Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neutron analysis explains dynamics behind best thermoelectric materials

07.06.2011
Neutron analysis of the atomic dynamics behind thermal conductivity is helping scientists at the Department of Energy's Oak Ridge National Laboratory gain a deeper understanding of how thermoelectric materials work. The analysis could spur the development of a broader range of products with the capability to transform heat to electricity.

Researchers performed experiments at both of ORNL's neutron facilities -- the Spallation Neutron Source and the High Flux Isotope Reactor -- to learn why the material lead telluride, which has a similar molecular structure to common table salt, has very low thermal conductivity, or heat loss -- a property that makes lead telluride a compelling thermoelectric material.

"The microscopic origin of the low thermal conductivity is not well understood. Once we do understand it better we can design materials that perform better at converting heat to electricity," said Olivier Delaire, a researcher and Clifford Shull Fellow in ORNL's Neutron Sciences Directorate.

Delaire's research, reported in Nature Materials, shows that an unusual coupling of microscopic vibrational modes, called phonons, is responsible for the disruption of the dynamics that transport the thermal energy in lead telluride.

In typical crystalline materials, which have a lattice-like atomic structure, the conduction of heat is enhanced by the propagation of phonons along the lattice. The atoms conduct heat by vibrating in a chain, similar to vibrations propagating along a spring.

Delaire's team determined through analysis at the SNS that lead telluride, although having the same crystal lattice as rock salt, exhibits a strong coupling of phonons, which results in a disruption of the lattice effect and cancels the ability to conduct heat.

"The resolution of the SNS's Cold Neutron Chopper Spectrometer, along with the high flux, have been quite important to making these time of flight measurements," Delaire said.

By controlling thermal conductivity in thermoelectrics, less energy is dispersed and more heat can be directed to power generation. Today, thermoelectric materials are used to power the deep-space probes that explore the outer planets and solar system. Cruising beyond the range of solar collectors, the crafts' reactor thermoelectric generators use heat from decaying radioisotopes to generate power.

New, advanced thermoelectric materials could be used to develop more earthly applications, such as vehicle exhaust systems that convert exhaust heat into electricity, reducing the need for alternators. New thermoelectric materials could also help concentrate solar energy for power generation and recover waste heat for industrial processes.

Delaire's team performed additional neutron measurements with HFIR's triple-axis spectrometer. Data analysis has been facilitated through collaboration with ORNL's Materials Theory group. Samples were synthesized and characterized in ORNL's Correlated Electrons Materials group.

The work was funded by DOE's Office of Science as part of the Solid-State Solar-Thermal Energy Conversion Center (S3TEC) Energy Research Frontier Center.

ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.

Bill Cabage | EurekAlert!
Further information:
http://www.ornl.gov

More articles from Materials Sciences:

nachricht Novel sensors could enable smarter textiles
17.08.2018 | University of Delaware

nachricht Quantum material is promising 'ion conductor' for research, new technologies
17.08.2018 | Purdue University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Quantum material is promising 'ion conductor' for research, new technologies

17.08.2018 | Materials Sciences

Low bandwidth? Use more colors at once

17.08.2018 | Information Technology

Protecting the power grid: Advanced plasma switch for more efficient transmission

17.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>