Cottrell Scholar Awards - 2015
Embracing Asymmetry - Designing Materials for Thermoelectric Power Conversion
It is a fundamental law of physics that energy can be neither created nor destroyed; but it can readily change form, which enables humans to power civilization.
Eric Toberer, assistant professor of physics, Colorado School of Mines, has received Cottrell Scholar funding to extend this basic principle to enhance the conversion of heat into electricity.
Toberer is interested in improving efficiencies in the field of solid-state thermoelectrics – the process by which matter with a crystalline molecular structure converts heat flow into electrical current. Specifically, he is working with single crystals of SnSe (tin selenide) and related alloys as model systems to test a novel algorithm that predicts electron scattering in new and exotic semiconductors.
(Semiconductors are critical components of all modern electronic devices such as computers.)
A major problem with solid-state thermoelectric semiconductors is that electrons interact with atomic nuclei as the electrons diffuse across a temperature gradient, leading to a resistance that reduces the electricity production.
This unfortunate interaction is primarily with phonons, which are “virtual particles” that arise in the quantum realm when a lattice of molecules oscillates uniformly.
By generating accurate models of electron-phonon interactions in tin selenide semiconductors, Toberer and his students hope to open new approaches to minimize inefficiencies and ultimately create thermoelectric generators which are cost competitive with conventional heat engines.
“Such a development would revolutionize our energy infrastructure much like the solid-state transistor revolutionized early vacuum tube computers,” he said. “Efficient solid-state heat engines would disrupt both existing technologies and create new technologies.”
Toberer is also using some of his Cottrell Scholar funding to pioneer active learning (problem solving) approaches in classes on solid-state physics.
“These efforts have led to a largely flipped curriculum, where short screencasts provide much of the course content and in-class time is devoted to discussion of the concepts and activities,” Toberer said.