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Sci Tech
New era in thermoelectrics
DREAMING OF the potential of thermocouple devices? Well, perhaps not .but maybe you should. The science journal Nature says there has been a major breakthrough recently in the world of thermoelectric materials.
Scientists funded by the Office of Naval Research and the Defence Advanced Research Projects Agency have taken a field that has stagnated for over forty years and come up with a very high efficiency thermocouple device that could someday make both freon-dependant refrigerators, as well as power generators, obsolete.
By passing a current through thousands of super-thin layers of two different semi-conducting materials, scientists at the Research Triangle Institute (RTI) in North Carolina can make something hotter or colder (depending on which way the current flows) over 20,000 times faster than anything we have today.
In addition to the astonishing cooling applications of such a device, these thermoelectric materials could someday be used to onvert heat into electrical energy in an efficient manner than is possible now. In the 1990s ONR set out to discover and understand the science that would ead to new thermoelectric materials with potentially higher efficiency.
RTI had a unique idea to separate electrical transport from thermaltransport through an artificially engineered material based on a semiconductor super lattice.
Over the years they had to surmount many obstacles: first they had to develop a chemical vapour deposition method to make thin films with repeating structures only tens of angstroms thick.
Next they had to measure the properties of the structure.
Finally they had to apply what they'd discovered and make a prototype device. This marks the beginning of a new era in thermo electrics.
Ultimately these new materials will be engineered into many devices-eventually into plug-in modules-all at an affordable price.
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