This presentation contains various aspects of Graphene like synthesis techniques, characterization, commercialization, mechanical and electrical properties and present and future application.

1. GRAPHENE
GRAPHENE
MSC PHYSICS
2017-2019

2. OUTLINE
• INTRODUCTION
• HISTORY
• STRUCTURE AND CHEMICAL PROPERTIES
• SYNTHESIS OF GRAPHENE BY VARIOUS METHODS
• CHARACTERIZATION OF GRAPHENE
• ENGINEERING PROPERTIES
• GRAPHENE- FROM LABORATORY TO COMMERCIALIZATION
• INDUSTRIAL APPLICATIONS
• CURRENT LIMITATIONS
• FUTURE SCOPE
• CONCLUSION

3. INTRODUCTION
• Described as a one- atom thick layer of graphite.
• Graphite itself consists of many graphene sheets stacked together.
• Basic structural element of other allotropes, including graphite, charcoal,
carbon nanotubes and fullerenes.

4. HISTORY
• The theory behind the substance GRAPHENE was first explored
by scientist PHILIP WALLACE in 1947.
• One of the first patents pertaining to the production of graphene
was filed by OCTOBER,2002 entitled ‘NANO- SCALED
GRAPHENE PLATES’.
• Two years later, in 2004 ANDRE GEIM and KOSTYA
NOVOSELOV at university of Manchester extracted single
atom- thick crystallites from bulk graphite.
• GEIM And NOVOSELOV received awards for their pioneering
research on graphene notably, ‘ 2010 NOBEL PRIZE IN
PHYSICS’.

6. STRUCTURE
• A 2D network of carbon atoms.
• By stacking of these layers on top of each
other, the well known 3D graphite crystal is
formed.
• It is 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..
• The carbon- carbon bond length in graphene
is approximately 0.142 nm.
• Strongest, thinnest material known to science
and conducts electricity better than any other
known substance.

8. CHEMICAL PROPERTIES
• Chemically the most reactive form of carbon.
• Only form of carbon in which each single atom is
exposure for chemical reaction from two sides.
• Carbon atoms at the edge of graphene sheets have
special chemical reactivity.
• Graphene burns at very low temperature (eg. 350
C)
• Graphene has the highest ratio of edgy carbon ( in
comparison with similar materials such as carbon
nanotubes).
• Graphene is commonly modified with oxygen-
and nitrogen- containing functional groups.

9. CVD(ChemicalVapourDeposition)
• Thecarrier gasesare combined in areaction chamberwhich is
maintained at certain temperature and pressure (as required by
reaction).
• Thereaction occurson the substrate on which one of the
product (carbon) is deposited and the by products are pumped
out.
• Substrate is usually atransition metal (Ni/Cu) orsome
ceramic suchasglass.
• Theselection of substrate depends upon the feasibilityof
transferring the graphene onto therequired material.

10. • The gases used are generally Methane (source of carbon) Hydrogen and
Argon are also used along with methane as reaction stabilizers and
enhancingthe filmuniformity.
• Although there are various types of CVDprocessesbutmost modern
processes(regarding CVDpressure)are asfollows:
->LPCVD(LowPressureCVD):Carried out under sub-atmospheric pressures.
Lowpressureprevents unwanted reactions and also increase the uniformity of
the films on the substrate.
->UHVCVD(Ultra HighVacuumCVD):Carried out under extremely low
atmospheric pressures(6-10Pa).
CVD(Chemical VapourDeposition)

11. CVD(Chemical VapourDeposition)
Fig2: CVDschematic diagram of theprocess.
Precision Fabricators Ltd Tutorial 2 - Chemical Vapour Deposition (© RiceUniversity)
1) Diffusion of reactants through boundarylayer.
2) Adsorption of reactants onto substratesurface.
3) Occurrenceof chemical reaction on thesurface.
4) Desorption of the by products from thesurface.
5) Diffusion of by products through boundarylayer.

