Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > When aluminum outshines gold: Two Rice University studies detail aluminum’s valuable plasmonic properties

When an electromagnetic wave (left) hits a nanomatryushka (center and right) – a solid core inside a hollow shell – the size of the gap determines the strength of the plasmonic response. If the gap is sufficiently small, quantum tunneling through the gap allows plasmons to resonate as though the core and shell are a single particle, dramatically changing their response.Credit: Vikram Kulkarni/Rice University
When an electromagnetic wave (left) hits a nanomatryushka (center and right) – a solid core inside a hollow shell – the size of the gap determines the strength of the plasmonic response. If the gap is sufficiently small, quantum tunneling through the gap allows plasmons to resonate as though the core and shell are a single particle, dramatically changing their response.

Credit: Vikram Kulkarni/Rice University

Abstract:
Humble aluminum's plasmonic properties may make it far more valuable than gold and silver for certain applications, according to new research by Rice University scientists.

When aluminum outshines gold: Two Rice University studies detail aluminum’s valuable plasmonic properties

Houston, TX | Posted on December 2nd, 2013

Because aluminum, as nanoparticles or nanostructures, displays optical resonances across a much broader region of the spectrum than either gold or silver, it may be a good candidate for harvesting solar energy and for other large-area optical devices and materials that would be too expensive to produce with noble or coinage metals.

Until recently, aluminum had not yet been seen as useful for plasmonic applications for several reasons: It naturally oxidizes, and some studies have shown dramatic discrepancies between the resonant "color" of fabricated nanostructured aluminum and theoretical predictions.

The combined work of two Rice labs has addressed each of those hurdles in a pair of new publications.

One paper by the labs of Rice scientists Naomi Halas and Peter Nordlander, "Aluminum for Plasmonics," demonstrates that the color of aluminum nanoparticles depends not only on their size and shape, but also critically on their oxide content. They have shown that, in fact, the color of an aluminum nanoparticle provides direct evidence of the amount of oxidation of the aluminum material itself. The paper appears in the American Chemical Society (ACS) journal ACS Nano.

Manufacturing pure aluminum nanoparticles has been a roadblock in their development for plasmonics, but the Halas lab created a range of disk-shaped particles from 70 to 180 nanometers in diameter to test their properties. The researchers found that while gold nanoparticles' plasmons resonate in visible wavelengths from 550 to 700 nanometers and silver from 350 to 700, aluminum can reach into the ultraviolet, to about 200 nanometers.

The labs also characterized the weakening effect of naturally occurring but self-passivating oxidation on aluminum surfaces. "For iron, rust goes right through," Nordlander said. "But for pure aluminum, the oxide is so hard and impermeable that once you form a three-nanometer sheet of oxide, the process stops." To prove it, the researchers left their disks exposed to the open air for three weeks before testing again and found their response unchanged.

"The reason we use gold and silver in nanoscience is that they don't oxidize. But finally, with aluminum, nature has given us something we can exploit," Nordlander said.

The second paper by Nordlander and his group predicts quantum effects in plasmonic aluminum that are stronger than those in an analogous gold structure when in the form of a nanomatryushka, multilayer nanoparticles named for the famous Russian nesting dolls. Nordlander discovered the quantum mechanical effects in these materials are strongly connected to the size of the gap between the shell and the core. The paper appeared recently in the ACS journal Nano Letters.

"In addition to being a cheap and tunable material, it exhibits quantum mechanical effects at larger, more accessible and more precise ranges than gold or silver," Nordlander said. "We see this as a foundational paper."

Nordlander used computer simulations to investigate the discrepancies between classical electromagnetics and quantum mechanics, and precisely where the two theories diverge in both gold and aluminum nanomatryushkas. "Aluminum exhibits much more quantum behavior at a given gap size than gold," he said. "Basically for very small gaps, everything is in the quantum realm (where subatomic forces rule), but as you make the gap larger, the system turns to classical physics."

