Multijunction Solar Cells Break Efficiency Records by Harvesting the Full Spectrum of Light

"Semprius incorporated the invention into their dual-stage optics, which are able to concentrate incident light more than one thousand times."

So is it 44% of the light that's being converted, or is this based on size..as in I can produce more in the same space with concentrated light..or is it based on spectrum, as in we are converting 44% of the spectrum? If you're concentrating the sunlight by 1000 times, shouldn't this figure be much higher...? This might be good for space, which then wouldn't require the concentration of the sunlight, but it seems to be going the wrong direction for Earth based use...

FULL SPECTRUM

It is based on spectrum:

Their mention of a lens in the article clouds the issue, but not entirely. Thing is, if the simple addition of a lens could 'raise' the efficiency by concentrating a larger collection area into a smaller one, than any PV technology could claim superior efficiencies merely by using a larger lens.

No, this is a fundamental improvement realised by simultaneously reducing the interlayer resistance and broadening the absorption spectrum over that of conventional, single-junction cells.

So it has to get to that high of a temperature to work at this efficiency.....?

How is this any different from the announcement by Sharp, Inc. or the German researchers? Just curious. That kind of efficiciency is great, but there will still be a tremendous quantity of waste heat (at a fairly high quality, IMHO) present on the cells that must be dissipated efficiently as well, or one could certainly count on problems with differential expansion ruining the device.

Basic math: If one assumes incident solar spectrum of 400 W/m², and the fresnel or other lens quality is sufficient for focusing that to 400,000 W/m², then at 44% conversion to P_e, and assuming reflection losses of 10%, we have 46% present as P_th to dissipate. This comes out to Pe = 176 kW/m2, and Pth = 184 kW/m2 (at a fairly high temperature.) Does anyone have information on how hot these chips are supposed to run?

Surely some genius could figure out how to use this for (a) driving an absorption refrigeration cycle, or (b) a Kalina cycle (like steam power, only using water ammonia), or even (c) ORC cycle, or (d) closed SCC Brayton cycle. Better have some really good quality heat pipes available to remove the heat from the small chips.

Gotta laugh at the clueless article writer:

"Semiconductor materials were used for the top three layers, while germanium comprised the bottom." (My emphasis.)

It looks like the array of layers will only work if directly aimed at the Sun, so these panels would need to be steered. That's a drawback.