Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Bejeweled: Nanotech gets boost from nanowire decorations

Decoration with nanoparticles creates intricate surface patterns full of nooks and crannies, twists and turns that greatly improve surface area. Image courtesy of the Stanford Nanocharacterization Laboratory.
Decoration with nanoparticles creates intricate surface patterns full of nooks and crannies, twists and turns that greatly improve surface area.

Image courtesy of the Stanford Nanocharacterization Laboratory.

Abstract:
Engineers at Stanford have found a novel method for "decorating" nanowires with chains of tiny particles to increase their electrical and catalytic performance. The new technique is simpler, faster and provides greater control than earlier methods and could lead to better batteries, solar cells and catalysts.

Bejeweled: Nanotech gets boost from nanowire decorations

Stanford, CA | Posted on April 27th, 2012

Like a lead actress on the red carpet, nanowires—those superstars of nanotechnology—can be enhanced by a little jewelry, too. Not the diamonds and pearls variety, but the sort formed of sinuous chains of metal oxide or noble metal nanoparticles.

Though science has known for some time that such ornamentation can greatly increase the surface area and alter the surface chemistry of nanowires, engineers at Stanford University have found a novel and more effective method of "decorating" nanowires that is simpler and faster than previous techniques. The results of their study were published recently in the journal Nano Letters.

The development, say the researchers, might someday lead to better lithium-ion batteries, more efficient thin-film solar cells and improved catalysts that yield new synthetic fuels.

Tree-like structures

"You can think of it like a tree. The nanowires are the trunk, very good at transporting electrons, like sap, but limited in surface area," explained Xiaolin Zheng, an assistant professor of mechanical engineering and senior author of the study. "The added nanoparticle decorations, as we call them, are like the branches and leaves, which fan out and greatly increase the surface area."

At the nanoscale, surface area matters a great deal in engineering applications like solar cells, batteries and, especially catalysts, where the catalytic activity is dependent on the availability of active sites at the surface of the material.

"Greater surface area means greater opportunity for reactions and therefore better catalytic capabilities in, for example, water-splitting systems that produce clean-burning hydrogen fuel from sunlight," said Yunzhe Feng, a research assistant in Zheng's lab and first author of the study.

Other applications such as sensing small concentrations of chemicals in the air—of toxins or explosives, for example—might also benefit from the greater likelihood of detection made possible by increased surface area.
A spark of an idea

The key to the Stanford team's discovery was a flame. Engineers had long known that nanoparticles could be adhered to nanowires to increase surface area, but the methods for creating them were not very effective in forming the much-desired porous nanoparticle chain structures. These other methods proved too slow and resulted in a too-dense, thick layer of nanoparticles coating the wires, doing little to increase the surface area.

Zheng and her team wondered whether a quick burst of flame might work better, so they tried it.

Zheng dipped the nanowires in a solvent-based gel of metal and salt, then air-dried them before applying the flame. In her process the solvent burns away in a few seconds, allowing the all-important nanoparticles to crystalize into branch-like structures fanning out from the nanowires.

"We were a little surprised by how well it worked," said Zheng. "It performed beautifully."

Using sophisticated microscopes and spectroscopes at the Stanford Nanocharacterization Laboratory, the engineers were able to get a good look at their creations.

"It created these intricate, hair-like tendrils filled with lots of nooks and crannies," said Zheng. The bejeweled nanowires look like pipe cleaners. The resulting structure increases the surface many fold over what went before, she said.

Dramatic performance, unprecedented control

"The performance improvements have so far been dramatic," said In Sun Cho, a post-doctoral fellow in Zheng's lab and co-author of the paper.

Zheng and team have dubbed the technique the sol-flame method, for the combination of solvent and flame that yields the nanoparticle structures. The method appears general enough to work with many nanowire and nanoparticle materials and, perhaps more importantly, provides an unprecedented degree of engineering control in creating the nanoparticle decorations.

The high temperature of the flame and brief annealing time ensure that the nanoparticles are small and spread evenly across the nanowires. And, by varying the concentration of nanoparticle in the precursor solution and the number of times the wires are dip-coated, the Stanford team was able to vary the size of the nanoparticle decorations from tens to hundreds of nanometers, and the density from tens to hundreds of particles per square micrometer.

"Though more research is needed, such precision is crucial and could bolster the wider adoption of the process," said Zheng.

Pratap M. Rao and Lili Cai also contributed to this research. The study was supported by the ONR/PECASE program.

Author Andrew Myers is associate director of communications for the Stanford School of Engineering.

####

For more information, please click here

Contacts:
Andrew Myers

650-736-2245

Copyright © Stanford 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 News Press

News and information

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Quantum manipulation power for quantum information processing gets a boost: Improving the efficiency of quantum heat engines involves reducing the number of photons in a cavity, ultimately impacting quantum manipulation power October 14th, 2017

Chemistry

What can be discovered at the junction of physics and chemistry October 6th, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Chemical hot spots: Scanning tunneling microscopy measurements identify active sites on catalyst surfaces September 7th, 2017

More durable, less expensive fuel cells: University of Delaware researchers have developed a new technology that could speed up the commercialization of fuel cell vehicles September 5th, 2017

Thin films

Rice University chemists make laser-induced graphene from wood July 31st, 2017

Graduate Students from Across the Country Attend Hands-on NanoCamp: Prominent scientists Warren Oliver, Ph.D., and George Pharr, Ph.D., presented a weeklong NanoCamp for hand-picked graduate students across the United States July 26th, 2017

Studying Argon Gas Trapped in Two-Dimensional Array of Tiny "Cages": Understanding how individual atoms enter and exit the nanoporous frameworks could help scientists design new materials for gas separation and nuclear waste remediation July 17th, 2017

Thinking thin brings new layering and thermal abilities to the semiconductor industry: In a breakthrough for the semiconductor industry, researchers demonstrate a new layer transfer technique called "controlled spalling" that creates many thin layers from a single gallium nitride July 11th, 2017

Discoveries

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Announcements

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Energy

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

On the road to fire-free, lithium-ion batteries made with asphalt October 12th, 2017

Organic/inorganic sulfur may be key for safe rechargeable lithium batteries October 12th, 2017

How to draw electricity from the bloodstream: A one-dimensional fluidic nanogenerator with a high power-conversion efficiency September 11th, 2017

A revolution in lithium-ion batteries is becoming more realistic September 5th, 2017

Solar/Photovoltaic

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 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