Fig. 3

Reflectivity and external quantum efficiency of one of the thermophotovoltaic cells. For this cell, sub-bandgap reflectivity is 94.5%. The above-bandgap reflectivity is the 34.5% Fresnel reflectivity at the air-semiconductor interface. The cell converts 65% of the above-bandgap incident photons to electron-hole pairs, as given by the external quantum efficiency on the right