Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Nanogenerator Provides Continuous Electrical Power

Abstract:
Device harvests energy from the environment to provide direct current

Nanogenerator Provides Continuous Electrical Power

Atlanta, GA | Posted on April 5th, 2007

Researchers have demonstrated a prototype nanometer-scale generator that produces continuous direct-current electricity by harvesting mechanical energy from such environmental sources as ultrasonic waves, mechanical vibration or blood flow.

Based on arrays of vertically-aligned zinc oxide nanowires that move inside a novel "zig-zag" plate electrode, the nanogenerators could provide a new way to power nanoscale devices without batteries or other external power sources.

"This is a major step toward a portable, adaptable and cost-effective technology for powering nanoscale devices," said Zhong Lin Wang, Regents' Professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. "There has been a lot of interest in making nanodevices, but we have tended not to think about how to power them. Our nanogenerator allows us to harvest or recycle energy from many sources to power these devices."

Details of the nanogenerator are reported in the April 6 issue of the journal Science. The research was sponsored by the Defense Advanced Research Projects Agency (DARPA), the National Science Foundation (NSF), and the Emory-Georgia Tech Center of Cancer Nanotechnology Excellence.

The nanogenerators take advantage of the unique coupled piezoelectric and semiconducting properties of zinc oxide nanostructures, which produce small electrical charges when they are flexed.

Fabrication begins with growing an array of vertically-aligned nanowires approximately a half-micron apart on gallium arsenide, sapphire or a flexible polymer substrate. A layer of zinc oxide is grown on top of substrate to collect the current. The researchers also fabricate silicon "zig-zag" electrodes, which contain thousands of nanometer-scale tips made conductive by a platinum coating.

The electrode is then lowered on top of the nanowire array, leaving just enough space so that a significant number of the nanowires are free to flex within the gaps created by the tips. Moved by mechanical energy such as waves or vibration, the nanowires periodically contact the tips, transferring their electrical charges. By capturing the tiny amounts of current produced by hundreds of nanowires kept in motion, the generators produce a direct current output in the nano-Ampere range.

Wang and his group members Xudong Wang, Jinhui Song and Jin Liu expect that with optimization, their nanogenerator could produce as much as 4 watts per cubic centimeter - based on a calculation for a single nanowire. That would be enough to power a broad range of nanometer-scale defense, environmental and biomedical applications, including biosensors implanted in the body, environmental monitors - and even nanoscale robots.

Nearly a year ago, in the April 14, 2006 issue of the journal Science, Wang's research team announced the concept behind the nanogenerators. At that time, the nanogenerator could harvest power from just one nanowire at a time by dragging the tip of an atomic force microscope (AFM) over it. Made of platinum-coated silicon, the tip served as a Schottky barrier, helping accumulate and preserve the electrical charge as the nanowire flexed - and ensuring that the current flowed in one direction.

With its multiple conducting tips similar to those of an AFM, the new zig-zag electrode serves as a Schottky barrier to hundreds or thousands of wires simultaneously, harvesting energy from the nanowire arrays.

"Producing the top electrode as a single assembly sets the stage for scaling up this technology," Wang said. "We can now see the steps involved in moving forward to a device that can power real nanometer-scale applications."

Before that happens, additional development will be needed to optimize current production. For instance, though nanowires in the arrays can be grown to approximately the same length - about one micron - there is some variation. Wires that are too short cannot touch the electrode to produce current, while wires that are too long cannot flex to produce electrical charge.

"We need to be able to better control the growth, density and uniformity of the wires," Wang said. "We believe we can make as many as millions or even billions of nanowires produce current simultaneously. That will allow us to optimize operation of the nanogenerator."

In their lab, the researchers aimed an ultrasound source at their nanogenerator to measure current output over slightly more than an hour. Though there is some fluctuation in output, the current flow was continuous as long as the ultrasonic generator was operating, Wang said.

