Ag-nanoparticle-decorated Au-fractal patterns on bowl-like-dimple arrays on Al foil as an effective SERS substrate for the rapid detection of PCBs.

Large-area Au-aggregate-assembled fractal patterns with tailored sizes and densities are achieved by sputtering Au nanoparticles on hexagonally patterned bowl-shaped-dimples on Al foil and subsequent annealing. After decorating with much smaller Ag nanoparticles, the resultant substrates exhibit an active and reproducible SERS effect.