Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Electricity controls nanocrystal shape


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 at Argonne.

Margret Chang | Argonne
Further information:

More articles from Materials Sciences:

nachricht From ancient fossils to future cars
21.10.2016 | University of California - Riverside

nachricht Study explains strength gap between graphene, carbon fiber
20.10.2016 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>