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Researchers squeeze more electricity from heat

Thermoelectric material offering double efficiency in converting heat into electricity, developed by researchers at Ohio State University, has an obvious application for cars.

Researchers at Ohio State University have invented a new material that can generate electricity from heat in hot machine environments at an unprecedented rate.

The new material is called thallium-doped lead telluride.

The development could have a direct application for converting car engine exhaust heat into electricity, according to a statement from the university.

Using thermoelectric materials for generating power is not new. It is the group's improvements on this type of alloy that are newsworthy.

The group, led by Joseph Heremans, Ohio Eminent Scholar in Nanotechnology at Ohio State University, developed a material that is effective between 450 and 950 degrees Fahrenheit, the temperature range for most car engines.

"The material does all the work. It produces electrical power just like conventional heat engines--steam, gas, or diesel engines--that are coupled to electrical generators, but it uses electrons as the working fluids instead of water or gases, and makes electricity directly," Heremans said in a statement to the press.

Heremans' group has also more than doubled the efficiency rating with which the previously most efficient thermoelectric material could convert heat into electricity, from 0.71 to 1.5.

The invention's story is also an example of how scientific breakthroughs are really the culmination of many people's efforts over long periods of time.

Heremans credits a breakthrough development published in 2006 by researchers at Michigan State University on the quantum mechanics of thallium and tellurium with directly inspiring him after 10 years to try a new approach to producing this type of material. Testing of the new thermoelectric material was a collaborative effort between Heremans's group and scientists at the California Institute of Technology and Osaka University.

Details on the physics behind how the thallium-doped lead telluride was developed can be found in the journal Science.