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Surprise: silicon nanotechnology turns heat into electricity

Chemistry World over at RSC.org tells of a happy new research result in the area of nanotechnology for energy:

Two teams of US scientists have demonstrated silicon-based ‘thermoelectric’ materials that could convert waste heat back into electricity – potentially giving a boost to the efficiency of everything from power stations to refrigerators…

The thermoelectric effect occurs when one end of a material, such as a wire, is heated. Electrons travel to the colder end, producing an electrical current. However, to harness this energy effectively it is critical that the temperature difference is maintained. This requires a material with an unusual combination of properties – excellent electrical conductivity but poor heat conductivity. As silicon conducts heat well, no-one was expecting it to be a good candidate.

But now, two teams have shown that silicon nanowires can act as efficient thermoelectric materials. James Heath of the California Institute of Technology led one of the teams. ‘It was a surprise,’ he told Chemistry World.

One of the more pleasant kind of surprises! Similar results have been obtained by Arun Majumdar and Peidong Yang at UC Berkeley. Proposed application: “personal power-jackets that could use heat from the human body to recharge cell-phones and other electronic devices.” Perhaps this effect could power molecular nanosystems as well? —Christine

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