Graphene is a single layer of carbon atoms arranged in a hexagonal lattice. It has many unique properties making it promising for electronics applications. Some key properties include high electron mobility, flexibility, strength and thermal conductivity. Current prototypes using graphene include transistors, solar cells, sensors, memory and transparent displays. Graphene transistors have been developed but achieving a bandgap remains a challenge. Non-volatile memory devices have been made using layered structures of reduced graphene oxide as the electrodes and active material.
As each era is defined by the material's age like STONE AGRE,BRONZE AGE etc,soon this very era is going to be regarded as GRAPHENE era because of its extraordinary properties.If it comes to the world in an easy production manner,each and every thing on this earth will have the best priority of its costruction as GRAPHENE. You will surely wanna be a GRAPHENE after reading the full article. [full work on by ISHAAN SANEHI]
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
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene Presentation
As each era is defined by the material's age like STONE AGRE,BRONZE AGE etc,soon this very era is going to be regarded as GRAPHENE era because of its extraordinary properties.If it comes to the world in an easy production manner,each and every thing on this earth will have the best priority of its costruction as GRAPHENE. You will surely wanna be a GRAPHENE after reading the full article. [full work on by ISHAAN SANEHI]
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
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Graphene Presentation
GRAPHENE SYNTHESIS AND ITS APPLICATIONS TERM PAPER PRESENTATIONAman Gupta
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Graphene synthesis process and its current and future applications explained in brief
Graphene_complete description_Introduction_history_synthesis_electrical appliactions other other miscellineus applcations,challeneges explained with full of animated diagrams.
If you need in PPT file with full of beautiful animations and transitions for FREE, then just email me on this adress:
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GRAPHENE: THE MIRACLE MATERIAL, SYNTHESIS AND APPLICATION RESEARCH PAPER PRES...Aman Gupta
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Graphene synthesis and applications:
ABSTRACT: Graphene, a two-dimensional, single-layer sheet of sp2 hybridized carbon atoms, has attracted tremendous attention, owing to its exceptional physical and chemical properties such as thermal stability, and mechanical strength, transparency, selective permeability, light weight, flexible, thin, biodegradable. Other forms of Graphene-related materials, like Graphene oxide, reduced Graphene oxide, and exfoliated graphite, have been produced on large scale. The promising properties together with the ease of processibility and functionalization make graphene based materials ideal candidates for incorporation with various functional materials. Importantly, graphene and its derivatives have been used in a wide range of applications, such as electronic, solar and photonic devices, clean energy, sensors, 3D-printing, super capacitors. Its future applications include water filtration, prosthetic organs, and flexible screens. In this paper, after a general introduction to Graphene and its derivatives, the characteristics, properties, and applications of Graphene based materials are discussed. Graphene synthesis being an important affair is also studied in this paper, methods like CVD, ion implation, arc discharge and many more are discussed. In this paper I have worked upon, different properties of graphene to make better and reliable electronics, improving future technology for completing the ultimate goal of increasing standards of human race.
WATCH THE VIDEO VERSION!
http://www.youtube.com/watch?v=Q_eTLPKdrHs&feature=relmfu
dailyreckoning.com
The 'wonder material' known as graphene can revolutionize technology of the world.
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Graphene: its increasing economic feasibility Jeffrey Funk
These slides use concepts from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze how Graphene is becoming economic feasible for an increasing number of applications as its price falls and its quality/performance rises through improvements in chemical vapor deposition processes. Graphene is one of the strongest materials discovered, has high electronic and thermal conductivities, and unusual optical properties. These slides describe a number of applications for which Graphene is gradually becoming economically feasible including displays, integrated circuits, solar cells, water desalination, and natural gas tanks.
GRAPHENE SYNTHESIS AND ITS APPLICATIONS TERM PAPER PRESENTATIONAman Gupta
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene synthesis process and its current and future applications explained in brief
Graphene_complete description_Introduction_history_synthesis_electrical appliactions other other miscellineus applcations,challeneges explained with full of animated diagrams.
