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Will photovoltaics be replaced by an antenna and rectifier?

Thu Oct 20, 2016 12:49 am

It appears that GA Tech has developed a diode fast enough to rectify a signal at 100s of THz. That allows them to convert light into DC current using a light-frequency antenna followed by a rectifier. Like all things new, the efficiency is not there, yet, but they feel there are orders of magnitude of improvement still possible. Time (and toil) will tell.

From the article:
GA Tech wrote:“We could ultimately make solar cells that are twice as efficient at a cost that is ten times lower, and that is to me an opportunity to change the world in a very big way” said Baratunde Cola, an associate professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. “As a robust, high-temperature detector, these rectennas could be a completely disruptive technology if we can get to one percent efficiency. If we can get to higher efficiencies, we could apply it to energy conversion technologies and solar energy capture.”
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Re: Will photovoltaics be replaced by an antenna and rectifier?

Thu Oct 20, 2016 2:37 am

Tesla (the genius inventor, not the car company) would be pleased to read this.
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Re: Will photovoltaics be replaced by an antenna and rectifier?

Thu Mar 09, 2017 12:02 am

I don't think they will. The wavelength of light is in the 400 - 800 nanometer range, so a dipole would be about half that. The voltage derived from the electromagnetic field of sunlight would seem unlikely to be enough to overcome the forward voltage drop of a diode. Further, the junction capacitance of the diode would soak up a lot of the current from such a small source.

The quote says something like 'if they can get efficiency to 1 percent', so they are a long ways below the 18 - 20 percent of solar cells.

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Re: Will photovoltaics be replaced by an antenna and rectifier?

Thu Mar 09, 2017 2:40 am

“We think we can reduce the resistance by several orders of magnitude just by improving the fabrication of our device structures,” he said. “Based on what others have done and what the theory is showing us, I believe that these devices could get to greater than 40 percent efficiency.”
I hope they succeed.
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