Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electricity controls nanocrystal shape

18.03.2004


Wires, tubes and brushes make it possible to build and maintain the machines and devices we use on a daily basis. Now, with help from a surprising source, these same building blocks can easily be created on a scale 10,000 times smaller than the period at the end of this sentence.


LEAD NANOPARTICLES — Scanning electron microscopy images of lead nanoparticles created with the electrodeposition technique. Shaped nanoparticles such as icosahedrons (a) and decahedrons (b) can be produced with voltages lower than 1.2 volts while elongated structures such as tripods (c) and nanobrushes (d) appear at higher voltages. The bar at the top of each image represents 500 nanometers (billionths of an inch).



Researchers at Argonne have figured out the basics of using electrochemistry to control the architecture of nanocrystals – small structures with dimensions in billionths of meters. Their findings, published in the March 3 edition of the Journal of the American Chemical Society, provide a practical method of generating large quantities of architecture-controlled nanocrystals, such as superconductors, ferromagnets and noble metals.

"The architectures of the nanocrystals are mainly controlled by applied voltages," said lead scientist Zhili Xiao of Argonne’s Materials Science Division and Northern Illinois University’s Physics Department. "This gives us much greater control over the growth conditions of the nanocrystals. We were able to create a great variety of structures with greater convenience and predictability compared with more traditional methods."


Traditional methods of fabricating nanocrystals involve rapidly injecting chemicals into a heated solution at high temperatures. The downside to this approach, however, is the difficulty of controlling the solution concentration, which changes as the reaction proceeds. This change in concentration leads to changes in the electrochemical potential – the measure of a compound’s ability to react in solution. Since a stable electrochemical potential is crucial for forming well-shaped nanocrystals, scientists using this method often found themselves struggling to control solution concentrations and to time the right moment to stop the reaction.

In contrast, Xiao and his colleagues found that they could easily control the electrochemical potential by using electric voltage. The scientists used a technique called electrodeposition, which uses electricity passing through an electrode to reduce ions from solution on a given surface. By changing the applied voltage value and the type of chemicals in the solution, the Argonne researchers were able to synthesize large quantities of nearly 30 different nanostructures, including nanoparticles of various shapes, nanowires, nanobrushes and nanoscale tripods.

"We found, for example, that shaped nanoparticles tend to form at lower voltages while higher voltages tend to produce structures such as nanowires and nanobrushes," explained Xiao.

With large quantities of these nanocrystals in hand, scientists are exploring their unique physical and chemical properties. These structures can lead to discoveries of new phenomena and applications, such as the use of ferromagnetic nanocrystals as components in ultra high-density storage media and the use of certain metal nanocrystals as catalysts for hydrogen production and sensing.

"When you alter the shape of a nanocrystal, you’re basically setting new boundaries to the space in which its electrons can move," said Wai-Kwong Kwok, leader of the Superconductivity and Magnetism group in the Materials Science Division. "This, in turn, affects its physical properties, which explains why a triangle and a sphere made of lead can have completely different superconducting properties."

The research was supported by the U.S. Department of Energy’s Office of Basic Energy Sciences and the University of Chicago-Argonne Consortium for Nanoscience Research.

The nation’s first national laboratory, Argonne National Laboratory conducts basic and applied scientific research across a wide spectrum of disciplines, ranging from high-energy physics to climatology and biotechnology. Since 1990, Argonne has worked with more than 600 companies and numerous federal agencies and other organizations to help advance America’s scientific leadership and prepare the nation for the future. Argonne is operated by the University of Chicago for the U.S. Department of Energy’s Office of Science.

For more information, please contact Margret Chang (630/252-5549 or media@anl.gov) at Argonne.

Margret Chang | Argonne
Further information:
http://www.anl.gov/OPA/news04/news040317.htm

More articles from Materials Sciences:

nachricht Magnesium magnificent for plasmonic applications
23.05.2018 | Rice University

nachricht New concept for structural colors
18.05.2018 | Technische Universität Hamburg-Harburg

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Molecular switch will facilitate the development of pioneering electro-optical devices

24.05.2018 | Power and Electrical Engineering

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>