Near-field thermophotonic system for power generation and electroluminescent refrigeration

Near-field thermophotonic (TPX) systems that replace the high-temperature emitter in the thermophotovoltaic systems with a light-emitting diode (LED) have been reported to achieve low-grade heat harvesting and electroluminescent cooling, respectively. Nevertheless, the requirements for the two functionalities are different, leading to challenges to coordinate them. In our work, we propose a near-field TPX system composed of the CdTe LED and InP photovoltaic (PV) cell to realize two such functionalities with high performance. With wide-bandgap and high-quality semiconductors, the proposed system achieves a bandgap alignment at various temperatures and has low nonradiative recombination rates, thus enabling the functionality integration. Without changing the structures and materials, the system can switch functionality from power generation to electroluminescent refrigeration by tuning the LED temperature from 800 to 260 K while the PV temperature is maintained at 300 K. In addition, we suggest an additional layer of a thin Pt film on the PV cell to suppress phonon-polaritons parasitic heat transfer and further improve the system efficiency of both functionalities. This work theoretically demonstrates the possible integration of multiple functionalities and triggers further explorations of practical TPX systems.