Ideal efficiency and potential of solar thermophotonic converters under optically and thermally concentrated power flux

Proposed recently, thermophotonic (TPH) converters use a hot photovoltaic (PV) device operating as a light-emitting diode (LED) to transform heat into narrow band luminous energy, which is efficiently transformed into electricity by another cool PV cell. They resemble a thermophotovoltaic (TPV) system with the passive emitter replaced by an LED. In the ideal limit, these converters have a very high potential efficiency. They are ideally capable of working at high power fluxes at temperatures around 300 degreesC with more than 40% efficiency. Thanks to the thermal concentration scheme proposed here, at this temperature the absorber can be static and no optical concentration is needed. The main drawback of the converters is the sensitivity of the efficiency to the external quantum efficiency of the LED, which must be very high at a high temperature.