If you need in PPT file with full of beautiful animations and transitions for FREE, then just email me on this adress:
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ENJOY ...!!!
GRAPHENE: THE MIRACLE MATERIAL, SYNTHESIS AND APPLICATION RESEARCH PAPER PRES...Aman Gupta
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene synthesis and applications:
ABSTRACT: Graphene, a two-dimensional, single-layer sheet of sp2 hybridized carbon atoms, has attracted tremendous attention, owing to its exceptional physical and chemical properties such as thermal stability, and mechanical strength, transparency, selective permeability, light weight, flexible, thin, biodegradable. Other forms of Graphene-related materials, like Graphene oxide, reduced Graphene oxide, and exfoliated graphite, have been produced on large scale. The promising properties together with the ease of processibility and functionalization make graphene based materials ideal candidates for incorporation with various functional materials. Importantly, graphene and its derivatives have been used in a wide range of applications, such as electronic, solar and photonic devices, clean energy, sensors, 3D-printing, super capacitors. Its future applications include water filtration, prosthetic organs, and flexible screens. In this paper, after a general introduction to Graphene and its derivatives, the characteristics, properties, and applications of Graphene based materials are discussed. Graphene synthesis being an important affair is also studied in this paper, methods like CVD, ion implation, arc discharge and many more are discussed. In this paper I have worked upon, different properties of graphene to make better and reliable electronics, improving future technology for completing the ultimate goal of increasing standards of human race.
WATCH THE VIDEO VERSION!
http://www.youtube.com/watch?v=Q_eTLPKdrHs&feature=relmfu
dailyreckoning.com
The 'wonder material' known as graphene can revolutionize technology of the world.
Follow Us On Facebook:
http://www.facebook.com/TheDailyReckoning
Follow Us On Twitter:
https://twitter.com/DailyReckoning
Graphene: its increasing economic feasibility Jeffrey Funk
These slides use concepts from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze how Graphene is becoming economic feasible for an increasing number of applications as its price falls and its quality/performance rises through improvements in chemical vapor deposition processes. Graphene is one of the strongest materials discovered, has high electronic and thermal conductivities, and unusual optical properties. These slides describe a number of applications for which Graphene is gradually becoming economically feasible including displays, integrated circuits, solar cells, water desalination, and natural gas tanks.
Graphene is an allotrope of carbon, whose structure is one-atom-thick planar sheets of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice.
The development of this technology is still largely research-based, with a relatively large portion of academic participation, although real-world consumer applications such as flexible touchscreen displays are getting closer to reality and could be widely available within the next few years.
Because of its range of extraordinary properties, people are considering using graphene in a myriad of different applications. For example, because graphene is so strong, people want to use it to reinforce plastics, making them conductive at the same time. Because it's transparent and conducts electricity, people want to use it in applications like mobile phone screens, touch screens, TV screens and so on. People are also considering using it to go beyond silicon technology and make our integrated circuits even denser and speedier.
This report categorizes and graphically analyzes graphene technologies, research activity, applications, companies active in this research area, the filings spread, key comparisons etc.
In this experimental study, the reinforcing effects of graphene oxide (GO) on portland cement paste are investigated. It is dis- covered that the introduction of 0.05% by weight GO sheets into the cement paste can increase the compressive strength and tensile strength Of the cement composite due to the reduction of the pore structure of the cement paste.The inclusion of the GO Sheets enhances the degree of hydration of the cement paste. However, the workability of the GO-cement composite becomes somewhat Reduced. The overall results indicate that GO reinforcing the engineering properties of portland cement.
Characterization of Carbon Fiber Reinforced Thermoplastics for Induction Proc...Fluxtrol Inc.
Characteristics of Induction heating Carbon Fiber-Reinforced Thermoplastic (CFRT):
-Electrical Resistivity Determination of two specific CFRT’s
-Direction-specific by four-point method
-Equivalent resistivity by impedance method
-Thermal behavior of the studied materials
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-Different coil designs examined
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The reinforcing effects of graphene oxide (GO) on portland cement paste are investigated. It is dis- covered that the introduction of 0.05% by weight GO sheets into the cement paste can increase the compressive strength and tensile strength Of the cement composite due to the reduction of the pore structure of the cement paste.The overall results indicate that GO reinforcing the engineering properties of portland cement.
