Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

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

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

NANOPOSTER 2015 - 5th Virtual Nanotechnology Conference - call for abstracts January 24th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Govt.-Legislation/Regulation/Funding/Policy

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Harper Government Supports Research Innovation in Western Canada January 22nd, 2015

EnvisioNano: An image contest hosted by the National Nanotechnology Initiative (NNI) January 22nd, 2015

Nanomedicine

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

2nd International Conference on Infectious Diseases & Nanomedicine (December 15-18, 2015, Kathmandu, NEPAL) January 22nd, 2015

Anti-microbial coatings with a long-term effect for surfaces presentation at nano tech 2015 in Japan January 21st, 2015

A spoonful of sugar in silver nanoparticles to regulate their toxicity January 21st, 2015

Sensors

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Iranian Scientists Produce Graphene-Based Oxygen Sensor January 23rd, 2015

Graphene brings quantum effects to electronic circuits January 22nd, 2015

New method to generate arbitrary optical pulses January 21st, 2015

Discoveries

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Iranian Scientists Produce Graphene-Based Oxygen Sensor January 23rd, 2015

Silver nanowires demonstrate unexpected self-healing mechanism: The material has potential for flexible electronics January 23rd, 2015

Announcements

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

NANOPOSTER 2015 - 5th Virtual Nanotechnology Conference - call for abstracts January 24th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Photonics/Optics/Lasers

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

New method to generate arbitrary optical pulses January 21st, 2015

New signal amplification process set to transform communications, imaging, computing: UC San Diego researchers discover a mechanism to amplify signals in optoelectronic systems that is far more efficient than standard processes January 21st, 2015

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 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE