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This is an idea that's been bobbling around in my head for a while. I've looked, but (surprisingly) can't seem to find it being baked.
The original idea was for a transparent solar cell (all the ones I've seen are opaque black). Turns out that transparent (or translucent) cells are available but
aimed at replacing window glass. My idea is simply to stack these transparent cells to form 'bricks' - perhaps an inch or three thick.
While I doubt any existing cell absorbs anything close to 100% of it's target frequency, it may make sense to stack the layers so that each layer takes advantage of a light frequency ignored by the layer(s) above it. This assumes that the top-most layer(s) pass unused light to the layer(s) below.
This seems like a fairly obvious application, so I'd guess it's baked, but I honestly can't find anything close to this idea. This may mean it's impractical for some reason.
TRANSPARENT PV PANEL HAS POTENTIAL
http://edis.ifas.ufl.edu/BODY_EH323
[phoenix, May 26 2002, last modified Oct 21 2004]
Scientists Craft New Solar Panel Technology
http://www.abcnews....tingedge020404.html
[phoenix, May 26 2002, last modified Oct 21 2004]
Thinner Materials Improve Flexible Solar Cells
http://www.scienced...04/020410075934.htm
[phoenix, May 26 2002, last modified Oct 21 2004]
Integrated design of Solar Photovoltaic and Transparent Glass Panel
http://www.ecotech.com.hk/pv.htm
[phoenix, May 26 2002, last modified Oct 21 2004]
TOWARDS A PV ARCHITECTURE
http://www.smartarc...s/smartarch799.html
[phoenix, May 26 2002, last modified Oct 21 2004]
STA TITANIA SOLAR CELLS
http://www.sta.com.au/sol_cell.htm
[phoenix, May 26 2002, last modified Oct 21 2004]
"Using a new technique to sandwich two types of [material] into a single photovoltaic cell"
http://m.phys.org/n...ar-cells-cheap.html
This idea writ large. [phoenix, Nov 15 2016]
This idea sprayed large ... sort of.
Solar_20Panel_20in_20a_20can
[normzone, Nov 15 2016]
[link]
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I'm skeptical of the potential here. I'll explain without a great deal of investigation of, or substantiation for my skepticism. Two broad inefficiencies will decrease the power obtained by stacking cells: |
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1. Matter that is transparent is so because it bends all light entering a piece of its substance to the same direction. It is for this reason you can nearly see 'around corners' of a piece of glass. Because bending light reduces the available energy at the point photon collides with the e˜ emitting substrate that generates power from light, light collecting cells are inefficient to a degree. Stacking the cell would cause the light to be bent twice (unless you have a superconducting nanopure glass), causing more reduction in available energy. |
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2. Something to do with what I recall from Feynman's lectures about how light passing through a substance contends with multiple (simultaneous) reflections, positive and negative, from every face of the substance through which the light must pass. That is four faces in a pane of glass, or fiber; I can only guess at how many faces a sphere is considered to have. Figure on a reduction in available energy of 80-90% for the first cell, and probably more if the substrate involved in energy production captures a substantial portion of the 10-20% of the high energy unswerving photons. |
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I might be being stupid here, but how's a transparent solar cell going to absorb any light? Does it work on UV? |
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[pottedstu] From what I've read the 'transparent' cells either use UV or lots of small holes through which visible light passes. I make no claims as to my understanding of how well either one works. 'Translucent' cells use photosensitive dyes to accomplish the same task and appear to be the more popular option for future use - especially in skyscrapers and other commercial buildings because they not only generate electricity, but block glare and look good, too. |
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[reensure] I'm not entirely sure what point you're trying to make unless it's that the second layer won't get as much light as the first which seems self-evident. The point of my idea is to take advantage of every square inch of area the solar array would occupy rather than reflecting or absorbing unused light. The order in which the layers absorbed light could probably be tweaked to maximize electrical output. |
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I think the Idea is good. I understand the idea is this: Opaque panles reflect alot of the potential energy so energy islost (not all is collected). Transparent PV do not reflext that much so loss due to reflextion is not that big but instead the transparent PV lose by alowwing energy to pass through. By having layers of transparent then very little is reflected and very little passes through. However the last layer would be the catcher of a minute amout of energy. Question is if its worth it. I would say that 2-3 layers would be enough. I dont know the figures but lets just say that a transparent PV catches 80% of the solar energy and lets through 20%, then the second layer would catch 80% of the lost 20% from the first panel. Now already most energy is caught. Adding a 3rd panel would be very expensive just to ty catch a minute loss from the combined 2 layers. A double layered transparent PV could be a good idea, that is if it is tue that opaque PVs really do lose alot due to reflextion. |
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Solar cells absorb most of the energy of any light wave above a certain frequency (said frequency having an activationg energy needed to get the electrons moving). |
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I think the poster is thinking that they absorb a range of light frequencies. If that were so, you could have a layer that absorbed UVB rays, then a layer that absorbed UVA rays, then visible light, etc., and utilize more light that way. But that's not so, solar cells absorb light from ALL frequencies above their activation energy. Making one transparent is just raising that activation energy above the visible spectrum. |
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I think it could be very effective if someone did clear balck then some light color and then black again. I think this would work because black aborbs most of the light...wat pass through it would hit a light color so what light didn't pass through would bounce back at the first layer while the rest should be aborbed by the last layer.....just a thought |
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black-colored objects absorb heat as well as light - the idea is that the solar cell's bandgap has to match the radiation being absorbed, otherwise it "misses" and creates heat. proposed system is inefficient and not cost-efficient. this is why they have multi-junction cells. see www.spectrolab.com and www.emcore.com - multi-junction cells that approach 40% efficient b/c of multiple layers - not alternatingly transparent and non-transparent |
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