Breakthrough rectenna converts light into DC current

Rectifying antennas – “rectennas” – are used as parasitic power capture devices that absorb radio frequency (RF) energy and convert it into usable electrical power. Constructing such devices to absorb and rectify at optical wavelengths has proved impractical in the past, but the advent of carbon nanotubes and advances in microscopic manufacturing technology have allowed engineers at the Georgia Institute of Technology to create rectennas that capture and convert light to direct electrical current. The researchers believe that their creation may eventually help double the efficiency of solar energy harvesting.

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CrazyNeutrino said:

Breakthrough rectenna converts light into DC current

Rectifying antennas – “rectennas” – are used as parasitic power capture devices that absorb radio frequency (RF) energy and convert it into usable electrical power. Constructing such devices to absorb and rectify at optical wavelengths has proved impractical in the past, but the advent of carbon nanotubes and advances in microscopic manufacturing technology have allowed engineers at the Georgia Institute of Technology to create rectennas that capture and convert light to direct electrical current. The researchers believe that their creation may eventually help double the efficiency of solar energy harvesting.

more..

For “rectenna” read “diode”. The first “thermionic valve” versions of the diode sufficed at long radio wavelengths. Semiconductor diodes reduced this wavelength first to UHF and then to microwave frequencies. I hadn’t heard of a diode fast enough to operate at up to IR frequencies, but that it exists doesn’t surprise me. This new device is a diode that works at up to visible wavelengths. “For the past 40 years researchers have been trying to create devices that operate at visible wavelengths with little success … the new devices currently operate at less than one percent efficiency”, but even that’s a major breakthrough.