Features foldable electronics
I know perfectly that many people could think: Hey guy, this stuff is only a dream, good for some sci-fi movies.
This general opinion is normal because so far we have seen electronics always opaque but, before show these project, I wanted to be sure they were feasible.
Well, if you read the ebook " A foldable world" - http://www.biodomotica.com/foldable-nanotech.htm - you will find that all this is true.
Most important universities, companies and research centers around the world are working on nanotechnology and on projects that I like: transparent electronics.
You don't need a Ph.D. in Physics to understand articles inside the ebook. At the end of reading you will begin to ask for a new foldable & transparent laptop ;-)
These devices are not yet available but are NOT sci-fi.
Printed electronics and nanotechnology will rules and changes the world before than you think.
Forget what have seen so far about electronic gadgets: printed electronics is coming with new unbelievable features.
This products will be thin, light, without wires, flexible, water-proof, shock resistant, low energy, solar recharge and recyclable.
This technology will be out of laboratory and completely available by a few years, so it’s not too early to think how the nanotechnology will change our life and how interact with invisible electronics.
Transparent and foldable electronic is a part of the coming printed electronics and these forecasts are my personal point of view:
Electronics should be user-friendly and eco-friendly, cheap and standard.
Some products will have only 2 dimensions. If you want 3rd dimension is possible use packaging technology (boxes) or glued printed electronics sheets or print directly on surfaces of 3d objects.
Philosophy of product designer is going to be more near to fashion designers or graphic designers:
products thought as dress, using ribbons and sheets.
Transparent and thin means not only invisible electronics but you can also customize it with your creativity.
Help and tutorial “how use it” are visible on the products’ surface.
With “artificial muscles” inside is possible move, vibrate or open printed sheets.
Using surface’s treatment like gecko's paws is possible shape or attach devices everywhere.
Solar nanocells recharge devices by sun or infrared rays.
Without wires for electric energy is possible use it everywhere.
Neither fall or water can damage our precious electronic friend.
Graphene: the world's first 2D material. Since graphene's isolation in 2004, it has captured the attention of scientists, researchers, and industry worldwide.
Solar power is looking more and more attractive, as other power generation
methods such as fossil fuels and nuclear power come under increasing scrutiny
Nano material solar cells shows special promise to both enhance efficiency of
solar energy conservation and also reduce the manufacturing cost
It increase efficiently by the absorption of light as well as the overall radiation
to electricity would help preserve the environment, decrease wastage, provide
electricity for rural areas, and have a wide array of commercial applications
due to its capabilities
In our conventional electronic devices we use semi conducting materials for logical operation and magnetic materials for storage, but spintronics uses magnetic materials for both purposes. These spintronic devices are more versatile and faster than the present one. One such device is Spin Valve Transistors (SVT).
Spin valve transistor is different from conventional transistor. In this for conduction we use spin polarization of electrons. Only electrons with correct spin polarization can travel successfully through the device. These transistors are used in data storage, signal processing, automation and robotics with less power consumption and results in less heat. This also finds its application in Quantum computing, in which we use Qubits instead of bits.
Graphene is one the wonder materials in modern world,I Shaunak Bhattacharya with help of my group mates has made this presentation. Since I referred to slideshare.net for my presentation it was my duty to give it something back. I would be really happy if my presentation comes handy to anyone.
