Characterization and Spectral Selectivity of Sn-Al_2O_3 Solar Absorber

摘要

Tin-pigmented alumina (Sn-Al_2O_3) solar absorber on aluminium substrate was successfully prepared by anodic anodization and further characterized by different methods. The phase, morphology and reflectance (R) of the Sn-Al_2O_3 solar absorber were measured by using X-ray Diffraction (XRD), a Scanning Electron Microscope (SEM) equipped with an energy dispersive X-ray (EDX) analyzer and Ultraviolet-visible-near infrared. The solar absorptance (a) was calculated based on the relationship of the spectral reflectance, R(λ), and the solar spectral irradiance of AM 1.5, I_s(λ), in the wavelength range of 300-2500 nm. The result was a dark-black surface color on the Sn-Al_2O_3 film. The XRD pattern of the Sn-Al_2O_3 film was indexed as aluminium and tin phases. The chemical composition of the Sn-Al_2O_3 film was tin (Sn), aluminum (Al) and oxygen (O) elements. The average thickness of the produced film was 18.9 urn. The Sn-Al_2O_3 film showed low R (0.09) and high a (0.93) values for the whole 300-2500 nm wavelength range, corresponding to the theoretical properties of the solar absorber. Therefore, it can be concluded that the Sn-Al_2O_3 film on aluminium substrate can be applied as a solar absorber in solar collectors due to the high α, which is similar to commercial solar absorbers.