KAUST scientists harness electricity from earth’s infrared heat

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Overlapping metal arms shaped like a bowtie form a ‘rectenna’ that captures free, renewable infrared energy. — Photo courtesy: Atif Shamim (KAUST)
Overlapping metal arms shaped like a bowtie form a ‘rectenna’ that captures free, renewable infrared energy. — Photo courtesy: Atif Shamim (KAUST)

Saudi Gazette report

Jeddah — A team of scientists at the King Abdullah University of Science and Technology (KAUST) has been able to transform infrared radiation from the earth, which is heated by the sun, as well as waste heat from industrial processes into electricity, according to the university’s website.

Most sunlight striking the earth is absorbed by its surfaces, oceans and atmosphere. As a result of this warming, infrared radiation is emitted constantly all around us — estimated to be millions of Gigawatts per second, the scientists said in their research paper.

Unlike solar panels that are limited by daylight hours and weather conditions, infrared heat can be harnessed 24 hours a day.

One way to achieve this is to treat waste or infrared heat as high-frequency electromagnetic waves.

Using appropriately designed antennas, collected waves are sent to a rectifier, typically a semiconductor diode, that converts alternating signals to direct current charge for batteries or power devices.

Tunneling devices, such as metal-insulator-metal (MIM) diodes, rectify infrared waves into current by moving electrons through a small barrier.

Since this barrier is only a nanometer thin, MIM diodes can handle high-frequency signals on the order of femtoseconds. To generate the intense fields needed for tunneling, the team turned to a unique ‘bowtie-shaped’ nano-antenna that sandwiches the thin insulator film between two slightly overlapped metallic arms.

“This is just the beginning — a proof of concept,” said Atif Shamim, project leader at KAUST.

“We could have millions of such devices connected to boost overall electricity generation.”


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