12. Mechanical Exfoliation
Process:
• Afresh piece of Scotchtape istaken (about sixincheslong).
• Theadhesivesideispressedonto the HOPG(Highly Ordered Pyrolytic
Graphite) for about tenseconds.
• Thetape isgently peeled awaywith thick shinylayers ofgraphite attached to it.
• Thepart of the tape with layers from the HOPGwasrefolded upon aclean
adhesive sectionof the samepiece of the tape and then the tape isunfolded.
• Thisprocessisrepeated several times until the end of the tape is no longer shiny
but becomesdark/dull andgrey.
• Thesegraphite layers on the tape are transferred onto the surfaceof the
Si/SiO2wafers by gently pressingthem ontothe tape for sometime and then
peeling off.
• Thewafers are then examined usingvariouscharacterization techniques.

13. Mechanical Exfoliation
(a) Adhesivetape ispressedonto theHOPG.
(b) Thetape ispeeled off when somelayers stick tothe surface.
(c) Thistape ispressedonto the surfaceofthe target substrate.
(d) Thetape ispeeled off when the layersstickto the target surface.
Fig3: Schematic diagram for the mechanical exfoliation of graphene fromgraphite using Scotch tape.
KSNovoselov andAHCastroNeto 2012 Phys. Scr. 2012 014006, Two-dimensional crystals-based heterostructures: materials with tailored
properties.

14. • Themain concept behind the processisthat thevapour pressure of Siliconis
higher, asaresult on heating the SiCwafer, the Si evaporatesleaving behind the
graphenelayers on theSiC.
• Thetheoretical studies show the various stable structures of carbon that
grow on SiCwhich determines the mechanismfor growth of carbon layers
on SiCsubstrate.
• Theevaluation of number of graphenelayersis doneby
observingthe quantized oscillationsof the electron reflectivity.
• Multilayer, bilayer or singlelayer graphenecanbe grown onthe SiCsubstrate
by controlling various parameters suchasSiCtemperature andpressure.
• Graphenesinglecrystals canalsobe synthesized using this processsince
few layer graphene(FLG)alwaysmaintains it’s epitaxial growth with the
SiCsubstrate.
Epitaxial Growth of Graphene onSiC

15. Epitaxial Growth of Graphene onSiC
Fig4: Schematic illustration of the
thermal decomposition method.
Hiroki Hibino†, Hiroyuki Kageshima, and Masao
Nagase, “Graphene Growth on Silicon Carbide”,
NTTTechnical review.
• TheSiCsubstrate isheated at atemperature (around 1200°C)
and the conditions of the chamber are setaccordingly.
• UHV(Ultra HighVacuum)technique hinders the uniform growth of
MLG(Multi LayerGraphene)and favor thebilayer graphene.
• TheSiatoms evaporate due to thermionic emissionleaving
behind the carbon atoms on the remainingsubstrate.
• Thecarbon layersaccumulating on the substrate are controlled by
controlling the temperature andpressure.
• Thefinal SiCsubstrate iscoveredwith the carbon layers which can
be either bilayer, monolayer or multilayer graphene.
• Thetype isdistinguished by usingthe suitable characterization
techniques (suchasTEM),the shadeof the layer in the imagescanbe used
asthe classifying method for recognizingthe type ofgraphene.

16. • TheHummers method isusedfor producing grapheneby oxidising graphiteto GOby using
suitable oxidising agentssuchasKMnO4.
• TheGOsoproduced isagainthen chemically reduced to getgraphene.
• Themodified Hummers method introduces awayto get amore stableGOcolloidal
solution.
• Ultra-sonication isusedfor stabilizing the GOsolution and enhancingthe exfoliation in
the GOsolution.
Hummers Method (modified)
Fig5:Atypical illustration of the difference between the graphite and the GOsoformed.
Mateusz CISZEWSKI,Andrzej MIANOWSKI,“Survey of graphite oxidation methods using oxidizing mixtures in inorganic acids”, CHEMIKInternational Edition, CHEMIK
2013, 67, 4, 267-274

