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DailyTech – August 11, 2008
Maybe I am wrong! Most people that know me haven’t heard me say that very often. Maybe Mr. Al Gore is correct. I don’t think anyone has ever heard me say that! But here we have a technology that may make solar cells live up to Mr. Gore’s challenge of several weeks ago. Although, to be honest, if the technology is being discussed on paper and in prototypes now, the likelihood of it making a significant dent in 10 years is not very likely. So maybe I am not wrong and Mr. Gore is incorrect after all!
This new nano-antenna technology evidently doesn’t convert sunlight to electricity as a traditional solar cell does. Instead, it converts infrared radiation (heat) into electricity. This is very cool, literally, since it may also be used to cool our energy hog electronics!
Seems there are some engineering challenges right now. That is fine, solving engineering problems makes it plausible. It is when we are talking about scientific challenges that makes me worried. The problems appear to be getting the energy out in a way that we can use it as well as mass producing the film.
The new cells consist of massive arrays of nanoantennas, which can collect energy from light and other sources. The INL team discovered a way to mass produce these arrays on flexible sheets of plastic. The only crucial problem remaining unresolved is developing additional components to harvest the collected energy by transforming it to electricity.
The nanoantennas absorb a targeted wavelength range of mid-infrared rays. The Earth continuously emits these rays thanks to the solar energy that it absorbs during the day. This would allow for continuous solar panel operation, in theory. Traditional panels can only absorb visible light and thus are idle at night.
The effort marks perhaps the first successful effort to capture infrared rays with nanoantennas. Past efforts have been able to harvest other lower-frequency wavelengths but have fallen short with high-frequency wavelengths like IR. This is due in part to the fact that materials’ properties change at high frequencies.
A major obstacle remains in that though the device already produces alternating current, it alternates at a rate of trillions of times per second, far to fast for modern rectifiers to convert to DC current. Further, the current smallest rectifier would need to be shrunk to a thousandth of its size to fit next to the nanoantenna. This would require new manufacturing techniques. An alternative might be to develop nanodevices to slow down the alternating current to more manageable levels.
You can read the entire article here.
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