Researchers figure out how to 'grow' carbon nanotubes with specific atomic structures

August 26, 2013

Move over, silicon. In a breakthrough in the quest for the next generation of computers and materials, researchers at USC have solved a longstanding challenge with carbon nanotubes: how to actually build them with specific, predictable atomic structures.

"We are solving a of the carbon nanotube," said Chongwu Zhou, professor in the Ming Hsieh Department of Electrical Engineering at the USC Viterbi School of Engineering and corresponding author of the study published August 23 in the journal Nano Letters. "To be able to control the atomic structure, or , of nanotubes has basically been our dream, a dream in the nanotube field."

If this is an age built on silicon, then the next one may be built on carbon nanotubes, which have shown promise in everything from optics to to touch screens. Not only are nanotubes transparent, but this research discovery on how to control the atomic structure of nanotubes will pave the way for computers that are smaller, faster and more energy efficient than those reliant on .

"We are now working on scale up the process," Zhou said. "Our method can revoutionize the field and significantly push forward the real applications of nanotube in many fields."

Until now, scientists were unable to "grow" carbon nanotubes with specific attributes—say metallic rather than semiconducting—instead getting mixed, random batches and then sorting them. The sorting process also shortened the nanotubes significantly, making the material less practical for many applications.

For more than three years, the USC team has been working on the idea of using these short sorted nanotubes as "seeds" to grow longer nanotubes, extending them at to get the desired atomic structure.

A paper last year by the same team in Nature Communications outlined the technique, and in the current Nano Letters paper, the researchers report on their latest major success: identifying the "growth recipes" for building carbon nanotubes with specific atomic structures.

"We identify the mechanisms required for mass amplification of nanotubes," said co-lead author Jia Liu, a doctoral student in chemistry at the USC Dornsife College of Letters, Arts and Sciences, recalling the moment when, alone in a dark room, she finally saw the spectral data supporting their method. "It was my Eureka moment."

"To understand nanotube growth behaviors allows us to produce larger amounts of nanotubes and better control that growth," she continued.

Each defined type of has a frequency at which it expands and contracts. The researchers showed that the newly grown nanotubes had the same atomic structure by matching the Raman frequency.

"This is a very exciting field, and this was the most difficult problem," said co-lead author Bilu Liu, a postdoctoral research associate at the USC Viterbi School of Engineering. "I met Professor Zhou [senior author of the paper] at a conference and he said he wanted to tackle the challenge of controlling the atomic structure of nanotubes. That's what brought me to his lab, because it was the biggest challenge."

In addition, the study found that nanotubes with different structures also behave very differently during their growth, with some nanotube structures growing faster and others growing longer under certain conditions.

"Previously it was very difficult to control the chirality, or atomic structure, of nanotubes, particularly when using metal nanoparticles," Bilu Liu said. "The structures may look quite similar, but the properties are very different. In this paper we decode the atomic structure of nanotubes and show how to control precisely that ."

Explore further: Carbon nanotube forest camouflages 3-D objects

Related Stories

Carbon nanotube forest camouflages 3-D objects

November 21, 2011

Carbon nanotubes, tiny cylinders composed of one-atom-thick carbon lattices, have gained fame as one of the strongest materials known to science. Now a group of researchers from the University of Michigan is taking advantage ...

Future looks bright for carbon nanotube solar cells

June 18, 2013

(Phys.org) —In an approach that could challenge silicon as the predominant photovoltaic cell material, University of Wisconsin-Madison materials engineers have developed an inexpensive solar cell that exploits carbon nanotubes ...

Recommended for you

New nanomaterial maintains conductivity in 3-D

September 4, 2015

An international team of scientists has developed what may be the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in three dimensions.

Graphene made superconductive by doping with lithium atoms

September 2, 2015

(Phys.org)—A team of researchers from Germany and Canada has found a way to make graphene superconductive—by doping it with lithium atoms. In their paper they have uploaded to the preprint server arXiv, the team describes ...

Making nanowires from protein and DNA

September 3, 2015

The ability to custom design biological materials such as protein and DNA opens up technological possibilities that were unimaginable just a few decades ago. For example, synthetic structures made of DNA could one day be ...

For 2-D boron, it's all about that base

September 2, 2015

Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.