Carbon Nano Tubes In Flexible Electronics

INTRODUCTION

      A new generation of computers and smartphones could run much faster if they were made from the world's thinnest substance, scientists have claimed.

The researchers found that electrons travel a lot more quickly in grapheme than they do in silicon; the substance current computer chips are made out of.

 And given the material's flexible properties, the commercial benefits would be truly groundbreaking - leading to phones and computers that could be rolled up like a pencil. Here in this seminar we discuss about the current advancements in the field of flexible electronics where carbon nano tubes play an important role. The report presents the basic concepts about a carbon nano tube, the flexible electronics field and hoe we can create miracles by clubbing carbon nano tubes and flexible electronics.

SELECTION OF THE TOPIC

    Electronics is not a field to be simply experimented and stydied. But the facts that we study and invent should reach the society with ease. Then only we can tell that electronics is a success. The most important thing to be done is to help the technology reach the common. For the common man to have access to these technologies we, the engineers should work on it and make electronics cheaper and useful. Nanotechnology actually makes systems smaller and thereby reduces cost on mass production. Carbon nano tubes along with flexible electronics make this a reality. The seminar gives some basic concepts of carbon nano tubes and some of its applications in flexible electronics.  

CARBON NANO TUBES AND ITS STRUCTURE

It is an allotrope of carbon which is cylindrical in shape with length to diameter ratio 132000000:1.it finds numerous applications in the fields of nanotechnology, optics, electronics; material science etc.It is of great importance due to its thermal, electrical and mechanical properties.

       A carbon nano tube a long, cylindrical, hollow tube with 1 atom thick wall of graphene sheet. Its rolled at specific discrete angles known as chiral.The properties of CNT is defined by its rolling angle and radius. The two types of CNTs are single walled and multi walled.

     Wrapping of graphene is represented by the vector (n, m) which is known as the chiral vector.

                               The integers n and m denote the number of unit along two directions in the honeycomb of graphene. If m = 0, the nanotubes are called zigzag nanotubes, and if n =m, the nanotubes are called armchair nanotubes. Otherwise, they are called chiral. The diameter of an ideal nanotube can be calculated from its (n, m) indices as follows

POTENTIAL APPLICATIONS

Because of the carbon nanotube's superior mechanical properties, many structures have been Nanotube-based transistors, also known as carbon nanotube field-effect transistors (CNFETs), have been made that operate at room temperature and that are capable of digital switching proposed.

A paper battery is a battery engineered to use a paper-thin sheet of cellulose (which is the major constituent of regular paper, among other things) infused with aligned carbon nanotubes. The nanotubes act as electrodes; allowing the storage devices to conduct electricity.

FLEXIBLE ELECTRONICS

Flexible electronics, also known as flex circuits, is a technology for assembling electronic circuits Flexible electronic assemblies may be manufactured using identical components used for rigid printed circuit boards, allowing the board to conform to a desired shape, or to flex during its use. These flexible printed circuits (FPC) are made with a photolithographic technology. by mounting electronic devices on flexible plastic substrates, such as polyimide.

• Tightly assembled electronic packages, where electrical connections are required in 3 axes (static application).
• Electrical connections where the assembly is required to flex during its normal use,(dynamic application).
• Electrical connections between sub-assemblies to replace wire harnesses, which are heavier and bulkier, such as in cars.
• Electrical connections where board thickness or space constraints are driving factors.

Flex circuits are often used as connectors in various applications where flexibility, space savings, or production constraints limit the serviceability of rigid circuit boards or hand wiring. In addition to cameras, a common application of flex circuits is in computer keyboard manufacturing; most keyboards made today use flex circuits for the switch matrix.

In LCD fabrication, glass is used as a substrate. If thin flexible plastic or metal foil is used as the substrate instead, the entire system can be flexible, as the film deposited on top of the substrate is usually very thin, on the order of a few micrometers.

Organic light-emitting diodes (OLEDs) are normally used instead of a back-light for flexible displays, making a flexible organic light-emitting diode display.

APPLICATIONS

INVISCIBLE ELECTRONICS WITH CNT

The emerging field of transparent and flexible electronics not only holds the promise of a new class of device components that would be more environmentally benign than current electronics; being able to print transparent circuits on low-cost and flexible plastic substrates also opens up the possibility of a wide range of new applications, ranging from windshield displays and flexible solar cells to clear toys and artificial skins and even sensor implants. Three broad application areas for this technology are taking shape:  

Transparent displays. These are of interest for applications such as heads-up displays on windshields and informational displays on eyeglasses or even contact lenses.  

Flexible displays. Emerging applications such as electronic paper require flexible electronics to be integrated within the pixel array of the display area. Reliable thin-film transistors (TFTs) on flexible substrates represent an important step toward the required circuitry  

Transparent/flexible electronics Flexible circuitry would allow integration on curved and non-rigid surfaces. Transparency would allow integration into multi-layer packaging, in a fashion such that product information could be seen beneath the electronics

Electron emitting source

The fabrication of a very efficient electron source using millimeter-long and highly crystalline carbon nanotubes. These devices start to emit electrons at fields as low as 0.17 V/μm and reach threshold emission at 0.24 V/μm. In addition, these electron sources are very stable and can achieve a peak current density of 750 mA cm–2 at only 0.45 V/μm. In order to demonstrate intense electron beam generation, these devices were used to produce visible light by cathode -luminescence.

SINGLE MOLECULE ELECTRONICS

Carbon nano tubes link at molecules.Link active materials with conductive nanowires.Chemical bonding in between is done by-chemical soldering.Links memory bit, transistors and molecular switches.

SPEEDY TRANSISTORS

Transistors that incorporate what is best described as a tangle of material – pick-up stick jumbles of semiconducting carbon nanotubes.

 Despite their tangled nature, nanotube networks are actually quite good at transporting electrons from tube to tube across a channel. The behaviour has already been used to make simple devices.ansistors, which contain channels made with carbon nanotube ink.

MERCURY SENSOR

SW CNT is used instead of  a copper wire.CNT is connected to gold film electrode.During compression and relaxation current flows through cnt .C connected gathers output.Led indicates presence of  mercury.

SOLAR POWER GENERATION

The researchers fabricated, tested and measured a simple solar cell called a photodiode, formed from an individual carbon nanotu device converts light to electricity in an extremely efficient process that multiplies the amount of electrical current that flows. This process could prove important for next-generation high efficiency solar cells, the researchers say.CNT based photodiode are used for energy production. Light is made to fall on the device. On excitation EHPs are formed. This creates electric current.

CNT CUPCAKES 

Measure terahertz laser.Vertically aligned CNT arrays on Si are fabricated.Placed on top of laser power detector. They measure the power.

SUPER CAPACITORS

Super capacitors are electrical storage devices that can deliver a huge amount of energy in a short time.

Electrodes of electrochemical energy storage devices due to their superb characteristics: chemical stability, low mass density, low resistivity, and large surface area. Recent developments in massive synthesis of carbon nanotubes have accelerated a new application of these materials in the area of electrical energy storage systems.

ADVANTAGES OF USING CNT IN FLEXIBLE ELECTRONICS

• Reduces dimensions

• Transparency

• Cheap stretchable displays

• Fast electronics

CONCLUSION

With wide applications cnt can make electronics more advanced. With cheaper ways common people can access new technologies. IT Makes electronics more friendly. Thus we can make electronics much more social. Carbon nano tubes along with flexible electronics can make this possible to certain extend. And thus technology can be made accessible.