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Posted: July 24, 2007
Development of an inexpensive method for mass synthesis of single-walled carbon nanotubes
(Nanowerk News) Kenji Hata and Tatsuki Hiraoka of the Nano-Carbon Materials Team, the Research Center for Advanced Carbon Materials of the National Institute of Advanced Industrial Science and Technology (AIST) and Zeon Corporation have jointly developed a technology to synthesize a large amount of single-walled carbon nanotubes directly on large area metal substrates for the first time. They used a "super-growth" CVD method, which is one of the methods of synthesizing single-walled carbon nanotubes.
The standard "super-growth" method uses an expensive silicon substrate to synthesize single-walled carbon nanotubes, but this research succeeded in synthesis on inexpensive nickel alloy substrates.
Synthesis of single-walled carbon nanotubes structure fabricated on the various mixed alloy substrates (Ni-Fe-Cr); magnified view shows vertically aligned nanotubes in the structure. (Images: AIST)
At the same time, the research team designed and built a trial synthesis furnace that can utilize the newly developed technology jointly with Zeon Corp., and successfully synthesized single-walled carbon nanotubes with a uniform structure spanning an A4 size foil substrate. This large area synthesis is a 100-fold jump from conventional levels, and production was scaled in units of grams.
Single-walled carbon nanotubes synthesized by this newly-developed technology grow upward vertically from the metal foil, and it takes only 10 minutes to form a structure of 1 mm height. The single-walled carbon nanotubes exhibit excellent properties, including the world's highest level of purity and greatest specific surface and length, similar to those synthesized on silicon substrates, and they are considered to be promising for various applications such as super-capacitors and actuators.
The newly developed technology reduces the substrate cost to one-hundredth of the existing cost. As the key technology for developing a large-area and continuous production technology for carbon nanotubes, it is paving the way for industrial mass production of single-walled carbon nanotubes. Some of the results of this research have been published in the Journal of the American Chemical Society.