Researchers at the University of Colorado Boulder say a new method of improving thermoelectric materials could lead to the development of better solar panels, more energy-efficient cooling equipment and effective devices that could turn waste heat from power plants into electricity.
The technique, which involves constructing an array of nanoscale pillars on top of a sheet of thermoelectric material, could be a new solution to a century-old problem, Mahmoud Hussein, an assistant professor of aerospace engineering sciences who pioneered the discovery, said.
Thermoelectric materials utilize the thermoelectric effect, which refers to the ability to generate an electric current from a temperature different between two sides of a material and are valued for their ability to create electricity from a heat source and to cool instruments by consuming electricity.
However, says Hussein, these materials, while enabling electricity to flow through them, also allow heat to flow through them, reducing the temperature difference between two sides of a material and weakening the current created. To mitigate this problem, scientist began to engineer special thermoelectric materials with built-in nanoscale barriers such as holes or particles to impede the flow of heat—however, many of these barriers also impeded the flow of electricity.
Using a computer simulation, the UC-boulder estimated their nanoscale pillars could reduce heat flow through a thermoelectric material by half without affecting the flow of electricity. THeir research is published in the journal Physical Review Letters.
According to the team, heat is carried through a material as a series of vibrations known as phonons. These vibrations can be interrupted by vibrations from the atoms that make up the pillars, effectively interrupting the flow of heat. The pillar vibrations are not expected to affect the electric current.
The team plans to fabricate the pillars with assistance from other university faculty and institutions in order to test the idea in a laboratory setting.
