Presentation on graphene

1. Graphene
Presented By
Rocky Kashyap
M.Sc. 3rd semester
Department of Chemistry
Deen Dayal Upadhyaya Gorakhpur University

3. Content
 Discovery of Graphene
 Structure of Graphene
 Bonding
 Chemical Properties
 Mechanical Properties
 Electrical Properties
 Thermal and Optical Properties
 Applications of Graphene

4. Discovery of Graphene
 Graphene was explored theoretically
by P. R. Wallace in 1947.
 The term graphene was introduced in
1986 by chemists Hanns-Peter Boehm.
 It is a combination of the word
graphite and the suffix -ene, referring
to polycyclic aromatic hydrocarbons.
P. R. Wallace
Hanns-Peter Boehm

5. It was first produced and identified in
2004, by the group of Andre
Geim and Konstantin Novoselov.
They produced graphene by using a
sticky tape and graphite.
Geim and Novoselov received several awards
for their pioneering research on graphene. In
2010, they get Nobel Prize in Physics.
Andre Geim and Konstantin Novoselov.

6. Structure of Graphene
 Graphene can be described as a
one- atom thick layer of graphite.
 Graphene is an allotrope of
carbon consisting of a single layer
of atoms arranged in a two-
dimensional honeycomb lattice.
 Graphene is nothing but a single
graphite layer.

7. Bonding
 All carbon atoms are
sp2‐bonded to adjoining carbon
atoms.
 sp2 electrons form σ bonds and
they form the honeycomb net of
carbon atoms.

8.  A combination of orbitals s, px and py - that are shared
with the three nearest atoms, forming σ-bonds and pz
perpendicular to the plane.
 The length of these bonds is about 0.142 nanometers.

9. Chemical Properties
 Graphene is chemically the most reactive
form of carbon.
 Only form of carbon in which each single
atom is in exposure for chemical reaction
from two sides.
 graphene burns at very low temperature
(e.g., 350 °C).
 Graphene is commonly modified with
oxygen- and nitrogen- containing
functional groups.

10. Mechanical Properties
 Graphene is the strongest material ever
tested.
 It was found that graphene is harder than
diamond and about 300 times harder than
steel.
 The tensile strength of graphene exceeds
1 Tpa (150,000,000 psi).
 It is stretchable up to 25% of its initial
length.

11. Electrical Properties
 Graphene is a zero-gap semiconductor,
because its conduction and valence
bands meet at the Dirac points.
 It has excellent electrical conductivity.
Its high electron mobility is 100x faster
than silicon; its electrical conductivity is
13x better than copper.

12. Thermal and Optical Properties
 Graphene is only 1 atom thick still
visible to the naked eye.
 It absorbs 2.3% of light that passes
through it.
 Graphene is a perfect thermal
conductor.
 Its thermal conductivity is much higher
than all the other carbon structures like
graphite and diamond.

13. Applications of Graphene
Graphene Transistors
The main advantage of graphene-
based transistors is that they can be
operated easily at room temperature
and also have the capability to operate
at low voltage with high sensitivity.
These qualities make graphene-based
transistors better than silicon-based
transistors .

14. graphene transistors are extremely flexible and
foldable.
The movement of electrons through graphene is 100
to 1000 times faster than in silicon.

15. Graphene displays
 Graphene is a suitable material for
utilising in EED (electron emission
display) as it displays a high aspect
ratio.
 Graphene can turn on an electric field at
0.1 V/m.
 The graphene displays are now in the
market and used for the various
applications.

16. Graphene for lithium-sulfur (Lie-S)
battery
 Graphene offers higher electrical
conductivity than lithium-ion
batteries.
 This allows for faster-charging
cells that are able to deliver very
high currents as well.

17.  Graphene batteries are also lighter and slimmer than
today’s lithium-ion cells.
 Lithium-ion stores up to 180Wh of energy per kilogram
while graphene can store up to 1,000Wh per kilogram.

18. Water Filteration
 The UN reports that 3.5 million
people die each year as a direct result
of their inadequate water supply.
 Graphene sheets are able to let water
molecules pass but block the passage
of contaminants and substances.
 They able to remove impurities in one
step.

19. Why hasn’t graphene taken over the
world yet?
 At the moment, one gram of graphene is
estimated to cost around US$100.
 Currently it is very difficult to produce
graphene in large amounts that has no
defects or faults in its atomic structure.
 Research is still needed to understand
graphene better.
 Most of the miraculous applications require
relatively large sheets of graphene.

20.  Graphene has not taken over the world
because we haven’t found a way to make
large sheets of it yet.

21. References
 Supramolecular Chemistry by Jonathan W. Steed and Jerry L.
Atwood Second Edition
 Structure of graphene and its disorders: a review by Gao Yang,
Lihua Li, Wing Bun Lee & Man Cheung Ng
 Graphene research and their outputs: Status and prospect:[35]
Y. Qian, K. Liu, CW. Macosko, A. Stein
[42] R. Bogue.
The rise of graphene: Andre Geim and Novoselov .

22. Acknowledgement
I would like to special thanks of gratitude to my teachers
of Inorganic chemistry who gave me golden opportunity
to do this wonderful topic
Graphene, I came to know so many knew things.
I am really thankful to them.