Investigators from the FAMU-FSU College of Engineering and the National High Magnetic Field Laboratory revealed that when the tin selenide compound is heated, structural changes at the atomic level occur, allowing it to conduct electricity but not heat.
The National Science Foundation and the Department of Energy funded this research, which could create new technologies for applications such as refrigeration or waste heat recovery from cars or nuclear power plants. natural communication publish findings.
Tin selenide is a strange compound. It has received a lot of attention because of its exceptional high-temperature thermoelectric properties. Optimizing those characteristics can lead to viable options for sustainable electricity generation and other uses in the future..
According to Siegrist, Professor, Chemical and Biomedical Engineering, Florida State University
Researchers already know that tin selenide has a high thermoelectric coefficient at high temperatures, implying that it can generate strong currents from a temperature gradient. Understanding how and why this happened was a question the team set out to answer.
The scientists found that when the compound was heated, the bonds between tin and selenium remained mostly unchanged, with three short bonds and some long bonds still connecting the two elements. However, the tin atoms in the compound began to move around, turning it from a fully ordered lattice structure to a partially disordered lattice structure.
The original idea of this change was that the atoms were displaced, but we discovered that it was the disordered phase transition that was actually taking place. So to speak, the tin atom is flying around. That’s what allows tin selenide to disperse heat-conducting energy waves.
According to Siegrist, Professor, Chemical and Biomedical Engineering, Florida State University
A good thermoelectric material must have high electrical conductivity but low thermal conductivity. This is accomplished in tin selenide by dynamic partial disturbance of the tin atoms at high temperature, resulting in a decrease in thermal conductivity.
Siegrist worked with investigators from Oak Ridge National Laboratory and the University of Tennessee, Knoxville, on the project. To examine the material, they used a collision neutron source, a type of particle accelerator at ORNL. The accelerator fires protons at the target, creating bursts of neutrons that allow scientists to examine the crystal structure of the target.
Investigators can understand what is driving certain properties that engineers may want to optimize by investigating what is happening at the atomic scale.
This is basic research and we are interested in the mechanism and effect of the material to make it do what we want in a thermoelectric device. All these ideas can improve energy conversion devices by making them more efficient.
According to Siegrist, Professor, Chemical and Biomedical Engineering, Florida State University
Simon AJ Kimber from the University of Burgundy-Franche-Comté contributed to the study along with scientists from ORNL and the University of Tennessee,
Reference magazine:
Giang, B., et al. (2023). Strange case of structural phase transitions in SnSe insights from the total scattering of neutrons. natural communication. doi.org/10.1038/s41467-023-38454-0.
Source: https://www.fsu.edu/
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