PRESENTATION OUTLINE Introduction,History of Nanotechnology,What is Nanotechnology, Definition of Nano,History of Graphene,Graphene,Why Nanotechnology,Size of Nanotechnology,What is Graphene, Properties of Graphene,Graphene Structure,Types of Graphene ,Synthesize Graphene,Applications,Conclusions,References

1. NEAR EAST UNIVERSITY
NAME: ISMAIL HUSSAIN ALSARHI
STUDENT NUMBER: 20175487
SUPERVISED BY: Asst. Prof. Dr. AYDIN HASSANI
FACULTY OF ENGINEERING
DEPARTMENT OF MATERIALS SCIENCES AND NANOTECHNOLOGY ENGINEERING
MSN208:
NANOMATERIALS
Graphene

2. PRESENTATION OUTLINE
Introduction
History of
Nanotechnology
What is
Nanotechnology
Definition of
Nano
Size of
Nanotechnology
Why
Nanotechnology
Graphene
History of
Graphene
What is
Graphene
Properties of
Graphene
Graphene
Structure
Types of
Graphene
Synthesize
Graphene
Applications Conclusions
References

3. Introduction
• 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.
• Graphene is the strongest, thinnest material known to exist.

5. History of Nanotechnology
The first ever concept was presented in 1959 by
the famous professor of physics Dr. Richard P.
Feynman.
1959
Invention of the scanning tunneling microscope in
1981 and the discovery of fullerene(C60) in 1985
lead to the emergence of nanotechnology.
1981
The early 2000s also saw the beginnings of
commercial applications of nanotechnology,
although these were limited to bulk application
of nanomaterials.
2000s

6. What is Nanotechnology
• A Nano meter is a unit of length in the metric system, equal to one billionth
of a meter (10−9
).
• Technology is the making, usage, and knowledge of tools, machines and
techniques, in order to solve a problem or perform a specific function.

7. Definition
of Nano
• Nano scale: Includes dimensions of
nanometers in length and one up to the 100-
nm.
• Nano science: is the study of the properties
of molecules and compounds that do not
exceed their standards of 100 nm.
• Nanotechnology: is the application of these
sciences and engineered to produce useful
inventions.
• Nano science and nanotechnology one of the
areas of materials science.

8. Size of Nanotechnology
• It’s hard to imagine just how small nanotechnology is. One nanometer is a
billionth of a meter, or 10-9 of a meter.

9. Why Nanotechnology
• At the nanoscale, the physical, chemical, and biological properties of
differing materials in fundamental and valuable ways from the properties of
individual atoms and molecules or bulk matter.
• Nanotechnology R&D is directed toward understanding and creating
improved materials, devices, and systems that exploit these new properties.

11. Graphene
• Graphene physically acts as a 2-Dimensional material.
• This leads to many properties that are electrially beneficial, such as high
electron mobility and lowered power usage.
• Graphene is currently in its infant stages and is undergoing many
applications and studies.

12. History of Graphene
It was discovered at Manchester University
by Russian born scientists ANDRE GEIM
and KOSTYA NOVOSELOV in 2004.
They won Nobel prize in 2010 for their
discovery.

13. What is Graphene
2-dimensional, crystalline allotrope of carbon
Allotrope: property of chemical elements to exist in two or more forms
Single layer of graphite
Honeycomb (hexagonal) lattice

14. Properties
of
Graphene
Chemical
Properties
Electronic
Properties
Mechanical
Properties
Thermal
Properties
Optical
Properties

15. Properties of Graphene
• It is thinnest material imaginable( 0.345 nm thick.)
• It is the strongest material measured. 200x stronger than steel and Stiffer
than diamond
• It is electrically conductive-best known so far.
• 1,000,000x more conductive than copper.
• It conducts heat even better than diamond.
• It is flexible :The first elastic 2D crystal.

16. Chemical Properties
Graphene is chemically the most reactive form of carbon.
Only form of carbon (and generally all solid materials) in which each single atom is in exposure for chemical reaction
from two sides (due to the 2D structure).
Carbon atoms at the edge of graphene sheets have special chemical reactivity.
Graphene burns at very low temperature (e.g., 350 °C).
Graphene has the highest ratio of edgy carbons (in comparison with similar materials such as carbon nanotubes).
Graphene is commonly modified with oxygen- and nitrogen- containing functional groups.

