High-temperature thermal stable solar selective absorbing coating based on the dielectric-metal-dielectric structure

Obtaining high-temperature thermal stable solar selective absorbing coatings is a big challenge for ultra-high temperature solar-thermal conversion applications. In this paper, a dielectric-metal-dielectric (DMD) structured solar selective absorbing coating (SSAC), AlN/TiB2/AlN/Mo/AlN/substrate is proposed and then prepared by direct current magnetron sputtering. The as-deposited SSACs have a high absorptance of 93.4% and a low emittance of 6.9% at room temperature. The SSACs with the DMD structure deposited on the stainless steel (SS) substrate can maintain stability at 800 °C for 200 h in vacuum. The performance criterion (PC) value, a key factor to evaluate thermal stability, is only 0.010 for the coatings after heat treatment. The SSACs deposited on the quartz substrate can even remain stable at 900 °C with a low PC value of 0.008. Our findings will have great potential applications in ultra-high-temperature solar-thermal conversion, and satisfy fully the requirements of thermal stability for current CSP projects.