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Topology, structure and defects in carbon nanosystems
Published on May 09, 20077167 Views
In this talk we will explore how in the last twenty years carbon science has made the fundamental step from the flat world of graphite into the three dimensional world of fullerenes and nanotubes, the
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Topology, structure and defects in carbon nanosystems 00:00
Institute of Materials Nantes, France01:53
slide302:16
In English often called a “lead pencil” Not correct! It´s actually GRAPHITE One of the pure forms of carbon02:29
Carbon02:46
slide603:07
slide703:36
3 equivalent bonds leads to formation of hexagons03:55
slide903:56
Graphite sheets are flat04:14
slide1104:23
slide1205:05
Graphite Electrodes05:46
Vacuum06:02
Generate a large electric spark between two graphite electrodes, and study the soot that comes off…06:07
Exxon Data Cox et al JACS 110 1588 (1988)06:20
slide1707:17
slide1807:31
C60 Buckminsterfullerene “Buckyball”07:50
Generate a large electric spark between two graphite electrodes, and study the soot that comes off…08:03
How do we make a pentagon from graphite?08:16
How do we make a pentagon from graphite?0108:22
How do we make a pentagon from graphite?0208:28
How do we make a pentagon from graphite?0308:32
Pentagon08:56
12 pentagons and any number of hexagons will form a closed object08:59
slide2709:16
Zoran Pavlovic 09:27
Jonathan Hare Creative Science Centre09:32
H. Kroto09:59
H. Kroto0110:10
H. Kroto0210:17
H. Kroto0310:22
H. Kroto0410:23
slide3510:39
Ernst Haeckel The Art of Nature 190010:44
Ernst Haeckel The Art of Nature 1900 0111:04
Ernst Haeckel The Art of Nature 1900 0211:08
slide3911:23
slide4011:33
From patent application of R. Buckminster Fuller for “geodesic dome”.11:35
From patent application of R. Buckminster Fuller for “geodesic dome”.11:52
slide4312:12
EPCOT Centre, Florida, USA12:15
Buckminster Fuller On the cover of Time Magazine12:20
Buckminster Fuller On the cover of Time Magazine12:24
Buckminster Fuller On the cover of Time Magazine12:26
How else can we go from flat to curved?12:30
Nanotube12:49
slide5012:59
slide5113:28
Typical Nanotube Properties13:48
Typical Nanotube Properties0113:59
Harry Kroto14:25
Harry Kroto0114:38
Nanotube flexing14:45
Arc-electric process makes nanotubes too (as for C60)15:11
© Calvin (2006)15:19
slide5915:27
slide6015:32
M. Endo (Shinshu University) 15:52
slide6216:10
Also Multi-walled Carbon Nanotubes (tubes within tubes)16:24
6416:37
Single walled nanotubes containing Li metal produced by electrolysis 16:52
1nm17:05
Electronic Properties?17:08
Electronic properties depend on how the tubes are rolled, and what diameter they have.17:13
Cees Dekker, Delft Institute of Technology, the Netherlands 17:45
A nanotube transistor using conventional silicon as the “gate” (switch)17:53
The “kink” separates metallic and semi-conducting regions18:00
Current-voltage characteristics across the kink at 100 K.18:13
Nanotubes for field-emission18:20
Spinning fibres with a composite of carbon nanotubes and a polymer matrix18:36
Damaging Nanotubes19:39
Damaging Nanotubes 0119:49
Defects improving mechanical properties20:48
Defects improving mechanical properties0121:53
Defects reducing mechanical properties23:06
Defects reducing mechanical properties0124:00
Defects reducing mechanical properties 0224:30
“Active Sites” also good for…25:30
How to induce ‘active sites’?27:20
Convergence27:39
Electron microscopy of ‘pea-pod’ defects28:08
Electron microscopy of ‘pea-pod’ defects 0128:45
Electron microscopy of ‘pea-pod’ defects 0229:27
What happens when we shine an electron beam on a carbon nanotube?30:25
What happens when we shine an electron beam on a carbon nanotube? 0130:57
Molecular dynamics simulations of emission process31:15
Calculation of the ejection energy threshold through DFT methods32:13
Emission energy threshold anisothropy32:29
Below the irradiation energy threshold32:50
Below the irradiation energy threshold 0133:26
Below the irradiation energy threshold 0234:27
Just above the irradiation energy threshold34:40
slide9735:39
slide9836:03
Thanks to…36:11