Tunable narrowband metamaterial thermophotovoltaic emitter: Ideal performance analysis and structural design based on photovoltaic cell performance matching

In thermophotovoltaic(TPV) systems, the selective emitter is a key component for improving the thermoelectric conversion efficiency. In order to optimize the design of selective emitter, this paper presents an ideal analysis method based on the matching of external quantum efficiency(EQE) performance curves of photovoltaic(PV) cells to provide theoretical guidance for the design of narrowband emitters for TPV applications. A systematic analysis on the theoretical performance and influencing factors of an ideal narrowband emitter was conducted for commonly used GaSb cells, InGaAsSb cells, and InAs cells, and a selective metamaterial emitter with centrally symmetric tantalum strip was proposed. By optimizing the structural parameters, an emitter with radiation spectrum close to that of the ideal emitter was achieved. The results show that with the final optimized three sets of structural parameters, the emitters matched well with the GaSb cells, InGaAsSb cells, and InAs cells, achieving the highest thermoelectric conversion efficiencies of 0.4038, 0.4034, and 0.2564, respectively. Additionally, the potential mechanism for the emitter’s excellent spectral selectivity was analyzed, revealing that by adjusting structural parameters, different plasmonic modes can be coupled to achieve spectral emissivity peaks in the target band, with insensitivity to polarization and incident angles.