Nanoribbons from conjugated macromolecules on amorphous substrates observed by SFM and TEM

Micrometre long nanoribbons have been grown from solutions of functionalize d poly(para-phenyleneethynylene)s (PPE)s on noncrystalline insulating subst rates including glass and carbon coated copper grids. Tapping mode scanning force microscopy (SFM) and transmission electron microscopy (TEM) revealed that these nanostructures possess a molecular cross section with a typical thickness of 2-3 molecular layers and a width which reflects the distribut ion of macromolecular lengths. The ribbons are therefore quite similar to t he ones found on the crystalline mica substrate except that they are not or iented within the surface plane. This indicates that the,growth of these ar chitectures from solution is mainly governed by intermolecular interactions between the pi-conjugated macromolecules. The possibility to self-assemble these nanoribbons also on amorphous silica opens a prospect for their appl ication as molecular nanowires bridging gold nanoelectrodes grown on oxidiz ed silicon wafers.