Study of Boron Based Superconductivity and Effect of High Temperature Cuprate...IOSR Journals
This paper illustrates the main normal and Boron superconducting state temperature properties of magnesium diboride, a substance known since early 1950's, but lately graded to be superconductive at a remarkably high critical temperature Tc=40K for a binary synthesis. What makes MgB2 so special? Its high Tc, simple crystal construction, large coherence lengths, high serious current densities and fields, lucidity of surface boundaries to current promises that MgB2 will be a good material for both large scale applications and electronic devices. Throughout the last seven month, MgB2 has been fabricated in various shape, bulk, single crystals, thin films, ribbons and wires. The largest critical current densities >10MA/cm2 and critical fields 40T are achieved for thin films. The anisotropy attribution inferred from upper critical field measurements is still to be resolved, a wide range of values being reported, γ = 1.2 ÷ 9. Also there is no consensus about the existence of a single anisotropic or double energy cavity. One central issue is whether or not MgB2 represents a new class of superconductors, being the tip of an iceberg that waits to be discovered. Until now MgB2 holds the record of the highest Tc among simple binary synthesis. However, the discovery of superconductivity in MgB2 revived the interest in non-oxides and initiated a search for superconductivity in related materials, several synthesis being already announced to become superconductive: TaB2, BeB2.75, C-S composites, and the elemental B under pressure.
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Graphene -Applications in Electronics
1. Graphene-The Wonder Material
w.r.t
Application in Electronics
Submitted to
Dr.A.Kasi.Vishwanath
Reader
Center for Nanoscience &
Technology Zaahir Salam
3. Introduction
Graphene is an Allotrope of Carbon.
Andre Geim and Konstanstin Novoslev won 2010
Physics Nobel prize for “Groundbreaking
Experiments with 2D material Graphene”.
Researches are testing various prototypes of
Graphene which could replace Silicon based devices.
Graphene could possibly replace or enhance current
Silicon based devices.
4. Salient Features
Thinnest imaginable material.
Largest surface area(~3,000 m2 per gram).
Strongest material ever measured(theoretical limit).
Stiffest know material(stiffer than diamond)
Most stretchable & pliable crystal(up to 20% elastically)
Record thermal conductivity(outperforming diamond).
Highest current density at room temp(million times of
Cu)
Completely impermeable (even He atoms cannot
squeeze through)
Highest intrinsic mobility(100 times of Si)
Lightest charge carriers(zero rest mass)
Longest mean free path at room T (micron range).
5. Impediments to Silicon Design
After replacing Vacuum Tubes,
Silicon is so far used for most of
the electronic components.
Conduction due to Diffusion in
Silicon.
Power consumption by Silicon
devices is higher.
Fragile and Non-Flexible.
Temperature dependent
properties.
Limit on integration of circuits.
6. Graphene Vs CNT
Electrical properties of CNT
are dependent on Chirality
that is width of tube.
It is difficult to control
Chirality on such a micro-
scale.
Graphene is Unzipped CNT.
2D structure of Graphene
allows movement of Electrons
with constant speed,
regardless of individual
energy level.
8. Electronic Properties of Graphene
For physicists and device engineers, the most important
behavior of graphene comes from its electronic
properties !
How do the pz electrons (1 for each atom, 2 for each
hexagon) in graphene behave?
9. Like electrons in atoms, Quantum Physics tells us that electrons
can occupy states that are grouped in energies, i.e., energy
bands! [This is Solid State Physics
Metal Insulator
E.g. sodium, potassium, … E.g. diamond (gap = 6 eV)
[Consequence of quantum physics]
10. Semiconductor [E.g., GaAs, silicon, germanium, …]
y-axis is energy and x-axis is
proportional to momentum
11. Historical Note: Dirac (1928) suggested the
existence of antiparticle. In addition to
looking for antiparticles in cosmic ray and
huge particle accelerators, semiconductors
provide a table-top realization of
antiparticles in the form of holes (missing
electrons) in the valence band! [Crossover
of relativistic quantum physics and solid
state physics!]
12. Conclusion Of Dirac
[Lighter electron effective mass, higher curvature, faster
electronics!
Key idea behind the whole semiconductor industry! Electrons
in semiconductors behave as “free electrons” but with a
different mass!]
13. Graphene has unusual energy bands
• The Pz electrons (2 in each hexagon) completely fill the lower
band.
[Ordinary semiconductors or insulators] Graphene (gapless semiconductor)
14. Dirac Equation in Graphene
Quite Fast!
Electrons in Graphene behave as if they are massless!
