High-temperature selective solar thermal absorber based on Fabry-Perot resonance cavity

In this work, we investigate the design, fabrication and characterization of a multilayer selective solar absorber made of metallic and dielectric thin films. The investigated selective absorber exhibits theoretical spectral absorptance higher than 95% within solar spectrum and infrared emittance lower than 5%, due to the Fabry-Perot resonance and antireflection effect. In terms of fabrication, different materials are tested under high temperatures in order to obtain the structure with best thermal stability. Structures with different materials are fabricated with sputtering, chemical vapor deposition and electron beam evaporation techniques. The near normal reflectance is characterized with a Fourier Transform Infrared spectrometer for these structures before and after heat treatment. Meanwhile, Rutherford backscattering Spectroscopy is employed to analyze the diffusion and oxidation conditions during the heating process. Moreover, better material choice and fabrication techniques are considered to construct solar absorber sample with better high temperature thermal stability.