0:00:15.819,0:00:21.319
Nano materials and nanostructures[br]exist everywhere in our natural world.

0:00:21.319,0:00:24.670
Take a look at the wing of a dragonfly.

0:00:24.670,0:00:28.335
If we zoom in 100,000 times

0:00:28.335,0:00:31.506
and look at the transparent membrane,

0:00:31.506,0:00:34.052
we can see the nanostructures

0:00:34.052,0:00:37.668
which are invisible to the naked eye.

0:00:37.668,0:00:40.237
Graphene is transparent.

0:00:42.987,0:00:46.089
This is a molecular model of graphene.

0:00:46.089,0:00:48.398
To make it visible, it has been magnified

0:00:48.398,0:00:52.307
over 280 million times.

0:00:53.497,0:00:56.478
Graphene consists of [br]only one single element:

0:00:57.968,0:00:58.959
carbon.

0:00:59.869,0:01:01.691
It's so simple.

0:01:01.691,0:01:05.652
However, graphene has [br]lots of special properties.

0:01:06.492,0:01:11.648
It's the thinnest of all materials, [br]only one atom thick.

0:01:12.658,0:01:15.776
It's the strongest material ever measured.

0:01:16.516,0:01:19.594
The in-plane carbon bond is stronger

0:01:19.594,0:01:23.057
than the tetrahedral carbon bond [br]in a diamond.

0:01:24.527,0:01:28.487
At the same time, it is [br]flexible and stretchable.

0:01:29.187,0:01:34.183
We can fully bend graphene [br]and stretch it up to 20%.

0:01:34.993,0:01:40.552
It has the highest thermal conductivity [br]of all materials, including copper.

0:01:41.452,0:01:46.005
It can withstand the highest [br]current density at room temperature,

0:01:46.745,0:01:49.878
it has the highest intrinsic mobility,

0:01:49.878,0:01:53.163
which is 100 times more [br]than that in silicon,

0:01:54.523,0:01:58.068
it is the most impermeable material,

0:01:58.068,0:02:02.951
even the smallest helium atoms [br]cannot squeeze through.

0:02:04.501,0:02:07.165
Graphene will change the world.

0:02:07.165,0:02:11.777
There will be, for sure, a completely [br]different intelligent society

0:02:11.777,0:02:14.451
in 10 to 20 years.

0:02:14.451,0:02:18.199
Let's spend some time [br]thinking about the future.

0:02:19.249,0:02:22.985
Imagine if all the transparent [br]glass windows

0:02:22.985,0:02:27.059
could constantly generate [br]electricity under sunlight

0:02:27.849,0:02:30.912
and supply the energy [br]for all the buildings.

0:02:31.972,0:02:36.367
Imagine if all the electrical vehicles [br]and electronic devices

0:02:36.367,0:02:40.632
could be charged within 10 minutes [br]and last for a few days.

0:02:41.582,0:02:47.259
Imagine if the sea water could be [br]desalinated with a pocket device

0:02:47.259,0:02:51.307
so it turns into drinking [br]water everywhere.

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

0:02:57.642,0:03:01.466
and some of them [br]even implanted under our skins.

0:03:02.786,0:03:06.584
Imagine if light weight [br]composite materials

0:03:06.584,0:03:08.062
could be stronger than ever

0:03:08.062,0:03:12.175
so it turns into [br]the main structural material

0:03:12.175,0:03:16.498
for the body of ships, [br]vehicles, and airplanes.

0:03:17.288,0:03:21.733
Imagine if electronic chips [br]could do computations

0:03:21.733,0:03:24.268
a thousand time faster

0:03:24.268,0:03:27.694
with plasmons instead of electrons.

0:03:27.694,0:03:33.208
All these dreams will one day become real [br]and revolutionize our society,

0:03:34.022,0:03:37.186
and I believe it will happen [br]in our lifetime,

0:03:37.186,0:03:40.765
thanks to the exploration [br]of this new nanomaterial.

0:03:41.655,0:03:44.979
But how to produce graphene [br]is a serious problem.

0:03:46.239,0:03:49.949
Although graphene was known [br]to exist in graphite,

0:03:49.949,0:03:53.381
most scientists believed [br]that it would be impossible

0:03:53.381,0:03:56.010
to isolate a stable graphene.

0:03:56.010,0:04:00.340
In the 1930s, Landau and Peierls predicted

0:04:00.340,0:04:04.782
that 2D crystals would be [br]thermodynamically unstable

0:04:04.782,0:04:07.169
and thus could not exist.

