PHOLEDs (short for PHOsphorescent Light Emitting Diodes) are light sources that are almost 100% efficient.

 

Would it be possible to create solar cells that use a similar principle, but in reverse, so that they too would be almost 100% efficient?

 

 

The answer to your question is probably not. However, nanotechnology may provide very efficient solar cells. Visible light has a wavelength of between 10^-7 and 10^-6 meters. Nanotechnology may be able to make antenna arrays that absorb light rays in the same way radio antennas absorb radio waves. That process may make very efficient solar cells. We have to wait to find out.

Phosphorescence is not reversible.

 

Many Leds are nearly 100% efficient, without phosphorescence, but the reverse operation, which is essentially a photovoltaic cell, is not efficient.

 

A few reasons:

- Sunlight is a broad spectrum, but photons below some energy are not converted, the others above are converted only to this energy.

- The voltage at which the resulting current is available can't equate this energy.

- And then you have the usual nasty technological reasons, but this time they aren't the worse ones.