By Resonance Science Foundation
It is now common place to use solar panels to convert solar rays into electricity – but what about all the other rays that are absorbed by the Earth’s surface?
Sunlight is absorbed by the Earth’s surface, its oceans and atmosphere and is continuously re-emitted as infrared radiation – so why isn’t this energy utilized as electricity? Solar panels work via the photoelectric effect, or more specifically the photovoltaic effect, where light incident upon a metal results in the emission of electrons which are excited to move as charge through the metal. The amount of charge – electric current – that can be generated depends on the wavelength of the photons and the threshold wavelength of the metal. Sunlight is predominately in the visible and infrared wavelengths and a small amount of UV, so most solar panels work in the visible range as that is more efficient, although the latest developments are utilizing full-spectrum photovoltaic material.
Another way to tap into these infrared waves is in the same way you would tap into radio waves and micro waves – with an antenna. However infrared waves are much shorter than micro and radio waves so require nano scale antennas. As well the diodes – required to convert the alternating signal to direct current charge for batteries or other power devices – do not operate at the high frequencies of infrared rays. A team at KAUST now believe they have overcome this with the help of quantum tunneling – the quantum property of borrowing energy (read more here). They achieve this by utilizing a unique bowtie-shaped nano-antenna and a metal-insulator-metal (MIM) diode.
If such devices prove efficient, it could have huge implications for electricity generation around the world.
This article (Quantum Tunneling used to Harvest Electricity from the Earths Heat) was originally published on Resonance Science Foundation and syndicated by The Event Chronicle.