Efficient selective planar emitters for thermophotovoltaic systems at 1473 K

The development of efficient thermophotovoltaic (TPV) energy conversion systems can significantly address global energy crises and environmental pollution. Selective emitters in TPV systems play a crucial role in converting broad-spectra thermal radiation into narrowband radiation, thus effectively enhancing the energy conversion efficiency of TPV systems. However, achieving selective emitters with superior thermal stability, particularly at temperature above 1273 K, remains a significant challenge. The selective emitter exhibits an exceptional performance with a high in-band emittance of 0.92 under normal incidence, an outstanding emittance over 0.83 at an oblique incidence angle of 60°, as well as excellent thermal stability at 1473 K. The superior performance of the emitter is predominantly attributed to innovative optical design, including the introduction of co-sputtered ultra-high-temperature ceramics composite ceramic layers, thermal barrier layers and surface encapsulation layers. The TPV system combined with a 0.72 eV-GaSb photovoltaic cell, a filter, and the designed emitter, is predicted to achieve an energy conversion efficiency of approximately 27.4 % and a power output of 1.15 W/cm² at 1473 K. These findings highlight the potential of the multilayer selective thermal emitters as promising candidates for improving the performance of TPV systems.