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Low-temperature scanning tunneling microscopy, molecular dynamics (MD) and density functional theory (DFT) calculations are used for examining self-assembly of the binary molecular system of pentacene and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on Ag(111). The results have shown that the formation of large-scale, highly periodic two dimensional supramolecular assemblies have depended on a combination specific and relatively strong molecule-substrate interactions with weak but directional intermolecular interactions.

A new strategy is used for fabricating surface nanotemplates featuring well-ordered nanocavity arrays made up by [C.sub.60] molecules, referred to as a [C.sub.60] nanomesh, which is formed by adjusting the binary molecular phases of [C.sub.60] and pentacene on Ag(111). The [C.sub.60] nanomesh has served as a effective template to selectively accommodate guest [C.sub.60] molecules at the nanocavities, thus leading to the formation of an ordered 2D [C.sub.60] array with a large intermolecular distance between the nearest neighboring [C.sub.60] on top of the [C.sub.60] nanomesh template.

Self-assembled functionalized aromatic thiols, oligophenylenes composed of building blocks of dimethoxy-substituted phenylenes, perfluoro-substituted phenylenes and a terminal thiol group, are used to tune the hole injection barrier of copper(II) phthalocyanine (CuPc) on Au(111). The molecular orientations of CuPc on self-assembled monolayer (SAM)/Au(III) have indicated an upright configuration of CuPc on SAMs, facilitating their effective incorporation in organic field-effect transistor (OFET) and other planar organic devices.

The growth behaviors of C60 molecules on SiC nanomesh at room temperature is systematically investigated using in situ scanning tunneling microscopy. After deposition of 1 ML C60, a complete layer of hexagonally close-packed C60 molecules forms on top of the SiC nanomesh.

A SiC nanomesh is used as a nanotemplate to direct the epitaxy of C60molecules. The epitaxial growth of C60molecules on SiC nanomesh at room temperature is investigated by in situ scanning tunneling microscopy, revealing a typical Stranski−Krastanov mode (i.e., for the first one or two monolayers, it is a layer-by-layer growth or 2-D nucleation mode; at higher thicknesses, it changes to island growth or a 3-D nucleation mode). At submonolayer (0.04 and 0.2 ML) coverage, C60molecules tend to aggregate to form single-layer C60islands that mainly decorate terrace edges, leaving the uncovered SiC nanomesh almost free of C60molecules. At 1 ML C60coverage, a complete wetting layer of hexagonally close-packed C60molecules forms on top of the SiC nanomesh. At higher coverage from 4.5 ML onward, the C60stacking adopts a (111) oriented face-centered-cubic (fcc) structure. Strong bright and dim molecular contrasts have been observed on the first layer of C60molecules, which are proposed to originate from electronic effects in a single-layer C60island or the different coupling of C60molecules to SiC nanomesh. These STM molecular contrast patterns completely disappear on the second and all the subsequent C60layers. It is also found that the nanomesh can be fully recovered by annealing the C60/SiC nanomesh sample at 200 °C for 20 min. [ABSTRACT FROM AUTHOR]

The article describes the fabrication of nanocavity arrays made up by C60 nanomesh, which is formed by adjusting the binary molecular phases of C60 and pentacene on Ag(111). According to the authors, the nanomesh can act as a template for the selective inclusion of guest C60 into the nanocavities, forming ordered two-dimensional C60 arrays. They add that the skeleton of the nanomesh is stabilized by the strong molecule-metal interfacial interactions.

Abstract: Self-assembly of the binary molecular system of pentacene and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on Ag(1 11) has been investigated by low-temperature scanning tunneling microscopy, molecular dynamics (MD), and density functional theory (DFT) calculations. Well-ordered two-dimensional (2D) pentacene:PTCDA supramolecular chiral networks are observed to form on Ag(111). The 2D chiral network formation is controlled by the strong interfacial interaction between adsorbed molecules and the underlying Ag(1 11), as revealed by MD and DFT calculations. The registry eftect locks the adsorbed pentacene and PTCDA molecules into specific adsorption sites due to the corrugation of the potential energy surface. The 2D supramolecular networks are further constrained through the directional C=O ߪ H-C multiple intermolecular hydrogen bonding between the anhydride groups of PTCDA and the peripheral aromatic hydrogen atoms of the neighboring pentacene molecules. [ABSTRACT FROM AUTHOR]