Researchers Grow Single-Walled Carbon Nanotubes with Identical Electronic Properties


Using custom-made organic precursor molecules, researchers have succeeded for the first time in growing single-walled carbon nanotubes with identical electronic properties.

In future, it will be possible to specifically equip carbon nanotubes with properties which they need for electronic applications, for example. Researchers at Empa in Dübendorf/Switzerland and the Max Planck Institute for Solid State Research in Stuttgart have succeeded for the first time in growing single-walled carbon nanotubes (CNTs) with only a single, prespecified structure. The nanotubes thereby have identical electronic properties. The decisive trick here: The team has taken up an idea which originated from the Stuttgart-based Max Planck researchers and produced the CNT from custom-made organic precursor molecules. The researchers started with these precursor molecules and have built up the nanotubes on a platinum surface, as they report in the latest issue of the scientific journal Nature. Such CNTs could be used in future, for instance, in ultra-sensitive light detectors and very tiny transistors.

 

For 20 years, material scientists working on the development of carbon nanotubes for a range of applications have been battling a problem – now an elegant solution is at hand. With their unusual mechanical, thermal and electronic properties, the tiny tubes with their honeycomb lattice of graphitic carbon have become the embodiment of nanomaterials. They could be used to manufacture the next generation of electronic and electro-optical components so that they are even smaller and with even faster switching times than before. But to achieve this, the material scientists must specifically equip the nanotubes with desired properties, and these depend on their structure. The production methods used to date, however, always result in a mixture of different CNTs. The team from Empa and the Max Planck Institute for Solid State Research has now remedied the situation with a new production path for single-walled nanotubes.

The researchers have thus proved that they can unambiguously specify the growth and thus the structure of long SWCNTs using custom-made molecular seeds. The SWCNTs synthesized in this study can exist in two forms, which correspond to an object and its mirror image. By choosing the precursor molecule appropriately, the researchers were able to influence which of the two variants forms. Depending on how the honeycomb atomic lattice is derived from the original molecule – straight or oblique with respect to the CNT axis – it is also possible for helically wound tubes, i.e. with right- or left-handed rotation, and with non-mirror symmetry to form. And it is precisely this structure that then determines which electronic, thermo-electric and optical properties of the material. In principle, the researchers can therefore specifically produce materials with different properties through their choice of precursor molecule.

 

In further steps, Roman Fasel and his colleagues want to gain an even better understanding of how SWCNTs establish themselves on a surface. Even if well in excess of 100 million nanotubes per square centimeter already grow on the platinum surface, only a relatively small fraction of the seeds actually develop into «mature» nanotubes. The question remains as to which processes are responsible for this, and how the yield can be increased.

 

Publication: Juan Ramon Sanchez-Valencia, et al., “Controlled Synthesis of Single-Chirality Carbon Nanotubes,” Nature 512, 61–64 (07 August 2014) doi:10.1038/nature13607

 

Source: scitechdaily.com

Researchers at Empa in Switzerland and at the Max Planck Institute in Germany have perfected a new way of producing single-walled carbon nanotubes with identical electrical properties.  According to scientists involved in the ground-breaking project, these new nanotubes "could be used to manufacture the next generation of electronic and electro-optical components so that they are even smaller and with faster switching times than before."  Researchers believe such devices could "be used in ultra-light sensitive light detectors and very tiny transistors."  Applications of this new technology could be used in fields ranging from optical astronomy to amateur radio communications.  Keep your eye on this development.  Aloha de Russ (KH6JRM).

See on Scoop.itKH6JRM’s Amateur Radio Blog

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