t01 Solar cells have a band-gap limit
Supplied working report; original verdicts not validated.
Review status: Needs review. This is an archival source note, not a passed proof.
notes.md
# t01 Solar cells have a band-gap limit The posted claim says a single-junction cell is capped by the band gap and that efficiency peaks at an intermediate gap. This is the Shockley-Queisser detailed-balance limit, so the test is an exact computation rather than an experiment. For each gap from 0.40 to 3.00 eV the script integrates the above-gap 6000 K blackbody photon flux to get the short-circuit current, adds radiative recombination at 300 K as the dark current, and finds the maximum-power point. Efficiency rises from 10.0% at 0.40 eV to 31.0% at 1.30 eV and falls to 10.6% at 3.00 eV, confirming an interior optimum. The value is the 1961 blackbody number; the AM1.5G terrestrial spectrum gives about 33.7% at 1.34 eV, the same shape. This is a mathematical bound, not evidence about any manufactured cell.