I’ll be honest, I know absolutely nothing about the science or the tech itself. It just seems like it would help by reflecting the light back at the panel (like trapping it I guess), instead of just bouncing off once. I’m just curious and this seemed like a good place to ask about it
In: 0
A two way mirror is a piece of glass with an extremely thin coating of silver or aluminum on one side. This reflects roughly half the light that enters the surface while the rest passes through into the glass behind and out the other side.
If the mirrored layer was on the sun-facing side, then this would reduce the current output of the cell by half. It wouldn’t effect the efficiency of the PV cell itself, it would merely act like a pair of sunglasses, reducing the light iluminance reaching the cell in the first place.
PV cells typically have a relatively thick layer of aluminum, copper or silver as a backside contact for conducting current into the cell. This has the added advantage of reflecting any stray visible light that isn’t absorbed by the active region, back up towards the active layer. In practice this improves efficiency a few percent. It also has the advantage of helping conduct extra heat out of the cell, keeping it from getting too hot, which shortens the lifespan of PV cells.
The efficiency of modern PV cells is mainly limited by physical effects. Namely the cell is most efficient only on a barrow band of wavelengths. It cannot use longer wavelengths of light in the red and infrared range, which is either reflected or absorbed as heat without producing any current. Meanwhile the energy of shorter wavelengths in the blue range aren’t fully utilized, the extra energy ends up likewise as heat.
Latest Answers