1
00:00:15,819 --> 00:00:21,319
Nano materials and nanostructures
exist everywhere in our natural world.

2
00:00:21,319 --> 00:00:24,670
Take a look at the wing of a dragonfly.

3
00:00:24,670 --> 00:00:28,335
If we zoom in 100,000 times

4
00:00:28,335 --> 00:00:31,506
and look at the transparent membrane,

5
00:00:31,506 --> 00:00:34,052
we can see the nanostructures

6
00:00:34,052 --> 00:00:37,668
which are invisible to the naked eye.

7
00:00:37,668 --> 00:00:40,237
Graphene is transparent.

8
00:00:42,987 --> 00:00:46,089
This is a molecular model of graphene.

9
00:00:46,089 --> 00:00:48,398
To make it visible, it has been magnified

10
00:00:48,398 --> 00:00:52,307
over 280 million times.

11
00:00:53,497 --> 00:00:56,478
Graphene consists of 
only one single element:

12
00:00:57,968 --> 00:00:58,959
carbon.

13
00:00:59,869 --> 00:01:01,691
It's so simple.

14
00:01:01,691 --> 00:01:05,652
However, graphene has 
lots of special properties.

15
00:01:06,492 --> 00:01:11,648
It's the thinnest of all materials, 
only one atom thick.

16
00:01:12,658 --> 00:01:15,776
It's the strongest material ever measured.

17
00:01:16,516 --> 00:01:19,594
The in-plane carbon bond is stronger

18
00:01:19,594 --> 00:01:23,057
than the tetrahedral carbon bond 
in a diamond.

19
00:01:24,527 --> 00:01:28,487
At the same time, it is 
flexible and stretchable.

20
00:01:29,187 --> 00:01:34,183
We can fully bend graphene 
and stretch it up to 20%.

21
00:01:34,993 --> 00:01:40,552
It has the highest thermal conductivity 
of all materials, including copper.

22
00:01:41,452 --> 00:01:46,005
It can withstand the highest 
current density at room temperature,

23
00:01:46,745 --> 00:01:49,878
it has the highest intrinsic mobility,

24
00:01:49,878 --> 00:01:53,163
which is 100 times more 
than that in silicon,

25
00:01:54,523 --> 00:01:58,068
it is the most impermeable material,

26
00:01:58,068 --> 00:02:02,951
even the smallest helium atoms 
cannot squeeze through.

27
00:02:04,501 --> 00:02:07,165
Graphene will change the world.

28
00:02:07,165 --> 00:02:11,777
There will be, for sure, a completely 
different intelligent society

29
00:02:11,777 --> 00:02:14,451
in 10 to 20 years.

30
00:02:14,451 --> 00:02:18,199
Let's spend some time 
thinking about the future.

31
00:02:19,249 --> 00:02:22,985
Imagine if all the transparent 
glass windows

32
00:02:22,985 --> 00:02:27,059
could constantly generate 
electricity under sunlight

33
00:02:27,849 --> 00:02:30,912
and supply the energy 
for all the buildings.

34
00:02:31,972 --> 00:02:36,367
Imagine if all the electrical vehicles 
and electronic devices

35
00:02:36,367 --> 00:02:40,632
could be charged within 10 minutes 
and last for a few days.

36
00:02:41,582 --> 00:02:47,259
Imagine if the sea water could be 
desalinated with a pocket device

37
00:02:47,259 --> 00:02:51,307
so it turns into drinking 
water everywhere.

38
00:02:51,307 --> 00:02:57,642
Imagine if smart electronic devices 
could be integrated into our clothes,

39
00:02:57,642 --> 00:03:01,466
and some of them 
even implanted under our skins.

40
00:03:02,786 --> 00:03:06,584
Imagine if light weight 
composite materials

41
00:03:06,584 --> 00:03:08,062
could be stronger than ever

42
00:03:08,062 --> 00:03:12,175
so it turns into 
the main structural material

43
00:03:12,175 --> 00:03:16,498
for the body of ships, 
vehicles, and airplanes.

