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Controlled preparation and modification of carbon nanotubes

Controlled preparation and modification of carbon nanotubes

Forschungszentrum Karlsruhe
Lecture Hall, Bldg. 640, 0-167




Yan Li
College of Chemistry and Molecular Engineering
Peking University, China



Abstract: Single-walled carbon nanotubes (SWCNTs), which can be considered as a seamless cylinders formed by rolling a piece of graphene, may be either metallic or semiconducting depending on the manner of rolling denoted as (n,m) (or the ‘chirality’). Attribute to this unique electronic property and other excellent characteristics, SWCNTs are expected to be one of the most possible candidates of materials for future nanodevices. Our research concentrates on the controlled preparation and modification of SWCNTs for device applications.
 Some effective strategies for the preparation of horizontally-aligned ultralong SWCNT arrays were developed either by controlling the feeding gas flow or by using different new catalysts. Especially, nearly pure semiconducting SWCNT arrays on quartz substrates were prepared by using methanol and ethanol as the carbon source.
 A very simple method was developed to selectively and reversibly modify the metallic and large diameter semiconducting SWCNTs in ionic liquids by adding certain anion surfactants. The electronic band structure of SWCNTs can be controlled and tuned over a range by varying the surfactants used and their concentration. This method is mild without destroying the structure of SWCNTs.
 In addition, a method was developed for the full detection of SWCNTs on substrates by SERS. An electroless method comprising seed deposition and seeded growth realizes the decoration of surface-grown SWCNTs with gold nanoparticles of controlled size and small interparticle distance.