17. Themodified hummers method canbe carried out in three major stepsasfollows:
Oxidation
• Natural graphite flake ismixed with astrong acid suchasH2SO4/HNO3followedby
continuous stirring in icebath.
• ThenKMnO4isaddedandstirred at roomtemperature.
• Thenthe solution iskeptovernightafter addingDIwater andH2O2.
• Centrifugationisusedfor dilutionuntil the pHisaround7.
• Ultra-sonicationiscarriedout to get monolayer GO.
Reduction
• Additionof certain reducingagentssuchashydrazineor NaBH4ismade to the measured solution.
• Theattached functionalgroupsareremoved andto enhancethe exfoliation certain polar aprotic solvents canbe
usedalong withorganic compounds.
• Althoughthermal reduction givesabetter qualitygraphenebut hasits own disadvantages.
Post-treatment
• Thenthe solution isfiltered andwashedwith DIwater until neutrality.
• Theproduct isdried andgrinded.
• Thegraphenesoproduced canthen besendfor characterizationtests.
Hummers Method (modified)

18. Characterization of Graphene
• For the characterization of graphene, it is
important to know the number of layers, the purity
or presence of defects, structure, electronic
characteristics, etc.

19. CHARACTERIZATION
1.
MICROSCOPIC
2. OPTICAL
3. SPECTROSCOPIC
4. MECHANICAL
MEASUREMENT
5. THERMAL
EFFECTS
ANALYSIS
6. ELECTRICAL
PROPERTIES

20. METHODS DISCUSSED AHEAD:
MICROSCOPIC
• SEM,
STM
&TEM
• AFM
SPECTROSCOPIC
• RAMAN
• FTIR
• UV-VIS
• XRD
• XPS
• NMR
THERMAL
ANALYSIS
• THERMAL
CONDUCTIVITY
(RAMAN
SCATTERING)
• TGAAND
THERMAL
STABILITY

21. A. Microscopic Methods:
1. (i) SEM:
• In the SEM, a focused beam of high-energy
electrons are used instead of light to form an
image. This examination can yield
information about:
i. Topography (surface features of an object)
ii. Morphology (shape and size of the particles
making up the object)
iii. Composition (the elements and compounds
that the object is composed of and the
relative amounts of them)
iv. Crystallographic information (how the atoms
are arranged in the object).

22. (ii) STM:
• To reveal:
i. The number of
graphene layer
ii. The honeycomb
hexagonal structure of
graphene can be
visualized.

23. (iii) TEM:
• In transmission electron
microscopy (TEM), a beam
of electrons is transmitted
through an ultra-thin
specimen, interacting with
the specimen as it passes
through.
• TEMs are capable of
imaging at a significantly
higher resolution.
• Therefore, TEM forms a
major analysis method for
understanding the
morphology of material.

24. 2. AFM:
• AFM is capable of measuring nanoscale forces.
• Used to study the surface morphology, thickness,
uniformity of layer and domain growth of graphene.
• The measurement of graphene by AFM can be done
in three different modes:
i. The conventional AC Mode: This mode in
combination with TERS helps in determining the exact
number of stacked layers.
ii. Quantitative Imaging Mode: The advantage of this
mode is that it allows exact force control in both lateral
and vertical direction, thus enabling sensitive imaging of
loosely attached graphene flakes.
iii. Contact Mode or Conducting AFM (CAFM):
Helps in electrical measurement. CAFM mode, in
addition to topography data, also reveals the conductivity
distribution.

25. B. Thermal Effects and Thermal Effect
Analysis:
1. Thermal Conductivity:
• Thermal conductivity of
suspended pristine graphene is
measured by micro-Raman or
Raman scattering spectroscopy.
• Thermal conductivity of
graphene is much better than
most of the materials.
• This is one of the reasons that
graphene sheet is being
considered for use as a heat sink
in many electronic devices.

26. 2. TGAAND THERMAL STABILITY:
• TGA (thermo-gravimetric analysis)
can provide information about:
i. The thermal stability
ii. The ability of the reducing agent to
restore the crystal structure of the
graphene sheet, which may be altered
during the oxidation.
• TGA of graphite, graphene oxide and
reduced graphene is usually carried
out under N2 flow using thermo-
gravimetric analyzer equipment.

