Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Thermoelectric materials switch between heat and electricity in a unique and clean solid-state approach.

Abstract:
In the last couple of decades, thermoelectrics have been drawing more and more research interest due to the limited availability and the negative environmental impact of conventional energy strategies.

In the past, as a measuring stick of the conversion efficiency, the term "dimensionless figure-of-merit," also referred to as ZT, has been widely used. A high ZT value usually promises high thermoelectric performance. Typically, good thermoelectric materials should simultaneously display low thermal conductivity and good electrical conductivity.

Thermoelectric materials switch between heat and electricity in a unique and clean solid-state approach.

Boston, MA | Posted on April 23rd, 2012

Striving to enhance the performance of thermoelectric materials, researchers from Boston College and MIT have recently reported a novel materials design to achieve a 30 to 40% enhancement in the peak ZT value for n-type SiGe semiconducting alloys.

Bo Yu, lead author of a paper describing the recent work, says that SiGe has been almost the exclusive choice for high temperature thermoelectric applications. The material has been used in the radioisotope thermoelectric generators (RTGs) employed by US NASA ever since 1976.

Nevertheless, the broader application of SiGe has been limited by the fact that germanium, which is used to reduce the thermal conductivity in such alloys, is extremely expensive and the cost has to justify the performance.

Bo Yu, is a graduate researcher in the Department of Physics at Boston College working in Zhifeng Ren` s group. He worked on this project with MIT collaborators, Mona Zebarjadi, Gang Chen, and Mildred S. Dresselhaus.

The scientists reported that the modulation-doping strategy, conventionally used in the thin-film semiconductor industry, could also be utilised in the 3D bulk thermoelectric materials to enhance their carrier mobility and therefore the electrical conductivity, by over 50% in this case.

By improvising materials design, the team also achieved a simultaneous reduction in the thermal conductivity which combines to provide a high ZT value of about 1.3 at 900 C.

"To improve materials ZT is extremely challenging because all the internal parameters are closely related to each other. Once you change one of them, the others may most likely change accordingly to the other extreme, leading to no net improvement. As a result, a more popular trend in this field of study is to look into new opportunities, or say new material system. However, our study proved that opportunities are still there for the existing materials, if one could work smartly enough to find some alternative material designs," explains Bo Yu.

Zhifeng Ren also points out that this reported ZT peak value competes well with the state-of-art n-type SiGe alloy materials while the new material design requires over 30% less of germanium. "That is a significant advantage to cut down the fabrication cost as we want all the materials we studied in the group be really used by people in reality and that is always the goal for our everyday research," adds Ren.

By using a similar strategy, researchers are also looking into other traditional materials systems trying for more breakthroughs. Actually, this Boston College and MIT team, led by Ren and Chen, has been a pioneer in the clean energy research community for years especially for their contribution in understanding and controlling the phonon and electron transport in bulk thermoelectric composite materials.

Currently, their research is funded by the S3TEC (Solid state solar thermal energy conversion) Centre which is part of the US DOE Energy Frontier Research Centre program, aiming at advancing fundamental science and developing materials to harness heat from the sun and convert this heat into electricity via solid-state thermoelectric and thermophotovoltaic technologies.

This work has been described in more detail in the paper, "Enhancement of Thermoelectric Properties Modulation-Doping in Silicon Germanium Alloy Nanocomposites" by Bo Yu et al, Nano Letters, 2012, 12 (4), pp 2077-2082. DOI: 10.1021/nl3003045.

####

For more information, please click here

Contacts:
Bo Yu
Higgins RM160, 140 Commonwealth Ave.
Chestnut Hill, MA 02467
United States

Copyright © Boston College

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Composite Pipe Long Term Testing Facility February 10th, 2016

Scientists take nanoparticle snapshots February 10th, 2016

Chemical cages: New technique advances synthetic biology February 10th, 2016

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Discoveries

Scientists take nanoparticle snapshots February 10th, 2016

Chemical cages: New technique advances synthetic biology February 10th, 2016

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Electron's 1-D metallic surface state observed: A step for the prediction of electronic properties of extremely-fine metal nanowires in next-generation semiconductors February 9th, 2016

Materials/Metamaterials

Chemical cages: New technique advances synthetic biology February 10th, 2016

Superconductivity: Footballs with no resistance - Indications of light-induced lossless electricity transmission in fullerenes contribute to the search for superconducting materials for practical applications February 9th, 2016

Making sense of metallic glass February 9th, 2016

Graphene decharging and molecular shielding February 8th, 2016

Announcements

Composite Pipe Long Term Testing Facility February 10th, 2016

Scientists take nanoparticle snapshots February 10th, 2016

Chemical cages: New technique advances synthetic biology February 10th, 2016

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Energy

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Host-guest nanowires for efficient water splitting and solar energy storage February 7th, 2016

February 4th, 2016

Research partnerships

Chemical cages: New technique advances synthetic biology February 10th, 2016

SUNY Poly and GLOBALFOUNDRIES Announce New $500M R&D Program in Albany To Accelerate Next Generation Chip Technology: Arrival of Second Cutting Edge EUV Lithography Tool Launches New Patterning Center That Will Generate Over 100 New High Tech Jobs at SUNY Poly February 9th, 2016

Making sense of metallic glass February 9th, 2016

Nanoscale cavity strongly links quantum particles: Single photons can quickly modify individual electrons embedded in a semiconductor chip and vice versa February 8th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic