
Scientists build the first all-carbon solar cell - wglb
http://www.sciencedaily.com/releases/2012/10/121031125037.htm#.UJFwqaaa9Mw.twitter
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mercuryrising
Exciting times to be living in. The head honcho of materials has competitors!
And no matter which materials win, we all win, as the boundaries of
electronics as we know them are pushed to their extremes.

Silicon is a bitch. The equivalent doping density of silicon is something like
the area of the United States, with 25 trees in it. Spread out, over the whole
thing. That's what you target, and that's what we get because humans are
awesome. But now we get something different. We get new materials that exhibit
properties that we haven't seen before.

The nanotubes absorb IR. Awesome... transparent screens that make power (only
at 1% efficiency, but it will get better). Still, there is a limit to how much
power you can get if you're only able to absorb IR. So let's make it better,
let's take Graphene (or nanotubes, although I'm not sure if they do it as
well) and make the bandgap adjustable. It's like the "smart glass" (putting a
voltage across a material 'scares' it into interacting with light differently)
[1]. Now imagine we can do that with Graphene, but instead of just diffusing
light, we can control when we absorb it. Put this on top of your tablet
screen, when you're using the device, it is in IR mode, absorbing all the
photons you can't see. When you shut it off, it starts absorbing all the
visible photons, charging up your device. Put this material in your cars, keep
the heat out of them in the summer while you charge your EV. On top of your
house (although a plexiglas roof would be kind of scary).

The moment that we start being able to purchase the 'carbon train' is a great
one. Technology is kind of a mixed feeling for me, it's so cool that we can
talk to anyone, do anything (in imaginary land), but there isn't much
environmental good that comes from it. Now you can use computers to do climate
research or whatever, but we go out and grab the rarest materials to throw
into our new fancy screens. Then we throw them away (eventually) when a newer,
cooler one comes out. We are locking up all our of materials in electronic
sarcophaguses that may never be separated again (at least until we get fusion
and heat is free). I don't care how 'green' your laptop is, the amount of
energy that went into making those teeny chips is absolutely ridiculous and
I'm sure the 'energy footprint' of laptops is near the top of things we
purchase. Carbon will change that though. It's plentiful. It's fast, it's new,
it's sexy. It's different. We may need a little sprinkling of something
special to make it really do what we want (hopefully not), but it's better in
almost every way. It's going to blow our minds what the computers of tomorrow
are capable of. Not because we know what's going to happen, but because the
path we're headed down is going to be very, very rocky. It's time for a good
electronic disruption.

[1] <http://www.youtube.com/watch?v=1i8keEAez2k>

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ph0rque
Carbon can be anything from an electrical insulator (diamond) to a pseudo-
superconductor (nanotubes). So it's "just" a matter of getting the correct
structure to tailor the bandgap to the light we want to absorb.

Also, I can think of an excellent use of IR solar cells: turning heat into
electricity. Wouldn't it be cool if you could always keep the heat in your
house less than 75 degrees F, and produce electricity in the process, because
your whole floor is a huge IR solar cell?

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Retric
What? If your room and floor are the same temperature you can't extract energy
from that system.

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mercuryrising
You can capture photons from the black body spectrum. You can't extract much
energy, but you could get some.

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Retric
Sure you 'capture' a few, but if everything is the same temperature your
losing just as photons back up.

It's a lot like the tiny paddlewheel attached to a ratchet Richard Feynman
analyzed, you end up with an even dice roll 4/5 times you win but that 1/5
makes up for all those gains.

PS: Don't forget solar cells work because the sun is hot, and there is plenty
of black body radiation to go around.

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JeffL
I honestly have no idea which solar cell stories to pay attention to anymore.
They are so abundant, and it seems like we never get any follow ups. Does
someone with expert knowledge care to comment about if this story is more
significant than all the other solar cell breakthroughs?

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durkie
Cool that they did it, and it's a nice first step, but I think the "cheap,
abundant carbon!" angle of the story is misleading.

Silicon is pretty damn abundant, and they're complaining about how expensive
it is -- it's the processing that matters, and right now processing cheap,
abundant carbon to make defect-free layers of graphene, or uniform mixtures of
carbon nanotubes (free of catalyst particles, of identical chiralities,
lengths, diameters and tube number) is very hard and expensive.

Personally, I'm super interested in what Twin Creeks Technologies
(<http://www.twincreekstechnologies.com/solar/> \-- no affiliation) is going
to do. Their processing technology is completely out of left field and seems
like it has huge potential.

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makomk
They seem to be talking about the abundance of carbon in comparison to the
indium used in silicon-based panels, rather than because silicon itself is
scarce.

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bathat
Indium is only used for the clear ITO electrode, though. So if scarcity of
Indium were the only concern, then only the "front" carbon electrode would be
relevant--the rest of the photovoltaic structure could be anything you wanted
(including Si).

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wglb
And here is the article (rather abstract) with the original report:
<http://pubs.acs.org/doi/full/10.1021/nn304410w>

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sadfaceunread
Actually this is I believe the second published all carbon solar cell.

First one came out of MIT [http://web.mit.edu/newsoffice/2012/infrared-
photovoltaic-062...](http://web.mit.edu/newsoffice/2012/infrared-
photovoltaic-0621.html)

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johnrgrace
Move biology ahead a bit and maybe we could grow these. Way past current tech
but I'm sure we will get that point within the next 100 years

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ars
I have lots of them growing in my backyard.....

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ck2
LESS than 1% efficiency?

Might want to hold off on press releases until it hits double digits.

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ntumlin
First car only went ~4 miles an hour. Everything's gotta start somewhere.