27. C. Spectroscopic Methods:
1. Raman Spectroscopic Analysis of
Graphene:
• Using Raman spectroscopy, we can
determine composition, crystallinity, lattice
strain, defects and crystal size.
• Apart from conventional Surface Enhanced
Raman Spectroscopy (SERS), in 2000 Tip
Enhanced Raman Spectroscopy (TERS)
was developed, which is similar to SERS
but has much better lateral resolution.
• Raman spectroscopy is a non-destructive
and quick characterization technique to
find out even the number of layers present
in the graphene sheet.
• Raman spectroscopy can provide
information such as whether the film is
graphitic or diamond-like, and how many
layers are present in the graphene film.

28. 2. FTIR Analysis of Graphene:
• It is used to identify the presence
of certain functional groups
present in a molecule.
• FTIR spectra of graphite does not
exhibit a significant peak
• Whereas the presence of different
types of oxygen functionalities in
graphene oxide can be confirmed.
• The FTIR peak of reduced
graphene exhibits the O-H
stretching vibrations.

29. 3. UV-Vis Spectroscopic Analysis of
Graphene:
• UV-Vis spectroscopy has been
very useful in characterizing the
graphene oxide (GO) and
reduced graphene.

30. 4. XRD Analysis of Graphene:
• When X-rays interact with a crystalline
substance, the result is a diffraction pattern.
• Hence, X-ray diffraction analysis is done to
know the structure of the pristine graphene.
• Graphene is an isolated atomic plane of
graphite. From this perspective, graphene
has been known since the invention of X-
ray crystallography.
• There are two major peaks exhibited in X-
ray diffraction analysis of graphene-related
materials.
• The shift of the diffraction peak of graphite
for GO means that the spacing between the
graphene layers has increased.

31. 5. XPS of Graphene:
• Used to analyze the surface chemical
composition, depth profile of the
composition and bonding.
• While studying the ability of graphene
films grown by chemical vapor deposition
to protect the surface of the metallic growth
substrates of Cu and Cu/Ni alloy from air
oxidation, have shown by XPS studies that
the metal surface is protected from
oxidation.
• Reduction of the oxygen content of the
graphene films; heating in ultra-high
vacuum was found to be particularly
effective.
• XPS spectra was key in assigning the
degree of reduction.

32. 6. NMR:
• NMR analysis is undertaken to
achieve structural information, e.g.,
sp2 and sp3 carbon information.
• Graphene oxide (GO) shows
amorphous and non-stoichiometric
nature. This property makes it
difficult to understand its actual
structure. In addition, GO does not
show the same level of oxidation.
• 13C NMR of functionalized GO
shows about 60% of the carbon
atoms are sp3 or aromatic carbons.
The remaining 40% are alkene
atoms (sp2-hybridized).

33. ENGINEERING PROPERTIES I

34. MECHANICAL PROPERTIES
• Strongest material-breaking strength(42 N/m )
• High young’s modulus (~1.100GPa)
• Density :0.77 mg/m2
• The thinnest material imaginable (~0.345nm thick)
• Stiffer than diamond
• Able to retain it initial size after strain ~(elasticity)
• Flexible ~ extend 20%of it original like

35. MAGNETIC PROPERTIES
• Graphene is non magnetic ,but magnetic properties can be observed by doping graphene
with either certain impurities or by creating defects in the structure by irradiating graphene
with electron or ions .
• This type of situation is developed in graphene due to presence of “pi ”bond.
• This behaviors cannot be observed with diamond structure because all its bond are”
sigma” bond and no “pi “bond.
• Magnetism of ad-atoms is itinerant and can be controlled by doping; so that the magnetic
moment are switched On &OFF.
• Spintronics : In magnetic material ,each micro magnet allows information (“0”or”1”) which
is store in two magnetization direction (north and south)
• This area of electronic is called spintronics.

36. FIELD EMISSION PROPERTIES
• Carbon material has work function in graphene in the range of 4-4.5ev; but due to
structure arrangement work function can be reduced .
• A cylindrical CNT possesses carbon at its circumference as well as on the sides of the tube .
• Carbon present at circumference of CNT possesses almost zero work function .
• The graphene film exhibits different field emission behaviors after selective ad
sorption different gases .N2 adsorbing “does not “alter the field emission properties
graphene.
• O2 and carbon dioxide (Co2) adsorption increases the turn on field reduce the field
emission current and also affects the field emission hysteresis
• Graphene gas adsorbate system can be used for cold cathode material application .

