Thermophotovoltaic Energy Conversion in Far-to-Near-Field Transition Regime

Recent experimental studies on near-field thermophotovoltaic (TPV) energy conversion have mainly focused enhancing performance via photon tunneling of evanescent waves. In the sub-micron gap, however, there exist peculiar phenomena caused by interference propagating waves, which is seldom observed due to dramatic increase radiation waves in full spectrum range. Here, we experimentally demonstrate oscillatory nature TPV far-to-near-field transition regime (250-2600 nm), where and modes are comparable selective spectral response PV cell. Noticeably, it was possible produce same amount photocurrent at different vacuum gaps 870 322 nm, 10\% larger than far-field value. Considering great challenges maintaining nanoscale gap practical devices, this study suggests an alternative approach design a system that will outperform conventional counterparts.