Abstract
The solar selective absorber coating (SSAC), which can maximally harvest solar energy over a broad wavelength range with near-perfect spectral selectivity, is of essential importance for many applications especially the generation of solar-thermal electricity. Herein, inspired by the emerging field of high-entropy nanoceramics, we propose and numerically demonstrate a high-performance AlTiZrHfNbN-based SSAC. Enabled by the synergetic intrinsic absorption and destructive interference characteristics, the AlTiZrHfNbN-based coating demonstrates a high absorptance (alpha = 0.95) across an ultrabroad wavelength range of 300-3220 nm. Meanwhile, the coating possesses a low emittance (epsilon = 0.12, 82 degrees C) in the infrared region. Furthermore, the multilayer coating is stable at elevated temperatures, which shows promising solar-thermal conversion efficiency that enables it to reach 83.9% (C = 200, T = 600 degrees C). Upon further elevating the annealing temperature to 700 degrees C, obvious oxidation becomes the driving force for the attenuation of optical properties and changes in microscopic morphology. The finite-difference time-domain (FDTD) indicates that the physical mechanisms of ultrabroad wavelength absorption and degradation are related to a high density of hybrid cavity and surface plasmon polariton modes overlapped with the double-absorption layers, respectively. All these properties of the multilayer coating suggest its great promise for application in on-site solar-thermal utilization facilities.

Keywords Plus：STABILITYMICROSTRUCTUREALLOYSLAYERFILMS

Published in JOURNAL OF MATERIALS CHEMISTRY C；10.1039/d2tc01298g，MAY 2022