17. Electronic Properties
• It is a zero-overlap semimetal (with both holes and electrons as charge
carriers) with very high electrical conductivity.
• Electrons are able to flow through graphene more easily than through even
copper.
• The electrons travel through the graphene sheet as if they carry no mass, as
fast as just one hundredth that of the speed of light.
• High charge carrier mobility, for which values of 10,000 cm2/Vs, in some
cases even 200,000 cm?/Vs were reported.

18. Mechanical Properties
To calculate the strength
of graphene, scientists
used a technique called
Atomic Force Microscopy.
It was found that graphene
is harder than diamond
and about 300 times
harder than steel.
The tensile strength of
graphene exceeds 1 TPa.
It is stretchable up to 20%
of its initial length.

19. 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 (> 5000 W/m/K) at room
temperature.
• Graphite, the 3 D version of graphene, shows a thermal conductivity about 5
times smaller (1000 W/m/K).
• The ballistic thermal conductance of graphene is isotropic, i.e. same in all
directions.

20. Optical Properties
• Graphene, despite it is only 1 atom thick, is still visible to the naked eye.
• Due to its unique electronic properties, it absorbs a high 2.3% of light that
passes through it.

21. Graphene Structure
• Graphene is a crystalline allotrope
of carbon with 2-dimensional
properties. Its carbon atoms are
densely packed in a regular atomic
scale chicken wire (hexagonal)
pattern.
• Each atom has four bonds, one σ
bond with each of its three
neighbors and one π-bond that is
oriented out of plane. The atoms
are about 1.42 Å apart.

22. Types of Graphene
• There are many types of graphene. True Graphene is only one atomic layer
thick (often called a monolayer) and it typically exists as a film but it can be
floated off the substrate and can be redeposited onto another substrate or
used in it’s isolated form.

23. Graphene
Oxide (GO)The multiple functional groups provide an enhanced layer
separation and improved hydrophilicity. The hydrophilicity
allows the graphene oxide to undergo ultrasonic irradiation,
which produces a single/a few graphene layers that are
highly stable when dispersed in DI Water and other
solvents.
Is most commonly produced by the oxidation of graphite
oxide. The oxidation process is beneficial, as it
functionalizes the surface of the graphene layers with
multiple species of oxygenated functional groups.

24. Graphene Oxide (con)…
GO has many desirable properties. It disperses very easily in various
mediums including aqueous solvents, organic solvents and various
matrices.
The presence of both electron rich oxygen species and an electron
rich graphene backbone allow for further surface functionalization,
which gives rise to an adaptable material for multiple applications.
Graphene oxide does however suffer from a low electrical
conductivity and is an electrical insulator. Graphene oxide is also
soluble in many solvents, both aqueous and organic.

25. Graphene
and
Graphene
Oxide
Quantum
Dots
(GQDs)
Graphene and graphene oxide quantum
dots (GQDs) can be synthesized into
various forms, from single-layer to tens of
layers, but are generally less than 30 nm.
GQDs also show similar properties to other
types of quantum dots.
Like many graphene-based materials, GQDs
exhibit a large surface area, a good linear
dispersibility and a high charge carrier
mobility. GQDs also exhibit an efficient
hole transporting ability, making them
efficient materials for hole-transport layers.

26. Graphene and Graphene Oxide Quantum
Dots (GQDs) (con)…
• They are useful materials for both electronic and opto-electronic
applications.
• GQDs can now be produced by a multitude of methods which includes both
top-down and bottom-up approaches. Production by bottom-up methods
can produce GQDs with a controlled size (due to the ability to control the
band gap), but the synthesis itself can be complex which requires stringent
conditions.

27. Graphene
Nanoribbons
(GNRs)The electrical properties that GNRs exhibit
are highly tunable and can be manipulated by
dimension confinement, edge morphology
and functionalization of the GNR.
Unlike many other forms of graphene which
are two-dimensional, graphene nanoribbons
(GNRs) are quasi-one-dimensional materials
with an ultra-thin width.

28. Graphene
Nanoribbons
(GNRs)
(con)…
GNRs are produced by various methods.
One of the most common methods
involves unzipping the walls of MWCNTs
with sodium and potassium-based
compounds, sonicating and drying under
vacuum.
GNRs are produced by various methods.
One of the most common methods
involves unzipping the walls of MWCNTs
with sodium and potassium-based
compounds, sonicating and drying under
vacuum.

