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This seems a bit weird. They claim that they think they will reach an efficiency of 12%, like normal solar cells, but that's of course neglecting the fact that

by lutorm 16y ago

This seems a bit weird. They claim that they think they will reach an efficiency of 12%, like normal solar cells, but that's of course neglecting the fact that only a fraction (max half) of the sunlight is in the IR. So the amount of energy you'd get is still only half (not that that is insignificant).

T_S_ 16y ago
If that's true then regular solar cells only get a shot a half the energy too. So it doesn't seem so weird to me. More weird to me, after spending some time in the business, is all these solutions which only require "some engineering" are perpetually around the corner. People, stop taking "some engineering" or granted! :)
- lutorm 16y ago
  Well, it depends on what you mean by efficiency. I would say that if I say "I have these solar cells that take sunlight and create electricity with 12% efficiency", I would expect that I get 12% of the total insolation in electricity. If I instead say "these solar cells take infrared sunlight and create electricity with 12% efficiency", then I expect it to be 12% of the infrared sunlight, not 12% of the total sunlight. It depends on what the hypothetical "fully efficient" case is.
gamble 16y ago
The 12% efficiency quote seems to originate in an interview with the authors. I read the actual paper,[1] and it only mentions a projected efficiency of 2-3%. You are right that there simply isn't enough energy in the near-infrared to achieve a 12% efficiency. As in a lot of scientific reporting, it's hard to know whether the journalist misinterpreted the authors, or if the authors were indulging in a bit of hyperbole to promote their work. =) The device described in the paper is intended for energy scavenging rather than as a competitor for standard opaque cells. The idea is that, since you already want an anti-reflective coating to block IR light and minimize your air conditioning bill, why not use a coating that also incorporates a solar cell? [1] http://apl.aip.org/resource/1/applab/v98/i11/p113305_s1?bypassSSO=1 http://apl.aip.org/resource/1/applab/v98/i11/p113305_s1?bypa...

by lutorm 16y ago

T_S_ 16y ago

If that's true then regular solar cells only get a shot a half the energy too. So it doesn't seem so weird to me. More weird to me, after spending some time in the business, is all these solutions which only require "some engineering" are perpetually around the corner. People, stop taking "some engineering" or granted! :)

lutorm 16y ago
Well, it depends on what you mean by efficiency. I would say that if I say "I have these solar cells that take sunlight and create electricity with 12% efficiency", I would expect that I get 12% of the total insolation in electricity. If I instead say "these solar cells take infrared sunlight and create electricity with 12% efficiency", then I expect it to be 12% of the infrared sunlight, not 12% of the total sunlight. It depends on what the hypothetical "fully efficient" case is.

gamble 16y ago

The 12% efficiency quote seems to originate in an interview with the authors. I read the actual paper,[1] and it only mentions a projected efficiency of 2-3%. You are right that there simply isn't enough energy in the near-infrared to achieve a 12% efficiency. As in a lot of scientific reporting, it's hard to know whether the journalist misinterpreted the authors, or if the authors were indulging in a bit of hyperbole to promote their work. =) The device described in the paper is intended for energy scavenging rather than as a competitor for standard opaque cells. The idea is that, since you already want an anti-reflective coating to block IR light and minimize your air conditioning bill, why not use a coating that also incorporates a solar cell? [1] http://apl.aip.org/resource/1/applab/v98/i11/p113305_s1?bypassSSO=1 http://apl.aip.org/resource/1/applab/v98/i11/p113305_s1?bypa...