37. BANDGAP OF GRAPHENE
• Graphene can be made to behave like a semiconductor if the band gap is introduced.
• Monolayer and Bilayer graphene have zero band gap , therefore it behave like a metal.
• If some of sp2 carbon is converted to sp3 carbon then it is possible to introduce a trigonal
structure into hexagonal structure of graphene.
• All alternate carbon atoms are converted to sp3 carbon ,then its band gap increase around
2.5ev.
• Method by this conversion can be achieved –
1. By applying electric displacements to the two layers.
2. By hydrogenation of hydrogen atom
3. By classical doping with Nitrogen and Boron atoms

39. ENGINEERING PROPERTIES - II

40. Electronic Properties
• Graphene is known to have remarkable electronic properties due to a
massless chiral character of charge carriers and due to this it exhibits
an unusual metallic conductivity.
• Graphene has Highest electron/holes mobility (), Highest carrier
concentration (), Extremely good thermal conductivity (), and very
high Young’s Modulus ().
• These properties make Graphene a unique material for designing or
engineering electronic properties.

41. Engineering for use in Transistors
• In maIn electronic circuits components are
connected to each other by conducting
metal like copper.
• Printed circuits do get hot due to some
resistance created in metals.
• Hence scientist replaced the metal with
graphene so that it creates almost no
resistance and negligible heat.
• Most electronic circuits are fabricated over
some polymer, it is proposed to modify
polymer with graphene so the heat is
dissipated faster and hence prolonging the
life of an electronic circuit.

42. Engineering for use in Solar Cell
• For solar cell graphene can be used as either a metal
or a semiconductor based on how its engineered.
• For Graphene to be used in a solar cell as a
semiconductor we need one p-type and one n-type.
• But graphene has zero band gap it cannot be used to
make p-n diodes but due to its transparency it can be
used as protective surface.
• Also due to its good carrier mobility it can be used as
a collector of carriers in p-n junction diode
• Moreover its good thermal properties make them a
good base material for a p-n junction diode to
dissipate heat. Dye Sensitized Solar Cell

43. • Schottky Junction Solar Cell
Metal Schottky junction type solar cell needs one metal as current collector
and a good conductor material of high mobility of carrier and almost zero
band gap.
Graphene meets both of these requirements and hence it is used and hence
a Graphene/Si type Schottky junction has been developed.

44. Engineering for Applications In Patterning
Graphene
• Patterning in making complex PCB is becoming
common these days.
• Scientist are trying to explore if graphene sheet can be
used as a base material to write a PCB mostly due to its
properties of high conductivity, high mobility and it
being a good conductor.

45. Engineering for use in Supercapacitor
• A supercapacitor that stores energy is comprised of
porous electrodes, electrolytes and a medium
separating them.
• Magnitude of capacity generated by a superconductor
depends on the surface area, pore size and conductivity
of the medium.
• Graphene is considered for application as we can alter
its pore size and surface area by chemical treatment,
and conductivity can be improved by doping.
• Example. Taking surface area of graphene to be
2630m2/g we get its ideal attainable capacitance to be
200-500 F/g.

46. Engineering for Piezoelectric Properties
• When mechanical stress is applied to a
piezoelectric material it accumulates charge and
on removal of that stress it loses the charge.
• Graphene sheet has a Young’s Modulus of
1.1GPa which means it can withstand high
mechanical stress and since its electron mobility
is high it can be used to generate voltage of high
magnitude.
• The size of sheet can be reduced to be as
Graphene nanoribbon we can get a nanosized
piezoelectric graphene for various applications.

47. Engineering for use in Fuel Cell
• In developing a fuel cell operating with
oxygen an hydrogen one critical
requirement is to develop an electrode
for reduction of oxygen without using
expensive platinum.
• Nitrogen Doped Graphene can replace
the Platinum electrodes due to its
good electrolytic activity for oxygen
reduction.
• Moreover it can also be loaded with Fe
or Co to enhance the electrocatalytic
activity.

