  Selective solar absorbers (SSAs) with high performance are the key to
concentrated solar power systems. Optical metamaterials are emerging as a
promising strategy to enhance selective photon absorption, however, the
high-temperature resistance (>500C) remains as one of the main challenges for
their practical applications. Here, a multilayered metamaterial system
(Al2O3/W/SiO2/W) based on metal-insulator-metal (MIM) resonance effect has been
demonstrated with high solar absorptance over 92%, low thermal emittance loss
below 6%, and significant high-temperature resistance: it has been proved that
the optical performance remains 93.6% after 1-hour thermal annealing under
ambient environment up to 500C, and 94.1% after 96-hour thermal cycle test at
400C, which is also confirmed by the microscopic morphology characterization.
The spectral selectivity of fabricated SSAs is angular independent and
polarization insensitive. Outdoor tests demonstrate that a peak temperature
rise (193.5C) can be achieved with unconcentrated solar irradiance and surface
abrasion resistance test yields that SSAs have a robust resistance to abrasion
attack for engineering applications.
