Tiny tuner turns heat into power

SEM image of the nanoantenna array at the heart of KAUST’s nano-rectenna. The tips of gold triangles that form the antennas are spaced by a gap of just 50nm.

© KAUST

A nanoscale integrated device that efficiently harvests energy from infrared thermal radiation has been developed by researchers in Saudi Arabia. The device captures the mid-infrared radiation that is emitted as waste heat from industrial equipment — in steam generation, metal melting and other applications — and turns it into useful electricity to help satisfy growing requirements for alternative and renewable forms of energy.

Known as the “nano-rectenna”, the device was designed and fabricated by Mena Gadalla and Atif Shamim from the Computer, Electrical and Mathematical Science and Engineering Division at KAUST with a collaborator from Prince Sultan Advanced Technology Research Institute at King Saud University.

While solar cells can convert visible light into electricity, their efficiency is quite poor. “The novel aspect of our device is that it treats the infrared or waste heat as an electromagnetic radiation which can be collected by a nano-antenna and converted into electricity through an integrated rectifier,” explains Shamim. “This approach has no theoretical efficiency limitations, in contrast to the solar cells approach”.

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