Getting to grips with graphene | Shou-En Zhu | TEDxDelft

This talk was given at a local TEDx event, produced independently of the TED Conferences.
Graphene, a nano-structure, has many different usages. Working on a PhD in Graphene Research at TU Delft, Shou-En Zhu set out on a new venture, designing and constructing a machine that can produce graphene from scratch on a very small budget.

Nano materials and nanostructures
exist everywhere in our natural world.

Take a look at the wing of a dragonfly.

If we zoom in 100,000 times

and look at the transparent membrane,

we can see the nanostructures

which are invisible to the naked eye.

Graphene is transparent.

This is a molecular model of graphene.

To make it visible, it has been magnified

over 280 million times.

Graphene consists of
only one single element:

carbon.

It's so simple.

However, graphene has
lots of special properties.

It's the thinnest of all materials,
only one atom thick.

It's the strongest material ever measured.

The in-plane carbon bond is stronger

than the tetrahedral carbon bond
in a diamond.

At the same time, it is
flexible and stretchable.

We can fully bend graphene
and stretch it up to 20%.

It has the highest thermal conductivity
of all materials, including copper.

It can withstand the highest
current density at room temperature,

it has the highest intrinsic mobility,

which is 100 times more
than that in silicon,

it is the most impermeable material,

even the smallest helium atoms
cannot squeeze through.

Graphene will change the world.

There will be, for sure, a completely
different intelligent society

in 10 to 20 years.

Let's spend some time
thinking about the future.

Imagine if all the transparent
glass windows

could constantly generate
electricity under sunlight

and supply the energy
for all the buildings.

Imagine if all the electrical vehicles
and electronic devices

could be charged within 10 minutes
and last for a few days.

Imagine if the sea water could be
desalinated with a pocket device

so it turns into drinking
water everywhere.

Imagine if smart electronic devices
could be integrated into our clothes,

and some of them
even implanted under our skins.

Imagine if light weight
composite materials

could be stronger than ever

so it turns into
the main structural material

for the body of ships,
vehicles, and airplanes.

Imagine if electronic chips
could do computations

a thousand time faster

with plasmons instead of electrons.

All these dreams will one day become real
and revolutionize our society,

and I believe it will happen
in our lifetime,

thanks to the exploration
of this new nanomaterial.

But how to produce graphene
is a serious problem.

Although graphene was known
to exist in graphite,

most scientists believed
that it would be impossible

to isolate a stable graphene.

In the 1930s, Landau and Peierls predicted

that 2D crystals would be
thermodynamically unstable

and thus could not exist.

30 years later, Mermin further
presented the analytical results

to fuller validate this hypothesis.

Until 2004, when two scientists,

Andre Geim and Kostya Novoselov,

used scotch tape to produce graphene.

By putting tape on graphite flakes
multiple times,

each time peeling off a layer,

the graphite will become
thinner and thinner.

Although most of the area consists
of thin graphite flakes,

a few small pieces
of a single layer graphene

were finally isolated.

Since then, thousands of scientists
started to do research

based on this tiny piece
of single layer graphene

using the scotch tape method.

Can you believe that
the Nobel Physics Prize in 2010

was awarded to these two scientists

based on their groundbreaking
scotch tape experiment? (Laughter)

Obviously, it is not a practical way

to mass produce graphene
and make useful products.

Nowadays, tons of small flakes
of multilayer graphene,

strictly speaking, thin graphite flakes,

can be produced using
the chemical exfoliation method.

It can be mixed into tennis
racquets or bicycle tires

to enhance the strength
and lower the composite weight.

However, the material produced is black,

which is inconsistent
with the transparent property of graphene.

If the color is black, it means
the flakes are too thick.

At the same time, the flakes are too small

to do the cool things
with that I was talking about.

As an experimental researcher
working on graphene,

I need lots of large area
single layer graphene

for my experiments.

However, I couldn't find
any research group

which could supply me
with high quality graphene

in the Netherlands at that moment.

I traveled between Leiden University
and Delft University every day,

and tried to figure out how I could
grow large size graphene samples.

With the existing facilities available,

I couldn't isolate high quality graphene,

either because the equipment had
very rough control of the gas flow,

or because the heating area was too small

to grow larger size samples of graphene.

Even the power of the heater
was not sufficient

to reach 1,000 degree Celsius.

Day after day, I woke up at 6 am,

and returned home at midnight.

I tried all the possibilities
that I could think of.

