Au nanoparticle-built mesoporous films based on co-electrophoresis deposition and selective etching

A simple and facile strategy is presented to fabricate mesoporous Au spherical nanoparticle films based on the combination of co-electrophoresis deposition in the mixed colloidal solutions of Au and Ag and selective etching of the Ag nanoparticles which act as a sacrificial metal. The film is homogeneous in the macroscale but with numerous nanoscaled pores. The film configuration can be easily tuned by the size of Au colloidal nanoparticles and the amount of Ag colloidal solution mixed. Importantly, such structured mesoporous film exhibits strong surface-enhanced Raman scattering activity with good reproducibility and repeatability. Additionally, this study provides a novel method for the controllable construction of other mesoporous films from simple metals to multicomponent hybrids, by using nanoparticles as building blocks.