[Expect fast electronic devices from graphene!]
15.
16. Ambipolar Electric Field –Good Semiconductor
when a pulse of excess electrons and excess holes are created at a particular point in a
semiconductor an induced internal electric field will be present between them. This internal
electric field will cause the negatively charged electron and positively charged hole to drift or
diffuse together with a single effective mobility or diffusion coefficient.
17. For Use in Electronics: Generation of Bandgap
• Graphene is an uniform
structure with no Band Gap.
• Band Gap can be induced by
layers of Graphene sheets or
application of external
electrical field.
• Electron mobility is 2500
cm^2/s, which is around 100
times faster than Silicon.
• Graphene has great
strength and is invisible.
• It is Photosensitive.
18. Current Prototypes Of Graphene
Graphene Transistors(Tunable Transistors)
Ultra Capacitors
Graphene Solar Cells
Graphene based Sensors.
Non-Volatile Memory
Transparent Display Screens
Heat Dissipation
19. Graphene Transistors
• No Band Gap as Such, Very small band gap, 250meV.
• Band gap is achieved by two layers of Graphene.
• Difficult to distinguish between On and Off stages.
• Problems
Pure graphene is a particularly good conductor, it is a terrible
semiconductor - the kind of material needed to make
transistors.
Adding metal contacts to graphene - to shuttle electric
charges into and out of it - is tricky, and often results in
damage.
20. GT Contd…….
• To tackle both issues, researchers at Friedrich-Alexander University
Erlangen-Nuremberg in Germany have enlisted the help of a somewhat
lesser-known material called silicon carbide - a simple crystal made of
silicon and carbon.
• In 2009, several members of the same team reported in Nature
Materials that when wafers of the material were baked, silicon atoms
were driven out of the crystal's topmost layer, leaving behind just
carbon in the form of graphene
Graphene transistors have been made before, but they have not achieved graphene's full potential.
21. GT Contd…….
• A high-energy beam of charged atoms to etch "channels" into thin silicon
carbide wafers defining where different transistor parts would be.
• A bit of hydrogen gas in during this process. This affected how the top graphene
layer was chemically joined to the underlying silicon carbide: either making a
given region conducting or semiconducting, depending on the etched channels.
Schematics of different graphene MOSFET types: back-gated MOSFET (left); top-gated MOSFET with a
channel of exfoliated graphene or of graphene grown on metal and transferred to a SiO2-covered Si
wafer (middle); top-gated MOSFET with an epitaxial-graphene channel (right). The channel shown in red
can consist of either large-area graphene or graphene nanoribbons
22. Characteristics of GMOSFET’s
Direct-current behaviour of graphene MOSFeTs with a large-area-graphene channel. a, Typical transfer
characteristics for two MOSFETs with large-area-graphene channels. The on–off ratios are about 3 (MOSFET 1)
and 7 (MOSFET 2), far below what is needed for applications in logic circuits. Unlike conventional Si MOSFETs,
current flows for both positive and negative top-gate voltages. b, Qualitative shape of the output
characteristics (drain current, ID, versus drain–source voltage, VDS) of a MOSFET with an n-type large-area-
graphene channel, for different values of the top-gate voltage, VGS,top. Saturation behaviour can be seen. At
sufficiently large VDS values, the output characteristics for different VGS,top values may cross75, leading to a
zero or even negative transconductance, which means that the gate has effectively lost control of the current.
23. Non Volatile Memory
• For the first time they demonstrate full solution-processed, flexible, all
carbon diodes. Both the top and bottom electrodes are made of highly
reduced GO (hrGO) films obtained by the high-temperature annealing of
GO. The active material is made of lightly reduced GO (lrGO) obtained by
low-temperature annealing and then light irradiation of GO. The fabricated
diode shows electrical bistability with a non-volatile WORM memory
effect. In particular, our all-solution procedure and all-rGO components
enable a low-cost, environment-friendly, and mass-production
manufacturing process of the devices.
