Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

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 method to reduce uranium concentration in contaminated water March 18th, 2019

Review of the recent advances of 2D nanomaterials in Lit-ion batteries March 15th, 2019

Converting biomass by applying mechanical force Nanoscientists discover new mechanism to cleave cellulose effectively and in an environmentally friendly way March 15th, 2019

Exotic “second sound” phenomenon observed in pencil lead: At relatively balmy temperatures, heat behaves like sound when moving through graphite, study reports March 15th, 2019

Govt.-Legislation/Regulation/Funding/Policy

Exotic “second sound” phenomenon observed in pencil lead: At relatively balmy temperatures, heat behaves like sound when moving through graphite, study reports March 15th, 2019

Researchers reverse the flow of time on IBM's quantum computer March 14th, 2019

When semiconductors stick together, materials go quantum: A new study led by Berkeley Lab reveals how aligned layers of atomically thin semiconductors can yield an exotic new quantum material March 12th, 2019

Arrowhead Pharmaceuticals Begins Dosing in Phase 1 Study of ARO-APOC3 for Treatment of Hypertriglyceridemia March 11th, 2019

Nanomedicine

Arrowhead Pharmaceuticals Begins Dosing in Phase 1 Study of ARO-APOC3 for Treatment of Hypertriglyceridemia March 11th, 2019

New optical imaging system could be deployed to find tiny tumors: Near-infrared technology pinpoints fluorescent probes deep within living tissue; may be used to detect cancer earlier March 8th, 2019

Computer-designed vaccine elicits potent antibodies against RSV: The nanoparticle platform for this respiratory syncytial virus study will be applied to vaccine research on flu, HIV, and more; Seattle startup Icosavax will advance related clinical trials March 8th, 2019

CEA-Leti Breakthrough Opens Path to New Vaccine for HIV: Lipidots Platform Strengthens Immune Response to Protein That Is Key to HIV Vaccine; Results Presented in Nature Publishing Group’s npj Vaccines February 27th, 2019

Sensors

Quantum sensing method measures minuscule magnetic fields: MIT researchers find a new way to make nanoscale measurements of fields in more than one dimension March 15th, 2019

Oxford Instruments and partners launch EU Horizon 2020 project ULISSES: Air sensors for everyone, everywhere March 7th, 2019

With nanopore sensing, VCU physics researchers detect subtle changes in single particles: The researchers' findings 'open the door to observe all kinds of interesting phenomenon on nanosurfaces,' an area of great interest to chemists February 21st, 2019

CEA-Leti & Stanford Target Edge-AI Apps with Breakthrough Memory Cell: Paper at ISSCC 2019 Presents Proof-of-Concept Multi-Bit Chip That Overcomes NVM’s Read/Write, Latency and Integration Challenges February 20th, 2019

Discoveries

New method to reduce uranium concentration in contaminated water March 18th, 2019

Review of the recent advances of 2D nanomaterials in Lit-ion batteries March 15th, 2019

Converting biomass by applying mechanical force Nanoscientists discover new mechanism to cleave cellulose effectively and in an environmentally friendly way March 15th, 2019

Quantum sensing method measures minuscule magnetic fields: MIT researchers find a new way to make nanoscale measurements of fields in more than one dimension March 15th, 2019

Announcements

New method to reduce uranium concentration in contaminated water March 18th, 2019

Review of the recent advances of 2D nanomaterials in Lit-ion batteries March 15th, 2019

Converting biomass by applying mechanical force Nanoscientists discover new mechanism to cleave cellulose effectively and in an environmentally friendly way March 15th, 2019

Exotic “second sound” phenomenon observed in pencil lead: At relatively balmy temperatures, heat behaves like sound when moving through graphite, study reports March 15th, 2019

Photonics/Optics/Lasers

New blueprint for understanding, predicting and optimizing complex nanoparticles: Guidelines have the potential to transform the fields of optoelectronics, bio-imaging and energy harvesting March 1st, 2019

Hybrid material may outperform graphene in several applications: A structure comprising a molybdenum disulfide monolayer on an azobenzene substrate could be used to build a highly compactable and malleable quasi-two-dimensional transistor powered by light February 28th, 2019

Researchers move closer to practical photonic quantum computing: New method fills critical need to measure large-scale quantum correlation of single photons February 28th, 2019

AIM Photonics Attends OFC 2019—the Optical Networking and Communication Conference & Exhibition to Share World-Class Capabilities and Partnership Opportunity Updates February 28th, 2019

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project