The growth of one-dimensional CuPcF16 nanostructures on gold nanoparticles as studied by transmission electron microscopy tomography.

The growth of one-dimensional (1D) fluorinated copper-phthalocyanine (CuPcF(16)) on gold (Au) nanoparticles (NPs) is studied by electron tomography. The shape of the 1D structure and its geometrical relationship with the associated Au NP are determined by a three-dimensional reconstruction analysis combined with high-resolution electron microscopy. The CuPcF(16) molecules nucleate at the <110> edge of the Au nanoparticle and grow parallel to a {111} facet of the particle along a direction close to <121>. This implies that the maximum diameter of the 1D structure is limited by the width of the <110> edge of the Au particle.

Growth mechanisms of phthalocyanine nanowires induced by Au nanoparticle templates.

We combine X-ray reflectivity and scanning electron microscopy measurements to investigate the mechanisms involved in the growth of vertical arrays of phthalocyanine nanowires directed by templates of Au nanoparticles. The study has been carried out for H(16)CuPc at different substrate temperatures. It is shown that three organic morphologies evolve during the growth: 1D nanostructures on top of the Au nanoparticles, a multilayer film on the substrate and a layer wetting the gold nanoparticles. For substrate temperatures below 100 °C there is a coexisting and competing growth of the three structures, whereas beyond this temperature the 1D growth on the nanoparticles is predominantly favored. The observance of two regimes with the temperature is characterized by two different activation energies. Both the length of the 1D structures and the thickness of the multilayer film can be precisely controlled by the substrate temperature which is of importance for application of vertical organic nanowires as donor/acceptor architecture in organic solar cells.

Supramolecular assembly of a 2D binary network of pentacene and phthalocyanine on Cu(100).

A crystalline nanoporous molecular network was tailored by supramolecular assembly of pentacene and F16CuPc on Cu(100). The structure and self-assembly mechanisms of the pure and binary layers were analyzed by STM. F16CuPc films and mixed layers of pentacene/F16CuPc in a ratio of 2:1 show two enantiomorphic chiral domains with high structural order in contrast to pentacene which exhibits no long-range order in pure films. A model of the epitaxial relationship on Cu(100) is given, which suggests C-F...H bonding as a possible driving force for the bimolecular self-assembly in addition to the still strong interaction between the substrate and the organic bilayer.

Three-dimensional molecular packing of thin organic films of PTCDI-C8 determined by surface X-ray diffraction.

We have determined the full molecular 3D packing of thin organic films of the archetypical organic n-type semiconductor N, N'-dioctyl-3,4:9,10-perylene tetracarboxylic diimide (PTCDI-C 8) by surface X-ray crystallography. We show that PTCDI-C 8 forms smooth layered films on Al 2O 3 (11-20) with an outstanding degree of molecular order. The thin-film structure is found to consist of a triclinic unit cell with the plane of the aromatic core tilted by 67 +/- 2 degrees with respect to the surface plane, which differs significantly from the bulk structure. The 3D crystallites extend with vertical coherent order across the entire film thickness.