Growing nanotubes in a targeted way

(Nanowerk News) They are light yet stronger than steel, as a semiconductor they are more efficient than silicon, and they conduct electricity better than copper: carbon nanotubes. For the first time, a team of international researchers, some of whom are based at FAU, have grown single-walled carbon nanotubes in a targeted way. It is hoped that their method could pave the way for new materials which could be used in light detectors, photovoltaic components, transistors or sensors.
Precursor molecules (yellow) act as seeds which allow the flat sheet of carbon atoms to form a nanotube
Precursor molecules (yellow) act as seeds which allow the flat sheet of carbon atoms to form a tube. (Image: Konstantin Amsharov)
In recent years, more and more research has been focusing on single-walled carbon nanotubes (SWCNT) due to their extraordinary thermal, mechanical, electronic and optical properties. They are currently the most promising material which could allow microelectronics to enter the nanometre range. However, until now, there has not been a suitable method which allows nanotubes with the desired properties to be produced simply, reliably and in large quantities.
The carbon nanotubes which the researchers have produced are made of a single-walled layer of carbon in the form of a cylinder. The tubes’ properties depend on two factors: the diameter of the tube – around one nanometre – and the chirality, which means whether and how the carbon lattice is twisted relative to the tube’s axis. However, for the nanotubes to be of interest for use in electronic components, it must be possible to produce them in a targeted way to make them suitable for their intended purpose – as a conductor or semiconductor, for example – and they should be virtually defect-free.
A team of researchers led by Dr. Konstantin Amsharov at the Chair of Organic Chemistry II and his colleague Prof. Dr. Roman Fasel from Empa (Swiss Federal Laboratories for Materials Science and Technology) have succeeded in creating single-walled and largely defect-free carbon nanotubes with a defined chirality from molecular precursors in a controlled way. These precursor molecules form a kind of seed on a platinum surface which helps a flat sheet of carbon atoms to form a tube. The researchers expect that they will soon have enough of these nanotubes to carry out detailed experiments on them and test their properties.
Source: Friedrich-Alexander-Universität Erlangen-Nürnberg
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