Spectral Reflectance of Chemically Oxidized Copper

Abstract

In this study, we developed a spectrally-selective solar absorber of a chemically oxidized copper with needle-like microstructures. Spectral normal-semispherical reflectance of the absorber in the range of 0.5-10μm was measured by using spectrometer with paraboloidal mirrors. The measured spectral reflectance shows high visible light absorption and low infrared light absorption. The selective absorptance cannot be explained by the thin interference of oxidized copper with Fresnel’s equations. The measured spectral absorptance is made by needle-like microstructures.