Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Sharpening the Nanofocus: Berkeley Lab Researchers Use Nanoantenna to Enhance Plasmonic Sensing

Top figure shows hydrogen (red) absorbed on a palladium nanoparticle, resulting in weak light scattering and barely detectable spectral changes. Bottom figure shows gold antenna enhancing light scattering and producing an easy to detect spectral shift. (Image courtesy of Alivisatos group)
Top figure shows hydrogen (red) absorbed on a palladium nanoparticle, resulting in weak light scattering and barely detectable spectral changes. Bottom figure shows gold antenna enhancing light scattering and producing an easy to detect spectral shift. (Image courtesy of Alivisatos group)

Abstract:
Such highly coveted technical capabilities as the observation of single catalytic processes in nanoreactors, or the optical detection of low concentrations of biochemical agents and gases are an important step closer to fruition. Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab), in collaboration with researchers at the University of Stuttgart in Germany, report the first experimental demonstration of antenna-enhanced gas sensing at the single particle level. By placing a palladium nanoparticle on the focusing tip of a gold nanoantenna, they were able to clearly detect changes in the palladium's optical properties upon exposure to hydrogen.

Sharpening the Nanofocus: Berkeley Lab Researchers Use Nanoantenna to Enhance Plasmonic Sensing

Berkeley, CA | Posted on May 17th, 2011

"We have demonstrated resonant antenna-enhanced single-particle hydrogen sensing in the visible region and presented a fabrication approach to the positioning of a single palladium nanoparticle in the nanofocus of a gold nanoantenna," says Paul Alivisatos, Berkeley Lab's director and the leader of this research. "Our concept provides a general blueprint for amplifying plasmonic sensing signals at the single-particle level and should pave the road for the optical observation of chemical reactions and catalytic activities in nanoreactors, and for local biosensing."

Alivisatos, who is also the Larry and Diane Bock Professor of Nanotechnology at the University of California, Berkeley, is the corresponding author of a paper in the journal Nature Materials describing this research. The paper is titled "Nanoantenna-enhanced gas sensing in a single tailored nanofocus." Co-authoring the paper with Alivisatos were Laura Na Liu, Ming Tang, Mario Hentschel and Harald Giessen.

One of the hottest new fields in technology today is plasmonics - the confinement of electromagnetic waves in dimensions smaller than half-the-wavelength of the incident photons in free space. Typically this is done at the interface between metallic nanostructures, usually gold, and a dielectric, usually air. The confinement of the electromagnetic waves in these metallic nanostructures generates electronic surface waves called "plasmons." A matching of the oscillation frequency between plasmons and the incident electromagnetic waves gives rise to a phenomenon known as localized surface plasmon resonance (LSPR), which can concentrate the electromagnetic field into a volume less than a few hundred cubic nanometers. Any object brought into this locally confined field - referred to as the nanofocus - will influence the LSPR in a manner that can be detected via dark-field microscopy.

"Nanofocusing has immediate implications for plasmonic sensing," says Laura Na Liu, lead author of the Nature Materials paper who was at the time the work was done a member of Alivisatos' research group but is now with Rice University. "Metallic nanostructures with sharp corners and edges that form a pointed tip are especially favorable for plasmonic sensing because the field strengths of the electromagnetic waves are so strongly enhanced over such an extremely small sensing volume."

Plasmonic sensing is especially promising for the detection of flammable gases such as hydrogen, where the use of sensors that require electrical measurements pose safety issues because of the potential threat from sparking. Hydrogen, for example, can ignite or explode in concentrations of only four-percent. Palladium was seen as a prime candidate for the plasmonic sensing of hydrogen because it readily and rapidly absorbs hydrogen that alters its electrical and dielectric properties. However, the LSPRs of palladium nanoparticles yield broad spectral profiles that make detecting changes extremely difficult.

"In our resonant antenna-enhanced scheme, we use double electron-beam lithography in combination with a double lift-off procedure to precisely position a single palladium nanoparticle in the nanofocus of a gold nanoantenna," Liu says. "The strongly enhanced gold-particle plasmon near-fields can sense the change in the dielectric function of the proximal palladium nanoparticle as it absorbs or releases hydrogen. Light scattered by the system is collected by a dark-field microscope with attached spectrometer and the LSPR change is read out in real time."

Alivisatos, Liu and their co-authors found that the antenna enhancement effect could be controlled by changing the distance between the palladium nanoparticle and the gold antenna, and by changing the shape of the antenna.