24. Non Volatile Memory Contind..
Briefly, after the patterned GO film on a Si/SiO 2 substrate, prepared by “scratching” method (Step 1), was
annealed at high temperature (1000 ° C) (Step 2), the obtained hrGO patterns were transferred onto a
poly(ethylene terephthalate) (PET) substrate by a modifi ed transfer process (Steps 3–6), i.e., the poly(methyl
methacrylate) (PMMA) film was removed by UV irradiation and subsequently using the developer of isopropyl
alcohol (IPA):methyl isobutyl ketone (MIBK) (Step 6), instead of the commonly used acetone. It is worth mentioning
that due to the effective UV irradiation and efficient lift-off process, PMMA was completely removed within 2 min.
The thickness and sheet resistance of the hrGO electrode is ∼ 10 nm and ∼ 2000 Ω sq − 1 , respectively. The
ultrathin feature of the hrGO electrode ( ∼ 10 nm), less than that of metallic electrodes (normally over 50 nm),
benefits the subsequent fabrication of multi-layer lrGO films by spin-coating to achieve multi-layer stackable
memory devices for ultrahigh density data storage.
25. Non Volatile Memory Contind..
All-rGO device with a sandwich configuration of hrGO/lrGO/hrGO. By
applying a voltage to the top/bottom electrode, the resistance state of
the memory device can be controlled.
Initially, the diode had a high resistance state (HRS). The resistance
gradually decreased with a negatively increased voltage (stage I), the
current varied from 3.67 × 10 − 12 to 2.97 × 10 − 6 A.
• When the voltage approached the switching threshold of ca. − 13.2 V
(stage II), the current abruptly increased from 2.97 × 10 − 6 to 4.66 × 10 −
4 A, indicating the resistive switching from a HRS (i.e., OFF state) to a low
resistance state (LRS, i.e., ON state). The switching from a HRS to a LRS is
equivalent to the “write” process in the data storage operation.
26. Ultra Capacitor
• Multiple layers of Graphene can hold greater charge in
smaller area.
• Graphene supercapacitors were created using a LightScribe
DVD burner.
• Power densities far beyond existing electrochemical
capacitors, possibly within reach of conventional lithium-
ion and nickel metal hydride batteries.
27. UC contnd..
• The team, which was led by Richard Kaner of UCLA, started by smearing
graphite oxide — a cheap and very easily produced material — films on blank
DVDs. These discs are then placed in a LightScribe drive, where a 780nm
infrared laser reduces the graphite oxide to pure graphene.
• The laser-scribed graphene (LSG) is peeled off and placed on a flexible
substrate, and then cut into slices to become the electrodes.
• Two electrodes are sandwiched together with a layer of electrolyte in the
middle — and voila, a high-density electrochemical capacitor, or supercapacitor
as they’re more popularly known are created.
28. Graphene in Li-Ion battery
• While computing power roughly doubles every 18 months, battery
technology is almost at a standstill.
• Supercapacitors, which suffer virtually zero degradation over 10,000
cycles or more, have been cited as a possible replacement for low-energy
devices, such as smartphones.
• With their huge power density, supercapacitors could also revolutionize
electric vehicles, where huge lithium-ion batteries really struggle to strike
a balance between mileage, acceleration, and longevity.
• It’s also worth noting, however, that lithium-ion batteries themselves
have had their capacity increased by 10 times thanks to the addition of
graphene. Either way, then, graphene seems like it will play a major role
in the future of electronics.
29. Solar cells with Graphene
• The discovery - made by researchers at the Institute of Photonic Science (ICFO), in
collaboration with Massachusetts Institute of Technology, Max Planck Institute for
Polymer Research, and Graphenea S.L. Donostia- San Sebastian - demonstrates that
graphene is able to convert a single photon that it absorbs into multiple electrons
that could drive electric current.
• We have seen that high energy photons are converted into a larger number of
excited electrons than low energy photons.
• The large scale production of highly transparent graphene films by chemical vapour
deposition.
• In this process, researchers create ultra-thin graphene sheets by first depositing
carbon atoms in the form of graphene films on a nickel plate from methane gas.
