. Nano Technology News .




.
NANO TECH
Perfect nanotubes shine brightest
by Staff Writers
Houston TX (SPX) Feb 06, 2012

See a video of fluorescent carbon nanotubes here. A video produced by the Rice University lab of chemist Bruce Weisman shows a selection of nanotubes fluorescing as they twist and turn in a solution. New work at Rice revealed how the fluorescent properties of specific types of nanotubes are influenced by the length of the tube and any imperfections. Weisman said those properties may be important to medical imaging and industrial applications. (Credit: Jason Streit/Rice University)

A painstaking study by Rice University has brought a wealth of new information about single-walled carbon nanotubes through analysis of their fluorescence.

The current issue of the American Chemical Society journal ACS Nano features an article about work by the Rice lab of chemist Bruce Weisman to understand how the lengths and imperfections of individual nanotubes affect their fluorescence - in this case, the light they emit at near-infrared wavelengths.

The researchers found that the brightest nanotubes of the same length show consistent fluorescence intensity, and the longer the tube, the brighter. "There's a rather well-defined limit to how bright they appear," Weisman said. "And that maximum brightness is proportional to length, which suggests those tubes are not affected by imperfections."

But they found that brightness among nanotubes of the same length varied widely, likely due to damaged or defective structures or chemical reactions that allowed atoms to latch onto the surface.

The study first reported late last year by Weisman, lead author/former graduate student Tonya Leeuw Cherukuri and postdoctoral fellow Dmitri Tsyboulski detailed the method by which Cherukuri analyzed the characteristics of 400 individual nanotubes of a specific physical structure known as (10,2).

"It's a tribute to Tonya's dedication and talent that she was able to make this large number of accurate measurements," Weisman said of his former student.

The researchers applied spectral filtering to selectively view the specific type of nanotube. "We used spectroscopy to take this very polydisperse sample containing many different structures and study just one of them, the (10,2) nanotubes," Weisman said. "But even within that one type, there's a wide range of lengths."

Weisman said the study involved singling out one or two isolated nanotubes at a time in a dilute sample and finding their lengths by analyzing videos of the moving tubes captured with a special fluorescence microscope. The movies also allowed Cherukuri to catalog their maximum brightness.

"I think of these tubes as fluorescence underachievers," he said. "There are a few bright ones that fluoresce to their full potential, but most of them are just slackers, and they're half as bright, or 20 percent as bright, as they should be.

"What we want to do is change that distribution and leave no tube behind, try to get them all to the top. We want to know how their fluorescence is affected by growth methods and processing, to see if we're inflicting damage that's causing the dimming.

"These are insights you really can't get from measurements on bulk samples," he said.

Graduate student Jason Streit is extending Cherukuri's research. "He's worked up a way to automate the experiments so we can image and analyze dozens of nanotubes at once, rather than one or two. That will let us do in a couple of weeks what had taken months with the original method," Weisman said.

Related Links
Rice University
Nano Technology News From SpaceMart.com
Computer Chip Architecture, Technology and Manufacture




.
.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries




.

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



NANO TECH
Bright Lights of Purity
Berkeley CA (SPX) Feb 06, 2012
To the lengthy list of serendipitous discoveries - gravity, penicillin, the New World - add this: Scientists with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered why a promising technique for making quantum dots and nanorods has so far been a disappointment. Better still, they've also discovered how to correct the problem. A team o ... read more


NANO TECH
China bans airlines from paying EU carbon charges

Helicopters set to become more manoeuvrable - using humpback whales as the prototype

Snow and fog ground half of London Heathrow's flights

Singapore Airlines 3Q net profit down 53 percent on-year

NANO TECH
China's satellite navigation sector annual output predicted to reach 35 bln USD in 2015

China plans to launch 21 rockets, 30 satellites this year

Shenzhou 9 Behind the Curtain

China Plans to Launch 30 Satellites in 2012

NANO TECH
Anonymous posts audio of FBI, Scotland Yard call

Turkey investigates army's 2007 'e-coup'

Russia Must Be Ready for Space, Cyber Wars

Report: Real arms race is in cyberspace

NANO TECH
Electricity Access Still Insufficient in Developing Countries

Portugal sells 40% of electric grid to China, Oman firms

Euro Parliament backs low-carbon road map

US Military Sets Ambitious Environmental Goals

NANO TECH
BP swings into huge profit before US criminal trial

Italy to hold gas talks as cold snap toll hits 26

Iraqi businessmen shy away from Iranian currency

Chinese workers freed in Sudan: foreign ministry

NANO TECH
AAI Logistics and Technical Services Awarded USAF Contract for B-1B Training System Support

Lockheed Martin Awarded Contract to Support US Army Research Lab

US 'bunker-buster' not powerful enough against Iran

Iran says it has laser-guided artillery rounds

NANO TECH
Self-assembling nanorods

Perfect nanotubes shine brightest

Bright Lights of Purity

Nano-oils keep their cool

NANO TECH
Robot competition in zero-gravity

JPL begins widespread adoption of Maplesoft technology

Snakes Improve Search-and-Rescue Robots

NASA Joins MIT and DARPA for Out-of-This-World Student Robotic Challenge


.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement