Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sweeping lasers snap together nanoscale geometric grids

23.06.2015

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.


This is a 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.

Credit: Brookhaven National Laboratory

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.

Media Contact

Justin Eure
jeure@bnl.gov
631-344-2347

 @brookhavenlab

http://www.bnl.gov 

Justin Eure | EurekAlert!

More articles from Materials Sciences:

nachricht Nagoya University researchers break down plastic waste
29.05.2017 | Nagoya University

nachricht A new tool for discovering nanoporous materials
23.05.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>