44
00:03:17,288 --> 00:03:21,733
Imagine if electronic chips 
could do computations

45
00:03:21,733 --> 00:03:24,268
a thousand time faster

46
00:03:24,268 --> 00:03:27,694
with plasmons instead of electrons.

47
00:03:27,694 --> 00:03:33,208
All these dreams will one day become real 
and revolutionize our society,

48
00:03:34,022 --> 00:03:37,186
and I believe it will happen 
in our lifetime,

49
00:03:37,186 --> 00:03:40,765
thanks to the exploration 
of this new nanomaterial.

50
00:03:41,655 --> 00:03:44,979
But how to produce graphene 
is a serious problem.

51
00:03:46,239 --> 00:03:49,949
Although graphene was known 
to exist in graphite,

52
00:03:49,949 --> 00:03:53,381
most scientists believed 
that it would be impossible

53
00:03:53,381 --> 00:03:56,010
to isolate a stable graphene.

54
00:03:56,010 --> 00:04:00,340
In the 1930s, Landau and Peierls predicted

55
00:04:00,340 --> 00:04:04,782
that 2D crystals would be 
thermodynamically unstable

56
00:04:04,782 --> 00:04:07,169
and thus could not exist.

57
00:04:07,169 --> 00:04:12,117
30 years later, Mermin further 
presented the analytical results

58
00:04:12,117 --> 00:04:16,037
to fuller validate this hypothesis.

59
00:04:16,037 --> 00:04:19,176
Until 2004, when two scientists,

60
00:04:19,176 --> 00:04:21,715
Andre Geim and Kostya Novoselov,

61
00:04:21,715 --> 00:04:25,454
used scotch tape to produce graphene.

62
00:04:25,454 --> 00:04:30,471
By putting tape on graphite flakes 
multiple times,

63
00:04:30,471 --> 00:04:33,466
each time peeling off a layer,

64
00:04:35,326 --> 00:04:38,684
the graphite will become 
thinner and thinner.

65
00:04:38,684 --> 00:04:42,870
Although most of the area consists 
of thin graphite flakes,

66
00:04:42,870 --> 00:04:46,282
a few small pieces 
of a single layer graphene

67
00:04:46,282 --> 00:04:49,304
were finally isolated.

68
00:04:49,304 --> 00:04:53,106
Since then, thousands of scientists 
started to do research

69
00:04:53,106 --> 00:04:56,974
based on this tiny piece 
of single layer graphene

70
00:04:56,974 --> 00:04:59,791
using the scotch tape method.

71
00:04:59,791 --> 00:05:04,082
Can you believe that 
the Nobel Physics Prize in 2010

72
00:05:04,082 --> 00:05:06,398
was awarded to these two scientists

73
00:05:06,398 --> 00:05:11,155
based on their groundbreaking 
scotch tape experiment? (Laughter)

74
00:05:11,155 --> 00:05:13,993
Obviously, it is not a practical way

75
00:05:13,993 --> 00:05:18,103
to mass produce graphene
and make useful products.

76
00:05:18,103 --> 00:05:21,749
Nowadays, tons of small flakes 
of multilayer graphene,

77
00:05:21,749 --> 00:05:25,160
strictly speaking, thin graphite flakes,

78
00:05:25,160 --> 00:05:29,761
can be produced using 
the chemical exfoliation method.

79
00:05:29,761 --> 00:05:33,577
It can be mixed into tennis
racquets or bicycle tires

80
00:05:33,577 --> 00:05:38,029
to enhance the strength 
and lower the composite weight.

81
00:05:38,029 --> 00:05:41,506
However, the material produced is black,

82
00:05:41,506 --> 00:05:46,444
which is inconsistent 
with the transparent property of graphene.

83
00:05:46,444 --> 00:05:51,286
If the color is black, it means 
the flakes are too thick.

84
00:05:52,266 --> 00:05:54,976
At the same time, the flakes are too small

85
00:05:54,976 --> 00:05:59,246
to do the cool things
with that I was talking about.

