The key to making it more practical, Dresselhaus explains, was in creating engineered semiconductor materials in which tiny patterns have been created to alter the materials behavior. This might include embedding nanoscale particles or wires in a matrix of another material. These nanoscale structures just a few billionths of a meter across interfere with the flow of heat, while allowing electricity to flow freely. Making a nanostructure allows you to independently control these qualities, Dresselhaus says.
She and her MIT collaborators started working on these developments in the 1990s, and soon drew interest from the US Navy because of the potential for making quieter submarines (power generation and air conditioning are some of the noisiest functions on existing subs). From that research, we came up with a lot of new materials that nobody had looked into, Dresselhaus says.
After some early work conducted with Ted Harman of MIT Lincoln Labs, Harman, Dresselhaus, and her student Lyndon Hicks published an experimental paper on the new materials in the mid 1990s. People saw that paper and the field started, she says. Now there are conferences devoted to it.
Her work in finding new thermoelectric materials, including a collaboration with MIT professor of Mechanical Engineering Gang Chen, invigorated the field, and now there are real applications like seat coolers in cars. Last year, a small company in California sold a million of the units worldwide.
OTHER POTENTIAL APPLICATIONS
The same principle can be used to design cooling systems that could be built right into microchips, reducing or eliminating the need for separate cooling systems and improving their efficiency.
The technology could also be used in cars to make the engines themselves more efficient. In conventional cars, about 80 percent of t
|Contact: Elizabeth Thomson|
Massachusetts Institute of Technology