Going chiral: Breakthrough in synthesizing carbon nanotubes with precise chirality

Researchers have achieved a significant breakthrough in the synthesis of carbon nanotubes (CNTs) by developing a novel catalyst that allows for precise control over their atomic arrangement, known as chirality. This advancement paves the way for the creation of innovative semiconductor devices, addressing a challenge that has remained unresolved for over 30 years.

The team consisting of researchers across Japan, led by Associate Professor Toshiaki Kato from the Advanced Institute for Materials Research (WPI-AIMR), has successfully synthesized CNTs with a chiral index of (6,5) at an ultra-high purity of over 95%.

These findings were published in ACS Nano on August 20, 2024.

"A carbon nanotube is basically a sheet of carbon rolled into a hollow tube," explains Kato, "While it sounds simple, CNTs are highly sought after for properties such as their exceptional conductivity, optical characteristics, and mechanical strength."

It's no wonder they're nicknamed the "king of nanomaterials." This laundry list of desirable traits makes them a promising option for a truly broad number of applications - from constructing aircrafts and spaceships to developing biomedical devices.

"The inability to control CNT chirality has been a major barrier to their industrial application, so this project was undertaken to find a catalyst that could consistently produce the desired target," says Kato. Thus far, single-chirality synthesis with a purity of over 90% has only been achieved for (14,4) and (12,6) chiralities.

By introducing a new catalyst composed of nickel (Ni), tin (Sn), and iron (Fe), the researchers have opened a new pathway for chirality-controlled synthesis. This NiSnFe catalyst acts as a highly specialized growth catalyst, enabling the selective synthesis of (6,5) chirality CNTs. Furthermore, these chirality-pure bundle structures of (6,5) CNTs show more than a 20-fold increase in their photoluminescence lifetime, compared to isolated (6,5) CNTs. This technique could potentially be used in the future to achieve other chiralities as well.

The research team anticipates that their findings will lead to significant advancements in how semiconductor devices are manufactured and utilized.

About the World Premier International Research Center Initiative (WPI)

The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).

See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI
Main WPI program site:  www.jsps.go.jp/english/e-toplevel

Advanced Institute for Materials Research (AIMR)
Tohoku University
Establishing a World-Leading Research Center for Materials Science

AIMR aims to contribute to society through its actions as a world-leading research center for materials science and push the boundaries of research frontiers. To this end, the institute gathers excellent researchers in the fields of physics, chemistry, materials science, engineering, and mathematics and provides a world-class research environment.