0:04:07.169,0:04:12.117
30 years later, Mermin further [br]presented the analytical results

0:04:12.117,0:04:16.037
to fuller validate this hypothesis.

0:04:16.037,0:04:19.176
Until 2004, when two scientists,

0:04:19.176,0:04:21.715
Andre Geim and Kostya Novoselov,

0:04:21.715,0:04:25.454
used scotch tape to produce graphene.

0:04:25.454,0:04:30.471
By putting tape on graphite flakes [br]multiple times,

0:04:30.471,0:04:33.466
each time peeling off a layer,

0:04:35.326,0:04:38.684
the graphite will become [br]thinner and thinner.

0:04:38.684,0:04:42.870
Although most of the area consists [br]of thin graphite flakes,

0:04:42.870,0:04:46.282
a few small pieces [br]of a single layer graphene

0:04:46.282,0:04:49.304
were finally isolated.

0:04:49.304,0:04:53.106
Since then, thousands of scientists [br]started to do research

0:04:53.106,0:04:56.974
based on this tiny piece [br]of single layer graphene

0:04:56.974,0:04:59.791
using the scotch tape method.

0:04:59.791,0:05:04.082
Can you believe that [br]the Nobel Physics Prize in 2010

0:05:04.082,0:05:06.398
was awarded to these two scientists

0:05:06.398,0:05:11.155
based on their groundbreaking [br]scotch tape experiment? (Laughter)

0:05:11.155,0:05:13.993
Obviously, it is not a practical way

0:05:13.993,0:05:18.103
to mass produce graphene[br]and make useful products.

0:05:18.103,0:05:21.749
Nowadays, tons of small flakes [br]of multilayer graphene,

0:05:21.749,0:05:25.160
strictly speaking, thin graphite flakes,

0:05:25.160,0:05:29.761
can be produced using [br]the chemical exfoliation method.

0:05:29.761,0:05:33.577
It can be mixed into tennis[br]racquets or bicycle tires

0:05:33.577,0:05:38.029
to enhance the strength [br]and lower the composite weight.

0:05:38.029,0:05:41.506
However, the material produced is black,

0:05:41.506,0:05:46.444
which is inconsistent [br]with the transparent property of graphene.

0:05:46.444,0:05:51.286
If the color is black, it means [br]the flakes are too thick.

0:05:52.266,0:05:54.976
At the same time, the flakes are too small

0:05:54.976,0:05:59.246
to do the cool things[br]with that I was talking about.

0:06:00.398,0:06:04.601
As an experimental researcher [br]working on graphene,

0:06:04.601,0:06:08.132
I need lots of large area [br]single layer graphene

0:06:08.132,0:06:10.503
for my experiments.

0:06:10.503,0:06:13.456
However, I couldn't find [br]any research group

0:06:13.456,0:06:17.040
which could supply me [br]with high quality graphene

0:06:17.040,0:06:19.144
in the Netherlands at that moment.

0:06:19.144,0:06:24.209
I traveled between Leiden University [br]and Delft University every day,

0:06:24.209,0:06:29.414
and tried to figure out how I could [br]grow large size graphene samples.

0:06:30.554,0:06:33.294
With the existing facilities available,

0:06:33.294,0:06:36.995
I couldn't isolate high quality graphene,

0:06:36.995,0:06:41.550
either because the equipment had [br]very rough control of the gas flow,

0:06:41.550,0:06:45.770
or because the heating area was too small

0:06:45.770,0:06:48.507
to grow larger size samples of graphene.

0:06:49.207,0:06:51.887
Even the power of the heater [br]was not sufficient

0:06:51.887,0:06:54.838
to reach 1,000 degree Celsius.

0:06:56.018,0:07:00.108
Day after day, I woke up at 6 am,

0:07:00.108,0:07:02.489
and returned home at midnight.

0:07:02.489,0:07:06.059
I tried all the possibilities [br]that I could think of.

0:07:06.629,0:07:12.435
However, what I got, was only frustration [br]and reiteration of the problems.

0:07:12.435,0:07:15.204
I thought: "If I continue in this way,

0:07:15.204,0:07:17.584
I will never finish my PhD research."

0:07:18.624,0:07:22.589
Four months later, I decided [br]to stop wasting time

0:07:22.589,0:07:24.579
and make a furnace myself.

