Angular solar absorptance and thermal stability of Mo-SiO2 double cermet solar selective absorber coating

In this paper, the angular solar absorptance of Mo-SiO2 double cermet solar selective absorber coating was simulated based on the deduced optical constants and calculated from measured reflectance spectra in the wavelength range 0.25-2.5 μm for incidence angles between 0° and 75° by interval of 15°. It was found that Mo-SiO2 double cermet solar selective absorber with angular absorptance α = 0.945 from 0° up to 60° is a wide-angle absorptance coating. The effect of thermal annealing on optical properties, microstructure and morphology of Mo-SiO2 double cermet solar selective coating was investigated. The annealing in vacuum at 600 °C results in grain refinement of Mo particle, denser cermet layer and photo-thermal conversion efficiency increasing of 0.6%. Annealing at 800 °C leads to grain growth of polycrystalline structure Mo, inter-diffusion in cermet layer and the photo-thermal conversion efficiency decreasing of 1.3%.