By small, Nordlander means well below a single nanometer (a billionth of a meter). With the gap between core and shell in a gold nanomatryushka at about half a nanometer, he and lead author Vikram Kulkarni, a Rice graduate student, found electrons gained the capability to tunnel from one layer to another in the nanoparticle. A 50 percent larger gap in aluminum allowed for the same quantum effect. In both cases, quantum tunneling through the gap allowed plasmons to resonate as though the core and shell were a single particle, dramatically enhancing their response.

The calculations should be of great interest to those who use nanoparticles as probes in Raman spectroscopy, where quantum tunneling between particles can dampen electric fields and throw off classical calculations, he said.

Nordlander noted that Kulkarni's algorithm allowed the team to run one of the largest quantum plasmonics calculations ever performed. They used the power of Rice's BlueBioU supercomputer to track a massive number of electrons. "It's easy to keep track of two children, but imagine if you had more than a million," he said.

Lead authors of "Aluminum for Plasmonics" are Rice graduate students Mark Knight and Nicholas King. Co-authors include graduate student Lifei Liu and Henry Everitt, a chief scientist at the U.S. Army's Charles Bowden Research Lab, Redstone Arsenal, Ala., and an adjunct professor at Duke University. The research was supported by the Robert A. Welch Foundation, the National Security Science and Engineering Faculty Fellowship, the Air Force Office of Scientific Research, the National Science Foundation's Major Research Instrumentation Program, the Army's in-house laboratory-independent research program and the Army Research Office.

Rice alumnus Emil Prodan, an assistant professor of physics at Yeshiva University, New York, is co-author of "Quantum Plasmonics: Optical Properties of a Nanomatryushka."

The research was supported by the Welch Foundation, the U.S. Army Research Laboratory, the National Institutes of Health, the National Science Foundation and an IBM Shared University Research Award in partnership with Cisco, Qlogic and Adaptive Computing. BlueBioU is administered by Rice's Ken Kennedy Institute for Information Technology.

Halas is the Stanley C. Moore Professor of Electrical and Computer Engineering, a professor of chemistry, biomedical engineering and physics and astronomy and director of the Laboratory for Nanophotonics. Nordlander is a professor of physics and astronomy and in electrical and computer engineering.

####

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 home to the Baker Institute for Public Policy. With 3,708 undergraduates and 2,374 graduate students, Rice’s undergraduate student-to-faculty ratio is 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. 2 for “best value” among private universities by Kiplinger’s Personal Finance. To read “What they’re saying about Rice,” go to tinyurl.com/AboutRiceU.

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

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 for “Aluminum for Plasmonics” at:

Read the abstract for “Quantum Plasmonics: Optical Properties of a Nanomatryushka” at:

Halas Nanophotonics Group:

Nordlander Nanophotonics Group:

Related News Press

News and information

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Unveiling the quantum necklace: Researchers simulate quantum necklace-like structures in superfluids May 26th, 2017

Discoveries

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Announcements

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Military

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Gas gives laser-induced graphene super properties: Rice University study shows inexpensive material can be superhydrophilic or superhydrophobic May 15th, 2017

'Hot' electrons don't mind the gap: Rice University scientists find nanogaps in plasmonic gold wires enhance voltage when excited May 8th, 2017

Energy

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Fed grant backs nanofiber development: Rice University joins Department of Energy 'Next Generation Machines' initiative May 10th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

Photonics/Optics/Lasers

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Researchers find new way to control light with electric fields May 25th, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Plasmon-powered upconversion nanocrystals for enhanced bioimaging and polarized emission: Plasmonic gold nanorods brighten lanthanide-doped upconversion superdots for improved multiphoton bioimaging contrast and enable polarization-selective nonlinear emissions for novel nanoscal May 19th, 2017

Solar/Photovoltaic

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Fed grant backs nanofiber development: Rice University joins Department of Energy 'Next Generation Machines' initiative May 10th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

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