0:07:24.579,0:07:27.526
Thanks to my supervisor, and the faculty,

0:07:27.526,0:07:31.143
I received extra budget [br]for the equipment.

0:07:31.143,0:07:35.536
At the same time, I also won [br]the Young Wild Idea Prize,

0:07:35.536,0:07:38.053
worth 10,000 EUR,

0:07:38.053,0:07:42.975
which allowed me to spend the money [br]freely on the material.

0:07:46.625,0:07:52.669
I still remember that moment[br]on Tuesday, April 17, 2012.

0:07:53.490,0:07:56.507
After a whole year of working long days,

0:07:56.507,0:08:00.066
I started the first testing [br]of my own setup.

0:08:00.066,0:08:03.546
The vacuum pump I grabbed [br]from somewhere in the lab

0:08:03.546,0:08:08.778
was over eight years old and had run [br]for over 29,000 hours.

0:08:09.948,0:08:13.747
Not only that, but the pump [br]will stop running

0:08:13.747,0:08:17.815
once the temperature [br]reached over 40 degree Celsius.

0:08:19.435,0:08:23.572
So I bought a small fan costing 30 EUR,

0:08:23.572,0:08:27.183
which did a perfectly good job [br]of cooling the pump.

0:08:28.483,0:08:32.964
This is the furnace I have built.

0:08:34.834,0:08:39.614
I will explain the advantages [br]of this homemade setup.

0:08:39.614,0:08:42.212
The furnace can heat up [br]the 1 inch quartz tube

0:08:42.212,0:08:45.280
to over 1,000 degree Celsius

0:08:45.280,0:08:50.340
with a temperature fluctuation [br]of less than one degree Celsius.

0:08:51.310,0:08:56.430
There is a transparent [br]bullet proof Lexan cover,

0:08:56.430,0:09:00.793
which can protect against [br]any possible gas explosion

0:09:00.793,0:09:03.900
and secure the safety of the researcher.

0:09:03.900,0:09:08.924
There is a small hand wheel which can [br]remotely control the moving of the furnace

0:09:09.974,0:09:11.173
to the left

0:09:12.373,0:09:13.506
and to the right,

0:09:14.536,0:09:17.784
with a gear and a chain,

0:09:17.784,0:09:21.323
similar to chain gears on a bicycle.

0:09:21.323,0:09:26.550
With this design, I was able to heat [br]the sample and cool the sample

0:09:26.550,0:09:30.816
10 times faster[br]than any commercial equipment.

0:09:30.816,0:09:37.246
The cost of this setup [br]is less than 20,000 EUR,

0:09:37.246,0:09:42.159
which is over seven times cheaper [br]than any commercially available equipment.

0:09:43.409,0:09:47.288
All the components can be optimized [br]and well controlled.

0:09:47.288,0:09:50.961
It delivers a much better performance.

0:09:50.961,0:09:54.536
I enjoyed conducting[br]the experiment with my own setup.

0:09:55.556,0:09:58.513
This is the graphene I have grown.

0:09:58.513,0:10:02.453
The graphene crystals [br]grow like snow crystals.

0:10:02.453,0:10:04.096
Methane gas,

0:10:04.906,0:10:09.805
which accounts for about 80% [br]of natural gas used for cooking,

0:10:10.835,0:10:13.689
can decompose to carbon atoms

0:10:17.449,0:10:19.959
on copper substrate

0:10:23.529,0:10:28.347
at one 1,000 degrees Celsius [br]in an inert gas environment.

0:10:33.243,0:10:36.385
The carbon atoms will attach to each other

0:10:36.385,0:10:40.287
and form carbon rings [br]with honeycomb structures,

0:10:40.287,0:10:42.109
such as in graphite.

0:10:43.019,0:10:47.081
I can use the carbon isotope [br]to mark the growth procedure.

0:10:48.091,0:10:53.027
Can you imagine, the size[br]of an individual graphene crystal

0:10:53.027,0:10:56.473
reached over a few millimeter,

0:10:56.473,0:11:02.921
which is over one million times larger [br]than the size of the carbon atom?

0:11:06.911,0:11:11.786
Can you believe that this sample [br]was made six months ago,

0:11:12.964,0:11:18.983
and the single layer graphene can still [br]protect the copper against any oxidation?

0:11:20.433,0:11:23.778
The graphene crystals [br]will grow larger and larger,

0:11:24.748,0:11:27.596
and connect with neighboring [br]graphene crystals,

0:11:27.596,0:11:30.191
to finally form a continuous film.

