Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sweeping Lasers Snap Together Nanoscale Geometric Grids

25.06.2015

New technique creates multi-layered, self-assembled grids with fully customizable shapes and compositions

Down at the nanoscale, where objects span just billionths of a meter, the size and shape of a material can often have surprising and powerful electronic and optical effects. Building larger materials that retain subtle nanoscale features is an ongoing challenge that shapes countless emerging technologies.


Brookhaven National Laboratory

Scanning electron microscope image of a self-assembled platinum lattice, false-colored to show the two-layer structure. Each inner square of the nanoscale grid is just 34 nanometers on each side.

Now, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have developed a new technique to rapidly create nano-structured grids for functional materials with unprecedented versatility.

“We can fabricate multi-layer grids composed of different materials in virtually any geometric configuration,” said study coauthor and Brookhaven Lab scientist Kevin Yager. “By quickly and independently controlling the nanoscale structure and the composition, we can tailor the performance of these materials. Crucially, the process can be easily adapted for large-scale applications.”

The results—published online June 23 in the journal Nature Communications—could transform the manufacture of high-tech coatings for anti-reflective surfaces, improved solar cells, and touchscreen electronics.

The scientists synthesized the materials at Brookhaven Lab’s Center for Functional Nanomaterials (CFN) and characterized the nanoscale architectures using electron microscopy at CFN and x-ray scattering at the National Synchrotron Light Source—both DOE Office of Science User Facilities.

The new technique relies on polymer self-assembly, where molecules are designed to spontaneously assemble into desired structures. Self-assembly requires a burst of heat to make the molecules snap into the proper configurations. Here, an intensely hot laser swept across the sample to transform disordered polymer blocks into precise arrangements in just seconds.

“Self-assembled structures tend to automatically follow molecular preferences, making custom architectures challenging,” said lead author Pawel Majewski, a postdoctoral researcher at Brookhaven. “Our laser technique forces the materials to assemble in a particular way. We can then build structures layer-by-layer, constructing lattices composed of squares, rhombuses, triangles, and other shapes.”

Laser-assembled nano-wires

For the first step in grid construction, the team took advantage of their recent invention of laser zone annealing (LZA) to produce the extremely localized thermal spikes needed to drive ultra-fast self-assembly.

To further exploit the power and precision of LZA, the researchers applied a heat-sensitive elastic coating on top of the unassembled polymer film. The sweeping laser’s heat causes the elastic layer to expand—like shrink-wrap in reverse—which pulls and aligns the rapidly forming nanoscale cylinders.

“The end result is that in less than one second, we can create highly aligned batches of nano-cylinders,” said study coauthor Charles Black, who leads the Electronic Nanomaterials group at CFN. “This order persists over macroscopic areas and would be difficult to achieve with any other method.”

To make these two-dimensional grids functional, the scientists converted the polymer base into other materials.

One method involved taking the nano-cylinder layer and dipping it into a solution containing metal salts. These molecules then glom onto the self-assembled polymer, converting it into a metallic mesh. A wide range of reactive or conductive metals can be used, including platinum, gold, and palladium.

They also used a technique called vapor deposition, where a vaporized material infiltrates the polymer nano-cylinders and transforms them into functional nano-wires.

Layer-by-layer lattice

The first completed nano-wire array acts as the foundation of the full lattice. Additional layers, each one following variations on that same process, are then stacked to produce customized, crisscrossing configurations—like chain-link fences 10,000 times thinner than a human hair.

“The direction of the laser sweeping across each unassembled layer determines the orientation of the nano-wire rows,” Yager said. “We shift that laser direction on each layer, and the way the rows intersect and overlap shapes the grid. We then apply the functional materials after each layer forms. It’s an exceptionally fast and simple way to produce such precise configurations.”

Study coauthor Atikur Rahman, a CFN postdoctoral researcher, added, “We can stack metals on insulators, too, embedding different functional properties and interactions within one lattice structure.

“The size and the composition of the mesh make a huge difference,” Rahman continued. “For example, a single layer of platinum nano-wires conducts electricity in only one direction, but a two-layer mesh conducts uniformly in all directions.”

LZA is precise and powerful enough to overcome interface interactions, allowing it to drive polymer self-assembly even on top of complex underlying layers. This versatility enables the use of a wide variety of materials in different nanoscale configurations.

“We can generate nearly any two-dimensional lattice shape, and thus have a lot of freedom in fabricating multi-component nanostructures,” Yager said. “It’s hard to anticipate all the technologies this rapid and versatile technique will allow.”

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation for the State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit applied science and technology organization.

Contact Information
Justin Eure
Public Affairs Representative
jeure@bnl.gov

Justin Eure | newswise
Further information:
http://www.bnl.gov

More articles from Physics and Astronomy:

nachricht Comet or asteroid? Hubble discovers that a unique object is a binary
21.09.2017 | NASA/Goddard Space Flight Center

nachricht First users at European XFEL
21.09.2017 | European XFEL GmbH

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>