Then they lay down a protective layer of thermo plastic over the graphene layer
and dissolve the nickel underneath in an acid bath. In the final step they attach the
plastic-protected graphene to a very flexible polymer sheet, which can then be
incorporated into a OPV cell (graphene photovoltaics).
30. Graphene-based Natural Dye-Sensitized Solar Cells
• The counter electrode (CE) - catalytic Platinum (Pt) film deposited
on TCOs like ITO or FTO.
• Require high temperature processing, hindering the deposition on
some substrates (e.g., polymeric substrates).
• Moreover, they are brittle- flexibility is required. On the other
hand, Pt tends to degrade over time when in contact with the (I-
/I3-) liquid electrolyte, reducing the overall efficiency of DSSCs.
• In this context carbonaceous materials(like Graphene) feature
good catalytic properties, electronic conductivity, corrosion
resistance towards iodine, high reactivity, abundance, and low
cost.
31. DSSC Continued…
• Dye - Transition metal coordination compound complexes, and
synthetic organic dyes -based on tedious and expensive
chromatographic purification procedures.
• Natural dyes and their organic derivatives are non toxic,
biodegradable, low in cost, renewable and abundant, so they are the
ideal candidate for environmentally friendly solar cells.
• The combination of Graphene and natural sensitizers opens up new
scenarios for totally green, natural, environmentally friendly and low
cost DSSCs.
32. DSSC Continued…
• Indeed, graphene matches all the key requirements for replacement as
CE:-
• High specific surface area.
• High exchange current density and
• Low charge-transfer resistance.
• Graphene thin films were produced by liquid phase exfoliation of
graphite , and spin-casted on stainless steel, FTO and glass.
• Indeed, DSSCs assembled with CE made of graphene deposited onto
FTO (1.42%) outperform the total conversion efficiency of those based
on Pt (1.21%).
• Graphene can both catalyses the reduction of tri-Iodide and back
transfers the electrons arriving from the external circuit to the redox
system.
• DSSCs assembled with graphene deposited onto glass as CE show
efficiency ~0.8%.
33. Sensors With Graphene
Many sensing approaches, such as electrochemistry, surface enhanced
Raman spectroscopy (SERS) and surface plasma resonance (SPR), have
been used to develop highly sensitive and selective, low cost sensing
devices aiming at the detection of numerous toxic chemicals and in
particular, biomolecules in the aqueous environment. Electronic sensors
based on field-effect transistors (FETs)are favored due to their high
sensitivity, simple device configuration, low cost, miniaturization of
devices, and real-time detection.
The realization of electronic detection is based on the conductance
change of FET semiconducting channels upon adsorption of target
molecules.
34. Transparent Touch Screens
Advancements in touch
screens
When mixed into plastics,
graphene can turn them into
conductors of electricity
Stiffer-stronger-lighter plastics
35. Heat Dissipation
• Graphene is also a better conductor of Heat than Copper.
• Innovative Micro Heat Sink designs are proposed which are
fabricated on current Silicon on Insulator devices (SOI).
37. CONCLUSION
• Graphene is a new hope for electronic devices and could
possibly replace or rejuvenate Silicon based devices. It
seems to be a better material than Silicon and CNT.
• Lack of Natural Band Gap prevents Graphene to replace
Silicon based devices very now.
• Successful prototypes include Superconductor, Flexible
Displays 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.
38. References
• Graphene http://en.wikipedia.org/wiki/Grapheneaccessed on March, 29
2009
• Graphene Confirmed the World’s Strongest Known Material
http://gizmodo.com/5026404/graphene-confirmed-as-the- worlds-
strongest-known-material accessed on March, 29 2009
• Nanotechnology Reserchers go Ballistic Over Graphene
http://www.nanowerk.com/spotlight/spotid=2340.php accessed
on
March 29, 2009
• TR10: Graphene Transistors
http://www.technologyreview.com/read_article.aspx?ch=specials
ections&sc=emerging08&id=20242 accessed on March 29, 2009
• Graphene: Charged Up http://www.natureasia.com/asia materials
/highlight.php ?id=77 accessed on March 29, 2009