Photoelectric conversion efficiencies for InGaAs photovoltaic cells illuminated by composite selective emitters

Thermophotovoltaics (TPV) is the term applied to the technique for energy conversion whereby the energy emitted by an incandescent source is converted to electrical energy by a photovoltaic cell. One of the approaches used in TPV is selective emission used in conjunction with a low bandgap photovoltaic cell, such as InGaAs. Because the alloying fraction of indium and gallium can be varied, the energy bandgap of InGaAs cells can be varied. This allows more of the infrared spectrum to be utilized in the photoconversion process in the InGaAs cells for lowering bandgaps. Conversion efficiencies of InGaAs photovoltaic cells have been reported under various illumination conditions. However, their efficiencies have not been reported using composite selective emitters. This paper reports the conversion efficiencies of three different InGaAs cells with bandgaps of 0.75, 0.66, and 0.6 eV which have been illuminated with four different composite selective emitters. The conversion efficiencies of the three InGaAs cells under composite selective emitter emission will be compared to that of a blackbody-like emitter.