External Luminescence and Photon Recycling in Near-Field Thermophotovoltaics

John Desutter (1) , Rodolphe Vaillon (2, 1) , Mathieu Francoeur (1)

1 Radiative Energy Transfer Lab, Department of Mechanical Engineering, University of Utah, USA
2 CETHIL - Centre d'Energétique et de Thermique de Lyon

The importance of considering near-field effects on photon recycling and spontaneous emission in a thermophotovoltaic device is investigated. Fluctuational electrodynamics is used to calculate external luminescence from a photovoltaic cell as a function of emitter type, vacuum gap thickness between emitter and cell, and cell thickness. The observed changes in external luminescence suggest strong modifications of photon recycling caused by the presence of the emitter. Photon recycling for propagating modes is affected by reflection at the vacuum-emitter interface and is substantially decreased by the leakage towards the emitter through tunneling of frustrated modes. In addition, spontaneous emission by the cell can be strongly enhanced by the presence of an emitter supporting surface polariton modes. It follows that using a radiative recombination model with a spatially uniform radiative lifetime, even corrected by a photon recycling factor, is inappropriate. Applying the principles of detailed balance, and accounting for non-radiative recombination mechanisms, the impact of external luminescence enhancement in the near field on thermophotovoltaic performance is investigated. It is shown that unlike isolated † Corresponding author.

Domaines: Sciences de l'ingénieur [physics]; Energie électrique

John Desutter, Rodolphe Vaillon, Mathieu Francoeur. External Luminescence and Photon Recycling in Near-Field Thermophotovoltaics. Physical Review Applied, 2017, 8 (1), pp.014030. ⟨10.1103/PhysRevApplied.8.014030⟩. ⟨hal-01829858⟩