Experimental Efficiency of 11.2 % in Germanium Thermophotovoltaic Devices

Germanium is a low cost alternative to the highly expensive III-V semiconductors commonly used on thermophotovoltaic (TPV) devices. Despite efficiencies up to 16.5 % have been theorized in previous works, no experimental efficiencies have been reported so far for germanium-based devices. In this work, we present the first TPV germanium efficiency measured in a high view factor calorimetry set up. Efficiencies and power densities up to 11.2 % and 1.43 W/cm2 have been obtained using a graphite emitter heated at 1544 ºC.