48. ENGINEERING STRUCTURAL
PROPERTIES
• Graphene has potential for many applications whether its alone
or combined with other materials.
• Once a few-layer Graphene synthesis was perfected, efforts
were soon directed towards altering the graphene structure for
the benefit of its application.
• Efforts included engineering in
1. Hybrid Structures
2. Hetero structures
3. Superstructures
4. Imperfections

49. 1.Engineering Hybrid Structures
• Making a hybrid or composite of
graphene offers significant
advantages, depending on the material
that has been used for hybridisation.
Eg.Graphene Hybridised with SnO2
Graphene has a high surface area for
excellent electronic conductivity and
high mechanical properties.
By increasing the spacing between
graphene layers and forming a composite
with SnO2 it can be used for direct Li-ion
storage.

50. Engineering Hetero Structures of Graphene
• Integration of Graphene and another material is done in
such a way that they do not form hybrid , but produce a
material where both the material exhibit and improvise
the desired properties of graphene.
• Because the monolayer of graphene is one atom in
thickness it can interact with other molecules
nanoparticles etc, thus forming graphene hetero
structures.
• When the substituted metals are used as a substrate, we
get alterations in graphene structure due to substrate-
induced distortion, adsorbate, atomic structure at the
edges , even atomic scale defects thus forming the hetero
structure of graphene.

51. • Hetero Structure using Silicon Dioxide(SnO2) as Substrate
SnO2 is an insulator and used as a support substrate for graphene sheet.
This hetero structure is used in electronic devices.
Study has revealed that in this device there is a break in

52. Engineering Super Structures of Graphene
• The Super structure of graphene is
mostly assessed by its moiré pattern
which is formed due to lattice
mismatch between graphene and
substrate.
• Superstructure is studied using X-ray
photo-electron spectroscopy, Raman
Spectroscopy,etc.
• It is used to fabricated a large scale,
high quality, single crystalline
graphene grown epitaxially on a
Substrate.

53. Introducing Imperfections in Graphene
• Graphene’s Strength is in its perfection.
• Imperfections in Graphene lessens its strength and it
becomes brittle.
• When multilayer of graphene is fabricated , Instead of
being flat sheet they grow in ripples.
• Defects in Graphene can be as small as missing atom from
the hexagonal lattice.
• Larger the sheet higher the probability of defects . But
imperfections also have certain advantages too.

54. • Imperfections to Improve Graphene Sensor
Though graphene makes very good chemical sensors, it
is said that sensor is better if graphene is worse.
Imperfection causing disruption to sp2 configuration of
graphene alters its mechanical, chemical and electric
properties.
• Engineering Single C atom Point Defects to Induce
Magnetism
Two type of defects are found to induce magnetism in
graphene 1.Hydrogen Chemisorption Defect and 2.
Vacancy Defect.
In both of them only one carbon atom is removed

55. APPLICATIONS OF GRAPHENE

56. There is no such thing as a special category of science called applied-science; there is Science and its Applications,
which are related to one another as the fruit is related to the tree that has borne it.
-Louis Pasteur
Major Fields of Application of Graphene
• Medical.
• Electronics.
• Energy Generation.
• Thermal Management.
• Other Applications.

57. Medical Applications
• Tissue Engineering :-
Graphene has been investigated for tissue
engineering. It has been used as a reinforcing agent to
improve the mechanical properties of biodegradable
polymeric nanocomposites for engineering bone
tissue applications.
• Constrast Agents :-
Iodine and manganese incorporating graphene
nanoparticles have served as multimodal MRI-
Computerized Tomography (CT-Scan) contrast
agents.

58. Medical Applications
• Polymerase chain reaction :-
Graphene is reported to have
enhanced PCR by increasing the yield
of DNA product.
Dox in the image is the drug ‘Doxorubicin’.

