Ultraefficient thermophotovoltaic power conversion by band-edge spectral filtering

Significance Thermophotovoltaic conversion utilizes thermal radiation to generate electricity in a photovoltaic cell. On a solar cell, the addition of a highly reflective rear mirror maximizes the extraction of luminescence, which in turn boosts the voltage. This has enabled the creation of record-breaking solar cells. The rear mirror also reflects low-energy photons back into the emitter, recovering the energy. This radically improves thermophotovoltaic efficiency. Therefore, the luminescence extraction rear mirror serves a dual function; boosting the voltage, and reusing the low-energy thermal photons. Owing to the dual functionality of the rear mirror, we achieve a thermophotovoltaic efficiency of 29.1% at 1,207 °C, a temperature compatible with furnaces, and a new world record at temperatures below 2,000 °C.