"By amplifying sensing signals at the single-particle level, we eliminate the statistical and average characteristics inherent to ensemble measurements," Liu says. "Moreover, our antenna-enhanced plasmonic sensing technique comprises a noninvasive scheme that is biocompatible and can be used in aqueous environments, making it applicable to a variety of physical and biochemical materials."

For example, by replacing the palladium nanoparticle with other nanocatalysts, such as ruthenium, platinum, or magnesium, Liu says their antenna-enhanced plasmonic sensing scheme can be used to monitor the presence of numerous other important gases in addition to hydrogen, including carbon dioxide and the nitrous oxides. This technique also offers a promising plasmonic sensing alternative to the fluorescent detection of catalysis, which depends upon the challenging task of finding appropriate fluorophores. Antenna-enhanced plasmonic sensing also holds potential for the observation of single chemical or biological events.

"We believe our antenna-enhanced sensing technique can serve as a bridge between plasmonics and biochemistry," Liu says. "Plasmonic sensing offers a unique tool for optically probing biochemical processes that are optically inactive in nature. In addition, since plasmonic nanostructures made from gold or silver do not bleach or blink, they allow for continuous observation, an essential capability for in-situ monitoring of biochemical behavior."

This research was supported by the DOE Office of Science and the German ministry of research.

####

About Berkeley Lab
Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 12 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

For more information, please click here

Contacts:
Lynn Yarris
(510) 486-5375

Copyright © Berkeley Lab

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

For more information about the research of Paul Alivisatos, visit the Website at:

Related News Press

Laboratories

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

News and information

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Properties of Polymeric Nanofibers Optimized to Treat Damaged Body Tissues February 12th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Graphene leans on glass to advance electronics: Scientists' use of common glass to optimize graphene's electronic properties could improve technologies from flat screens to solar cells February 12th, 2016

A metal that behaves like water: Researchers describe new behaviors of graphene February 12th, 2016

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

Silicon chip with integrated laser: Light from a nanowire: Nanolaser for information technology February 12th, 2016

Sensors

Scientists have put a high precision blood assay into a simple test strip: Researchers have developed a new biosensor test system based on magnetic nanoparticles February 3rd, 2016

Nanosheet growth technique could revolutionize nanomaterial production February 1st, 2016

New record in nanoelectronics at ultralow temperatures January 28th, 2016

NBC LEARN DEBUTS SIX-PART VIDEO SERIES, “NANOTECHNOLOGY: SUPER SMALL SCIENCE” Produced by NBC Learn in partnership with the National Science Foundation, and narrated by NBC News/MSNBC’s Kate Snow, series highlights leading research in nanotechnology January 25th, 2016

Discoveries

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Properties of Polymeric Nanofibers Optimized to Treat Damaged Body Tissues February 12th, 2016

Announcements

Graphene leans on glass to advance electronics: Scientists' use of common glass to optimize graphene's electronic properties could improve technologies from flat screens to solar cells February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Properties of Polymeric Nanofibers Optimized to Treat Damaged Body Tissues February 12th, 2016

Homeland Security

Detecting and identifying explosives with single test December 10th, 2015

Columbia engineers build biologically powered chip: System combines biological ion channels with solid-state transistors to create a new kind of electronics December 7th, 2015

Nanoparticle delivery maximizes drug defense against bioterrorism agent: UCLA team develops method for improving drug’s efficacy while reducing side effects November 6th, 2015

Toward clearer, cheaper imaging of ultrafast phenomena: A new, all-optical method for compressing narrow electron pulses to a billionth of a billionth of a second could improve real-time movies of chemical reactions and other ultrafast processes October 14th, 2015

Military

Scientists guide gold nanoparticles to form 'diamond' superlattices: DNA scaffolds cage and coax nanoparticles into position to form crystalline arrangements that mimic the atomic structure of diamond February 4th, 2016

Researchers develop completely new kind of polymer: Hybrid polymers could lead to new concepts in self-repairing materials, drug delivery and artificial muscles January 30th, 2016

Nano-coating makes coaxial cables lighter: Rice University scientists replace metal with carbon nanotubes for aerospace use January 28th, 2016

Scientists build a neural network using plastic memristors: A group of Russian and Italian scientists have created a neural network based on polymeric memristors -- devices that can potentially be used to build fundamentally new computers January 28th, 2016

Research partnerships

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Research reveals carbon films can give microchips energy storage capability: International team from Drexel University and Paul Sabatier University reveals versatility of carbon films February 11th, 2016

SLAC X-ray laser turns crystal imperfections into better images of important biomolecules: New method could remove major obstacles to studying structures of complex biological machines February 11th, 2016

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







Car Brands
Buy website traffic