Two-dimensional Assembling of Au Nanoparticles Mediated by Tetrapyridylporphine Molecules

TEM images, UV-vis and SERRS (surface-enhanced resonance Raman scattering) spectra of two-dimensional assemblies of tetrapyridylporphine-derivatized Au nanoparticles (Au colloid-H 2 TPyP films) are reported. The films are prepared by a spontaneous 2-D reassembling of multilayer interfacial films on water surface and a subsequent deposition, forming hexagonally packed arrays of Au nanoparticles with some lattice defects. Interparticle distances of ∼2 nm in the regular hexagons are in accord with the size of a H 2 TPyP molecule bridging two neighboring particles. UV-vis spectra indicate stabilization of the array by porphyrin−porphyrin hydrophobic interactions.