Did you know that, every second, millions of gigawatts of energy are lost for lack of alternatives to capture them? It is infrared radiation that is emitted anytime and anywhere that absorbs sunlight, such as the ocean or the earth’s surface. Aware of this, Saudi scientists have just taken the first step to take advantage of this potential. To do this, they have developed an innovative device that uses the tunnel effect to transform this energy or the waste heat of any industrial process into usable electricity.
How to meet the challenge was clear to this team from King Abdullah University of Science and Technology (KAUST): treat infrared heat like high frequency electromagnetic waves. With the appropriate antennas, these are sent to a rectifier whose role is none other than to convert alternating signals into current suitable for charging batteries or supplying devices.
However, being clear didn’t mean it was easy. With wavelengths as small as those of infrared emissions, antennas have to be created on micro or nano scales, which makes operation very difficult. Added to this is another bump to be filled: the oscillation speed of the waves exceeds thousands of times that of the movement of the electrodes by a typical semiconductor. “There is no commercial diode in the world that can operate at such a high frequency”Project manager Atif Shamim adds to the thread.
Despite what has been described, the answer has been found in the tunneling effect, a quantum phenomenon whereby particles circumvent the rules of classical mechanics which, now, have been put into practice in this design. So, keeping in mind the diagram of tunnel systems (i.e. metal-insulator-metal diodes), the Scientists have created a nano-antenna in the shape of a bow tie which basically reproduces the process, now with two metal arms in the center of which is a thin insulating layer.
With this approach, it was not only possible to generate the fields necessary for the tunnel effect. In addition, the device transformed infrared waves into current by moving electrons through a barrier only a nanometer thick, which precisely because of this was able to handle high-frequency signals in a matter of femtoseconds.
After overcoming the most complex phase of the project, the nanoscale overlap of the two antenna arms, the tests performed encouraged the team. These have already demonstrated their ability to capture energy from radiation, although scientists will have to keep working to perfect their idea. The effort is justified, both by the amount of clean energy available and by the fact that it is free of intermittences. Infrared heat can be picked up 24 hours a day. Hence the satisfaction and expectations of this team. “This is only the beginning, a proof of concept”, they point to KAUST before advancing that “We could have millions of devices like this connected to increase electricity production”.