Graphene-From Fundamentals to Applications

Usasi Chowdhury

Outline:

Introduction History of Graphene Structure of Graphene Fundamental Characteristics of Graphene

Synthesis of graphene Applications and Future Aspects

Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb structure.

First material among the class of two dimensional crystalline material

A rapidly rising star on the horizon of materials science and condensed matter physics

Makes experiments possible that give new twist to electronics field.

Introduction:

History of Graphene:

1916-2004

• The theory behind the substance graphene was first explored by theoretical physicist Philip Wallace in 1947.

• It was believed that physically graphene , cannot exist because of thermodynamic instability

2010 Nobel Prize

for “groundbreaking experiments

regarding the two-dimensional

material graphene”

(Both were later Knighted, twice)

In 2004,

Andre Geim Kostantin Novoselov

“

Structure of Graphene:

Basic Structure of Graphite

C-C Bond length is 0.142 nm. Interplanar spacing is of 0.335 nm. Graphite (layered material) formed by stacks of

graphene sheets separated by 0.3 nm and held together by weak vander Waals forces.

Each atom forming 3 bonds with each of its nearest neighbors, known as the sigma bonds.

Fourth valence electron is in the 2pz state oriented perpendicular to the sheet of graphite

Graphene: The motherElectronic Structure

of Graphene

Fundamental Characteristics of Graphene:

Mechanical Properties:Strongest material ~breaking strength (42 N/m) , high Young’s modulus(~1.100GPa)Density:0.77mg/m2

The thinnest material imaginable (~0.345 nm thick).Stiffer than diamondAble to retain its initial size after strain ~ ElasticityFlexible~ extend 20% of it’s original like.

Chemical Properties:Most reactive form of carbon

Electronic Properties:

Zero-overlap Semimetal with linear energy spectrumHigh electron mobility :15000-200000 cm2 /(V.sec)Resistivtity~ 10-6 Ω.cm, less than the resistivity of silverElectrical conductivity~108 S.m-1

Optical properties:

Monolayer transparent graphene absorbs 2.3% of white light

Thermal properties:

Thermodynamically most stable for size greater than 20nm and molecules larger than 24000 atoms.Thermal conductivity : (4.840-5.300)103 W/(mK)

S E M I m a g e o f G r a p h e n e S h e e t

Synthesis of Graphene

Exfoilation“Scotch tape”

Method

Dispersion of graphite

Grahite oxide exfoilation

Substrate preparation

Growth on Surfaces

Epitaxial Growth

Chemical vapour deposition

Biological Engineering:Targeted drug deliveryBone lubricantAntibacterial Graphene paper

ЖGraphene is used for water filteration

ЖGraphene membranes can be used for gas separation and desalination projects

Clean drinking water for millions

in developing countries

Membranes:

Sensors and energy:

1. Increase the longevity of lithium ion batteries2. Coating to improve current touch screens for phones and tablets3. High transparency of graphene : Increase in efficiency of solar cell4. Most effective super capacitors and organic organic LED.

Sheet of laser scribed graphene micro super capacitors

CNT alongwith graphene ribbon: flexible li-ion battery

Tony Stark’s Transparent phone

Heterostructures based on 2D atomic crystals for photovoltaic applications

Electronics:ᴥ Graphene chips; Graphene integrated circuits;

ᴥ Ideal support film for electron microscopy

ᴥ Folding TVs, tablets

Composite and coatings:

₰ Weatherproofing and packaging; Graphene for sport; By combining graphene with paint, a unique graphene coating is formed which could signal the end of the deterioration of ships and cars through rust.

₰ A graphene-based composite aircraft wing could drastically decrease weight, reduce the detrimental effects of lightning strike damage and increase fuel efficiency and range. This could result

₰ Graphene’s coating for protecting metals against corrosion: copper more resistant to corrosion - almost 100 times better than uncoated copper

₰ Graphene oxide can be used to create 'smart' food packaging products

World's lightest,

strongest, safest,

greenest plane

Head tennis racquet (Andy Murray, Maria Sharapova, Novak Djokovic and Gilles Simon)

Upcoming Devices:▪ Nokia G-Flex™, Morph™

▪ Samsung Galaxy Skin™

▪ Supercapacitor batteries▪ Water filter

Different research companies and multinational companes has invested billion of dollars on Graphene and related researchs .

EU has funded Nokia 1.3 billion Euro for Graphene based device construction