Flexible device harvests body heat for wearables

Described in Applied Energy, the flexible thermoelectric generator, or TEG, builds on work published by the same team in 2017. That device used semiconductor elements that were connected electrically in series using liquid-metal interconnects made of EGaIn - a non-toxic alloy of gallium and indium. EGaIn provided both electrical conductivity and stretchability, with the entire device embedded in a stretchable silicone elastomer.

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The upgraded device uses an improved silicone elastomer that envelops the EGain interconnects. It employs roughly the same architecture as the 2017 iteration, but significantly improves the thermal engineering while increasing the density of the semiconductor elements responsible for converting heat into electricity.

According to research lead Mehmet Ozturk, an NC State professor of electrical and computer engineering, the advance brings flexible TEGs closer to the efficiency of rigid devices, which have traditionally outperformed their flexible counterparts in harvesting body heat.