Superefficient Solar from Nanotubes - can wring twice the charge from light.

[The Straight Story]

Superefficient Solar from Nanotubes

Carbon nanotube photovoltaics can wring twice the charge from light.



Today's solar cells lose much of the energy in light to heat. Now researchers at Cornell University have made a photovoltaic cell out of a single carbon nanotube that can take advantage of more of the energy in light than conventional photovoltaics. The tiny carbon tubes might eventually be used to make more-efficient next-generation solar cells.
Tubular cells: The carbon nanotube at center is connected to several electrodes and acts as a superefficient photovoltaic cell.
Credit: AAAS/Science

"The main limiting factor in a solar cell is that when you absorb a high-energy photon, you lose energy to heat, and there's no way to recover it," says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory in Golden, CO. Loss of energy to heat limits the efficiency of the best solar cells to about 33 percent. "The material that can convert at a much higher efficiency will be a game-changer," says Beard.

Researchers led by Paul McEuen, professor of physics at Cornell, began by putting a single nanotube in a circuit and giving it three electrical contacts called gates, one at each end and one underneath. They used the gates to apply a voltage across the nanotube, then illuminated it with light. When a photon hits the nanotube, it transfers some of its energy to an electron, which can then flow through the circuit off the nanotube. This one-photon, one-electron process is what normally happens in a solar cell. What's unusual about the nanotube cell, says McEuen, is what happens when you put in what he calls "a big photon" -- a photon whose energy is twice as big as the energy normally required to get an electron off the cell. In conventional cells, this is the energy that's lost as heat. In the nanotube device, it kicks a second electron into the circuit. The work was described last week in the journal Science.

http://www.technologyreview.com/computing/23471/?a=f

[aquart]

1. Beeeyooooteeeefoooool.

[Ramulux]

2. Nanotech FTW

The widespread use of carbon nanotubes is going to be the next massive step towards the future. I suggest everyone do a little research on what carbon nanotubes are and the ridiculous amount of uses it has.

[Occulus]

9. +1, and welcome to DU

These are so useful.

Here's a video of a carbon nanotube sheet being used to play an audio stream. Note that the sheet can be stretched. here's another video showing an individual nanotube being used to receive a radio signal.

These seem to have enormous potential, don't they?

[ChairmanAgnostic]

3. gimme an effin break

Oh NOES, we are getting excess HEAT! Gawd forbid that we try to capture "excess" heat in some sort of engine.

let me see.
Coal power. excess heat, boiling water, driving turbines.
gas power. see above.
nuclear power. see above.

Duh. That excess heat can and should be captured, used, as a secondary source. Hell, even as a preheat source for conventional commercial power, the savings on heating water to steam are huge.

[Confusious]

8. There are mutiple problems with using that heat

Among them being a negative temperature coefficient with silicon. Turning it directly from light into power is more efficient.

[wroberts189]

4. All these stories.. the big question: Will technology save us?

I hope so.


I wish I could have these things installed now for cheap.

But I cannot afford a needed new roof right now regardless.

[tinrobot]

5. Technology alone will not save us...

We have to change our ways as well. Consume less, breed less, be kinder to the planet.

[wroberts189]

7. So they say.. but at this point we could really use a free energy source. nt

[Occulus]

10. Fusion power.

There's hope for that on a couple of fronts.

[wroberts189]

11. Lets hope sooner then later. I really want tech. to save us.

Even if we do not deserve it. Its becoming our last hope.

[daedalus_dude]

6. Waah, but solar energy is not feesibul!!11

Glen Beck said so.