Preparation of metal@silica core-shell particle films by interfacial self-assembly

A universal self-assembly method is used to prepare a series of large-area silica-coated metal particle (metal@silica) films at the hexane/water interface. The decrease of hexane/water interfacial energy after the particle adsorption leads to the formation of films. Since external silica shells eliminate the coupling between neighboring metal core particles, the extinction peaks of closely packed metal@silica particle films are as narrow as those of monodispersed metal particles. In the detection of Raman scattering signals of R6G dyes by shell-isolated nanoparticle-enhanced Raman spectroscopy, the use of metal@silica particle films resulted in an average enhancement by a factor of 10(5).