Why Efficiency Has Limits

A single silicon cell cannot convert 100% of sunlight. The Shockley-Queisser limit puts a theoretical ceiling near 33.7%, and real silicon falls below it.

Photons with too little energy pass right through the silicon. Photons with too much energy lose their excess as waste heat. Only photons in the sweet spot get converted cleanly. That gap between theory and reality is why real-world cells reach only around 22 percent, well below the theoretical ceiling.