Where to find a real world solar cell efficiency chart/table for different light wavelengths?

[DasKleineWunder]

I'm confused on how to read solar cell efficiency vs wavelength charts

http://en.wikipedia.org/wiki/Quantum_efficiency

This chart suggests that external quantum efficiency is over 80% for wavelengths from about 500 to 1000 nm.


However this doesn't relate to real world efficiency because of bandgap effects.

http://solarcellcentral.com/limits_page.html

Where can I find a real world results solar cell wavelength efficiency charts or tables?

 

[cranky108]

Good question. I don't have an answer, however from a plant light meter I have it dosen't match the bands that plants perfer. The meter reads very low light under blue or red LED's, which the plants grow very well.

 

[IRstuff]

?? your second graph essentially matches the first spectrally ??

What's missing are the entire string of efficiencies that must multiplied to get the overall efficiency, as well as consistent/inconsistent definitions of what the efficiencies refer to.
> Internal QE is the ability of the bulk material to convert photons that enter the bulk material into electrons, but the 1st graph, I think, makes some assumptions about how the photoelectrons are collected. One issue is that the 1st graph is a photon quantum efficiency, and the graph would need to be converted into a power quantum efficiency to have decent correlation to the 2nd graph.
> External QE accounts for the reflective losses and other collection losses, but the 1st graph does not account for all the losses of photoelectrons, and makes assumptions about photoelectron collection
> Temperature effect on QE
> All of the above essentially enters into the Shockley Queisser limit, which is not inconsistent with your second graph, but there is not sufficient information to determine how the graphs correlate.
> Electrical losses

All of this is of academic interest, since we already know that commercial solar cells are no more than about 20% efficient.

TTFN
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[BigInch]

Not exactly. As I understand what they are doing is the high efficiency cells make efficient use of 3 primary colors, because each has color has a different focal length after passing through the covering lens. Placing a receptor at each focal length effectively increases the efficiency of the cell as a whole. Each receptor yields around 17% efficiency x 3 = 51%, but minus what I'll call an area overlap, or maybe it's a diffusion, factor of 10-13% yields about a 38-40% net efficiency, which is well above the 17-18% that a typical single layer Si receptor cell can do with the same collection area.

If power required vs the cost of providing the collection area is high (as for spacecraft), well.. then these high efficiency cells become quite commercialy viable in their niche market.

Independent events are seldomly independent.

 

[IRstuff]

"17% efficiency x 3 = 51%"

Each band is has minimal overlap, so the efficiencies do not necessarily add.

TTFN
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[BigInch]

It's a fuzzy result.

I hate Windows 8!!!!

 

[IRstuff]

Note that physical absorption is a function of the wavelength and depth. This is partly what makes a tandem detector work. Per

from Link you could theoretically absorb all the usable photons if the cell were 30 mm thick, but the electrons and holes would recombine before you could actually collect them. The multiple stacks described in the other article attempts to shrink the physical thickness by tweaking the bandgaps of the layers.

TTFN
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