A High-temperature Near-perfect Solar Selective Absorber Combining Tungsten Nanohole and Nanoshuriken Arrays

Abstract

A solar selective absorber is a key component that directly influences the photothermal efficiency in high-temperature solar energy harvesting. In the present work, a solar selective absorber combining tungsten nanohole and nano shuriken arrays was proposed and studied. Firstly, the geometry of the absorber was optimized, obtaining a near-perfect absorber. Then, evaluation of the near-perfect absorber indicated that it can achieve near unit spectral absorptance within 0.28-1.25 μm and obtain a solar absorptance of 0.9457, thus achieving a photothermal efficiency of 91.52% at 1273 K under 1000 suns. Then, analysis of its absorbing mechanisms revealed that the high solar absorptance is contributed by the impedance matching, and the coupling effects of the cavity resonance, surface plasmon polaritons, magnetic polaritons, and local surface plasmon resonance. In addition, a study on the effects of the geometric parameters indicated that the absorber performance is insensitive to the changes in geometric parameters when the changes are within fabrication uncertainties. Finally, the effects of the polarization angle and incident angle were examined, indicating that the near-perfect absorber exhibits high insensitivities to wide-angle incidence and all-angle polarization. These results indicate the near-perfect absorber is promising for high-temperature solar energy harvesting.