Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



CHIP TECH
A semiconductor that can beat the heat
by Staff Writers
Berkeley CA (SPX) Aug 07, 2017


SEM images of suspended micro-island devices. Individual AIHP NW is suspended between two membranes. (insert) Rattling structures of halide perovskites: cesium tin iodide (left) and cesium lead iodide (right). Credit (Credit: UC Berkeley)

A newly discovered collective rattling effect in a type of crystalline semiconductor blocks most heat transfer while preserving high electrical conductivity - a rare pairing that scientists say could reduce heat buildup in electronic devices and turbine engines, among other possible applications.

A team led by scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) discovered these exotic traits in a class of materials known as halide perovskites, which are also considered promising candidates for next-generation solar panels, nanoscale lasers, electronic cooling, and electronic displays.

These interrelated thermal and electrical (or "thermoelectric") properties were found in nanoscale wires of cesium tin iodide (CsSnI3). The material was observed to have one of the lowest levels of heat conductivity among materials with a continuous crystalline structure.

This so-called single-crystal material can also be more easily produced in large quantities than typical thermoelectric materials, such as silicon-germanium, researchers said.

"Its properties originate from the crystal structure itself. It's an atomic sort of phenomenon," said Woochul Lee, a postdoctoral researcher at Berkeley Lab who was the lead author of the study, published the week of July 31 in the Proceedings of the National Academy of Sciences journal. These are the first published results relating to the thermoelectric performance of this single crystal material.

Researchers earlier thought that the material's thermal properties were the product of "caged" atoms rattling around within the material's crystalline structure, as had been observed in some other materials. Such rattling can serve to disrupt heat transfer in a material.

"We initially thought it was atoms of cesium, a heavy element, moving around in the material," said Peidong Yang, a senior faculty scientist at Berkeley Lab's Materials Sciences Division who led the study.

Jeffrey Grossman, a researcher at the Massachusetts Institute of Technology, then performed some theory work and computerized simulations that helped to explain what the team had observed. Researchers also used Berkeley Lab's Molecular Foundry, which specializes in nanoscale research, in the study.

"We believe there is essentially a rattling mechanism, not just with the cesium. It's the overall structure that's rattling; it's a collective rattling," Yang said. "The rattling mechanism is associated with the crystal structure itself," and is not the product of a collection of tiny crystal cages. "It is group atomic motion," he added.

Within the material's crystal structure, the distance between atoms is shrinking and growing in a collective way that prevents heat from easily flowing through.

But because the material is composed of an orderly, single-crystal structure, electrical current can still flow through it despite this collective rattling. Picture its electrical conductivity is like a submarine traveling smoothly in calm underwater currents, while its thermal conductivity is like a sailboat tossed about in heavy seas at the surface.

Yang said two major applications for thermoelectric materials are in cooling, and in converting heat into electrical current. For this particular cesium tin iodide material, cooling applications such as a coating to help cool electronic camera sensors may be easier to achieve than heat-to-electrical conversion, he said.

A challenge is that the material is highly reactive to air and water, so it requires a protective coating or encapsulation to function in a device.

Cesium tin iodide was first discovered as a semiconductor material decades ago, and only in recent years has it been rediscovered for its other unique traits, Yang said. "It turns out to be an amazing gold mine of physical properties," he noted.

To measure the thermal conductivity of the material, researchers bridged two islands of an anchoring material with a cesium tin iodide nanowire. The nanowire was connected at either end to micro-islands that functioned as both a heater and a thermometer. Researchers heated one of the islands and precisely measured how the nanowire transported heat to the other island.

They also performed scanning electron microscopy to precisely measure the dimensions of the nanowire. They used these dimensions to provide an exacting measure of the material's thermal conductivity. The team repeated the experiment with several different nanowire materials and multiple nanowire samples to compare thermoelectric properties and verify the thermal conductivity measurements.

"A next step is to alloy this (cesium tin iodide) material," Lee said. "This may improve the thermoelectric properties."

Also, just as computer chip manufacturers implant a succession of elements into silicon wafers to improve their electronic properties - a process known as "doping" - scientists hope to use similar techniques to more fully exploit the thermoelectric traits of this semiconductor material. This is relatively unexplored territory for this class of materials, Yang said.

CHIP TECH
Saelig introduces Sol Chip autonomous, solar-powered sensor station
Fairport, NY (SPX) Aug 02, 2017
Saelig has introduced the Sol Chip Comm SCC-S433 - an autonomous, wireless, solar-driven module that powers, controls, and wirelessly connects multiple sensors to a central computer via the cloud. This ultra-compact, maintenance-free solar-powered wireless module can be installed remotely for IoT applications that require autonomous operation, such as indoor/outdoor wireless sensor network ... read more

Related Links
Lawrence Berkeley National Laboratory
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com


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

CHIP TECH
A look inside the Space Station's experimental BEAM module

Two Voyagers Taught Us How to Listen to Space

NASA Offers Space Station as Catalyst for Discovery in Washington

Voyager spacecraft still in communication 40 years out into the void

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

Dragon to be packed with new experiments for International Space Station

ISRO Develops Ship-Based Antenna System to Track Satellite Launches

NASA taps BWXT for reactor design for future Mars missions

CHIP TECH
Five Years Ago and 154 Million Miles Away: Touchdown!

For Moratorium on Sending Commands to Mars, Blame the Sun

Tributes to wetter times on Mars

Opportunity will spend three weeks at current location due to Solar Conjunction

CHIP TECH
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

Chinese Rocket Fizzles Out, Puts Other Launches on Hold

CHIP TECH
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

UK space companies to develop international partnerships

CHIP TECH
BAE Systems reveals iMOTR radar system

Lockheed to intro radar demonstrator prototype

Algorithms that can sketch, recreate 3-D shapes

Ferroelectric phenomenon proven viable for oxide electrodes, disproving predictions

CHIP TECH
Unexpected life found at bottom of High Arctic lakes

NASA hiring a planetary protection officer to guard against alien invaders

Researchers detect exoplanet with glowing water atmosphere

Hubble detects exoplanet with glowing water atmosphere

CHIP TECH
Twilight observations reveal huge storm on Neptune

Jovian storm looms large in the Jupiter's High North

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

Juno spots Jupiter's Great Red Spot




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