Résumé
Thermophotovoltaics (TPV) is similar to solar photovoltaics (PV), with two main differences [1]: (1) the source of radiation, called “emitter”, is a body at high temperature (> 500 °C) instead of the Sun; (2) the emitter and the TPV converter are close to each other, thus enabling direct radiative exchange, unlike solar PV. As a consequence of (1), the TPV cells convert infrared radiation so that their bandgap is usually lower (down to ~0.2 eV) than that of the solar PV cells. Because of (2), the so-called spectral selectivity implies that electrical power density and efficiency cannot be optimized simultaneously, and that high efficiency (> 40%) can be reached, even with single junction cells [2]. The presentation will introduce the main principles of TPV conversion and highlight recent advances in the field. A particular attention will be paid to the case of narrow bandgap (< 0.5 eV) TPV cells – which are required to maximize electrical power – and to the challenges associated with their development.[1]Datas, A., & Vaillon, R. (2021). Thermophotovoltaic energy conversion. Ultra-High Temperature Thermal Energy Storage, Transfer and Conversion, Woodhead Publishing, chapter 11, 285–308.[2]Roux, B., Lucchesi, C., Perez, J.-P., Chapuis, P.-O., & Vaillon, R. (2024). Main performance metrics of thermophotovoltaic devices: analyzing the state of the art. Journal of Photonics for Energy, 14(4), 042403.