86
00:06:00,398 --> 00:06:04,601
As an experimental researcher 
working on graphene,

87
00:06:04,601 --> 00:06:08,132
I need lots of large area 
single layer graphene

88
00:06:08,132 --> 00:06:10,503
for my experiments.

89
00:06:10,503 --> 00:06:13,456
However, I couldn't find 
any research group

90
00:06:13,456 --> 00:06:17,040
which could supply me 
with high quality graphene

91
00:06:17,040 --> 00:06:19,144
in the Netherlands at that moment.

92
00:06:19,144 --> 00:06:24,209
I traveled between Leiden University 
and Delft University every day,

93
00:06:24,209 --> 00:06:29,414
and tried to figure out how I could 
grow large size graphene samples.

94
00:06:30,554 --> 00:06:33,294
With the existing facilities available,

95
00:06:33,294 --> 00:06:36,995
I couldn't isolate high quality graphene,

96
00:06:36,995 --> 00:06:41,550
either because the equipment had 
very rough control of the gas flow,

97
00:06:41,550 --> 00:06:45,770
or because the heating area was too small

98
00:06:45,770 --> 00:06:48,507
to grow larger size samples of graphene.

99
00:06:49,207 --> 00:06:51,887
Even the power of the heater 
was not sufficient

100
00:06:51,887 --> 00:06:54,838
to reach 1,000 degree Celsius.

101
00:06:56,018 --> 00:07:00,108
Day after day, I woke up at 6 am,

102
00:07:00,108 --> 00:07:02,489
and returned home at midnight.

103
00:07:02,489 --> 00:07:06,059
I tried all the possibilities 
that I could think of.

104
00:07:06,629 --> 00:07:12,435
However, what I got, was only frustration 
and reiteration of the problems.

105
00:07:12,435 --> 00:07:15,204
I thought: "If I continue in this way,

106
00:07:15,204 --> 00:07:17,584
I will never finish my PhD research."

107
00:07:18,624 --> 00:07:22,589
Four months later, I decided 
to stop wasting time

108
00:07:22,589 --> 00:07:24,579
and make a furnace myself.

109
00:07:24,579 --> 00:07:27,526
Thanks to my supervisor, and the faculty,

110
00:07:27,526 --> 00:07:31,143
I received extra budget 
for the equipment.

111
00:07:31,143 --> 00:07:35,536
At the same time, I also won 
the Young Wild Idea Prize,

112
00:07:35,536 --> 00:07:38,053
worth 10,000 EUR,

113
00:07:38,053 --> 00:07:42,975
which allowed me to spend the money 
freely on the material.

114
00:07:46,625 --> 00:07:52,669
I still remember that moment
on Tuesday, April 17, 2012.

115
00:07:53,490 --> 00:07:56,507
After a whole year of working long days,

116
00:07:56,507 --> 00:08:00,066
I started the first testing 
of my own setup.

117
00:08:00,066 --> 00:08:03,546
The vacuum pump I grabbed 
from somewhere in the lab

118
00:08:03,546 --> 00:08:08,778
was over eight years old and had run 
for over 29,000 hours.

119
00:08:09,948 --> 00:08:13,747
Not only that, but the pump 
will stop running

120
00:08:13,747 --> 00:08:17,815
once the temperature 
reached over 40 degree Celsius.

121
00:08:19,435 --> 00:08:23,572
So I bought a small fan costing 30 EUR,

122
00:08:23,572 --> 00:08:27,183
which did a perfectly good job 
of cooling the pump.

123
00:08:28,483 --> 00:08:32,964
This is the furnace I have built.

124
00:08:34,834 --> 00:08:39,614
I will explain the advantages 
of this homemade setup.

125
00:08:39,614 --> 00:08:42,212
The furnace can heat up 
the 1 inch quartz tube

126
00:08:42,212 --> 00:08:45,280
to over 1,000 degree Celsius

127
00:08:45,280 --> 00:08:50,340
with a temperature fluctuation 
of less than one degree Celsius.

