Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists announce first 3-D assembly of magnetic and semiconducting nanoparticles

26.06.2003


A collection of iron oxide nanoparticles (blue) and smaller lead selenide nanoparticles (red) -- a.k.a. quantum dots -- beginning to interact and organize in solution on their way to crystallizing into a binary superlattice. The resulting assembly captures the magnetic properties of the iron oxide while retaining the distinct optical signature of the quantum dots.


A schematic of a binary superlattice where thirteen small lead selenide quantum dots (red) are grouped together, filling the spaces between the 11 nm diameter iron oxide (blue). The distance between the iron oxide particle is exaggerated to allow a clear view of how the lead selenide particles pack together.


Scientists from Columbia University, IBM and the University of New Orleans today announced a new, three-dimensional designer material assembled from two different types of particles only billionths of a meter across.

In the June 26 issue of the journal Nature, the team describes the precision chemistry methods developed to tune the particles’ sizes in increments of less than one nanometer and to tailor the experimental conditions so the particles would assemble themselves into repeating 3-D patterns. The work was supported in part by the National Science Foundation, the independent agency that supports basic research in all fields of science and engineering, through the Center for Nanostructured Materials at Columbia University and by the Defense Advanced Research Agency (DARPA) through programs on metamaterials and advanced thermoelectric materials.

Designing new materials with otherwise unattainable properties, sometimes referred to as "metamaterials," is one of the promises of nanotechnology. Two-dimensional patterns had previously been created from gold nanoparticles of different sizes and mixtures of gold and silver. Extending this concept to three dimensions with more diverse types of materials demonstrates the ability to bring more materials together than previously realized.



"What excites us the most is that this is a modular assembly method that will let us bring almost any materials together," said Christopher Murray, manager of nanoscale materials and devices at IBM Research. "We’ve demonstrated the ability to bring together complementary materials with an eye to creating materials with interesting custom properties."

Murray worked with Stephen O’Brien, assistant professor of applied physics and applied mathematics at Columbia University; Franz Redl, a postdoctoral researcher affiliated with both Columbia and IBM; and Kyung Sang Cho, a post-doctoral researcher affiliated with IBM and supported by the Advanced Materials Research Institute of the University of New Orleans.

The scientists chose the materials for the experiments specifically because of their dissimilar, yet complementary properties. Lead selenide is a semiconductor that has applications in infrared detectors and thermal imaging and can be tuned to be more sensitive to specific infrared wavelengths. The other material, magnetic iron oxide, is best known for its use in the coatings for certain magnetic recording media.

The combination of these nanoparticles may have novel magneto-optical properties as well as properties key to the realization of quantum computing. For example, it might be possible to modulate the material’s optical properties by applying an external magnetic field.

"This was a demonstration of the ability to create such materials," O’Brien said. "Given the unique combination of these nanoscale materials, we’re in uncharted territory with respect to the properties, which we will be working on in the future."

The first step was to create the nanoparticles. The particle sizes were calculated from the mathematical ideal of the structures they wanted to create. In addition to fine-tuning the sizes, the particles had to be very uniform, all within 5 percent of the target size. They settled on iron oxide particles 11 nanometers in diameter, which were created by Redl, and lead selenide particles 6 nanometers in diameter, created by Cho. There are approximately 60,000 atoms in one of the iron oxide nanoparticles and approximately 3,000 atoms in the lead selenide particles.

Next, Redl assembled the nanoparticles--or more to the point, had the particles assemble themselves--into three different repeating 3-D patterns by tailoring the experimental conditions. Forming these so-called "crystal structures," as opposed to random mixtures of nanoparticles, is essential for the composite material to exhibit consistent, predictable behaviors. Various other materials are known to assemble spontaneously into these structures of close-packed particles, but none has been made of two components in three dimensions and at the length scales reported in the Nature paper.

"The precise and energy-efficient self-assembly of matter into material structures with properties that cannot be achieved otherwise is an important goal for nanotechnology," said Mihail Roco, NSF senior advisor for nanotechnology and chair of the National Science and Technology Council’s Subcommittee on Nanoscale Science and Engineering. "This is just one way that nanotechnology will help foster ’the next industrial revolution.’"



Media Contacts:
Joseph Kennedy, Columbia University, 212-854-9752, jjk2109@columbia.edu
My Luu, IBM, 914-945-2988, myluu@us.ibm.com
David Hart, NSF, 703-292-7737, dhart@nsf.gov


NSF Program Officer: Carmen Huber, 703-292-4939, chuber@nsf.gov
Stephen O’Brien, Columbia University, 212-854-9478, so188@columbia.edu
Christopher Murray, IBM, 914-945-3021, cbmurray@us.ibm.com

About the NSF Center for Nanostructured Materials, Columbia University
The Columbia University Materials Research Science and Engineering Center (MRSEC) is an interdisciplinary team of university, industrial, and national laboratory scientists and engineers working together to develop and examine new types of nanocrystals and ways of assembling them into thin films. http://www.cise.columbia.edu/mrsec/

About IBM Research
IBM Research is the information technology industry’s largest information technology research organization, with more than 3,000 scientists and engineers at eight labs in six countries. For more information about IBM’s nanotechnology research projects: http://www.research.ibm.com/pics/nanotech/

About the National Science Foundation
The National Science Foundation is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $5.3 billion. National Science Foundation funds reach all 50 states through grants to nearly 2,000 universities and institutions. Each year, NSF receives about 30,000 competitive requests for funding, and makes about 10,000 new funding awards. The National Science Foundation also awards over $200 million in professional and service contracts yearly.

Receive official National Science Foundation news electronically through the e-mail delivery system, NSFnews. To subscribe, send an e-mail message to join-nsfnews@lists.nsf.gov. In the body of the message, type "subscribe nsfnews" and then type your name. (Ex.: "subscribe nsfnews John Smith")

David Hart | National Science Foundation
Further information:
http://www.nsf.gov/
http://domino.research.ibm.com/Comm/bios.nsf/pages/selfassembly.html
http://www.nsf.gov/od/lpa/news/media/start.htm

More articles from Materials Sciences:

nachricht Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously
17.01.2017 | Sonderforschungsbereich 668

nachricht Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>