Facile fabrication of porous nickel films with tunable colors

Metal-based photonic structures have extraordinary potentials in many applications. However, the processing difficulty of metals remains a major obstacle in this field. Here we report a facile method for constructing of porous Ni films by templating porous Si (P-Si) photonic structures. The P-Si templates were fabricated by a facile electrochemical etching method and feature periodically varied porosities along the film thickness direction. Metallic Ni was successfully electrodeposited into the mesoporous structure of the P-Si templates. After removal of the P-Si template by chemical dissolution, the nickel replica thus obtained exhibited a periodic multilayered nanoporous structure. Moreover, by changing the electrochemical etching parameters used for constructing the P-Si template, the structure of the Ni replica can be conveniently adjusted. The fabricated nickel films show distinct optical responses in the visible spectra which is dependent on their structural periodicities. Furthermore, optical sensing capability is demonstrated on the fabricated porous nickel films. © 2012 The Electrochemical Society.