59. Application in Electronics
• Transistors :-
Graphene has a high carrier mobility, and low noise,
allowing it to be used as the channel (GATE) in a field-
effect transistor.
• Transparent conducting electrodes :-
Graphene's high electrical conductivity and high optical
transparency make it a candidate for transparent
conducting electrodes, required for such applications
as touch screens, liquid crystal displays, inorganic
photovoltaics cells, organic photovoltaic cells, and organic
light-emitting diodes (OLED).
• Hall effect sensors :-
Due to extremely high electron mobility, graphene may
be used for production of highly sensitive Hall effect
sensors. Potential application of such sensors is connected
with DC current transformers for special applications.

60. Application in electronics
• Quantum Dots :-
Graphene quantum dots (GQDs) keep all dimensions
less than 10 nm. Their size and
edge crystallography govern their electrical, magnetic,
optical, and chemical properties. GQDs with controlled
structure can be incorporated into applications in
electronics, optoelectronics and electromagnetics. Other
application of GQD are Bioimaging,Photovoltaic cells,
Light emitting diodes, Fuel Cells, Photocatalysis , etc.
• Organic electronics :-
A semiconducting polymer (poly(3-hexylthiophene))
placed on top of single-layer graphene vertically
conducts electric charge better than on a thin layer of
silicon.
• Conductive ink :-
Researchers used a printing process to deposit graphene
on paper. The ink was able to conduct electricity.
Applying pressure to the ink increased conductivity 50-
fold.

61. Application in Electronics
• Sensors:-
1. Biosensors :-
Graphene does not oxidize in air or in biological fluids,
making it an attractive material for use as a biosensor. It has
been used as a transducer in bio-field-effect transistors,
electrochemical biosensors, impedance biosensors,
electrochemiluminescence, and fluorescence biosensors,
etc.
2. Gas Sensors :-
Graphene has a large surface to volume ratio, large
surface area and it can be doped with various
cations/anions. These properties have made it possible to
use graphene as a gas sensor. Graphene can adsorb gas in
large quantity. The adsorbed gases change the concentration
of surface states, which in turn change the surface
resistance of graphene.

62. Applications in Electronics
3. Pressure Sensors:-
By applying stress on graphene it can develop potential, which
is a good property for its use as piezo-resistive material. This
means that when pressure is applied to graphene sheet, it
develops an electrical signal, which can be calibrated to
determine the amount of pressure applied. Graphene is also
impermeable to gases including helium; hence it is possible to
measure the gas pressure with the help of graphene sheet.
4. Chemi Sensors:-
Theoretically graphene makes an excellent sensor due to its 2D
structure. Gaseous molecules cannot be readily adsorbed onto
graphene surfaces, so intrinsically graphene is insensitive.The
sensitivity of graphene chemical gas sensors can be dramatically
enhanced by functionalization. The thin polymer layer acts like a
concentrator that absorbs gaseous molecules. The molecule
absorption introduces a local change in electrical resistance of
graphene sensors.

63. Application in
Energy Generation
Photovoltaic Cell
Image of a DSSC (Dye Sensitized Solar
Cell)

64. DSSC:-
When compared to other types of solar cells, DSSCs are different. They
comprise of a semi-conducting material (e.g. TiO2) with a photo-sensitive dye
as the anode coupled with an electrolyte solution and a pure metal cathode (e.g.
Platinum). Graphene has a number of favorable properties capable of
increasing the loading efficiency of the dye molecules, increasing the
interfacial area and enhancing the conductivity of the electrons in order to
compete against the effects of charge recombination. Balancing the ratio of
graphene and TiO2 is vital for achieving an efficient system.

65. Thermal Management Applications
• The thermal conducting property of graphene has
found applications at the nanoscale, microscale,
macroscale for HVAC (Heating, ventilation, and air
conditioning), giant computer servers, large area,
transparent heating elements, etc.
• The nanoflakes of graphene, due to their unique
physical and thermal properties, were investigated
(Rasheed et al. 2011) for their use in PCR
(polymerase chain reaction).
• Graphene was found to enhance the PCR by
increasing the yield of DNA by enhancing the thermal
conductivity of base fluids. The PCR yield was found
to be dependent on the size of nano graphene flakes.
Graphene plastic heat exchangers

66. Other applications
• High Surface Area Related Applications :
1. The possibility of applications of graphene that has
been envisaged due to its high surface area
includes it use as adsorbent material, for catalysts,
and so on.
2. A joint effort of Moscow State University and Rice
Lab of Chemists has developed microscopic, atom-
thick flakes of graphene oxide. These flakes are
water soluble and can be easily produced in bulk.
They have a remarkable ability to very quickly
bind to both natural as well as manmade
radioactive material from contaminated water and
condense them into clumps of solids.
The vial at left holds microscopic
particles of graphene oxide in a
solution. At right, graphene oxide
is added to simulated nuclear
waste, which quickly clumps for
easy removal.

