English: The Shockley-Queisser limit for the maximum possible efficiency of a solar cell (black), and its contributing factors (other curves). The x-axis is the bandgap of the solar cell. The red curve is the ideal efficiency if the only loss was the fact that below-gap photons are not absorbed; the blue curve is if the only loss was the relaxation of hot photogenerated electron-hole pairs down to the band edges; and the pink curve represents the other losses, namely the tradeoff between higher radiative recombination and lower operating voltage. If you multiply together these three curves, you get the black curve. The curves are all wiggly because of IR absorption bands in the atmosphere: I used the actual AM1.5G solar spectrum data. I cross-checked my total efficiency curve with independently-calculated ones and they agree to high accuracy, [1] [2]. The other curves besides the black curve are not published in exactly this form to my knowledge, but it's a straightforward part of the same calculation.