Subscribe free to our newsletters via your
. 24/7 Space News .




Subscribe free to our newsletters via your




















TECH SPACE
Scientists watch 'artificial atoms' assemble into perfect lattices with many uses
by Staff Writers
Menlo Park, CA (SPX) Aug 07, 2017


Characterization of ex situ templated growth using superlattices of 9.6-nm Pd nanocrystals.

Some of the world's tiniest crystals are known as "artificial atoms" because they can organize themselves into structures that look like molecules, including "superlattices" that are potential building blocks for novel materials.

Now scientists from the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have made the first observation of these nanocrystals rapidly forming superlattices while they are themselves still growing.

What they learn will help scientists fine-tune the assembly process and adapt it to make new types of materials for things like magnetic storage, solar cells, optoelectronics and catalysts that speed chemical reactions.

The key to making it work was the serendipitous discovery that superlattices can form superfast - in seconds rather than the usual hours or days - during the routine synthesis of nanocrystals.

The scientists used a powerful beam of X-rays at SLAC's Stanford Synchrotron Radiation Lightsource (SSRL) to observe the growth of nanocrystals and the rapid formation of superlattices in real time.

A paper describing the research, which was done in collaboration with scientists at the DOE's Argonne National Laboratory, was published in Nature.

"The idea is to see if we can get an independent understanding of how these superlattices grow so we can make them more uniform and control their properties," said Chris Tassone, a staff scientist at SSRL who led the study with Matteo Cargnello, assistant professor of chemical engineering at Stanford

Tiny Crystals with Outsized Properties
Scientists have been making nanocrystals in the lab since the 1980s. Because of their tiny size -they're billionths of a meter wide and contain just 100 to 10,000 atoms apiece - they are governed by the laws of quantum mechanics, and this gives them interesting properties that can be changed by varying their size, shape and composition.

For instance, spherical nanocrystals known as quantum dots, which are made of semiconducting materials, glow in colors that depend on their size; they are used in biological imaging and most recently in high-definition TV displays.

In the early 1990s, researchers started using nanocrystals to build superlattices, which have the ordered structure of regular crystals, but with small particles in place of individual atoms. These, too, are expected to have unusual properties that are more than the sum of their parts.

But until now, superlattices have been grown slowly at low temperatures, sometimes in a matter of days.

That changed in February 2016, when Stanford postdoctoral researcher Liheng Wu serendipitously discovered that the process can occur much faster than scientists had thought.

'Something Weird Is Happening'
He was trying to make nanocrystals of palladium - a silvery metal that's used to promote chemical reactions in catalytic converters and many industrial processes - by heating a solution containing palladium atoms to more than 230 degrees Celsius. The goal was to understand how these tiny particles form, so their size and other properties could be more easily adjusted.

The team added small windows to a reaction chamber about the size of a tangerine so they could shine an SSRL X-ray beam through it and watch what was happening in real time.

"It's kind of like cooking," Cargnello explained. "The reaction chamber is like a pan. We add a solvent, which is like the frying oil; the main ingredients for the nanocrystals, such as palladium; and condiments, which in this case are surfactant compounds that tune the reaction conditions so you can control the size and composition of the particles. Once you add everything to the pan, you heat it up and fry your stuff."

Wu and Stanford graduate student Joshua Willis expected to see the characteristic pattern made by X-rays scattering off the tiny particles.They saw a completely different pattern instead.

"So something weird is happening," they texted their advisor.

The something weird was that the palladium nanocrystals were assembling into superlattices.

A Balance of Forces
At this point, "The challenge was to understand what brings the particles together and attracts them to each other but not too strongly, so they have room to wiggle around and settle into an ordered position," said Jian Qin, an assistant professor of chemical engineering at Stanford who performed theoretical calculations to better understand the self-assembly process.

Once the nanocrystals form, what seems to be happening is that they acquire a sort of hairy coating of surfactant molecules. The nanocrystals glom together, attracted by weak forces between their cores, and then a finely tuned balance of attractive and repulsive forces between the dangling surfactant molecules holds them in just the right configuration for the superlattice to grow.

To the scientists' surprise, the individual nanocrystals then kept on growing, along with the superlattices, until all the chemical ingredients in the solution were used up, and this unexpected added growth made the material swell.

The researchers said they think this occurs in a wide range of nanocrystal systems, but had never been seen because there was no way to observe it in real time before the team's experiments at SSRL.

"Once we understood this system, we realized this process may be more general than we initially thought," Wu said.

"We have demonstrated that it's not only limited to metals, but it can also be extended to semiconducting materials and very likely to a much larger set of materials."

The team has been doing follow-up experiments to find out more about how the superlattices grow and how they can tweak the size, composition and properties of the finished product.

Research paper

TECH SPACE
One-nanometer trimetallic alloy particles created
Tokyo, Japan (SPX) Aug 07, 2017
The principal component of petroleum and natural gas are hydrocarbons and their mixtures, and are indispensable as resources supporting modern infrastructure as raw materials for the petrochemical industry. A technique which has been conventionally used to create beneficial chemical products from hydrocarbons was to use a large amount of metallic peroxides in hazardous organic solvents to oxidiz ... read more

Related Links
SLAC National Accelerator Laboratory
Space Technology News - Applications and Research

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TECH SPACE
SpaceX launches super-computer to space station

Disruptioneering: Streamlining the Process of Scientific Discovery

NASA Offers Space Station as Catalyst for Discovery in Washington

Two Voyagers Taught Us How to Listen to Space

TECH SPACE
SpaceX launches super-computer to space station

Space Launch System Solid Rocket Boosters 'on Target' for First Flight

NASA Guide Outlines Deep Space Rocket's Unprecedented Capabilities

VSS Unity Flies with Propulsion Systems Installed and Live

TECH SPACE
Curiosity watches Martian clouds pass over Gale Crater

Opportunity takes in the panoramic view while crossing some rocky terrain

China to build first Mars simulation base

Preserving the stress of volcanic uprise on Mars

TECH SPACE
China's satellite sends unbreakable cipher from space

China develops sea launches to boost space commerce

Chinese satellite Zhongxing-9A enters preset orbit

Chinese Space Program: From Setback, to Manned Flights, to the Moon

TECH SPACE
Lockheed Martin invests $350M in state-of-the-art satellite production facility

ASTROSCALE Raises a Total of $25 Million in Series C Led by Private Companies

LISA Pathfinder: bake, rattle and roll

Airbus DS to expand cooperation with Russia

TECH SPACE
Tiny terahertz laser could be used for imaging, chemical detection

NASA, Norway to develop Arctic laser-ranging station

Lockheed Martin integrates first modernized A2100 satellite

One-nanometer trimetallic alloy particles created

TECH SPACE
Scientists find four Earth-like exoplanets orbiting closest sun-like star

TRAPPIST-1 twice as old as our solar system

A New Search for Extrasolar Planets from the Arecibo Observatory

Gulf of Mexico tube worm is one of the longest-living animals in the world

TECH SPACE
Scientists probe Neptune's depths to reveal secrets of icy planets

New Horizons Video Soars over Pluto's Majestic Mountains and Icy Plains

Juno spots Jupiter's Great Red Spot

New evidence in support of the Planet Nine hypothesis




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement