Thermoelectric materials can generate electricity from waste heat which escapes through vehicle exhaust pipes, industrial equipment, and computer chips, but so far the materials have not been efficient and have been too expensive to be widely used. Many newer thermo-electric materials may be more effective but they require expensive and impractical layer-by-layer assembly.
Mechanical engineer Ronggui Yang has created an easy-to-make alternative: nanocomposites made of semiconductors such as silicon-germanium alloys and bismuth telluride alloys. Yang's method, developed with his colleagues at the University of Colorado at Boulder, involves fusing nanoparticles and nanowires to create a composite material. Use of nanoscale components helps to slow heat flow, which improves the material's ability to convert thermal energy into electricity. The resulting nanocomposite material performs well in tests and can also be mass-produced at a low cost using a common industrial process.
Yang has produced prototypes in conjunction with Massachusetts Institute of Technology, Boston College, and NASA's Jet Propulsion Laboratory at Caltech. Applications of this technology include military and commercial applications, ranging from refrigeration to self-powered sensors and possibly fuel-efficient cars.
Yang's breakthrough research has led Technology Review Magazine to name Dr Yang in the 2008 TR35 list. This list consists of 35 scientists and technologists under the age of 35 whose work is said to be changing the world in the fields of medicine, computing, communications, electronics, nanotechnology and energy.
Yang works in the areas of micro- and nanotechnology for energy conversion, thermal management in electronic devices, and nanostructured materials, and is a key figure in several large research grants to CUBoulder, Yang also has an ongoing grant from the Air Force Office of Scientific Research to research energy harvesting and storage systems, including new thermoelectric materials with nanoscale components that could convert waste heat from engines and high-power electronics to boost fuel efficiency.
Top Image: Ronggui Yang. Source: University of Colorado
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