Nanotechnology Boosts Solar Cell Performance 176
Roland Piquepaille writes "Physicists from the University of Illinois at Urbana-Champaign (UIUC) say they have improved the performance of solar cells by 60 percent. And they obtained this spectacular result by using a very simple trick. They've coated the solar cells with a film of 1-nanometer thick silicon fluorescing nanoparticles. The researchers also said that this process could be easily incorporated into the manufacturing process of solar cells with very little additional cost. Read more for additional references and a photo of a researcher holding a silicon solar cell coated with a film of silicon nanoparticles."
Oh no, it's Roland again! (Score:3, Insightful)
Re:Try reading the article. (Score:3, Insightful)
If I went around ripping off the AP, I'd get a nastygram from their lawyers. Why do we tolerate it more when it's a creepy-looking Frenchman?
Cost (Score:3, Insightful)
How about something to make solar cheaper to purchase, so that the initial investment can be recouped before the expected replacement date?
Seems best suited for non-terrestrial uses (Score:5, Insightful)
With the main advantage being in the UV spectrum, it seems to me the best application would be to UV preferential cells in orbit or on Mars, Luna, etc.. Doubly so given the difficulty in shedding excess heat in Space.
Re:Try reading the article. (Score:3, Insightful)
Doesn't that describe slashdot pretty well?
Re:Correction (Score:4, Insightful)
Whoa, whoa, whoa! Back up, bad idea!
Re:TiO2, UV, and Solar Cubes (Score:3, Insightful)
Which matters how if it still takes up 1 m2 of roof space?
Concentrator systems leave me cold because of this. They concentrate (pardon the pun) on increasing the output per cm2 of solar cell - when the real need is to increase the output per m2 of roof space occupied. (The difference is subtle, but important.)
Re:Another breakthrough.. (Score:3, Insightful)
Oh FFS, what is it with /.ers and their "Why can't I buy it at Walmart yet?" comments?
Have you people never heard of research?
A lot of these stories are of lab demonstrations, or even just theoretical breakthroughs that MAY, one day, be developed to the point that they become useful. Or they may inspire further research that may lead to further research that may eventually be commercialised in a completely different form to how they were first demonstrated.
If you want to read about new ideas and developments that are unlikely to impact your life for several years, you're in the right place. If you want to read about new products that you can buy right now at your local mega-mall, try the junk mail they stuff in your mail box.
This 60% UV is just ONE of the configs... (Score:5, Insightful)
It's still pretty cool, though.
This whole series of "only 60% of the UV part" threads is missing the rest of the article. That was just for ONE size of naonparticle, suitable for converting light to the middle of the visible range. They ran the tests for another size, suitable for converting to visible red, and got a higher conversion result, as expected.
Solar cells completely miss photons below the bandgap energy and only peel off the bandgap energy from those above it. They have a bandgap in the infrared so they get most photons, but only take that first 0.6 electron-volt chunk of their energy and lose the rest as heat. That's great if you have an infrared photon at 0.603 eV, not so hot for visible light photons at 1.8-3.1 eV, and pretty crummy for UV photons at 3.1 to 12 or so eV.
Films of nanoparticles have an interesting property: They absorb photons of various wavelengths and emit photons of particular wavelengths related to their size. But they don't do that in the solar-cell style of chopping the right-sized hunk off a more energetic photon and throwing the rest away. Instead they are able to combine energy from multiple lower-energy photons to generate one of the desired energy, chop several desired energy photons out of a high-energy one (and keep the leftover shavings to combine with others to make more desired-energy photons), and trade energy among their neighboring particles.
So it was expected that a film of nanoparticles on a solar cell would grab the energy from photons all over the spectrum, convert it to the energy characteristic of the nanoparticle size, and re-emit that. The improvement from efficiently salami-slicing and stacking photons should be better than losses from such things as emitting the photon in the wrong direction, giving a big boost to the cell.
And to some extent that was happening: Feed UV photons to nanoparticles that chunk 'em into something in the 3 eV range and you get more out of the UV hitting the cell than you would without the film - without appreciably affecting the output from the visible light. You're averaging about 1 2/3 IR photons worth of energy, instead of 1, for each incoming photon. Feed it to nanoparticles that chunk it up finer, down to 2 eV or so, and you get more out of your UV and also start improving on even visible light.
That's a good sign for doing what you really wanted to do: Use nanoparticles that emit just a tiny squidge above the solar-cell's bandgap, chunking all the photons into the right size for the cell and wasting very little of their energy. (But maybe still losing a bunch by emitting them in the wrong direction. That might be improved by putting the nanoparticles at the bottom of wells in the cell rather than on a flat surface.)
But the experiment produced a surprise: The VOLTAGE went up! WTF?
That means one of two things:
a) The nanoparticles affected the bandgap.
b) The nanoparticles coupled directly into the cell's "circuitry" in some non-obvious way.
b) might lead to something even better: Nanoparticles that capture the photons, chunk and stack them into some desired size (voltage), and deliver them directly to the wiring. That could get virtually ALL the incoming energy into your wires.
A solar cell with efficiencies in the
Hot DAMN!
Re:Try reading the article. (Score:1, Insightful)
Honest people don't mislead others. Natch.
Comment removed (Score:3, Insightful)
Re:Correction (Score:4, Insightful)
Having said that. I'm not a fan of the thin film PV that contain Cd (I don't use NiCd rechargeable's either). I know its not much, but its really nasty stuff.