Navigation Links
A recipe for controlling carbon nanotubes
Date:9/20/2009

CLEVELAND Nanoscopic tubes made of a lattice of carbon just a single atom deep hold promise for delivering medicines directly to a tumor, sensors so keen they detect the arrival or departure of a single electron, a replacement for costly platinum in fuel cells or as energy‐saving transistors and wires.

Single‐walled carbon nanotubes, made of a cheap and abundant material, have so much potential because their function changes when their atomic‐level structure, referred to as chirality, changes.

But for all their promise, building tubes with the right structure has proven a challenge.

A pair of Case Western Reserve University researchers mixed metals commonly used to grow nanotubes and found that the composition of the catalyst can control the chirality.

In a letter to be published Sept. 20 in the online edition of Nature Materials, R. Mohan Sankaran, an assistant professor of chemical engineering at the Case School of Engineering, and Wei‐Hung Chiang, who received his doctorate degree in chemical engineering in May, describe their findings.

"We have established a link between the structure of a catalyst and the chirality of carbon nanotubes," Sankaran said. "Change the catalyst structure by varying its composition, and you can begin to control the chirality of the nanotubes and their electrical and optical properties."

The chirality of a single‐walled carbon nanotube describes how a lattice of carbon atoms is rolled into a tube. The rolling can occur at different angles, producing different structures that exhibit very different properties.

Nanotubes are normally grown in bulk mixtures. When using a nickel catalyst, typically one‐third of those grown are metallic and could be used like metal wires to conduct electricity. About two‐thirds are semiconducting nanotubes, which could be used as transistors, Chiang explained. But, separating them according to properties, "is costly and can damage the nanotubes."

Better to make what you want.

Chiang and Sankaran found that a mixed iron and nickel catalyst could change the outcome. Of the compositions tested, a catalyst of 27 percent nickel and 73 percent iron produced the most dramatic result: the vast majority of the nanotubes were semiconducting. They are now working on assessing the purity and integrating the nanotubes into thin film transistors.

The authors say their findings open the door to experimenting with other elements as catalysts and different combinations, which may produce near‐pure nanotubes with desired properties.


'/>"/>

Contact: Kevin Mayhood
kevin.mayhood@case.edu
216-534-7183
Case Western Reserve University
Source:Eurekalert

Related biology technology :

1. China Biologic Products Completes Acquisition of 90% Controlling Interest in Chongqing Dalin Biologic Technologies Co., Ltd.
2. Light-speed nanotech: Controlling the nature of graphene
3. China Biologic Products Enters Into Agreement to Acquire 90% Controlling Interest in Chongqing Dalin Biologic Technologies Co., Ltd.
4. Controlling the size of nanoclusters
5. Light touch: Controlling the behavior of quantum dots
6. Controlling the size of nanoclusters: First step in making new catalysts
7. ProMetic to obtain controlling stake in Pathogen Removal and Diagnostic Technologies Inc.
8. Gladstone scientists identify role of tiny RNAs in controlling stem cell fate
9. Halocarbon Announces Licensing Agreement with IBM
10. Biopolymers Symposium 2009 Teams with Carbonfund.org to Create a Zero-Carbon Event
11. Ricardo Launches Consortium to Evaluate Lubricant Challenges of Future Low Carbon Engine Technologies
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... ... June 27, 2016 , ... Parallel 6 , the leading ... the Clinical Reach Virtual Patient Encounter CONSULT module which enables both audio ... and clinical trial team. , Using the CONSULT module, patients and physicians can schedule ...
(Date:6/24/2016)... TOKYO , June 24, 2016  Regular discussions on ... to take place between the two entities said Poloz. ... in Ottawa , he pointed to the ... and the federal government. ... Poloz said, "Both institutions have common economic goals, why not ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one ... of their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has ... add Target to its list of well-respected retailers. This list includes such fine ...
(Date:6/23/2016)... ... June 23, 2016 , ... Charm Sciences, Inc. is ... has received AOAC Research Institute approval 061601. , “This is another AOAC-RI approval ... Bob Salter, Vice President of Regulatory and Industrial Affairs. “The Peel Plate methods ...
Breaking Biology Technology:
(Date:6/22/2016)... June 22, 2016 On Monday, the Department ... industry to share solutions for the Biometric Exit Program. ... and Border Protection (CBP), explains that CBP intends to ... the United States , in order ... defeat imposters. Logo - http://photos.prnewswire.com/prnh/20160622/382209LOGO ...
(Date:6/9/2016)... June 9, 2016  Perkotek an innovation leader in attendance control systems is proud ... work hours, for employers to make sure the right employees are actually signing in, ... ... ... ...
(Date:6/2/2016)... 2, 2016   The Weather Company , an IBM ... an industry-first capability in which consumers will be able to ... ask questions via voice or text and receive relevant information ... Marketers have long sought an advertising solution that ... be personal, relevant and valuable; and can scale across millions ...
Breaking Biology News(10 mins):