New thermoelectric superlattice doubles rate at which waste heat is converted to electricity

Researchers from Hokkaido University and colleagues in Japan and Taiwan have improved the ability to transform wasted heat into usable electricity by narrowing the space through which spread electrons move, according to a new study published in Nature Communications.

Currently, more than 60 percent of the energy produced by fossil fuels is lost as waste heat. The wasted heat can be converted into electricity using thermoelectric materials, which convert heat into electricity when there is a temperature difference, a phenomenon known as the Seebeck effect.

Scientists have been investigating ways to confine electrons to a narrow space in order to improve conversion rates. In 2007, researchers built an artificial superlattice composed of conducting ultrathin layers sandwiched by thick insulating layers. They predicted that performance could be improved if electrons with longer de Broglie wavelength were confined to a narrow conducting layer, but this had not yet been proven experimentally.

The research team, led by Hiromichi Ohta of Hokkaido University, designed a superlattice in which electrons are spread at 30 percent wider intervals compared to previous experiments. This resulted in much higher voltage and doubled the thermoelectric conversion rate achieved by previous methods.

“This is a significant step forward towards reducing the amount of heat wasted by power plants, factories, automobiles, computers, and even human bodies,” says Hiromichi Ohta.

 

Source: Hokkaido University