Ultraefficient thermophotovoltaic power conversion by band-edge spectral filtering

TLDR

Thermophotovoltaic power conversion uses thermal radiation from a local heat source to generate electricity, and recent work has shown that a highly reflective rear mirror maximizes luminescence extraction, boosting voltage and enabling record‑breaking solar efficiencies. The authors aim to demonstrate that a rear mirror can be employed to create thermophotovoltaic systems with unprecedented high efficiency. The mirror reflects low‑energy infrared photons back into the heat source, recovering their energy while simultaneously boosting voltage. The reflective rear‑mirror concept permits a practical >50 % efficient thermophotovoltaic system, and the authors achieved 29.1 ± 0.4 % efficiency at an emitter temperature of 1,207 °C.

Abstract

Thermophotovoltaic power conversion utilizes thermal radiation from a local heat source to generate electricity in a photovoltaic cell. It was shown in recent years that the addition of a highly reflective rear mirror to a solar cell maximizes the extraction of luminescence. This, in turn, boosts the voltage, enabling the creation of record-breaking solar efficiency. Now we report that the rear mirror can be used to create thermophotovoltaic systems with unprecedented high thermophotovoltaic efficiency. This mirror reflects low-energy infrared photons back into the heat source, recovering their energy. Therefore, the rear mirror serves a dual function; boosting the voltage and reusing infrared thermal photons. This allows the possibility of a practical >50% efficient thermophotovoltaic system. Based on this reflective rear mirror concept, we report a thermophotovoltaic efficiency of 29.1 ± 0.4% at an emitter temperature of 1,207 °C.