29. Synthesize
Graphene
There are 3 main ways to
synthesize graphene, they are:
Chemical Vapor Deposition
Mechanical Exfoliation
Mechanical cleavage from
natural Graphite

30. Chemical Vapor Deposition
• A way of depositing gaseous reactants on a substrate.
• The carrier gases are combined in a reaction chamber which is maintained at
certain temperature and pressure (as required by reaction).
• The reaction occurs on the substrate on which one of the product (carbon)
is deposited and the by products are pumped out.
• Substrate is usually a transition metal (Ni/Cu) or some ceramic such as glass.

31. Chemical Vapor Deposition (con)…
• The selection of substrate depends upon the feasibility of transferring the
graphene onto the required material.
• The gases used are generally Methane (source of carbon) Hydrogen and
Argon are also used along with methane as reaction stabilizers and enhancing
the film uniformity.

33. Chemical
Vapor
Deposition
(con)…
ADVANTAGES :
High quality,
impervious, and
harder graphene is
obtained.
Producing large
domains of graphene
is easy.
High growth rates
possible.
Good reproducibility.

34. Mechanical
Exfoliation
A fresh piece of Scotch tape is taken (about six
inches long).
The adhesive side is pressed onto the HOPG
(Highly Ordered Pyrolytic Graphite) for about ten
seconds.
The tape is gently peeled away with thick shiny layers
of graphite attached to it.
The part of the tape with layers from the HOPG
was refolded upon a clean adhesive section of the
same piece of the tape and then the tape is unfolded.

35. Mechanical
Exfoliation
(con)…
• This process is repeated several times until the
end of the tape is no longer shiny but
becomes dark/dull and grey.
• These graphite layers on the tape are
transferred onto the surface of the Si/SiO2
wafers by gently pressing them onto the tape
for some time and then peeling off.
• The wafers are then examined using various
characterization techniques.

37. Mechanical Exfoliation (con)…
Advantages:
Safe and simple process.
Few layer graphene can be easily obtained.
The chances of impurity in the graphene so obtained are less.
Sample preparation is simplified.

38. Hummers
Method
The Hummers method is used for producing
graphene by oxidising graphite to GO by using
suitable oxidising agents such as KMnO4.
The GO so produced is again then chemically
reduced to get graphene.
The modified Hummers method introduces a
way to get a more stable GO colloidal solution.
Ultra-sonication is used for stabilizing the GO
solution and enhancing the exfoliation in the
GO solution.

40. Hummers Method
(con)…
Advantages:
High yield.
Scalable to industrial level.

41. Graphene
Aerogels
• Carbon aerogels are derived by sol-gel
synthesis methods and are a unique class of
high-surface-area materials. Their high mass-
specific surface area, electrical conductivity,
environmental compatibility, and chemical
inertness make them very promising materials
for many energy related applications.
• Recent developments in controlling their
morphology make them especially well suited
to super capacitor applications.

42. Graphene Aerogels (con)…
Aerogels are a special class of open-cell
foams that exhibit many unique and
interesting properties, such as low mass
density, continuous porosity and high
surface areas. These properties are
derived from the aerogel microstructure,
which consists of three-dimensional
networks of interconnected nanometer-
sized particles.
Aerogels are typically prepared by sol–gel
methods, a process that transforms
molecular precursors into highly cross-
linked inorganic or organic gels that can
then be dried using techniques such as
supercritical drying, freeze drying, ect to
preserve the insubstantial solid network.

43. Graphene Masterbatches
Graphene masterbatches are composite materials that contain a graphene-based
compound (most commonly GO) and a polymer.
The graphene is used to enhance the properties of various common polymeric materials.
Many polymers exhibit desirable properties such as low cost, low toxicity, bio-
compatibility and chemical resistance, but they lack desirable mechanical properties.

44. Graphene Masterbatches (con)…
• By incorporating graphene nanoplatelets into polymer matrices, the polymers
retain their original properties but benefit from enhanced rigidity and
stiffness, while still being lightweight.
• Using graphene as a filler compound rather than conventional inorganic
materials can bring an enhanced electrical conductivity to the polymer, but it
does have some issues.
• In many graphene-based composites, graphene oxide acts as the dispersing
support for other ions and molecules.

45. Applications
• While as of 2014, graphene is not used in commercial applications, many
have been proposed and/or are under active development, in areas including
electronics, biological engineering, filtration, lightweight/strong composite
materials, photovoltaics and energy storage.

