Advance in solar power technology

[ZenGum]

The original article includes a link to the peer-reviewed article, at http://www.opticsinfobase.org/oe/abs...=oe-21-101-A60

It has the numbers, but they are a bit disappointing.

Experimentally, the PlaCSH-SCs have achieved (1) light coupling-efficiency/absorptance as high as 96% (average 90%), broad-band, and Omni acceptance (light coupling nearly independent of both light incident angle and polarization); (2) an external quantum efficiency of 69% for only 27% single-pass active layer absorptance; leading to (3) a 4.4% power conversion efficiency (PCE) at standard-solar-irradiation, which is 52% higher than the reference ITO-SC (identical structure and fabrication to PlaCSH-SC except MESH replaced by ITO), and also is among the highest PCE for the material system that was achievable previously only by using thick active materials and/or optimized polymer compositions and treatments. In harvesting scattered light, the Omni acceptance can increase PCE by additional 81% over ITO-SC, leading to a total 175% increase (i.e. 8% PCE).

Working backwards from the final result, it seems the regular cells turned maybe 3% of the sunlight into electricity. All those claims of huge percentage increases are starting from a very low base. They've tweaked this up to 8 %.

That 44% efficiency you mentioned - is that the percentage of solar energy that ends up as electricty (i.e. PCE)? or the percentage of photons which, having reached the absorbtion area, get picked up by the system? There could be a big difference. We must make sure we're comparing apples and apples, not apples and apple juice.

[tw]

Originally Posted by ZenGum

That 44% efficiency you mentioned - is that the percentage of solar energy that ends up as electricty (i.e. PCE)? or the percentage of photons which, having reached the absorbtion area, get picked up by the system?

They discuss total efficiency of light to electricity. But do not detail where that incoming photon energy is measured (before entry, inside the semiconductor material, etc). The subtitle in IEEE Spectrum says

Silicon Valley start-up Solar Junction has raised the bar for solar efficiency to 44 percent, and even higher values are in the cards. The company has a road map for reaching 50% efficiency and beyond.

ZenGum is asking the right questions.

Does that mean we can expect solar cells to be that efficient in the next decade? Maybe not. The article remains vague about what might compromise the technology. Too much positive spin usually means an author did not ask damning questions. Maybe a business school graduate or communication major.

Maybe one in ten innovations defined by numbers actually make it. Products recommended without numbers have a near zero success rate.

I waited to reply here. To see how many would reach a conclusion or excitement when numbers for the Princeton cell were obviously missing or misleading.

The "News at Princeton" article referred to 81% and 175% improvement. Why do we always demand numbers? Those numbers never mentioned "improvement over what" (as ZenGum notes). Since they did not say improvement over what, then the author may have been a business school graduate or something just as naive.

Those who demanded numbers in 2003 saw that Saddam could not have WMDs. Numbers (mostly lack of them) exposed George Jr's administration as liars. Read posts back then to appreciate how few in 2003 were demanding numbers. How many knew only from subjective claims. Numbers identified a WMD myth before Mission Accomplished even started.

We may see products based in Solar Junction's innovation. But with numbers provided (by ZenGum) from those other citations, the Princeton solar cell is virtually zero improvement.

Another innovation in 2000 was a Foveon chip. That promised to fix a compromise in CCD or CMOS based cameras. One chip detected all three colors. Current technology only had black and white sensors each covered in a color filter for each primary color. Three sensors per pixel. And complex computer algorithms to adjust for variations in each sensor.

Foveon chip was even demonstrated and was to be marketed in a Sigma Designs camera. Innovation that actually works and is defined superior by numbers has maybe a one in ten chance of succeeding. The Foveon chip (that performs similar to that Solar Junction chip) did not succeed.

Most advanced solar cells, such as those on the Martian Rovers Spirit and Oppurtunity must be over 10% efficient. Best we could do. Curiousity, instead, uses a nuclear battery. Best solar cells possible when Curiousity was recently launched are still too inefficient.

Moving on to innovation. Quantum dots are expected to achieve a 60% efficiency. Numbers that suggest a promising success rate - maybe better than one in ten chance of succeeding. Innovation is that difficult. And now made harder since the Republican party is openingly subverting science and innovation (such as Quantum physics). But any promise that does not include numbers is best called a scam.

A point made obvious by the "News at Princeton" article. And how to identify so many news reports from Fox News as propaganda for the naive. The naive are told how to think without "reasons why" and numbers. A point that applies to more than just science. And so the question.

Did each reader see obvious problems with the Princeton cell? It was a perfect example of spin. To an educated layman, it was not promising. Essential and missing numbers were a first indication.

But then so many are so easily scammed as to believe in Listerine and Pond's "Age Defying Creams". Even numbers (or lack of them) make a scam obvious to a layman. Above examples recited here to demonstrate.