A small, thin-film thermoelectric generator (TEG) converts heat into electricity. Developer Nextreme, Research Triangle Park, N.C. (nextreme.com) says the film is ideal for making use of waste heat. The solid-state TEG delivers power generation densities of over 3W/cm², more than bulk materials and provides power in a form factor that can be as little as 5% the thickness of bulk-material alternatives. The latter TEGs are made from sintered powders of thermally active materials rather than the thin-film method Nextreme uses.

The device generates electricity by the Seebeck Effect, in which electricity is produced from a temperature differential. The temperature difference between hot and cold sources leads to a difference in the Fermi energy across the thermoelectric material and yields a potential difference, which drives a current.

Developers say TEG opens up waste-heat energy conversions for remote power applications. The film is manufactured with semiconductor-fabrication techniques, making it scalable, cost-effective, and useful in a broad range of markets and applications including medical implants, wireless sensor networks, and thermal batteries.

“With enough heat, power levels reach 300 mW from devices not much bigger than a piece of confetti,” says Nextreme CTO Seri Lee. “And in low temperature differences, we have demonstrated micro-watts of power - enough thermal energy conversion to power remote sensors and other distributed devices.”