To rule out other sources of the current measured, the researchers substituted carbon nanotubes - which are not piezoelectric - for the zinc oxide nanowires, and used a top electrode that was flat. In both cases, the resulting devices did not produce current.

Providing power for nanometer-scale devices has long been a challenge. Batteries and other traditional sources are too large, and tend to negate the size advantages of nanodevices. And since batteries contain toxic materials such as lithium and cadmium, they cannot be implanted into the body as part of biomedical applications.

Because zinc oxide is non-toxic and compatible with the body, the new nanogenerators could be integrated into implantable biomedical devices to wirelessly measure blood flow and blood pressure within the body. And they could also find more ordinary applications.

"If you had a device like this in your shoes when you walked, you would be able to generate your own small current to power small electronics," Wang noted. "Anything that makes the nanowires move within the generator can be used for generating power. Very little force is required to move them."

####

About Georgia Tech
The Georgia Institute of Technology is one of the nation's premiere research universities. Ranked eighth among U.S. News & World Report's top public universities, Georgia Tech's 17,000 students are enrolled in its Colleges of Architecture, Computing, Engineering, Liberal Arts, Management and Sciences. Tech is among the nation's top producers of women and African-American engineers. The Institute offers research opportunities to both undergraduate and graduate students and is home to more than 100 interdisciplinary units plus the Georgia Tech Research Institute.

For more information, please click here

Contacts:
Research News & Publications Office
Georgia Institute of Technology
75 Fifth Street, N.W., Suite 100
Atlanta, Georgia 30308 USA
John Toon (404-894-6986)

Copyright © Georgia Tech

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

Preparing for Nano

Durnham University's DEEPEN project comes to a close September 26th, 2012

Technical Seminar at ANFoS 2012 August 22nd, 2012

Nanotechnology shows we can innovate without economic growth April 12th, 2012

Thailand to host NanoThailand 2012 December 18th, 2011

Molecular Machines

One step closer to a single-molecule device: Columbia Engineering researchers first to create a single-molecule diode -- the ultimate in miniaturization for electronic devices -- with potential for real-world applications May 25th, 2015

UCLA nanoscientists are first to model atomic structures of three bacterial nanomachines: Cryo electron microscope enables scientists to explore the frontiers of targeted antibiotics April 21st, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Designer's toolkit for dynamic DNA nanomachines: Arm-waving nanorobot signals new flexibility in DNA origami March 27th, 2015

Molecular Nanotechnology

One step closer to a single-molecule device: Columbia Engineering researchers first to create a single-molecule diode -- the ultimate in miniaturization for electronic devices -- with potential for real-world applications May 25th, 2015

Nature inspires first artificial molecular pump: Simple design mimics pumping mechanism of life-sustaining proteins found in living cells May 19th, 2015

Feynman Prize Winners Announced! April 26th, 2015

Surface matters: Huge reduction of heat conduction observed in flat silicon channels April 23rd, 2015

Discoveries

Chemists discover key reaction mechanism behind the highly touted sodium-oxygen battery May 28th, 2015

New technique speeds nanoMRI imaging: Multiplexing technique for nanoscale magnetic resonance imaging developed by researchers in Switzerland cuts normal scan time from two weeks to two days May 28th, 2015

Squeezed quantum cats May 28th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Announcements

Chemists discover key reaction mechanism behind the highly touted sodium-oxygen battery May 28th, 2015

New technique speeds nanoMRI imaging: Multiplexing technique for nanoscale magnetic resonance imaging developed by researchers in Switzerland cuts normal scan time from two weeks to two days May 28th, 2015

Squeezed quantum cats May 28th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Human Interest/Art

INSIDDE: Uncovering the real history of art using a graphene scanner May 21st, 2015

Winner Announced for NNI’s First ‘EnvisioNano’ Nanotechnology Image Contest May 6th, 2015

To Conserve London's 300-Year-Old Masterpiece, Nanotech & Drones April 12th, 2015

2015 Nanonics Image Contest January 29th, 2015

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