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MIT Study Outlines a 'Perfect' Solar Cell
Daniel_Stuckey writes A new MIT study offers a way out of one of solar power's most vexing problems: the matter of efficiency, and the bare fact that much of the available sunlight in solar power schemes is wasted. The researchers appear to have found the key to perfect solar energy conversion efficiency—or at least something approaching it. It's a new material that can accept light from an very large number of angles and can withstand the very high temperatures needed for a maximally efficient scheme. Conventional solar cells, the silicon-based sheets used in most consumer-level applications, are far from perfect. Light from the sun arrives here on Earth's surface in a wide variety of forms. These forms—wavelengths, properly—include the visible light that makes up our everyday reality, but also significant chunks of invisible (to us) ultraviolet and infrared light. The current standard for solar cells targets mostly just a set range of visible light.
Is this the least helpful summary ever on /.? It could be. I read it, and found it really didn't tell me anything I didn't already know, and gave very little clue as to how this study's results might even be helpful. I have a strong suspicion it's clickbait and so am moving along.
Hard to tell, would depend on how it ramps up in large scale industrial application.
Interesting 85 percent absorption rate, though. Most of the PV growth in solar has been using cheaper materials, not efficiency of absorption.
-- Tigger warning: This post may contain tiggers! --
i think the most important feature for this technology would be cost/kwh. does it deliver that ?
(surface area we have enough of)
Yes, I'm left. You have a problem with that?
This system uses blackbody emission to re-radiate absorbed photons within a specific bandwidth, which can be selectively optimized for.
However, since it uses blackbody emission, it does not explicitly NEED light as the energy source. Any kind of heating will suffice. This is really just a very fancy means of converting entropic energy into something useful. Could be very useful when coupled with radio-isotope decay systems, for instance. (This, coupled with existing RTG tech, could produce more efficient RTGs)
Sadly, it requires that large numbers of useful photons be produced from the emitting blackbody source, which means it needs some pretty non-trivial temperatures. This isn't going to be something that is used in normal residential settings.
As I read the MIT statement the researchers claim is that their technique collects energy as heat from all available wavelengths. Then a conventional solar cell is used to generate electricity from the photons emitted from the heated collector. I didn't see anything about how much more efficient this is than generating electricity directly, but presumably it's better since the solar cell responds best to a specific wavelength which can be controlled by using the heated collector. Obviously to make it work need a concentrator.
limits the thermodynamic performance of heat engines to n=1-T_ambient/T_solar ~=1-293K/1000K=70%. Now there are going to be losses converting hot liquid into useful work (electrical energy), so actually probably around 30% efficiency will be achievable. High performance photovoltaics can reach 40% efficiency, and therefore this article is highly misleading.
This technology is not suitable for the majority of the U.S. because it relies on concentrated solar, i.e. mirrors and if the sun is behind the clouds, then this technology isn't working for you.
That was the turning point of my life--I went from negative zero to positive zero.
Anyway for a non-student to get access to the full article without paying for it? I'm okay with paying for it if that's what it comes down to. . .
... from whose perspective? At least one perspective holds that the perfect solar cell is one that doesn't even work, a thin strip of plastic made to look like a solar cell that costs a helluva lot less than the real thing:
Today I was walking home from an errand to a store.I saw the remains of a “Dual Power Calculator” in the gutter; it had an intact solar cell in the top.“Cool!”, I thought; “I’m going to rescue that solar cell for some DIY thing.”I grabbed the top part and tossed it in my bag.
When I got home, I dismantled it to remove the “solar cell”.I discovered that it was a fake, a thin strip of plastic separate from the body made to look like a solar cell.
WTF....
Work on getting the $/power down. If you can get energy efficiency gains cheap enough fine otherwise work on making them cheap enough to replace shingles on every house.
I love Jesus, except for his foreign policy.
In the article the intermediate body is simply absorbing heat energy but then re-radiating it at a specific frequency. Would the Carnot effiency rules apply?
Maybe...
In my case, the majority of installation cost is the PE saying the panels are not going to blow off the roof and the electrician connecting everything, not the 2 person crew who took 4 hours to install the 18 panels
I know Americans use some odd turns of phrase sometimes (for example, they'd use "anymore" instead of sometimes), but I have no idea what a "bare" fact is supposed to be.
Perfect Cell uses Solar Flare
Holy smokes Motherboard's posts suck. They don't even bother to try to understand the BS they're spewing.
"Light from the sun arrives here on Earth's surface in a wide variety of forms"
Light from the sun arrives here on Earth in exactly one form, photons. The only difference between a red photon and a blue photon is its kinetic energy. If a Honda Civic is driving down the road at 20 mph, and then speeds up to 30 mph, would you say those were two different forms of car?
"The band gap is a feature of photovoltaic solar cells in particular. "
The band gap is a feature of all semi-conductors, which is *why* they're semi-conductors.
"This collision delivers a bunch of extra force to those atoms, which respond by shedding electrons"
Gah.
'The catch with thermophotovoltaics is that in order to be suitably efficient..."
Which they aren't. That's why we don't use them. Or the large variety of other up- and down-conversion systems that attempt to do the same thing through different means. Like photo-emissive plastics. Silicon is cheap and getting cheaper, and that's the bottom line.
Many years back, I also came up with the idea that an indestructible 100000% efficient solar panel would be totally awesome! /sarc
The article seems to give no information about proof that any of this could be done, just "hey, wouldn't this be really cool if we could do this?".
One thing that has been investigated is films that absorb and re-emit in wavelengths that photovoltaics can use. That way you could get better than 100% of what is available in a narrow band. Then of course there's the obvious of having some sort of cheap collector bigger than the area of the more expensive photovoltaics, for instance fresnel lenses.