Mirrors for efficient energy conversion in optoelectronics (Conference Presentation)

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 devices. Now we report that the rear mirror can be used to create thermophotovoltaic systems with unprecedented high efficiency. This mirror reflects low-energy infrared photons back into the heat source, recovering their energy. This radically improves thermophotovoltaic efficiency. Therefore, the rear mirror serves a dual function; boosting the voltage and re-using infrared thermal photons. This allows the possibility of a practical >50% efficient thermophotovoltaic system. Based on this reflective rear mirror concept, we recently experimentally demonstrated a thermophotovoltaic efficiency of 29.1%, a new efficiency record. In this work,