Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Nanobelts support manipulation of light: Rice University lab discovers tiny gold bars have strong plasmonic properties

Gold nanobelts less than 100 nanometers wide, seen under a dark-field microscope, scatter light in specific colors depending on their cross-sectional aspect ratio -- width divided by height. The belts could be useful in biomedical and sensing applications.
(Credit Hafner Lab/Rice University)
Gold nanobelts less than 100 nanometers wide, seen under a dark-field microscope, scatter light in specific colors depending on their cross-sectional aspect ratio -- width divided by height. The belts could be useful in biomedical and sensing applications.

(Credit Hafner Lab/Rice University)

Abstract:
They look like 2-by-4s, but the materials being created in a Rice University lab are more suited to construction with light.

Researcher Jason Hafner calls them "nanobelts," microscopic strips of gold that could become part of highly tunable sensors or nanomedical devices.

Hafner, an associate professor of physics and astronomy and of chemistry, and his colleagues reported their discovery online this week in the American Chemical Society journal Nano Letters.

Nanobelts support manipulation of light: Rice University lab discovers tiny gold bars have strong plasmonic properties

Houston, TX | Posted on October 13th, 2011

Nanobelts represent a unique way to manipulate light at the microscopic scale. They join smaller nanoparticles like gold nanorods and nanoshells that can be tuned to absorb light strongly at certain wavelengths and then steer the light around or emit it in specific directions.

The effect is due to surface plasmons, which occur when free electrons in a metal or doped dielectric interact strongly with light. When prompted by a laser, the sun or other energy source, they oscillate like ripples on a pond and re-emit energy either as light or heat. They are the focus of much research for their potential benefits in biomedical applications, molecular sensing and microelectronics.

Nanobelts are unique because the plasmonic waves occur across their width, not along their length, Hafner said. "My intuition says that isn't likely. Why would you get a sharp resonance in the short direction when the electrons can go long? But that's what happens."

Nanobelts scatter light at a particular wavelength (or color), depending on the aspect ratio of their cross sections - width divided by height. That makes them highly tunable, Hafner said, by controlling that aspect ratio.

He was quick to point out his lab didn't make the first gold nanobelts. "We first searched the literature for a way to make a structure that might have a sharp resonance, because we wanted a large field enhancement," he said, referring to a technique he uses to characterize the effect of local environment on nanoparticle emissions.

The team found what it was looking for in a 2008 Langmuir paper by a Peking University team. "They made the same structure, but they didn't look too closely at the optical properties," he said. "They did beautiful work to discover the crystal structure and the growth direction, and they demonstrated the use of nanobelts in catalysis.

"As soon as we looked at the sample in a dark-field microscope, we instantly saw colors. We just couldn't believe it."

Hafner, a 1996 Rice alum who studied with the late Nobel laureate Richard Smalley, said growing nanobelts is a slow process. It takes 12 hours to synthesize a batch of nanobelts, which appear to grow in clusters from a central nucleus.

The team has grown nanobelts up to 100 microns long that range from basic square cross sections -- 25-by-25 nanometers -- to flattened, at 100 nanometers wide by 17 nanometers high. They found that the flatter the nanobelt, the more the scattered light shifted toward red.

"People have studied electrons moving the long way in these kinds of materials, but when they get too long the resonances detune out of the visible and the peaks become so broad that there's no sharp resonance anymore," Hafner said. "We're going across the nanobelt, so length doesn't matter. The nanobelt could be a meter long and still show sharp plasmon resonance."

Co-authors of the paper are graduate students Lindsey Anderson, Courtney Payne and Yu-Rong Zhen and Peter Nordlander, a professor of physics and astronomy and in electrical and computer engineering.

Support for the research came from the National Science Foundation and the Robert A. Welch Foundation.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its "unconventional wisdom." With 3,485 undergraduates and 2,275 graduate students, Rice's undergraduate student-to-faculty ratio is less than 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to www.rice.edu/nationalmedia/Rice.pdf.

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

Copyright © Rice University

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 Links

Read the abstract at:

Related News Press

News and information

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanosafety research – there’s room for improvement October 29th, 2014

Govt.-Legislation/Regulation/Funding/Policy

'Electronic skin' could improve early breast cancer detection October 29th, 2014

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanomedicine

'Electronic skin' could improve early breast cancer detection October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Molecular beacons shine light on how cells 'crawl' October 27th, 2014

New nanodevice to improve cancer treatment monitoring October 27th, 2014

Sensors

Tiny carbon nanotube pores make big impact October 29th, 2014

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Journal Nanotechnology Progress International (JONPI), 2014, Volume 5, Issue 1, pp 1-24 October 22nd, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Discoveries

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanoparticles Display Ability to Improve Efficiency of Filters October 28th, 2014

Announcements

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanosafety research – there’s room for improvement October 29th, 2014

Photonics/Optics/Lasers

Watching the hidden life of materials: Ultrafast electron diffraction experiments open a new window on the microscopic world October 27th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 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