Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Paperwork: Buckypapers Clarify Electrical, Optical Behavior of Nanotubes

Buckypaper: SEM image demonstrates a pseudo 2-D network of carbon nanotubes deposited like paper fibers in a thin, sparse sheet. The nanotubes here have an average length 820 nm and make a continuous, electrically conducting network overall in spite of obvious gaps. On a macroscale this material would be nearly transparent. Color added for clarity

Credit: Chastek/Talbott NIST
Buckypaper: SEM image demonstrates a pseudo 2-D network of carbon nanotubes deposited like paper fibers in a thin, sparse sheet. The nanotubes here have an average length 820 nm and make a continuous, electrically conducting network overall in spite of obvious gaps. On a macroscale this material would be nearly transparent. Color added for clarity

Credit: Chastek/Talbott NIST

Abstract:
Using highly uniform samples of carbon nanotubes—sorted by centrifuge for length—materials scientists at the National Institute of Standards and Technology (NIST) have made some of the most precise measurements yet of the concentrations at which delicate mats of nanotubes become transparent, conducting sheets. Their recent experiments* point up the importance of using relatively homogeneous—not overly short, but uniform in length— nanotubes for making high performance conducting films.

Paperwork: Buckypapers Clarify Electrical, Optical Behavior of Nanotubes

GAITHERSBURG, MD | Posted on October 15th, 2008

Among their other qualities, single-wall carbon nanotubes (SWCNTs) have attracted much attention as tiny electrical conductors. Relatively small concentrations of nanotubes can change a normally insulating polymer film to a transparent electrical conductor. Potential applications range from transparent electrical shielding materials to futuristic flexible video displays, thin-film chemical sensors and other foldable electronics. One key design parameter for conductive films is the so-called "percolation threshold"—essentially the concentration at which random two- or three-dimensional networks of nanotubes first become electrically conducting.

To test theories on how both the conductance and optical properties of such nanotube-infused films depend on the length of the tubes, the NIST team made samples of "buckypaper" by mixing nanotubes in water and draining the water away through nanoscale filters to leave behind a delicate nanotube mat. The highly refined, length-sorted nanotube samples were produced by an efficient technique developed earlier by the NIST group (see "Spin Control: New Technique Sorts Nanotubes by Length").

The NIST measurements validated one theory: buckypaper made of length-sorted carbon nanotubes closely follows the percolation theory for ideal two-dimensional sheets, with concentration threshold for conductivity getting lower as the tubes get longer. A sheet of 820 nanometer long nanotubes becomes conducting at an amazingly low 18 nanograms per square centimeter, the lowest yet reported. Interestingly, batches of short nanotubes or mixed-length batches form more three-dimensional networks that perform noticeably worse. On the other hand, predictions that optically the sheets would behave like thin metallic films turn out not to be the case. Optical properties are better predicted by the same general percolation theory, say the NIST researchers, which will provide a convenient theoretical framework for designing and engineering nanotech applications with these materials.

* D. Simien, J.A. Fagan, W. Luo, J.F. Douglas, K. Migler and J. Obrzut. Influence of nanotube length on the optical and conductivity properties of thin single-wall carbon nanotube networks. ACS Nano, Vol.. 2 , No. 9, 1879-1884.

####

For more information, please click here

Contacts:
Michael Baum

301-975-2763

Copyright © National Institute of Standards and Technology (NIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Oregon researchers glimpse pathway of sunlight to electricity: Collaboration with Lund University uses modified UO spectroscopy equipment to study 'maze' of connections in photoactive quantum dots December 19th, 2014

Instant-start computers possible with new breakthrough December 19th, 2014

Aculon Hires New Business Development Director December 19th, 2014

Iranian Scientists Use Nanotechnology to Increase Power, Energy of Supercapacitors December 18th, 2014

Nanotubes/Buckyballs

A sponge-like molecular cage for purification of fullerenes December 15th, 2014

'Trojan horse' proteins used to target hard-to-reach cancers: Scientists at Brunel University London have found a way of targeting hard-to-reach cancers and degenerative diseases using nanoparticles, but without causing the damaging side effects the treatment normally brings December 11th, 2014

Detecting gases wirelessly and cheaply: New sensor can transmit information on hazardous chemicals or food spoilage to a smartphone December 8th, 2014

Green meets nano: Scientists at TU Darmstadt create multifunctional nanotubes using nontoxic materials December 3rd, 2014

Discoveries

Oregon researchers glimpse pathway of sunlight to electricity: Collaboration with Lund University uses modified UO spectroscopy equipment to study 'maze' of connections in photoactive quantum dots December 19th, 2014

Instant-start computers possible with new breakthrough December 19th, 2014

Creation of 'Rocker' protein opens way for new smart molecules in medicine, other fields December 18th, 2014

Iranian Scientists Use Nanotechnology to Increase Power, Energy of Supercapacitors December 18th, 2014

Announcements

Oregon researchers glimpse pathway of sunlight to electricity: Collaboration with Lund University uses modified UO spectroscopy equipment to study 'maze' of connections in photoactive quantum dots December 19th, 2014

Instant-start computers possible with new breakthrough December 19th, 2014

Aculon Hires New Business Development Director December 19th, 2014

Iranian Scientists Use Nanotechnology to Increase Power, Energy of Supercapacitors December 18th, 2014

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE