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Nanotechnology Boosts Solar Cell Performance 176

Posted by Zonk
from the two-great-tastes dept.
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."
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Nanotechnology Boosts Solar Cell Performance

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  • by Baddas (243852) on Tuesday August 21, 2007 @06:36PM (#20311621) Homepage
    I wish I had access to the slashdot front page for my articles.
    • I wish I had access to the slashdot front page for my articles.
      Create a blog that's got interesting information, even if it's aggregated from other sources (such as, say, slashdot).
      Make it look attractive, not a MySpace style design. Tell people about it.

      Who cares if it leads to ??? and then to profit. I get something out of it - an informative article to read.

      If you don't want to read Roland's articles, don't click on the fucking links.
      • by Baddas (243852)
        I write my own (shitty) articles, with words I done made up myself, about (reasonably) original topics. Therefore I occupy a higher continuum than those who provide no original content.

        Note that, unless you're copying these comments from somewhere, you, too, occupy a higher continuum than Messr. Piquepaille. Linkjackers are slightly above spammers and trolls, in my pantheon.
        • Excellent! Stop your bitching here and come see me over on Technocrat [technocrat.net].

          No, I'm totally serious - it's crap like this that drives me away from slashdot towards more focussed and mature sites such as Technocrat.

          Start submitting stories you want to see, and stories you want to involve others in. Please, write your own submissions, don't copy-n-paste the first paragraph of the story you're linking to. Write totally original content and post it. Link us to your blog so we can see more. You'll find the technoc
    • oh.. wait! uh.. nevermind...
  • Correction (Score:5, Informative)

    by friedo (112163) * on Tuesday August 21, 2007 @06:37PM (#20311623) Homepage

    The nanoparticles improve efficiency by 60% in the ultraviolet spectrum. The visible light spectrum is only nominally affected.

    It's still pretty cool, though.

    • Re: (Score:2, Interesting)

      by sl70 (9796)
      Yeah, but the efficiency is so low to start with, anyway, that increasing it by 60% may not make much of a difference. Amorphous silicon cells have an efficiency of about 6%. Increase that by 60% and we get ... 9.6%! Nothing to write home about.
      • Re:Correction (Score:4, Interesting)

        by Original Replica (908688) on Tuesday August 21, 2007 @07:18PM (#20312015) Journal
        9.6%! Nothing to write home about.

        As gas prices creep ever higher and coal plants become less and less desirable a partial conversion to solar power starts to become a very possible reality. Adding just one kilowatt worth of solar power to each of America's 116 million homes would reduce the power consumption almost 1/3rd. http://www.frugalfun.com/solarfest.html [frugalfun.com] The system to get "off the grid" discussed my link costs a fair amount of money, and even a 1 KW system costs $10,000 right now, but if the solar panels can suddenly cost 60% less (by being more efficient) then the price of a 1 KW system could reasonably drop to $5000. Not a huge cost when you are talking about much of todays housing market. Five grand is less than the price difference between a Prius (22K) and a Ford Focus (15K). Solar might well become widespread after all, not because it is efficient, but because everything else is slowly rising to match solar power's high initial cost.
        • by mdsolar (1045926)
          Prices have come down a lot since 2002. Commercial installations a beating grid pricing and some financing mechanisms can get residential down to $0.07/kWh: http://mdsolar.blogspot.com/2007/08/tuppence-in-s u n.html [blogspot.com]. This trend of lower prices should continue for a decade at least and will make solar cheaper than all other sources of power. Some business developments in storage may make the combination of solar plus storage as cheap as any other form of power as well: http://mdsolar.blogspot.com/2007/01/s [blogspot.com]
        • Re: (Score:3, Interesting)

          by CodeShark (17400)
          That's because a 1 KW system in silicon is silly expensive, not to mention a poor use of "juice".

          Let me give you an example why. I spend about $200 for a set of solar "RV" ventilation fans, but used them in a better way -- ventilating my attic continuously when the sun is up. Each fan has about a 1W cell, but they move a fairly substantial amount of air at about 60 degrees celsius OUT of the attic. I also have about a 15 W panel pumping into an underground pipe array for "geothermal" cooling and back to t
      • by mikael (484)
        Another improvement to the efficiency of solar panels is to surround each cell with a little parabolic mirror. Apparently, this helps concentrate the sunlight onto the cell. Then there are methods of stacking two solar cells with different absorption characteristics on top of each other [sciencemag.org]

        I would guess that the future goal is to have solar cells be able to absorb every possible frequency of sunlight.
      • by misleb (129952)
        It is worse than that because it isn't even 60% total increase in efficiency. Just 60% in the ultraviolet range.

        That said, a percentage improvement is good because theoretically it could be applied to future solar cells which will presumably have a much better base efficiency.

        -matthew

    • by goldaryn (834427) on Tuesday August 21, 2007 @06:56PM (#20311843) Homepage
      Still pretty useful though I bet.. but:

      As the alcohol evaporated, a film of closely packed nanoparticles was left firmly fastened to the solar cell.

      Whoa, whoa, whoa! Back up, bad idea!




      (yeah I know it's only isopropyl alcohol. but still never something you want to hear!)
      • Re:Correction (Score:4, Insightful)

        by phoenixwade (997892) on Tuesday August 21, 2007 @07:29PM (#20312119)

        As the alcohol evaporated, a film of closely packed nanoparticles was left firmly fastened to the solar cell.
        Whoa, whoa, whoa! Back up, bad idea!
        Why? the only issue I could see would be dumping the alcohol into the environment, but since it's evaporating off - building a recovery system into the process would save money in manufacturing, and is a no-brainer. So I'd think it very unlikely that a regular dumping of alcohol into the environment would occur, for the best of reasons from a business point of view - it's cheaper to do it the right way.
        • by Anonymous Coward on Tuesday August 21, 2007 @08:32PM (#20312711)
          Hahahahahaha. Man, you totally missed his point.

          He wasn't talking about the effect it might have on the environment. He was joking about "alcohol" as in booze being left out and undrunk long enough that it evaporated.

          See, in a place like Ireland it's considered near criminal to waste ale or lager. So the thought of alcohol evaporating is a disturbing thought to most Irishmen and Irishwomen. It bothers them much like the thought of global warming bothers environmentalists.
          • by SirSlud (67381)
            Is it the Irish or the Scottish that like to imagine that all the beer you've left undrank in your life goes into a post-death barrel? You're supposedly hung over the barrel, by the feet. If you drown, to hell .. if you can breathe easy, to heaven.
          • by CaptDeuce (84529)

            See, in a place like Ireland it's considered near criminal to waste ale or lager. So the thought of alcohol evaporating is a disturbing thought to most Irishmen and Irishwomen. It bothers them much like the thought of global warming bothers environmentalists.

            Aye. And the fact that a post from someone who didn't get the bleepin' joke gets modded up as "Insightful" is highly disturbing to us humorists. So...

            A termite walks into a bar and says, "is the bar tender here?"

        • One does not want to hear of alcohol being allowed to evaporate... One wants to drink the alcohol.

          (Let us assume it is ethanol, for argument sake.)
          • One does not want to hear of alcohol being allowed to evaporate... One wants to drink the alcohol.

            (Let us assume it is ethanol, for argument sake.)
            DOH! My bad.

            It was the isopropyl reference that threw me the other way..... As a lame defence of my densness...
    • Still something (Score:5, Informative)

      by Moraelin (679338) on Tuesday August 21, 2007 @07:08PM (#20311941) Journal
      It's still something, because to knock an electron out, the minimum frequency of the photon has to be at least the difference between the conduction band (where you want that electron) and the lower-energy valence band (where the electron originally is.) So you have a minimum energy cut off point. Exactly where that is, depends on the material, but generally you won't get any power out of the infrared falling on that cell.

      However, the downside is that photons with higher energy than that bandgap, well, the extra energy is essentially wasted.

      So basically, say, if you used Germanium at 0.67 EV bandgap, you'd catch more photons than with Silicium at 1.11 EV bandgap, but get less useful energy (i.e., electricity as opposed to heat) out of each photon.

      And the higher frequency the photon, the more you waste as heat. So you won't waste more in the visible spectrum (well, unless the photon had less energy than the bandgap, in which case it's completely wasted), but in the UV spectrum you waste a lot.

      So reducing the waste in the UV spectrum is really where it counts the most. Sure, it would be neat to gain everywhere, but the UV range is where we waste the most.

      Their talk about fluorescent particles, makes me think they're essentially converting an UV photon into at least one lower frequency photon. The question is what they do with the extra energy. At the simplest imaginable way, you'd get at least two low energy photons from one UV photon.

      On the other hand, it seems to be a bit more than that, from that short summary linked to. From their claim that they improve voltage, not just current, and that something happens at the interface between the particles and the substrate, it sounds like essentially they created a bunch of new junctions there. I.e., that it's a new way to make a multi-junction solar cell.

      Multi-junction cells aren't exactly new, but traditionally they've been very expensive so far. If these guys invented a cheap way to make one, kudos to them.

      On yet another hand, it will be interesting to see on exactly what existing cells can their film be applied. On silicon or other semiconductors, ok, I can see how it would form an extra junction. Would it also work on, say, Dye-sensitized Solar Cells? There essentially their particles would come on top of the dye, and I'm not sure how well that works. It'll be interesting to find out, eventually.
      • Voltage (Score:3, Interesting)

        by benhocking (724439)

        So basically, say, if you used Germanium at 0.67 EV bandgap, you'd catch more photons than with Silicium at 1.11 EV bandgap, but get less useful energy (i.e., electricity as opposed to heat) out of each photon.

        Can't you just increase the operating voltage to capture most of the extra energy? An electron moving across a larger voltage produces more energy. How large you can set the voltage depends on the energy in the electrons being knocked out — or am I missing something?

      • At the end of the blog Roland asked why they didnt use multiple sizes of silicon nanoparticles, this was my long winded reply:

        I am a graduate student working on the synthesis of silicon nanoparticles for solar cells and other applications. While silicon nanoparticles have been syntheszed for over 20 years, and their are many ways of synthesizing them, it is still very difficult to control the size of the particles. Unlike CdSe based quantum dots where the size of the particles is determined by how long y
      • Silicium? (Score:4, Funny)

        by camperdave (969942) on Tuesday August 21, 2007 @11:32PM (#20314117) Journal
        Yes, you are too late to send your letter to the Prussian consulate via the 4:30 autogyro to Siam.
      • However, the downside is that photons with higher energy than that bandgap, well, the extra energy is essentially wasted.

        Since the energy that isn't converted into electricity becomes heat, would it not be sensible to mount the photovoltaic cells on the surface of thermal solar panels (i.e. water heaters)? That way, the solar panels on your roof can provide the power for your TV and the heat for your shower at the same time.
      • From a practical perspective, since this is a very thin nanoparticle film would it be possible to clean off these cells without damaging the film? And if you put a protective coating over the nanoparticle film would you lower the efficiency by doing so? Just look at the mars rovers for examples of how dust accumulation on cells can be a problem.
    • Re: (Score:3, Informative)

      by speculatrix (678524)
      there's quite bit of UV in sunlight, so for photovoltaic panels which are to be used outdoors this is a real gain.

      the cost of making PV panels is still too high compared to the energy you can harvest using them (I choose to use "harvest" specifically because they capture energy from the sun rather than generating from oil for example) over the expected lifetime of the panels. the other problem with PV panels is the environmental cost of manufacture + transport + ancillary electronics to make them useful an
      • Re:Correction (Score:5, Informative)

        by afidel (530433) on Tuesday August 21, 2007 @08:05PM (#20312475)
        the cost of making PV panels is still too high compared to the energy you can harvest using them (I choose to use "harvest" specifically because they capture energy from the sun rather than generating from oil for example) over the expected lifetime of the panels.
        I'm not sure if you're talking about energy cost or economic cost, but either way you are wrong. Solar panels make up their production energy cost in a fraction of their design life, and they are competitive with most non-renewables even at todays cost let alone the expected cost of those sources over the design life of the panels.
      • Re:Correction (Score:4, Insightful)

        by delt0r (999393) on Wednesday August 22, 2007 @03:47AM (#20315479)
        The total environmental cost of PV is far lower than almost anything else, and thats based on a 20 year lifetime which easily exceeded. Its pure fallacy that they are a net polluter. Problem is you need to wait 10+ years to get that net gain. Oh and consider that the energy to make the PV cell came from PV cells? Then what......

        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.
      • I just did a quick and dirty calculation of a 3-4kw home system and it showed that it would take approx 40 years to pay for itself based on electricity prices in my area. Now since electricty prices will probably go up over time, and the money I spent on the PV system is a one time investment, that number is actually going to be smaller. Still, even 30 years is longer than the 25 year lifetime I see for most PV systems.
    • Re:Correction (Score:5, Interesting)

      by hedwards (940851) on Tuesday August 21, 2007 @07:09PM (#20311949)
      That's correct, but what you failed to note is that the UV spectrum contains a much larger amount of energy than either the visible or the infrared spectra do. Shorter wavelength, higher energy. And the higher energy particles are the ones that are the most desirable anyways.
      • Re: (Score:2, Informative)

        by m4cph1sto (1110711)
        This is incorrect. UV radiation is of higher energy, but much lower intensity than light in the visible range, so overall much less energy is extracted from UV, and improving UV efficiency is not a big deal. The technological challenge in the development of photovoltaic materials is to develop a system that works efficiently in the visible range.
        • Re: (Score:2, Informative)

          The technological challenge in the development of photovoltaic materials is to develop a system that works efficiently in the visible range.

          That depends on your application. Residential solar power might not be affected as much by this improvement, but space applications are.

          Satellites dont have an ozone layer filtering UV light. They even get light in the UVC range (you know those UVA+UVB sunscreens? there's no UVC sunscreen except for NASA) so the 60% improvement is probably a big number, I'd have to calculate it. Making satellites with smaller panels with a thin film of particles is probably cost effective right away, given current launch c

    • by epine (68316)
      The whole stupid FA never once gives the percentage improvement when exposed to a sunlight spectrum. Not cool. Not cool at all. I'm sure it was an easy oversight. Sunlight is an obscure point of reference in this debate. After all, sunlight is nowhere near as common as water or air.
    • by Ungrounded Lightning (62228) on Tuesday August 21, 2007 @10:38PM (#20313707) Journal
      The nanoparticles improve efficiency by 60% in the ultraviolet spectrum. The visible light spectrum is only nominally affected.

      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 .90s could be a whole heck of a lot better than even the experimenters were originally chasing. So it's no wonder they published now, with only two sizes of particles tested.

      Hot DAMN!
      • by robbak (775424)
        What I'd like to know: Why wasn't _that_ the original article? Assuming it is correct, it is orders of magnitude more informative than either articles! mod informative +10!!
      • Are there PV materials that are transparent (or close to it) outside of their bandgap? If so it would be interesting to take a page from nature. Many animals (i.e. cats) have a reflective layer behind the retina that gives the neurons a 2nd chance to absoarb the photons they missed. If it hasn't been tried already, maybe a cell could be designed with the PV layer on top, a layer of "converter particles" for coverting photons into the desired bandwidth under it, and a reflective layer on the bottom. That
  • by purduephotog (218304) <{moc.tibroni} {ta} {hcsrih}> on Tuesday August 21, 2007 @06:48PM (#20311759) Homepage Journal
    While at Purdue one of my friends worked on a process to increase solar cell efficiency by etching TiO2 coatings into long, thin whiskers that helped 'whisk' photons down into the surface of the material. It basically doubled the efficiency of a 3% cell in the visible range. Solar hasn't taken off.

    Glass typically blocks UV. Most glazings contain glass. If this only boosts (and 60%, while a large number, is still a tiny increment in efficiency) the UV efficiency then there may be limited use... unless you count concentrator applications.

    The "Sun Cube" (http://www.treehugger.com/files/2007/04/sun_cube_ by_gre_1.php [treehugger.com] uses lenses to concentrate light onto small, very efficient space-grade solar panels. Each panel (if memory serves) was on the order of 1 sqcm, allowing these very expensive but very efficient (25%+) panels to be used. The overall effect was to to take 1 m2 down to 10 sqcm of chips.. and yet have the power output be about the same. Combine that concentrator technology with higher utilization of UV bands AND ultra-efficient space grade panels and you've got a winner (concentrators work ONLY in direct sun- no clouds).

    Just some food for thought.
    • Re: (Score:3, Insightful)

      by DerekLyons (302214)
      [on concentrators]

      The overall effect was to to take 1 m2 down to 10 sqcm of chips.. and yet have the power output be about the same.

      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.)
      • Which matters how if it still takes up 1 m2 of roof space?
        Because solar cells are expensive and concentrators are cheap. The problem with solar cells is primary cost, not space.
      • Which matters how if it still takes up 1 m2 of roof space?

        Good point. You can't increase insolation. Go higher or use mirrors, but you're stuck with that 1kw to 1.5kw /m2. BUT say you use a concentrator that only utilizes 10sqcm of capture material. You've invested in the land, the mirrors to drive them, the mechanisms... and suddenly they increase solar performance to 50%. You want to upgrade? Replace 10sqcm of material. Everyone else has to replace 1m2 of material.

        Seeing as the high efficiency sola
      • If it costs less energy to produce the smaller cells, then you might have something worth using. There's no point going solar if it takes more energy to produce the cell than is captured over its lifetime.
        • Unless you try and install the PV panels while drunk, and drop them off your roof, that just doesn't happen. Depending on the technology used, the initial energy payback for a PV panel is between six months and two years.
      • by syukton (256348)
        A one square meter polycarbonate or acrylic fresnel lens costs significantly less than a one square meter space-grade solar cell. We're talking orders of magnitude, here. I mean, you can get a 1 m2 fresnel lens for less than $50 ($39 for 0.8m2 here [goldmine-e...oducts.com]). I don't have a good figure for the cost of space-grade 20+ percent efficient solar cells, but I think we can assume that if your average 1KW system costs about $7K to $10K for 10-percent-ish efficient cells, then we'd probably be looking at a $50,000 or more co
  • by Chalex (71702) on Tuesday August 21, 2007 @06:56PM (#20311837) Homepage
    So I RTFA, and here's the bit: "improves power performance by 60 percent in the ultraviolet range of the spectrum" and "in conventional solar cells, ultraviolet light is either filtered out or absorbed by the silicon and converted into potentially damaging heat, not electricity."

    So a conventional solar cell gets ~0 energy from this part of the spectrum, but if you coat it with this special coating, it gets 60% more! And how much is that exactly?

    Now if you use a different coating (2.85nm), then it improves performance "in the visible part of the spectrum" by 10%. How much energy does a conventional solar cell get from just the visible part of the spectrum? Unspecified!
  • Cost (Score:3, Insightful)

    by grassy_knoll (412409) on Tuesday August 21, 2007 @07:16PM (#20312001) Homepage

    The process of coating solar cells with silicon nanoparticles could be easily incorporated into the manufacturing process with little additional cost, Nayfeh said.


    How about something to make solar cheaper to purchase, so that the initial investment can be recouped before the expected replacement date?
    • Making cells more efficient does make panels cheaper, since you need fewer cells for the same power output. Or, if you are trying to cover a fixed area, it means that you have more surplus power to sell back to the grid to help cover the cost.
      • I take your point; what I'm trying to get at is the inital outlay for solar isn't recouped over the life of the installation.

        For example[1]: if you need one $15,000 super duper efficient unit, or 10 $1,500 electric shack bargain bin units, if the savings over the life of the unit is $10,000 the inital outlay is too expensive. This doesn't cover maintenance costs over the life of the unit(s), which would decrease the savings.

        [1] costs illustrative only.
        • by dbIII (701233)
          These are photovoltaics - the things we have on satellites, navigation bouys and other places where nobody goes. Where do you get the idea that maintainance is a significant cost?
    • by dbIII (701233)
      Back in the 1960s photovoltaics were a very expensive proposition but wide scale semiconductor fabrication changed all that. The parent poster and moderators should consider more recent information.
      • by ErikZ (55491) *
        Why don't you just post more recent information instead of telling the OP that they're ignorant?
        • Re: (Score:3, Informative)

          by dbIII (701233)

          Why don't you just post more recent information instead of telling the OP that they're ignorant?

          OK. Zone refining of silicon is done in large quantities now at much lower energy usage and cost than before and the high qualitity single crystal silicon ingots are cut into large wafers that are used to make things like microprocessors and solar cells. Thanks to the huge demand for semiconductors silicon solar cells are nowhere near as expensive as they were in the 1960's. There are some that are not made t

          • Is that enough to address an argument that is thirty years out of date?
            no.
            Give us some numbers.
  • by Shadowlore (10860) on Tuesday August 21, 2007 @07:20PM (#20312043) Journal
    First, we need to be careful here. A 60% improvement in the conversion among UV spectrum does not necessarily equate to a 60% increase in a given PV cell. If the particular cell is more of an infrared or visible light spectrum oriented cell, you'll see a minor, if any, improvement. So before anyone starts grabbing random solar cell outputs and starts applying a 60% increase in power and get modded "insightful" for bad information, let's get that part out there.;)

    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.
    • by hacker (14635)

      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.

      As you no-doubt know, current PV cells only capture the visible light spectrum, and that means unobscured, near-direct sunlight during the daytime.

      The biggest advantage I see from a PV cell that can capture and turn UV into electricity, is the ability for it to continue to provide power d

    • The 60% number is pretty useless really. They need to state clearly the actual, real-world power output improvement to be expected by applying this coating to modern photocells. Is it 50%, or 0.02%, or what?
  • How many of these new cells would it take to power this [theonion.com] I wonder? With that 60% increase of the 0% we were getting previously from the UV band, I would imagine quite a few bananas will get eaten before those monkeys actually collide!
  • much UV light penetrates cloud cover directly, so this enhancement may be a good boost for solar power on cloudy days, when it may be needed more.
  • It's good to finally see an article about solar cell efficiency improvements where an actual prototype has been built and tested.
  • Yes! (Score:3, Funny)

    by Hanging By A Thread (906564) on Tuesday August 21, 2007 @08:18PM (#20312609)
    So now I can use my calculator with my black light......groovy!
  • Satellite Use? (Score:2, Interesting)

    by Yehooti (816574)
    If we could shed about 60% of the solar panels on our space vehicles, that would be a tremendous boost in our ability to launch neat stuff cheaper. The question that comes up though is, how well will this new coating survive the rigors of the space environment? If it degrades faster than our current choice then we probably cannot qualify it as a replacement for our current cells. Until that question is addressed, flown and tested, this remains as only a neat future potential. Space drives the race.
    • In reading this, (I support a customer who does sat cells) it would look like you might get between 3 and 10 percent possibly. But space level cells are gallium arsenide based and not silicon. Since I do not work in the front end i will not guess.
  • The numbers bandied about don't add up to anything.

    Voltage by itself is meaningless, we need POWER, which is voltage times current. No mention of the current in the article.

    If they're getting the extra voltage by putting these nanoparticles in series with the regular cell, then the nanoparticle layer current will be the limiting factor. And IIRC there's far fewer ultraviolet photons than visible or infrared ones.

    So it's not clear how much of a win, if any, this new development is.

    And as solar cell

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