128
00:08:51,310 --> 00:08:56,430
There is a transparent 
bullet proof Lexan cover,

129
00:08:56,430 --> 00:09:00,793
which can protect against 
any possible gas explosion

130
00:09:00,793 --> 00:09:03,900
and secure the safety of the researcher.

131
00:09:03,900 --> 00:09:08,924
There is a small hand wheel which can 
remotely control the moving of the furnace

132
00:09:09,974 --> 00:09:11,173
to the left

133
00:09:12,373 --> 00:09:13,506
and to the right,

134
00:09:14,536 --> 00:09:17,784
with a gear and a chain,

135
00:09:17,784 --> 00:09:21,323
similar to chain gears on a bicycle.

136
00:09:21,323 --> 00:09:26,550
With this design, I was able to heat 
the sample and cool the sample

137
00:09:26,550 --> 00:09:30,816
10 times faster
than any commercial equipment.

138
00:09:30,816 --> 00:09:37,246
The cost of this setup 
is less than 20,000 EUR,

139
00:09:37,246 --> 00:09:42,159
which is over seven times cheaper 
than any commercially available equipment.

140
00:09:43,409 --> 00:09:47,288
All the components can be optimized 
and well controlled.

141
00:09:47,288 --> 00:09:50,961
It delivers a much better performance.

142
00:09:50,961 --> 00:09:54,536
I enjoyed conducting
the experiment with my own setup.

143
00:09:55,556 --> 00:09:58,513
This is the graphene I have grown.

144
00:09:58,513 --> 00:10:02,453
The graphene crystals 
grow like snow crystals.

145
00:10:02,453 --> 00:10:04,096
Methane gas,

146
00:10:04,906 --> 00:10:09,805
which accounts for about 80% 
of natural gas used for cooking,

147
00:10:10,835 --> 00:10:13,689
can decompose to carbon atoms

148
00:10:17,449 --> 00:10:19,959
on copper substrate

149
00:10:23,529 --> 00:10:28,347
at one 1,000 degrees Celsius 
in an inert gas environment.

150
00:10:33,243 --> 00:10:36,385
The carbon atoms will attach to each other

151
00:10:36,385 --> 00:10:40,287
and form carbon rings 
with honeycomb structures,

152
00:10:40,287 --> 00:10:42,109
such as in graphite.

153
00:10:43,019 --> 00:10:47,081
I can use the carbon isotope 
to mark the growth procedure.

154
00:10:48,091 --> 00:10:53,027
Can you imagine, the size
of an individual graphene crystal

155
00:10:53,027 --> 00:10:56,473
reached over a few millimeter,

156
00:10:56,473 --> 00:11:02,921
which is over one million times larger 
than the size of the carbon atom?

157
00:11:06,911 --> 00:11:11,786
Can you believe that this sample 
was made six months ago,

158
00:11:12,964 --> 00:11:18,983
and the single layer graphene can still 
protect the copper against any oxidation?

159
00:11:20,433 --> 00:11:23,778
The graphene crystals 
will grow larger and larger,

160
00:11:24,748 --> 00:11:27,596
and connect with neighboring 
graphene crystals,

161
00:11:27,596 --> 00:11:30,191
to finally form a continuous film.

162
00:11:31,091 --> 00:11:33,574
Once there is no bare copper,

163
00:11:33,574 --> 00:11:35,871
the graphene growth will stop.

164
00:11:37,281 --> 00:11:42,385
So in the end, we will have a single layer
high quality graphene film.

165
00:11:43,369 --> 00:11:46,414
My colleague and I proved 
for the first time

166
00:11:46,414 --> 00:11:49,613
that the quality 
of this synthetic graphene

167
00:11:49,613 --> 00:11:53,418
is as good as the one 
with the scotch tape method,

168
00:11:53,418 --> 00:11:56,767
however, the size is considerably larger.

169
00:11:58,387 --> 00:12:02,910
To mass produce graphene, 
and reduce the cost dramatically,

170
00:12:02,910 --> 00:12:08,045
a bigger and better furnace 
was designed and built.