46. Biomedical
• Graphene could soon be used to analyze DNA at a record-
breaking pace.
• That's the claim of a physicist in the US who has proposed a new
way of reading the sequence of chemical bases in a DNA strand
by sending the molecule through a tiny slit in a graphene shéet.

47. Integrated Circuits
• Graphene has a high carrier mobility, as well as low noise, allowing it to be
used the channel in a field-effect as transistor.
• Processors using 100 GHz transistors on 2-inch (51 mm) graphene sheets.
• Graphene-based handled frequencies up to 10 GHz.
• Integrated circuit Transistors printed on flexible plastic that operate at 25
gigahertz Terahertz-speed transistor.

48. Optical Electronics
• Graphene's high electrical conductivity and high optical transparency make it
a candidate for transparent conducting electrodes.
• Graphene's mechanical strength and flexibility are advantageous compared to
indium tin oxide, which is brittle.
• So it would work very well in optoelectronic touchscreens, liquid crystal
displays, organic photovoltaic cells, and organic light-emitting diodes.
• applications:

49. Filters
• Desalination: By very precise control over the size of the holes in the
graphene sheet, graphene oxide filters could outperform other techniques of
desalination by a significant margin.
• Ethanol distillation: Graphene oxide membranes allow water vapor to pass
through, but are impermeable to other liquids and gases.
• Such membranes could revolutionize the economics of biofuel production
and the alcoholic beverage industry.

50. Solar cells
• Graphene turned to be a promising material for photoelectrochemical energy
conversion in dye sensitized solar cells.
• The transparent, conductive, and ultrathin graphene films are fabricated from
exfoliated graphite oxide, followed by thermal reduction.
• The obtained films exhibit a high conductivity and a transparency of more
than 70% over 1000-3000 nm.

51. Energy Storage Devices
• Due to the extremely high surface area to mass ratio of graphene, one
potential application is in the conductive plates of Supercapacitors.
• It is believed that graphene could be used to produce Supercapacitors with a
greater energy storage density than is currently available.

52. Anti Bacterial
• In 2010, the Chinese Academy of Sciences has found that sheets of
graphene oxide are highly effective at killing bacteria such as Escherichia coli.
• This means graphene could be useful in applications such as hygiene
products or packaging that will help keep food fresh for longer periods of
time.

53. Conclusions
• In conclusions graphene as newly born material, has great potential in
various fields. The usage of Graphene in coming years, will give tremendous
difference to current technologies. Like any other newly rose phenomenon in
the world , Graphene has its own downsides and dark side, but the advantage
s are far greater than what this burred points could affect them.

54. References
• Huang X., Xiaoying Q., Boey F. and Zhang H., Graphene based composites, Chem Soc. Rev.,
2012, 41, 666-686
• Zhou G., Yin L., Wang D. and Cheng H., A fibrous hybrid of graphene and sulfur nanocrystals
for high performance lithium-sulfur batteries, ACS Nano, 2013, 7(6)
• Cheng Q., Tang J., Zhang H., Graphene and carbon nanotube composite electrodes for
supercapacitors with ultra-high energy density, Phys. Chem. Chem. Phys., 2011, 13, 17615-17624
• Peng Z., Xiang C., Yan Z., Natelson D., Graphene Nanoribbon and Nanostructured SnO2
Composite Anodes for Lithium Ion Batteries, ACS Nano, 2013, 7(7)
• Haegyeom K., Dong-Hwa S., Sung Wook None K., Kisuk K., Highly reversible
Co3O4/graphene hybrid anode for lithium rechargeable batteries, Carbon, 2011, 49(1), 326-332

55. References (con)…
• Bak S., Kim D., Lee H., Graphene quantum dots and their possible energy applications: A review,
Current Applied Phyics, 2016, 11, 1192-1201.
• Liu Y., Dobrinksy A., Yakobson B. I., Graphene edge from armchair to zigzag: The origins of
nanotube chirality, Phys. Rev. Lett., 2010, 105, 235502.
• Begliarbekov M., Sasaki K., Sul O., Yang E., Strauf S., Nano Lett., 2011, 11(11), 4874-4878
• Pop E., Varshney V., Roy A., Thermal properties of graphene: Fundamentals and applications,
MRS bulletin, 2012, 37, 1273-1281.
• Lei W., Li C., Cole M., Qu K., Ding S., Zhang Y., Warner J., Zhang X., Wang B., Milne W., A
graphene -based large area surface-conduction electron emission display, Carbon, 2013, 56, 255-
263.