Effect of nanoporous anodic aluminum oxide (AAO) characteristics on solar absorptivity

Nanoporous anodic aluminum oxide (aao) has been used in many different fields of science and technology,due to its great structural characteristics. solar selective surface is an important application of this type porousmaterial. this paper investigates the effect of nanoporous aao properties, including; film thickness, pore areapercentage and pore diameter, on absorption spectra in the range of solar radiation. the parameters were verifiedindividually depending on anodization condition, and the absorption spectra were characterized usingspectrophotometer analysis. the results showed that the absorptivity was increased with growth of the filmthickness. furthermore, increasing the pore diameter shifted the absorption spectra to the right range, and viceversa. the investigation revealed the presence of an optimum pore area percentage around 14% in which theabsorptivity was at its maximum value.