GRAPHENE LIGHT BULB

IntroductionHistoryGRAPHENE : GRAPHITE+ENEStructureSalient features of GrapheneThermal PropertiesAnomalous Graphene WorkingApplicationsChallenges to UnlockDisadvantageReference

CONTENTS

INTRODUCTION

BULB: THE ILLUMINATION REVELUTION

October 21,1879 life of men changed with an innovation invention.At Melno Park,New Jersey Edison invented electric light bulb.From the day bulb has taken new forms.Graphene light bulb: Most modern product of technology.

‘Graphene’ was first isolated in the lab by Professor Andre Geim with former student Konstantin Novoselov at the University of Manchester, England in 2004

Konstantin Novoselow and Andre Geim were awarded the 2010 Nobel Prize for physics.

HISTORY

GRAPHENE : GRAPHITE+ENE

•British-Dutch physicist Andre Geim defines " graphene is a single atomic plane of graphite, which is sufficiently isolated from environment to be free standing ".•Graphene can be described as a one-atom thick layer of graphite.•It is the basic structural element of other allotropes, including graphite, charcoal, carbon nanotubes and fullerenes.

STRUCTURE• A crystalline allotrope of

carbon.• 2 Dimensional structure

in atomic scale.• These carbon atoms are

bound within the plane by strong bonds into a honeycomb array comprised of six-membered rings.

• By stacking of these layers on top of each other, the well known 3-dimensional graphite crystal is formed.

• It is a basic building block for graphitic materials of all other dimensionalities.

• It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D graphite.

• Thus, graphene is nothing else than a single graphite layer.

Graphene is a 2D crystal of carbon atoms, arranged in a honeycomb lattice

Each carbon atom is sp2 hybridized and it is bound to its three neighbors.

• Thinness material.• Strongest.• Electrically Conductive.• Flexible & Stretchable.• Transparent.

• Elastic.• Stiff.• Harder than diamond and steel

etc.

SALIENT FEATURES OF GRAPHENE

THERMAL PROPERTIES

• Graphene is a perfect thermal conductor• Its thermal conductivity is much higher than all the other

carbon structures as carbon nanotubes, graphite and diamond at room temperature and better by far than brilliant heat conductors such as silver and copper

• Graphite, the 3 D version of Graphene, shows a thermal conductivity about 5 times smaller

ANOMALOUS GRAPHENE

•At high temperatures graphene becomes a poor conductor "Umklapp scattering".•Temperatures confine to a hot spot at center.•Electron temperature is higher than of acoustic vibrational mode of graphene lattice, so less energy is needed to attain temperature for visible light emission.

•Single layer GRAPHENE is made as the filament of the bulb.

GRAPHENE LIGHT BULB

•GRAPHENE is attached to metal electrodes, current allowed to flow, filament heats up, at about 2500 degrees Celsius light of visible range is produced.

WORKING

•Graphene is freely suspended and is electrically biased.•A clean Graphene channel is established using current induced annealing method.•At high temperature (~2800 K) hot electrons get spacially localized at center of suspended Graphene.•The suspended Graphene channel begin to emit visible light at the center once the voltage exceeds threshold value.

BRIGHT VISIBLE LIGHT EMISSION OF GRAPHENE

ADVANTAGES OF GRAPHENE LIGHT BULB

oThinnest bulb.oBrightest bulb.oNo self heating.o20% more efficient than LED bulb.oLast around 25 years.oEasily recyclable.

Graphene as a light source.Advancements in touch

screens. Hand holding transparent future

tablet.Graphene transistor.Graphene integrated circuits.Organic light-emitting

diodes(OLED)s

APPLICATIONS

CHALLENGES TO UNLOCK

• Single sheet of graphene is hard to produce.

• Production of Graphene is highly costly.• The new fabrication & manufacturing

methods of Graphene has to be evolved used in electronic device .

DISADVANTAGE

•The main disadvantage of graphene as a catalyst is its susceptibility to oxidative environments.•Research has proven that graphene exhibits some toxic qualities.•Scientists discovered that graphene features jagged edges that can easily pierce cell membranes, allowing it to enter into the cell and disrupt normal functions.

“Bright visible light emission from graphene”, Nature Nanotechnology“Graphene photonics and optoelectronics", Nature Photonphys.orgWikipedia.org

Reference

Presented By: Jefry John

Sachu Sanil