphous carbon, graphite, nanotubes, and fullerenes. Some of these allotropes have already made big

At the beginning of new millennium, we can see tremendous progress in developed & developing countries and noticeable advancement in use of technology in each and every sector. In this era, science & technology play a keen and vital role and also became a dominant key factor for development of a country. Therefore, countries are striving hard to diversify their economies through the development and adoption of advanced technologies like Nanotechnology.

Diamond-like carbon (DLC), exhibits a number of properties similar to diamond. DLC is a family of amorphous carbon materials, existing in seven different forms that contain sp2 and sp3 hybridised carbon atoms. Sp2 refers to the graphite bonding structure, whilst sp3 refers to a diamond bonding structure. Graphite and diamond have very similar structures, but the bonding type differentiates them. By altering the ratio of sp2 to sp3 bonding and hydrogen content, different mechanical properties in DLC films are observed. Figure 6.26 shows a phase diagram illustrating different DLC coating structures and their bonding type. More sp2 bonding gives rise to films of lower hardness and abrasion resistance, but improved tribological properties. Films containing a higher proportion of sp3 bonding and less hydrogen have a tetrahedral structure similar tantamount to diamond, exhibiting high surface toughness but reduced ductility.56 The relative proportion of the two bonding types is highly dependent on the deposition method and processing parameters.57 Values of Young’s modulus have above 900GPa have been obtained.58 Nuclear magnetic resolution (NMR) and electron energy loss spectroscopy (EELS) are common techniques to characterise the hybridization of DLC films.59

Quantum dots (QDs) also known as, semiconductor nanocrystals which are bright, photo stable flurophores that have a broad excitation spectrum but a narrow Gaussian emission at wavelengths controllable by the size of the material. It can be synthesized in many ways like Epitaxial growth modes such as Vander Merve, Volmer-Weber, and Stranski-Krastanow are layer by layer methods of synthesizing quantum dots on a crystal substrate. Newer methods used to produce colloidal quantum dots give better control of the size and shape formed during nucleation [1, 13] .The most basic characteristic shared by all quantum dots is that they quantumly confine electrons in three dimensions, thus making it behave like an artificial atom [10,19].

Thin flakes of TMDs can be peeled off from bulk materials using adhesive tape, applied to the substrates and then identified by light interference using similar techniques used to develop graphene. Fig 6c shows a thin monolayer flake peeled off from the bulk material (Fig 6a) mechanically with the tape. Oxide nanosheets as well as other materials can be obtained using this method. Using the mechanical method of exfoliation helps to produce flakes of high purity that can be used for fabrication of individual devices, however, the size and thickness of the flakes produced by this method cannot be controlled. In recent research, lasers have been used to control the thickness of MoS2 flakes by thermal ablation, this method however has a lot of challenges attached to it.