171
00:12:09,145 --> 00:12:11,474
The furnace has a larger quartz tube,

172
00:12:11,474 --> 00:12:15,929
and the furnace will always 
maintain a constant temperature.

173
00:12:15,929 --> 00:12:18,598
Once the graphene growth has finished,

174
00:12:18,598 --> 00:12:24,425
the only thing I need to do is to move 
the furnace completely away from the tube

175
00:12:24,425 --> 00:12:26,722
and take out the graphene sample.

176
00:12:26,722 --> 00:12:30,814
Immediately, I can start 
the second graphene growth cycle.

177
00:12:31,784 --> 00:12:34,482
The efficiency of high quality 
graphene growth

178
00:12:34,482 --> 00:12:37,179
can be improved ten to twentyfold

179
00:12:37,179 --> 00:12:41,457
and the energy consumption 
will become much lower.

180
00:12:41,457 --> 00:12:44,133
If we build hundreds of bigger furnaces,

181
00:12:44,133 --> 00:12:47,895
the mass production of graphene 
will become possible soon.

182
00:12:51,585 --> 00:12:56,389
There is a layer of graphene
on a transparent substrate.

183
00:12:58,389 --> 00:13:01,098
I can see you all through it.

184
00:13:04,688 --> 00:13:07,319
But there is something special.

185
00:13:19,644 --> 00:13:21,520
It is conductive

186
00:13:25,260 --> 00:13:26,831
and flexible.

187
00:13:29,661 --> 00:13:31,261
(Applause)

188
00:13:40,651 --> 00:13:46,236
Now you can imagine all kinds
of future applications with this graphene.

189
00:13:51,312 --> 00:13:54,258
Currently, the price
of this small piece of graphene

190
00:13:54,258 --> 00:13:56,984
will be around 1,000 EUR.

191
00:13:57,934 --> 00:14:03,742
I believe the price of this graphene 
will go down to less than 1 EUR

192
00:14:03,742 --> 00:14:05,044
within a few years,

193
00:14:05,044 --> 00:14:08,624
because the material we use 
to produce graphene,

194
00:14:09,344 --> 00:14:10,523
such as

195
00:14:11,773 --> 00:14:14,942
natural gas and copper foil,

196
00:14:16,238 --> 00:14:17,884
are widely accessible.

197
00:14:18,914 --> 00:14:22,752
All of us will have access to graphene 
in the near future,

198
00:14:23,565 --> 00:14:25,585
and realize this dream.

199
00:14:25,597 --> 00:14:29,586
Remember that I told you
we are going to have better world.

200
00:14:30,908 --> 00:14:33,928
Now, I cannot show you 
the transparent glass windows

201
00:14:33,928 --> 00:14:36,585
which could generate electricity,

202
00:14:36,585 --> 00:14:40,556
and I cannot show you 
the electronics in my clothes.

203
00:14:41,776 --> 00:14:45,700
But I can show you something 
you have never seen before.

204
00:14:47,589 --> 00:14:53,297
There is a transparent graphene 
patterned into wired structures

205
00:14:54,225 --> 00:14:57,775
on this transparent polymer wing.

206
00:14:58,486 --> 00:15:01,756
The graphene is so special

207
00:15:01,756 --> 00:15:05,536
that once we put a tiny amount 
of energy, it will shrink.

208
00:15:06,486 --> 00:15:10,136
And graphene is so strong 
that it can lift up

209
00:15:10,136 --> 00:15:14,486
this polymer wing, which is 
a thousand times heavier,

210
00:15:14,486 --> 00:15:18,486
and mimic the flapping
function of a bio robot.

211
00:15:23,615 --> 00:15:28,225
Look at what I have done 
and achieved in these few years.

212
00:15:29,925 --> 00:15:32,385
With all of you involved in my endeavor

213
00:15:32,385 --> 00:15:35,965
to mass produce high quality 
large scale graphene,

214
00:15:35,965 --> 00:15:39,965
I believe we can make our dream 
come true together.

215
00:15:39,965 --> 00:15:41,485
Thank you.

216
00:15:41,485 --> 00:15:42,675
(Applause)