Influence of Al substrate on the optical properties of porous anodic alumina films

This letter reports structural color of porous anodic alumina thin film fabricated by electrochemical oxidation of Al. The results indicate that Al substrate has an important effect on the color of the thin film. FE-SEM and SPM measurements show that the film has an ordered hexagonal pattern. Optical photograph and UV-vis reflectance spectra reveal that the color has a change and that the saturation is substantially enhanced after removing the Al substrate. Theoretical analysis further demonstrates the experimental results. Multicolor patterns are obtained by an organics-assisted process. The film with brilliant colors may have potentials in color displays, decoration and anti-counterfeiting technology. (C) 2012 Elsevier B.V. All rights reserved.