However, what I got, was only frustration
and reiteration of the problems.

I thought: "If I continue in this way,

I will never finish my PhD research."

Four months later, I decided
to stop wasting time

and make a furnace myself.

Thanks to my supervisor, and the faculty,

I received extra budget
for the equipment.

At the same time, I also won
the Young Wild Idea Prize,

worth 10,000 EUR,

which allowed me to spend the money
freely on the material.

I still remember that moment
on Tuesday, April 17, 2012.

After a whole year of working long days,

I started the first testing
of my own setup.

The vacuum pump I grabbed
from somewhere in the lab

was over eight years old and had run
for over 29,000 hours.

Not only that, but the pump
will stop running

once the temperature
reached over 40 degree Celsius.

So I bought a small fan costing 30 EUR,

which did a perfectly good job
of cooling the pump.

This is the furnace I have built.

I will explain the advantages
of this homemade setup.

The furnace can heat up
the 1 inch quartz tube

to over 1,000 degree Celsius

with a temperature fluctuation
of less than one degree Celsius.

There is a transparent
bullet proof Lexan cover,

which can protect against
any possible gas explosion

and secure the safety of the researcher.

There is a small hand wheel which can
remotely control the moving of the furnace

to the left

and to the right,

with a gear and a chain,

similar to chain gears on a bicycle.

With this design, I was able to heat
the sample and cool the sample

10 times faster
than any commercial equipment.

The cost of this setup
is less than 20,000 EUR,

which is over seven times cheaper
than any commercially available equipment.

All the components can be optimized
and well controlled.

It delivers a much better performance.

I enjoyed conducting
the experiment with my own setup.

This is the graphene I have grown.

The graphene crystals
grow like snow crystals.

Methane gas,

which accounts for about 80%
of natural gas used for cooking,

can decompose to carbon atoms

on copper substrate

at one 1,000 degrees Celsius
in an inert gas environment.

The carbon atoms will attach to each other

and form carbon rings
with honeycomb structures,

such as in graphite.

I can use the carbon isotope
to mark the growth procedure.

Can you imagine, the size
of an individual graphene crystal

reached over a few millimeter,

which is over one million times larger
than the size of the carbon atom?

Can you believe that this sample
was made six months ago,

and the single layer graphene can still
protect the copper against any oxidation?

The graphene crystals
will grow larger and larger,

and connect with neighboring
graphene crystals,

to finally form a continuous film.

Once there is no bare copper,

the graphene growth will stop.

So in the end, we will have a single layer
high quality graphene film.

My colleague and I proved
for the first time

that the quality
of this synthetic graphene

is as good as the one
with the scotch tape method,

however, the size is considerably larger.

To mass produce graphene,
and reduce the cost dramatically,

a bigger and better furnace
was designed and built.

The furnace has a larger quartz tube,

and the furnace will always
maintain a constant temperature.

Once the graphene growth has finished,

the only thing I need to do is to move
the furnace completely away from the tube

and take out the graphene sample.

Immediately, I can start
the second graphene growth cycle.

The efficiency of high quality
graphene growth

can be improved ten to twentyfold

and the energy consumption
will become much lower.

If we build hundreds of bigger furnaces,

the mass production of graphene
will become possible soon.

There is a layer of graphene
on a transparent substrate.

I can see you all through it.

But there is something special.

It is conductive

and flexible.

(Applause)

Now you can imagine all kinds
of future applications with this graphene.

Currently, the price
of this small piece of graphene

will be around 1,000 EUR.

I believe the price of this graphene
will go down to less than 1 EUR

within a few years,

because the material we use
to produce graphene,

such as

natural gas and copper foil,

are widely accessible.

All of us will have access to graphene
in the near future,

and realize this dream.

Remember that I told you
we are going to have better world.

Now, I cannot show you
the transparent glass windows

which could generate electricity,

and I cannot show you
the electronics in my clothes.

But I can show you something
you have never seen before.

There is a transparent graphene
patterned into wired structures

on this transparent polymer wing.

The graphene is so special

that once we put a tiny amount
of energy, it will shrink.

And graphene is so strong
that it can lift up

this polymer wing, which is
a thousand times heavier,

and mimic the flapping
function of a bio robot.

Look at what I have done
and achieved in these few years.

With all of you involved in my endeavor

to mass produce high quality
large scale graphene,

I believe we can make our dream
come true together.

Thank you.

(Applause)