67. Other Applications
• High Specific Strength Related Applications:
There are reports of carbon nanofibres (CNF)–impregnated polymer composites,
which are used in the production of lightweight and strong aircraft. However, one
application due to graphene’s high strength has reached the commercial arena, as the
YouTek™ SPEED tennis racquet series from HEAD is ready to make an appearance.

68. • Commercialization of a product and demand for the application of products are
interrelated.
• Though there is a need, opportunity and market for graphene and graphene-based
products, in the absence of scaled-up mass production of desired-quality graphene
(i.e., layers of graphene, band gap or electrical and optical properties), most
applications are only slowly coming out of the research labs.
• To meet both these aspects, there is a need for collaborative research towards the
development of large-scale graphene production for device integration.
Commercialization

69. To realize the commercialization of graphene one must know:
• What are the timelines and roadmaps for these applications?
• Will material capability translate into device performance?
• How much will the material cost, and to keep the price low, how much would be its
demand?
• Is production scalable?
• Is it economically viable?

70. Factors responsible for slow commercialization:
It was after 10 years since the Nobel Prize winners Andre Geim and
Konstantin Novoselov published the first of a series of seminal papers that triggered a
sharp rise in the level of graphene research efforts worldwide.
Challenges:
• Production volume.
• Cost.
• Storage and transport.
• Health and safety.
• Standardization.

71. Progress in Commercialization:
The size of the graphene market was estimated to be around US$12 million in
2013, indicating that so far we are still in a phase of research and development. It is
estimated that by 2020 it will grow upto US$280 million.
Progress towards the commercialization of graphene has been considerable,
especially in the past 10 years. The extraordinary growth in the number of
organizations developing graphene applications and in the number of patents filed,
may suggest an opportunity for a further acceleration of graphene commercialization.
The availability of material with the right volume, quality and cost to meet the
requirements of industrial applications will be key to rapid graphene
commercialization.
As technical knowledge, manufacturing methods and the development of
applications mature, key factors will affect the pace of commercialization of graphene.

72. • It is non-renewable and incredibly hard to isolate.
• Synthesis is an option, but not a sustainable one, since it consumes other
resources.
• It can’t act as a semiconductor since it cannot switch off its excited state.
• Sheet graphene is still very expensive to make. ($100 per gram)
• Environmental concerns.

73. FUTURE SCOPE OF GRAPHENE-RELATED
PRODUCTS

74. • Graphene Composites of Very High Mechanical Strength
• Graphene to Replace Flash Memory of SD Cards
• Next Generation Speakers
• Could enable a new generation unique laser technology.
• A graphene-infused nylon material for use in 3D printing is being envisaged by graphene
3D Lab, a US based company.
• Development of a graphene-based scanner.
• Super-insulator and fire retardant foam; by freezing a mixture of graphene oxide,
cellulose nanofibers and clay nanorods..
• The day is not far off when one can plug his phone and within five seconds the phone
will be charged.

75. • Similar graphene batteries, which are nontoxic, inexpensively produced and
charge superfast, can be used in electric cars and will charge as fast as filling
a car with gas.
• Ultra-thin thermal sensors for night-vision technology.
• Super-sensitive elastomer “skin” for robots.
• For water desalination. Could help in cleaning out radioactive waste like
Fukushima
• The graphene droplets change their structure at the presence of an external
magnetic field. This finding opens the door for potential use of carrying drug
in the graphene droplets and drug release upon reaching the targeted tissue
when the droplets change shape under the magnetic field.

77. Thank you for being such
great audience.