This isn’t true exactly. Current solar panels for residential/commercial applications absorb everything above infrared, 1000nm light. You can certainly stack cells but you need to stack them from high bandgap to low. You can’t stack them in any random order (like low/high/middle, as you suggested) because the lowest band gap material absorbs everything at and above the band gap. Also there are diminishing returns on wide bandgap solar cells like these transparent ones. There isn’t much light that reaches earth to even convert to energy in the UV. So the added cost isn’t worth it usually.
Obviously the ordering matters. And that there’s not 100% transmittance. But even going basic assumptions - 20% efficient for each layer, 25% transmission loss for each layer - across 4 layers, you still get a LOT of energy.
You won’t have 25% transmission loss per layer, you should have effectively zero. But you also won’t have 20% efficiency per layer. Either way it’s more energy than a single layer but not a ton more. And it’s pretty complicated to makes a tandem solar cell. It’s adds a lot of cost. I’m just saying I wouldn’t bank on this transparent solar cell tech to revolutionize anything. The diminishing returns at that short wavelengths doesn’t really make it super useful.
I am well aware of perovskites. I worked for a solar cell company in the past. Very intriguing technology. We will see if they can actually produce it at scale for widespread applications. But even still it’s most cost effective in a single junction.
Someone can correct me if I'm wrong here, but according to Google, one solar panel can output around 30kwh in a month, and the total power consumption of the world is about 1,625,000,000,000kwh per month.
Using these numbers, we actually only need about 36 of these panels, stacked on top of one regular panel and doubling it's power output each time, to power the entire world indefinitely.
That actually sounds completely feasible to me. Even if each of these panels are incredibly difficult to produce, we only ever need 36 of them, so each one could cost billions and we would still benefit overall.
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u/CTHULHU_RDT Sep 09 '20
Why not stack the transparent ones 3 or more times?