Science, Solar Energy.
Those darn band gaps. Oh but wait! We aren’t doomed to waste all those below-the-band-gap photons for all of eternity. Different materials have different band gaps. Indium gallium phosphide (InGaP) has a band gap of 1.86 eV, but Gallium arsenide (GaAs) has a band gap of 1.4 eV, and Germanium (Ge)