W/AlSiTiNx/SiAlTiOyNx/SiAlOx multilayered solar thermal selective absorber coating

•Solar selective absorber design for high temperature applications.•High stability and good oxidation resistance of solar thermal optical stack.•Improved selective solar thermal absorber based on AlSiTiNx and SiAlTiOyNx. Solar thermal energy has often been used as a renewable green energy source. Here we present a design composed of a highly selective solar thermal absorber coating that has been deposited by DC magnetron sputtering. This will consist of four layers: W/AlSiTiNx/SiAlTiOyNx/SiAlOx. The coating that was utilised revealed an excellent average solar thermal absorbance, (α = 95.5%) with very low emittance, (ε = 9.6% calculated for 500 °C) together with an excellent thermal stability after annealed at 500 °C, in air for 350 h, and at 630 °C in vacuum for 220 h.