WEBVTT

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Nano materials and nanostructures
exist everywhere in our natural world.

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Take a look at the wing of a dragonfly.

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If we zoom in 100,000 times

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and look at the transparent membrane,

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we can see the nanostructures

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which are invisible to the naked eye.

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Graphene is transparent.

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This is a molecular model of graphene.

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To make it visible, it has been magnified

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over 280 million times.

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Graphene consists of 
only one single element:

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carbon.

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It's so simple.

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However, graphene has 
lots of special properties.

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

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It's the strongest material ever measured.

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The in-plane carbon bond is stronger

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than the tetrahedral carbon bond 
in a diamond.

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At the same time, it is 
flexible and stretchable.

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

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

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It can withstand the highest 
current density at room temperature,

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it has the highest intrinsic mobility,

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which is 100 times more 
than that in silicon,

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it is the most impermeable material,

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even the smallest helium atoms 
cannot squeeze through.

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Graphene will change the world.

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

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in 10 to 20 years.

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Let's spend some time 
thinking about the future.

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Imagine if all the transparent 
glass windows

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could constantly generate 
electricity under sunlight

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and supply the energy 
for all the buildings.

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Imagine if all the electrical vehicles 
and electronic devices

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

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

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so it turns into drinking 
water everywhere.

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

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and some of them 
even implanted under our skins.

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Imagine if light weight 
composite materials

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could be stronger than ever

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so it turns into 
the main structural material

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for the body of ships, 
vehicles, and airplanes.

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Imagine if electronic chips 
could do computations

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a thousand time faster

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with plasmons instead of electrons.

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

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and I believe it will happen 
in our lifetime,

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thanks to the exploration 
of this new nanomaterial.

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But how to produce graphene 
is a serious problem.

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Although graphene was known 
to exist in graphite,

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most scientists believed 
that it would be impossible

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to isolate a stable graphene.

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In the 1930s, Landau and Peierls predicted

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that 2D crystals would be 
thermodynamically unstable

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and thus could not exist.

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30 years later, Mermin further 
presented the analytical results

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to fuller validate this hypothesis.

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Until 2004, when two scientists,

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Andre Geim and Kostya Novoselov,

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used scotch tape to produce graphene.

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By putting tape on graphite flakes 
multiple times,

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each time peeling off a layer,

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the graphite will become 
thinner and thinner.

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Although most of the area consists 
of thin graphite flakes,

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a few small pieces 
of a single layer graphene

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were finally isolated.

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Since then, thousands of scientists 
started to do research

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based on this tiny piece 
of single layer graphene

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using the scotch tape method.

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Can you believe that 
the Nobel Physics Prize in 2010

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was awarded to these two scientists

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based on their groundbreaking 
scotch tape experiment? (Laughter)

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Obviously, it is not a practical way

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to mass produce graphene
and make useful products.

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Nowadays, tons of small flakes 
of multilayer graphene,

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strictly speaking, thin graphite flakes,

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can be produced using 
the chemical exfoliation method.

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It can be mixed into tennis
racquets or bicycle tires

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to enhance the strength 
and lower the composite weight.

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However, the material produced is black,

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which is inconsistent 
with the transparent property of graphene.

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

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At the same time, the flakes are too small

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

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As an experimental researcher 
working on graphene,

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I need lots of large area 
single layer graphene

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for my experiments.

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However, I couldn't find 
any research group

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which could supply me 
with high quality graphene

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in the Netherlands at that moment.

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I traveled between Leiden University 
and Delft University every day,

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

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With the existing facilities available,

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I couldn't isolate high quality graphene,

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

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or because the heating area was too small

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to grow larger size samples of graphene.

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Even the power of the heater 
was not sufficient

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to reach 1,000 degree Celsius.

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Day after day, I woke up at 6 am,

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and returned home at midnight.

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I tried all the possibilities 
that I could think of.

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

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I thought: "If I continue in this way,

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I will never finish my PhD research."

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Four months later, I decided 
to stop wasting time

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and make a furnace myself.

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Thanks to my supervisor, and the faculty,

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I received extra budget 
for the equipment.

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

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worth 10,000 EUR,

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

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

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After a whole year of working long days,

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I started the first testing 
of my own setup.

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The vacuum pump I grabbed 
from somewhere in the lab

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

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Not only that, but the pump 
will stop running

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once the temperature 
reached over 40 degree Celsius.

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So I bought a small fan costing 30 EUR,

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which did a perfectly good job 
of cooling the pump.

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This is the furnace I have built.

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I will explain the advantages 
of this homemade setup.

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The furnace can heat up 
the 1 inch quartz tube

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to over 1,000 degree Celsius

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with a temperature fluctuation 
of less than one degree Celsius.

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There is a transparent 
bullet proof Lexan cover,

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which can protect against 
any possible gas explosion

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and secure the safety of the researcher.

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

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to the left

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and to the right,

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with a gear and a chain,

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similar to chain gears on a bicycle.

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

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10 times faster
than any commercial equipment.

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

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

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All the components can be optimized 
and well controlled.

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It delivers a much better performance.

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I enjoyed conducting
the experiment with my own setup.

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This is the graphene I have grown.

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The graphene crystals 
grow like snow crystals.

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Methane gas,

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

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can decompose to carbon atoms

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on copper substrate

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

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The carbon atoms will attach to each other

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and form carbon rings 
with honeycomb structures,

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such as in graphite.

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

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Can you imagine, the size
of an individual graphene crystal

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reached over a few millimeter,

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

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

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

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The graphene crystals 
will grow larger and larger,

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and connect with neighboring 
graphene crystals,

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to finally form a continuous film.

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Once there is no bare copper,

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the graphene growth will stop.

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

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My colleague and I proved 
for the first time

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that the quality 
of this synthetic graphene

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

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however, the size is considerably larger.

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To mass produce graphene, 
and reduce the cost dramatically,

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a bigger and better furnace 
was designed and built.

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The furnace has a larger quartz tube,

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and the furnace will always 
maintain a constant temperature.

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Once the graphene growth has finished,

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

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and take out the graphene sample.

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Immediately, I can start 
the second graphene growth cycle.

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The efficiency of high quality 
graphene growth

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can be improved ten to twentyfold

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and the energy consumption 
will become much lower.

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If we build hundreds of bigger furnaces,

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the mass production of graphene 
will become possible soon.

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There is a layer of graphene
on a transparent substrate.

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I can see you all through it.

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But there is something special.

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It is conductive

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and flexible.

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(Applause)

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

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Currently, the price
of this small piece of graphene

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will be around 1,000 EUR.

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

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within a few years,

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because the material we use 
to produce graphene,

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such as

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natural gas and copper foil,

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are widely accessible.

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

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and realize this dream.

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

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Now, I cannot show you 
the transparent glass windows

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which could generate electricity,

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and I cannot show you 
the electronics in my clothes.

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

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There is a transparent graphene 
patterned into wired structures

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on this transparent polymer wing.

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The graphene is so special

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

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And graphene is so strong 
that it can lift up

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this polymer wing, which is 
a thousand times heavier,

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and mimic the flapping
function of a bio robot.

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

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With all of you involved in my endeavor

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to mass produce high quality 
large scale graphene,

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I believe we can make our dream 
come true together.

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Thank you.

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(Applause)