Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shaping the future

15.03.2017

Iron nanocubes may be key in the future of NO2 sensing

While nanoparticles sound like a recent discovery, these tiny structures have been used for centuries. The famous Lycurgus cup, made by 4th century Roman artisans, features dichroic glass, with gold and silver nanoparticles sprinkled throughout, producing a green appearance when light is shining on it from the front, and a red appearance when illuminated from behind.


This schematic depicts the production of iron nanocubes using magnetron-sputtering inert-gas condensation and the use of these cubes in NO2 sensors.

Credit: Dr. Panagiotis Grammatikopoulos

In the centuries since the time of the ancient artisans, researchers have come a long way in understanding nanoparticles. The production of nanocubes has been of particular interest due to their potential applications as biosensors and gas sensors.

Nanoparticles can be produced using either physical or chemical methods, though physical methods are advantageous due to the absence of organic contaminants commonly introduced by chemical methods.

However, uniformly sized nanocubes are difficult to produce in sufficient quantities by physical methods. Researchers from the Nanoparticles by Design Unit at the Okinawa Institute of Science and Technology (OIST) Graduate University have recently discovered a new approach to overcome this problem. Their research was recently published in Advanced Functional Materials.

"The cube shape is not the lowest energy structure for iron nanoparticles", explains Dr. Jerome Vernieres, first author of the publication, "thus, we couldn't rely on equilibrium thermodynamics considerations to self-assemble these nanocubes". Instead, the OIST scientists, under the guidance of Prof. Mukhles Sowwan, exploited the possibilities offered by a technique called magnetron-sputtering inert-gas condensation to create their iron nanocubes.

With this method, argon gas is first heated up and turned into ionized plasma. Then, a magnet, suitably located behind a target made of the desired material, in this case, iron, controls the shape of the plasma, and ensures that argon ions bombard the target; hence the name "magnetron". As a result, iron atoms are sputtered away from the target, collide with argon atoms and with each other, and form nanoparticles. Accurate control of the plasma via controlling the magnetic field can produce uniform nanocubes. "Uniformity is key in sensing applications. We needed a way to control the size, shape, and number of the nanocubes during their production", explained Dr. Stephan Steinhauer.

To control the size and shape of these cubes, the researchers made a simple but significant observation: iron is magnetic in its own right! In other words, the researchers discovered that they could exploit the intrinsic magnetism of the target itself as an innovative way to modify the magnetic field of the magnetron. This way they managed to manipulate the plasma where the particles are grown, and thus to control the nanocube sizes during formation.

"This is the first time uniform iron nanocubes have been made using a physical method that can be scaled for mass production" clarifies Vernieres. To better understand the mechanics of this process, the OIST team collaborated with researchers from the University of Helsinki to make theoretical calculations. "The work relied heavily on both experimental methods and theoretical calculations. The simulations were important for us to explain the phenomena we were observing", illuminates Dr. Panagiotis Grammatikopoulos.

Once the researchers invented a way to produce these uniform iron cubes, the next step was to build an electronic device that can utilize these nanocubes for sensing applications. "We noticed that these cubes were extremely sensitive to the levels of gaseous NO2. NO2 sensing is used for a variety of different purposes, from diagnosis of asthma patients to detecting environmental pollution, so we immediately saw an application for our work", states Steinhauer.

The researchers from the Nanoparticles by Design Unit, in collaboration with researchers from the Université de Toulouse, then built a prototype NO2 sensor that measured the change in electrical resistance of the iron nanocubes due to exposure to NO2 gas.

Because exposure to even a very tiny amount of NO2 can produce a measurable change in electrical resistance that is considerably larger than for other atmospheric pollutants, the iron nanocube-based sensor is both extremely sensitive and specific. "These nanocubes have many potential uses. The fact that we can produce a relatively large quantity of uniform nanocubes using an increasingly common synthesis method makes this research highly promising for industrial applications," emphasized Vernieres.

Kaoru Natori | EurekAlert!

Further reports about: NO2 Nanoparticles chemical methods magnetic field sensing applications

More articles from Life Sciences:

nachricht If Machines Could Smell ...
19.07.2019 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

nachricht Algae-killing viruses spur nutrient recycling in oceans
18.07.2019 | Rutgers University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Better thermal conductivity by adjusting the arrangement of atoms

Adjusting the thermal conductivity of materials is one of the challenges nanoscience is currently facing. Together with colleagues from the Netherlands and Spain, researchers from the University of Basel have shown that the atomic vibrations that determine heat generation in nanowires can be controlled through the arrangement of atoms alone. The scientists will publish the results shortly in the journal Nano Letters.

In the electronics and computer industry, components are becoming ever smaller and more powerful. However, there are problems with the heat generation. It is...

Im Focus: First-ever visualizations of electrical gating effects on electronic structure

Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.

Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...

Im Focus: Megakaryocytes act as „bouncers“ restraining cell migration in the bone marrow

Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.

Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...

Im Focus: Artificial neural network resolves puzzles from condensed matter physics: Which is the perfect quantum theory?

For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.

Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...

Im Focus: Extremely hard yet metallically conductive: Bayreuth researchers develop novel material with high-tech prospects

An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".

The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

Heat transport through single molecules

19.07.2019 | Physics and Astronomy

Welcome Committee for Comets

19.07.2019 | Earth Sciences

Better thermal conductivity by adjusting the arrangement of atoms

19.07.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>