What is the Right Approach Toward Spectral Filtering in Thermo-PhotoVoltaics? 

Luminescence extraction has led to all the recent records in solar cell efficiency. These same design principles also create opportunities to use photovoltaic cells in non-solar applications. For example, thermophotovoltaics converts radiation from a local hot body into electricity. A highly reflective rear mirror, critical for luminescent extraction, can employ the semiconductor bandgap itself for spectral filtering and to re-cycle unused sub­bandgap radiation. This can lead to a practical thermophotovoltaics efficiency exceeding 50%. Semiconductor band-edge spectral filtering will be compared with the traditional spectral emissivity engineering approach.