Non-equilibrium mid-infrared black phosphorus light emitter and absorber for thermophotonic applications

•A non-equilibrium mid-infrared black phosphorus (BP) light emitter and absorber for a thermophotonic (TPX) system was investigated•A fluctuational electromagnetic simulation was performed to evaluate the non-equilibrium spectral energy fluxes from the bulk BP and between the bulk BPs•Calculated spectral energy flux of the BP emitter exceeded the blackbody limit•The underlying resonant mechanisms were discovered by examining the dispersion relation and the gap transition from the near-field to the far-field of the transmission factor A non-equilibrium mid-infrared black phosphorus (BP) light emitter and absorber for a thermophotonic (TPX) system was investigated in this study. A fluctuational electromagnetic simulation was performed to evaluate the non-equilibrium spectral energy fluxes from the bulk BP and between the bulk BPs, and the calculated spectral energy flux of the BP emitter exceeded the blackbody limit. The underlying resonant mechanisms were discovered by examining the dispersion relation and the gap transition from the near-field to the far-field of the transmission factor. The electric power generation and efficiency of the TPX system utilizing BP emitter and absorber were calculated and discussed. The results of this study are useful for not only fundamental energy-transfer research but also efficient heat energy recovery via TPX power-generation systems.