Optimization of a near-field thermophotovoltaic system operating at low temperature and large vacuum gap

Tailoring near-field thermal radiation between metallo-dielectric multilayers using coupled surface plasmon polaritons

“…In Fig. 5d–f , (see Methods for the definition) is plotted in log scale with SPP dispersion curves for each configuration 25 , 45 , 46 . Although becomes relatively large along the SPP dispersion curve close to the vacuum light line, for bulk Ti, such enhancement as occurs in the sharp β region cannot contribute much to the total heat transfer.…”

“…For example, recent experimental works have reported that strong enhancements in heat transfer between polar dielectric materials like SiC 11 or SiO 2 12 , 20 separated by vacuum gaps of 25–50 nm resulted from increased spectral heat flux at resonance condition of surface phonon polaritons (SPhPs) corresponding to the characteristic wavelength of thermal radiation at room temperature. However, the resonance frequency of SPhPs is lower than the bandgap frequency of thermophotovoltaic (TPV) cells 21 – 25 , such that we cannot expect a highly efficient near-field TPV system that uses polar dielectric materials as an emitter. On the other hand, metals have plasma frequencies that are much higher than the characteristic frequencies of thermal radiation at room temperature; thus, no substantial enhancement in near-field thermal radiation due to coupling of surface plasmon polaritons (SPPs) in metals is expected under typical conditions 26 .…”

“…To overcome these issues, focus has now shifted to controlling of near-field thermal radiation via the introduction of nanomaterials 24 , 25 , 27 – 37 . In particular, metallo-dielectric (MD) multilayers have been extensively studied because mutual interactions of surface polaritons at multiple interfaces inside multilayers 24 , 25 , 35 , 36 provide exotic features including tuning of near-field thermal radiation.…”

“…To overcome these issues, focus has now shifted to controlling of near-field thermal radiation via the introduction of nanomaterials 24 , 25 , 27 – 37 . In particular, metallo-dielectric (MD) multilayers have been extensively studied because mutual interactions of surface polaritons at multiple interfaces inside multilayers 24 , 25 , 35 , 36 provide exotic features including tuning of near-field thermal radiation. Given that such tuning capability is a pivotal issue in enhancing the performance of electricity-generation systems 24 , 25 , 37 – 40 and in thermal management 41 , 42 , an experimental demonstration of the modulation of thermal radiation between MD multilayers is indispensable.…”

Indium antimonide photovoltaic cells for near-field thermophotovoltaics

“…Even though multiple theoretical analyses dealt with modelling the transport of electrical charges within the photovoltaic cell of a NF-TPV device [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], the steps of (1) designing, (2) fabricating and characterizing, and (3) operating a PV cell in the near field were never completed successively. The present article is about realizing the second step in that series in the case of a cell made of indium antimonide (InSb).…”