nano-antennas promise much higher conversion efficiencies than current solar cells -

[Bill USA]

.. Nano-antennas, arrays of antennas each about the size of one fourth the diameter of a human hair, offer much greater efficiencies than current solar cells. One big hurdle to clear is the development of rectifiers that can handle teraherz frequencies of the a/c coming from the nantennas. Once that is achieved, then of course, you have the challenge of getting the cost of manufacturing these things down to be commercially viable. But the researchers sound hopeful.

Research is being done on this technology at the US Department of Energy's Idaho National Laboratory....


A new breed of electronic solar cells that harvests power from heat could double the output of conventional panels - New Scientist

SOLAR cells that work at night. It sounds like an oxymoron, but a new breed of nanoscale light-sensitive antennas could soon make this possible, heralding a novel form of renewable energy that avoids many of the problems that beset solar cells.

The key to these new devices is their ability to harvest infrared (IR) radiation, says Steven Novack, one of the pioneers of the technology at the US Department of Energy's Idaho National Laboratory in Idaho Falls. Nearly half of the available energy in the solar spectrum resides in the infrared band, and IR is re-emitted by the Earth's surface after the sun has gone down, meaning that the antennas can even capture some energy during the night.

Lab tests have already shown that, under ideal conditions, the antennas can collect 84 per cent of incoming photons. Novack's team calculates that a complete system would have an overall efficiency of 46 per cent; the most efficient silicon solar cells are stalled at about 25 per cent. What's more, while those ideal conditions are relatively narrowly constrained for silicon solar cells - if the sun is in the wrong position, light reflects off a silicon solar cell instead of being absorbed - the antennas absorb radiation at a variety of angles. If the antennas can be produced cheaply, the technology could prove to be truly disruptive, says Novack.

Unlike photovoltaic cells, which use photons to liberate electrons, the new antennas resonate when hit by light waves, and that generates an alternating current that can be harnessed.
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Harvesting the Sun's Energy with Antennas

Researchers at Idaho National Laboratory, along with partners at Microcontinuum Inc. (Cambridge, MA) and Patrick Pinhero of the University of Missouri, are developing a novel way to collect energy from the sun with a technology that could potentially cost pennies a yard, be imprinted on flexible materials and still draw energy after the sun has set.

The new approach, which garnered two 2007 Nano50 awards, uses a special manufacturing process to stamp tiny loops of conducting metal onto a sheet of plastic. Each "nanoantenna" is as wide as 1/25 the diameter of a human hair.

Because of their size, the nanoantennas absorb energy in the infrared part of the spectrum, just outside the range of what is visible to the eye. The sun radiates a lot of infrared energy, some of which is soaked up by the earth and later released as radiation for hours after sunset. Nanoantennas can take in energy from both sunlight and the earth's heat, with higher efficiency than conventional solar cells.

"I think these antennas really have the potential to replace traditional solar panels," says physicist Steven Novack, who spoke about the technology in November at the National Nano Engineering Conference in Boston.
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[mopinko]

1. cool

sound promising.

[ret5hd]

2. They have solved global warming!!!

Hear me out:\

e=mc2

They are taking heat (infrared) and turning it into electricity, then turning it into motion (cars, fans, etc)

All we have to do is blanket the planet with these things and we will be in the next ice age!

I know I know...there's some fault to my (lack of) knowledge of physics, so no need to ridicule me here.

[Yo_Mama]

3. No, theoretically that's right. If you were to do this large-scale, it would cool cities

noticeably.

[Bill USA]

4. or we could just sigh, and all bend over and kiss our asses good-bye.

"What, me worry?"