0:11:31.091,0:11:33.574
Once there is no bare copper,

0:11:33.574,0:11:35.871
the graphene growth will stop.

0:11:37.281,0:11:42.385
So in the end, we will have a single layer[br]high quality graphene film.

0:11:43.369,0:11:46.414
My colleague and I proved [br]for the first time

0:11:46.414,0:11:49.613
that the quality [br]of this synthetic graphene

0:11:49.613,0:11:53.418
is as good as the one [br]with the scotch tape method,

0:11:53.418,0:11:56.767
however, the size is considerably larger.

0:11:58.387,0:12:02.910
To mass produce graphene, [br]and reduce the cost dramatically,

0:12:02.910,0:12:08.045
a bigger and better furnace [br]was designed and built.

0:12:09.145,0:12:11.474
The furnace has a larger quartz tube,

0:12:11.474,0:12:15.929
and the furnace will always [br]maintain a constant temperature.

0:12:15.929,0:12:18.598
Once the graphene growth has finished,

0:12:18.598,0:12:24.425
the only thing I need to do is to move [br]the furnace completely away from the tube

0:12:24.425,0:12:26.722
and take out the graphene sample.

0:12:26.722,0:12:30.814
Immediately, I can start [br]the second graphene growth cycle.

0:12:31.784,0:12:34.482
The efficiency of high quality [br]graphene growth

0:12:34.482,0:12:37.179
can be improved ten to twentyfold

0:12:37.179,0:12:41.457
and the energy consumption [br]will become much lower.

0:12:41.457,0:12:44.133
If we build hundreds of bigger furnaces,

0:12:44.133,0:12:47.895
the mass production of graphene [br]will become possible soon.

0:12:51.585,0:12:56.389
There is a layer of graphene[br]on a transparent substrate.

0:12:58.389,0:13:01.098
I can see you all through it.

0:13:04.688,0:13:07.319
But there is something special.

0:13:19.644,0:13:21.520
It is conductive

0:13:25.260,0:13:26.831
and flexible.

0:13:29.661,0:13:31.261
(Applause)

0:13:40.651,0:13:46.236
Now you can imagine all kinds[br]of future applications with this graphene.

0:13:51.312,0:13:54.258
Currently, the price[br]of this small piece of graphene

0:13:54.258,0:13:56.984
will be around 1,000 EUR.

0:13:57.934,0:14:03.742
I believe the price of this graphene [br]will go down to less than 1 EUR

0:14:03.742,0:14:05.044
within a few years,

0:14:05.044,0:14:08.624
because the material we use [br]to produce graphene,

0:14:09.344,0:14:10.523
such as

0:14:11.773,0:14:14.942
natural gas and copper foil,

0:14:16.238,0:14:17.884
are widely accessible.

0:14:18.914,0:14:22.752
All of us will have access to graphene [br]in the near future,

0:14:23.565,0:14:25.585
and realize this dream.

0:14:25.597,0:14:29.586
Remember that I told you[br]we are going to have better world.

0:14:30.908,0:14:33.928
Now, I cannot show you [br]the transparent glass windows

0:14:33.928,0:14:36.585
which could generate electricity,

0:14:36.585,0:14:40.556
and I cannot show you [br]the electronics in my clothes.

0:14:41.776,0:14:45.700
But I can show you something [br]you have never seen before.

0:14:47.589,0:14:53.297
There is a transparent graphene [br]patterned into wired structures

0:14:54.225,0:14:57.775
on this transparent polymer wing.

0:14:58.486,0:15:01.756
The graphene is so special

0:15:01.756,0:15:05.536
that once we put a tiny amount [br]of energy, it will shrink.

0:15:06.486,0:15:10.136
And graphene is so strong [br]that it can lift up

0:15:10.136,0:15:14.486
this polymer wing, which is [br]a thousand times heavier,

0:15:14.486,0:15:18.486
and mimic the flapping[br]function of a bio robot.

0:15:23.615,0:15:28.225
Look at what I have done [br]and achieved in these few years.

0:15:29.925,0:15:32.385
With all of you involved in my endeavor

0:15:32.385,0:15:35.965
to mass produce high quality [br]large scale graphene,

0:15:35.965,0:15:39.965
I believe we can make our dream [br]come true together.

0:15:39.965,0:15:41.485
Thank you.

0:15:41.485,0:15:42.675
(Applause)