Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Grain orientation boosts thermoelectric performance

The peak dimensionless thermoelectric figure-of-merit (ZT) of Bi2Te3-based n-type single crystals is about 0.85 in the ab plane at room temperature, which has not been improved over the last 50 years due to the high thermal conductivity of 1.65 W m−1 K−1 even though the power factor is 47  10−4 W m−1 K−2.  Credit Nano Letters
The peak dimensionless thermoelectric figure-of-merit (ZT) of Bi2Te3-based n-type single crystals is about 0.85 in the ab plane at room temperature, which has not been improved over the last 50 years due to the high thermal conductivity of 1.65 W m−1 K−1 even though the power factor is 47 10−4 W m−1 K−2. Credit Nano Letters

Abstract:
Thermoelectric materials promise everything from clean power for cars to clean power from the sun, but making these materials widely useful has been a challenge.

Grain orientation boosts thermoelectric performance

Chestnut Hill, MA | Posted on January 23rd, 2011

Now researchers from Boston College, MIT and GMZ Energy have developed an inexpensive, simple mechanical process for achieving a major increase in the efficiency of a common thermoelectric material: bismuth telluride selenide (BiTeSe), which has been used in commercial devices since the 1950s. "Power generation applications for thermoelectrics are not big now because the materials aren't good enough," said MIT professor Gang Chen. He believes their findings could pave the way for a new generation of products - from semiconductors and air conditioners to car exhaust systems and solar power technology - that run cleaner.

Xiao Yan and his colleagues from BC, MIT and GMZ Energy achieved a 22% improvement in peak thermoelectric figure of merit (ZT - see 1 below) from 0.85 to 1.04 at 125 degrees C in Bi2Te2.7Se0.3 by repressing the as-pressed samples. The main improvement is the large increase of electrical conductivity with only small increase of thermal conductivity and similar Seebeck coefficient. "We want to attain the single-crystal-like high power factor (see 2 below) by preparing preferential grain orientation while maintaining low thermal conductivity by nanocomposite approach," said Boston College professor Zhifeng Ren.

An innovative mechanical process technique was employed by Xiao Yan and his co-workers from BC, MIT and GMZ Energy. As-pressed samples were initially obtained by ball milling the mixture of individual element materials into alloyed BiTeSe nanopowders and then hot pressing the powder into bulk forms with nano constituents. Then as-pressed bulks were pressed again at elevated temperatures in a bigger diameter die to obtain re-pressed bulk samples. "During repressing process, lateral flow takes place, which helps to orient the grains and thus improve the power factor," explained Ren and Chen.

This work was published in Nano Letters, pubs.acs.org/doi/abs/10.1021/nl101156v

(1) ZT is a measure of the thermoelectric performance of a material

(2) Power factor is defined as a product of squared Seebeck coefficient and electrical conductivity.

####

For more information, please click here

Contacts:
Ed Hayward
Boston College Office of Public Affairs
617-552-4826

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

Tough foam from tiny sheets: Rice University lab uses atom-thick materials to make ultralight foam July 29th, 2014

Zenosense, Inc. July 29th, 2014

Optimum inertial design for self-propulsion: A new study investigates the effects of small but finite inertia on the propulsion of micro and nano-scale swimming machines July 29th, 2014

A new way to make microstructured surfaces: Method can produce strong, lightweight materials with specific surface properties July 29th, 2014

Possible Futures

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Surface Characteristics Influence Cellular Growth on Semiconductor Material March 12th, 2014

Materials/Metamaterials

Flexible Metamaterial Absorbers July 29th, 2014

Tough foam from tiny sheets: Rice University lab uses atom-thick materials to make ultralight foam July 29th, 2014

A new way to make microstructured surfaces: Method can produce strong, lightweight materials with specific surface properties July 29th, 2014

Iranian Scientists Use Waste Cotton Fibers to Produce Cellulose Nanoparticles July 29th, 2014

Environment

Iranian Scientists Use Waste Cotton Fibers to Produce Cellulose Nanoparticles July 29th, 2014

Production of Toxic Gas Sensor Based on Nanorods July 28th, 2014

Researchers Use Various Zinc Oxide Nanostructures to Boost Efficiency of Water Purification Process July 13th, 2014

Using Sand to Improve Battery Performance: Researchers develop low cost, environmentally friendly way to produce sand-based lithium ion batteries that outperform standard by three times July 8th, 2014

Energy

Oregon chemists eye improved thin films with metal substitution: Solution-based inorganic process could drive more efficient electronics and solar devices July 21st, 2014

Steam from the sun: New spongelike structure converts solar energy into steam July 21st, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2014 conference July 8th, 2014

Automotive/Transportation

Stanford team achieves 'holy grail' of battery design: A stable lithium anode - Engineers use carbon nanospheres to protect lithium from the reactive and expansive problems that have restricted its use as an anode July 27th, 2014

Nano-supercapacitors for electric cars July 25th, 2014

Using Sand to Improve Battery Performance: Researchers develop low cost, environmentally friendly way to produce sand-based lithium ion batteries that outperform standard by three times July 8th, 2014

Up in Flames: Evidence Confirms Combustion Theory: Berkeley Lab and University of Hawaii research outlines the story of soot, with implications for cleaner-burning fuels July 1st, 2014

Solar/Photovoltaic

Steam from the sun: New spongelike structure converts solar energy into steam July 21st, 2014

Making dreams come true: Making graphene from plastic? July 2nd, 2014

Shrinky Dinks close the gap for nanowires July 1st, 2014

New Study Raises Possibility of Production of P-Type Solar Cells July 1st, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE