Solar energy that doesn't block the view
sciencedaily.com
sciencedaily.com
Infrared, on the other hand, has some power production capability (though visible contains a much better resource). Even though we may only be looking at 0.3V (high wavelengths have low voltages), we might be getting a few amps with a square foot of this material.
Makes a lot more sense than other PV-related window technologies. They're going to have to figure out how to cool the concentrator cells lest they cause adjacent construction materials to catch fire with how hot they run. (I^2R losses mean that these high current cells will be dumping a lot of heat per watt generated).
Last decade I followed news of XsunX and their Power Glass ... and it was like following news of flying cars, or returning to the moon: a continuous parade of stories, every single one saying "we're almost there, next year we'll really have it ready!"
The concept of "Power Glass" was similar to the article here; the glass had tiny PV technology buried inside, with the idea that skyscrapers with their glass facades could generate their own power, along with any other building using lots of glass in its skin.
I see XsunX no longer mentions Power Glass on their website [1]. Now it looks like any PV manufacturer. You have to go back 8 years in the Internet Archive to see it [2]. They were sure proud of this revolutionary technology ... 8 years ago.
Oh well. At least flying cars are showing [3] progress [4].
[2] https://web.archive.org/web/20060705005757/http://www.xsunx....
Windows are useful because they let light through. Solar panels are useful because they don't.
If you ended up with some sort of hybrid that let 50% of the visible through and absorbed 50% of the balance, it would not be a very good window (too dim or obstructed), and it would cost at least double what a comparable solar panel would cost (per watt). You'd also take some hits to aesthetics and efficiency (humans want reflective coatings on smooth window glass, solar cells want antireflective coatings on textured low-iron glass).
Wiring up the windows would likewise add to the installation cost. Solar panels produce their rated power facing somewhere between up and south (in the northern hemisphere), and building windows almost never face in that direction, making for an ever bigger hit to performance.
Installing panels on buildings can be a good idea, but not where the windows go. Rooftops and south-facing walls are about it.
By contrast, conventional rooftop solar is about 18-23% efficient and you need a whole roof of those (often more) to power your house.
I don't think this would provide more than a tiny trickle of electricity, and probably at quite high cost.
Just about the only situation it would make economic sense to do this would be if it were almost the same cost of regular glass, and you already had a PV system set up with virtually all the wiring & inverters necessary already in place (these are a significant cost - roughly 50% of a regular PV installation).
Otherwise the cost simply wouldn't make it worthwhile.
OTOH, it would help as well if windows did not filter IR radiation. You know, a greenhouse works because glass is transparent to visible and near IR radiation, but is quite opaque to far IR. Visible light is the peak of the spectrum of solar e.m. radiation and its frequency is proportional to the temperature of the sun photosphere (~6000 K). Visible and near IR radiations traverse the glass, gets absorbed by objects and heat them. Part of this heat will be re-emitted as far IR radiation, with a frequency proportional to room temperature (~300 K), which is 20 times smaller than visible light. This factor 20 is enough for the glass to turn from transparent to opaque. That's why you can have a greenhouse, or simply a car with its windows closed, get hotter than the surrounding atmosphere.
https://en.wikipedia.org/wiki/Greenhouse_effect#Real_greenho...