Lowered infrared emittance and enhanced thermal stability of solar selective absorption properties of anodic aluminum oxide photonic crystal coatings.

[Display omitted] • The spectral positions of photonic bandgaps were estimated by theoretical simulation. • The first-order photonic bandgap was verified to be located in the infrared region. • The formation of the photonic bandgaps appreciably improved the overall properties. • A small amount of CuAl 2 O 4 was produced by controlling electrodeposition voltage. • The CuAl 2 O 4 formation enhanced the thermal stability of the coating properties. Solar selective absorption coatings based on anodic aluminum oxides (AAO) were prepared via an anodization technique and a subsequent alternating current electrodeposition of Cu-Ni nanoparticles at the bottom. The phase structure, microstructure and solar selective absorption properties of the AAO coatings were investigated with respect to their preparation conditions. Moreover, the dependence of the solar selective absorption properties on thermal annealing history was examined. One-dimensional AAO photonic crystal coatings were produced by anodization under period pulse voltages. The spectral positions of photonic bandgaps were estimated for the AAO photonic crystal coatings. The first-order photonic bandgap was verified to be located in the infrared region. The construction of the photonic crystal structure appreciably lowered the infrared emittance and as a result improved the overall properties of the AAO photonic crystal coatings. A small amount of CuAl 2 O 4 was formed in the electrodeposition layer of AAO photonic crystal coatings by controlling the amplitude of applied electrodeposition voltage at 14 V. The formation of the CuAl 2 O 4 minimized the oxidization of the Cu-Ni nanoparticles at elevated temperatures and thereby enhanced the thermal stability of the solar selective absorption properties. The AAO photonic crystal coating prepared under the electrodeposition voltage showed a solar absorptance of 0.90, an infrared emittance of 0.11 and a spectral selectivity of 8.12 at room temperature, while retaining a spectral selectivity of 6.47 after being annealed at 300 °C for 24 h. [ABSTRACT FROM AUTHOR]