Colored solar selective absorbing coatings with metal Ti and dielectric AlN multilayer structure

The colored solar–thermal collectors have the advantages of architectural integration and color appearance. The solar selective absorbing coatings with a metal–dielectric multilayer structure can show different colors by changing the layer number and thickness. In this work, five colored coatings with a metal titanium (Ti) and dielectric aluminum nitride (AlN) multilayer structure were designed by the optical multilayer software and fabricated by magnetron sputtering. The color of the five coatings is black, purple, yellowish green, red, and yellowish orange. The energy performance, chromaticity, and brightness of the coatings were studied and compared. The results show that the solar absorbance of these coatings is between 0.82 and 0.94, the thermal emittance is between 0.05 and 0.27, and the brightness is in the range of 0.65–8.89%. These colored coatings can be produced by a commercial production process, and is suitable for the application of building integration.