graphene

1. GRAPHENE
COURSE INSTRUCTOR
Dr.Venkata Girish Kotnur
University Of Hyderabad
PRESENTED BY
Mahfooz Alam
(17ETMM10)

2. Contents
History
Introduction of graphene
Properties
 Application
Characterization
Future scope
Conclusion

3. History
 In 2004 Andre Geim and Kostya Novoselov at
University of Manchester extracted single-atom-
thick crystallites from bulk graphite.
 Geim and Novoselov received several awards for
their pioneering research on graphene, notably the
2010 Nobel Prize in Physics.
Refs THE RISE OF GRAPHENE http://arxiv.org/ftp/condmat/papers/0702.pdf A.K Geimand K.S novoselov
University of Manchester,oxford Road M139PL,U.K
Andre Geim
Kostya Novoselov

4. Introduction
 Graphene is a one-atom-thick planar sheet of sp2
bonded carbon atoms that are densely packed in a
honeycomb crystal lattice.
 It is the basic structural element of other allotropes,
including graphite, carbon nanotubes and fullerenes.
 Graphene is the strongest, thinnest material known to
exist.
 The name ‘graphene' comes from graphite + - ene =
graphene
Graphene is a 2D crystal of carbon
atoms, arranged in a honeycomb lattice

5. Properties of graphene
 Electrical properties
High electron mobility (at room temperature ~ 200000 cm2/(V·s)
(Si at RT~ 1400 cm2/(V·s) ,carbon nanotube ~ 100.000 cm2/(V·s).
Resistivity of the graphene sheet ~106 Ω·cm,less than the resistivity of
silver (Ag).
Graphene Electrical conductivity~108 (s.m-1 ),which is greater than the
silver electrical conductivity(63×106) s.m-1

6. In graphene the gap is infinitesimal. This is the main reason why graphene’s electron can move easily
and very fast.
Electrons are able to flow through graphene more easily than through even copper.

7. 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.
 High young modulus (~1100 Gpa )
 High fracture strength (~125 Gpa)
 It is stretchable up to 20% of its initial length.

8. It is expected that graphene’s
mechanical properties will
find applications into making
a new generation of super
strong composite materials
and along combined with its
optical properties, making
flexible displays.
Ref. K.S. Novoselov, et al.Nature, 490 (2012)
p. 192

9. 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
fs Yousefzadi Nobakht, Ali; Shin, Seungha "Anisotropic control of thermal property of graphene.
urnal of Applied Physics. 120 (22): 225111. Bibcode:2016JAP...120v5111Y. doi:10.1063/1.4971873

10. The material's high electron
mobility and high thermal
conductivity could lead to
chips that are not only faster
but also better at dissipating
heat.
This schematic shows a three-
dimensional stacked chip with
layers of graphene acting as
heat spreaders.
Refs Touloukian, Y S. (1970). Thermophysical
Properties of Matter:
Thermal conductivity : nonmetallic solids

11. 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.
Photograph of graphene in transmitted light. This one-atom-
thick crystal can be seen with the naked eye.
Refs Kuzmenko, A. B.; Van Heumen, E.; Carbone, F.; Van Dyer Marel, D. (2008). "Universal
infrared conductance of graphite". Physical Review Letters. 100 (11): 117401.
arXiv:0712.0835 . Bibcode:2008PhRvL.100k7401K. doi:10.1103/PhysRevLett.

12. Chemical vapour deposition(CVD)
Mechanical exfoliation
Epitaxial Growth of Graphene on SiC
Chemical Methods such as hummers method
Electrochemical exfoliation
SYNTHESIS METHOD

13. 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.
Refs Pech, D. et al. Ultrahigh-power micrometre-sized supercapacitors based on onion-like
carbon. Nat. Nanotechnol.651–654 (2010
APPLICATIONS

14. Anti-Bacterial
• In 2010, the Chinese Academy
of Sciences has found that
sheets of graphene oxide are
highly effective at killing
bacteria .
• 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.
Cont……

15.  Graphene would work very well in optoelectronic applications:
touchscreens, liquid crystal displays, organic photovoltaic cells, and
organic light-emitting diodes
 Desalination: By very precise control over the size of the holes in the
graphene sheet,its used to removal of salt from the saline water.
 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.
 Graphene used in photoelectro chemical energy conversion in solar cells.
Cont…..

16. APPLICATION

17. Characterization Method

18. CHALLENGES TO UNLOCK
COST REDUCTION
HANDELING
GROWTH ON WAFER SCALE
CHALLENGES IN MAKING STRONGER
COMPOSITE MATERIAL
APPLICATION IN AIRCRAFT PARTS
LOW COST HIGH SENSITIVITY SENSORS
APPLICATION IN ELECTRICAL ENERGY
STORAGE

19. CONCLUSION
Graphene is a new hope for electronic devices and could replace silicon based devices
Successful prototype include superconductors ,flexible display and ultra capacitor.
It shall introduce new era of devices for electronics ,space ,bio-medical and energy harvesting.
Graphene devices might surround us very soon.

20. Its a Wonder material that could
revolutionize the world