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

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Researchers developed nanoparticle based contrast agent for dual modal imaging of cancer June 21st, 2017

Leti’s Autonomous-Vehicle System Embedded in Infineon’s AURIX Platform: Leti’s Low-Power, Multi-Sensor System that Transforms Distance Data into Clear Information About the Driving Environment Will Be Demonstrated at ITS Meeting in Strasbourg, June 19-22 June 20th, 2017

Chemistry

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

New carbon nitride material coupled with ruthenium enhances visible-light CO2 reduction in water June 15th, 2017

Learning with light: New system allows optical “deep learning”: Neural networks could be implemented more quickly using new photonic technology June 12th, 2017

Electrocatalyst nanostructures key to improved fuel cells, electrolyzers June 5th, 2017

Thin films

New prospects for universal memory -- high speed of RAM and the capacity of flash: Thin films created at MIPT could be the basis for future development of ReRAM June 17th, 2017

Discoveries

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Researchers developed nanoparticle based contrast agent for dual modal imaging of cancer June 21st, 2017

Announcements

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Researchers developed nanoparticle based contrast agent for dual modal imaging of cancer June 21st, 2017

Energy

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Cambridge Nanotherm partners with Inabata for global sales and distribution June 20th, 2017

Development of low-dimensional nanomaterials could revolutionize future technologies June 15th, 2017

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

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Smart materials used in ultrasound behave similar to water, Penn chemists report June 16th, 2017

X-ray Study Reveals Way to Control Molecular Vibrations that Transmit Heat: Findings open new pathway for "tuning" materials to ease or insulate against the flow of heat, sound, and other forms of energy June 7th, 2017

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

Solar/Photovoltaic

Tiny bubbles provide tremendous propulsion in new microparticles research-Ben-Gurion U. June 21st, 2017

Enhanced photocatalytic activity by Cu2O nanoparticles integrated H2Ti3O7 nanotubes June 21st, 2017

Development of low-dimensional nanomaterials could revolutionize future technologies June 15th, 2017

In a project funded by the Austrian Science Fund FWF, the physicist Serdar Sarıçiftçi investigates possible uses in electronics of the semiconductor properties of indigo pigment June 14th, 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