New solar cell and the 2 nd Law

By rtrski on 8/12/2008 9:29:32 AM , Rating: 2
Look, all they did is come up with an antenna that's resonant in the mid-IR, and produce it on a thin film plastic. That's kind of neat, and a nice first step. But otherwise totally meaningless to all the BS speculation presented in the article and the linked pages.

"Could absorb IR and re-emit at lower wavelengths..." Nothing remotely demonstrated about this. An antenna is simply a coupling mechanism between free-space EM and some form of 'guided' EM mode, antennas are PASSIVE. They don't do frequency multiplication or division. They trap a wave out of the air into a circuit, but it's still at the same frequency, and has to then go somewhere. Otherwise, it comes right back out.

Spiral antennas, square slots, split-ring resonators, etc have all been around forever. Simple wavelength scaling lets you "design" them for almost any frequency range you want. But etching techniques and tolerances might mean you can't get the desired linewidth and spacing for a given application. The only 'new' thing here is that they managed to get a small enough pattern placed on a thin, flexible, and inexpensive material. But without something to connect to, reciprocity says if you receive, you radiate as well. All that mid-IR frequency EM "captured" by the antenna has got to go to a load circuit of some kind, or else it's reflecting right back out as soon as it hits a discontinuity (less some dissipative losses).

If they're just 'block stamping' the antenna pattern, it would be interesting to hear how well they aligned the pattern 'blocks' (certainly they're not stamping each individual spiral, but larger groups thereof). Without the ability to line up your circuitry, you can never realize a larger array. Without the right registration tolerances you're also never connecting any sort of circuitry to these antennas to keep whatever EM they received in the first place.

I'm really becoming more and more disillusioned by the "science" reporting here at Dailytech. Michael still has some pride of authorship, but certain other authors are either ignorant or lazy enough to just parrot whatever grandiose claims anyone else posts (nearly word-for-word, no less) without even performing a basic sniff test.

It extracts energy and cools in a uniform temperature environment according to how I understand the article. Can someone explain why it doesn't? (I have no idea.)

The skins could also act as cooling devices by drawing away waste heat, according to the researchers.
[and]
As heat typically is emitted as IR rays from many objects, the antennas could cool objects by collecting these rays and reemitting them at a harmless wavelength.