Featured Research

from universities, journals, and other organizations

Engineers weld nanowires with light

Date:
February 6, 2012
Source:
Stanford School of Engineering
Summary:
At the nano level, researchers have discovered a new way to weld together meshes of tiny wires. Their work could lead to exciting new electronics and solar applications. To succeed, they called upon plasmonics.

A titled, cross-sectional scanning electron microscope image of plasmonically welded nanowires of silver.
Credit: Mark Brongersma, Stanford

At the nano level, researchers at Stanford have discovered a new way to weld together meshes of tiny wires. Their work could lead to innovative electronics and solar applications. To succeed, they called upon plasmonics.

One area of intensive research at the nanoscale is the creation of electrically conductive meshes made of metal nanowires. Promising exceptional electrical throughput, low cost and easy processing, engineers foresee a day when such meshes are common in new generations of touch-screens, video displays, light-emitting diodes and thin-film solar cells.

Standing in the way, however, is a major engineering hurdle: In processing, these delicate meshes must be heated or pressed to unite the crisscross pattern of nanowires that form the mesh, damaging them in the process.

In a paper just published in the journal Nature Materials, a team of engineers at Stanford has demonstrated a promising new nanowire welding technique that harnesses plasmonics to fuse the wires with a simple blast of light.

Self-limiting

At the heart of the technique is the physics of plasmonics, the interaction of light and metal in which the light flows across the surface of the metal in waves, like water on the beach.

"When two nanowires lay crisscrossed, we know that light will generate plasmon waves at the place where the two nanowires meet, creating a hot spot. The beauty is that the hot spots exist only when the nanowires touch, not after they have fused. The welding stops itself. It's self-limiting," explained Mark Brongersma, an associate professor of materials science engineering at Stanford and an expert in plasmonics. Brongersma is one of the study's senior authors.

"The rest of the wires and, just as importantly, the underlying material are unaffected," noted Michael McGehee, a materials engineer and also senior author of the paper. "This ability to heat with precision greatly increases the control, speed and energy efficiency of nanoscale welding."

In before-and-after electron-microscope images, individual nanowires are visually distinct prior to illumination. They lay atop one another, like fallen trees in the forest. When illuminated, the top nanowire acts like an antenna of sorts, directing the plasmon waves of light into the bottom wire and creating heat that welds the wires together. Post-illumination images show X-like nanowires lying flat against the substrate with fused joints.

Transparency

In addition to making it easier to produce stronger and better performing nanowire meshes, the researchers say that the new technique could open the possibility of mesh electrodes bound to flexible or transparent plastics and polymers.

To demonstrate the possibilities, they applied their mesh on Saran wrap. They sprayed a solution containing silver nanowires in suspension on the plastic and dried it. After illumination, what was left was an ultrathin layer of welded nanowires.

"Then we balled it up like a piece of paper. When we unfurled the wrap, it maintained its electrical properties," said co-author Yi Cui, an associate professor materials science and engineering. "And when you hold it up, it's virtually transparent."

This could lead to inexpensive window coatings that generate solar power while reducing glare for those inside, the researchers said.

"In previous welding techniques that used a hotplate, this would never have been possible," said lead author, Erik C. Garnett, PhD, a post-doctoral scholar in materials science who works with Brongersma, McGehee and Cui. "The Saran wrap would have melted far sooner than the silver, destroying the device instantly."

"There are many possible applications that would not even be possible in older annealing techniques," said Brongersma. "This opens some interesting, simple and large-area processing schemes for electronic devices -- solar, LEDs and touch-screen displays, especially."

This research was supported by the Center for Advanced Molecular Photovoltaics (CAMP) at Stanford University funded by King Abdullah University of Science and Technology (KAUST).


Story Source:

The above story is based on materials provided by Stanford School of Engineering. The original article was written by Andrew Myers. Note: Materials may be edited for content and length.


Journal Reference:

  1. Erik C. Garnett, Wenshan Cai, Judy J. Cha, Fakhruddin Mahmood, Stephen T. Connor, M. Greyson Christoforo, Yi Cui, Michael D. McGehee, Mark L. Brongersma. Self-limited plasmonic welding of silver nanowirejunctions. Nature Materials, 2012; DOI: 10.1038/nmat3238

Cite This Page:

Stanford School of Engineering. "Engineers weld nanowires with light." ScienceDaily. ScienceDaily, 6 February 2012. <www.sciencedaily.com/releases/2012/02/120206092633.htm>.
Stanford School of Engineering. (2012, February 6). Engineers weld nanowires with light. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2012/02/120206092633.htm
Stanford School of Engineering. "Engineers weld nanowires with light." ScienceDaily. www.sciencedaily.com/releases/2012/02/120206092633.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins