A high-temperature stable spectrally-selective solar absorber based on cermet of titanium nitride in SiO2 deposited on lanthanum aluminate

Spectrally-selective solar absorber is required to be thermally stable at high operational temperature. However the currently available absorbers aren't stable beyond 700 °C. Here we explore a new absorber with cermet of TiN in SiO2 on LaAlO3 substrate that can be used for long term at 700 °C. The optimized cermets contain TiN with volume fraction of 60% and 65% as sun-light absorption media, SiO2 as anti-reflection coating (ARC), and tungsten (W) as infrared (IR) reflection layer. The absorbers demonstrate an absorptance higher than ~95% before annealing and ~94% after annealing at 700 °C, which will be useful for especially concentrated solar applications.