Low-temperature perspective of microgap thermophotovoltaics

It is commonly thought that the thermophotovoltaic (TPV) electric generators operate only at very high temperatures. This condition implies that their heat sources must be gas burners, furnaces hot flue gases, combustors of the waste, etc. However, we theoretically show that a TPV system with sufficiently narrow cavity between the cold (photovoltaic) and hot (emitting) parts allows a high electric output (inherent to TPV systems) to arise from modest temperatures of the emitter (like those in thermoelectric power generators). This way one will be able to combine the advantages of the TPV system with those of the thermoelectric one. For it one has to introduce a wire metamaterial into a micron cavity. Nanowires are prepared in the cold layer and have free standing ends in the vacuum cavity without a contact to the hot surface.