Multicolor Anodized Aluminum Film with Gold and Silver Nanorod Array

Abstract

Anodization of aluminum plate followed by the electrodeposition of Ag or Au has yielded the metal nanorod-incor-porated porous aluminum oxide film (NR/AO). This 2-step electrochemical method enabled us to arbitrarily control the aspect ratio of the nanorods by changing the electrodeposition time. The Ag- and Au-NR/AO exhibited clear light-incident-angle dependent color variation, the so-called flip-flop phenomenon. This was achieved by the synergy of the interference wave of AO and the surface plasmon absorption of the NRs. Further, the color was finely tunable by variation of their aspect ratio.