Quantifying the “Subtle Interplay” between Intermolecular and Molecule–Substrate Interactions in Molecular Assembly on Surfaces

Abstract

The effect of the concurrent action of intermolecular and molecule−substrate interactions on the two-dimensional (2D) self-assembly of organic molecules on solid surfaces is investigated in a combined experimental and theoretical effort. Scanning tunneling microscopy measurements of terephthalic acid on the Cu(111) surface, a model system where the interplay between the two interactions is particularly evident, are used to develop a general, simple, and computationally inexpensive model that quantitatively accounts for the experimental observations. The model, related to the well-known Frenkel−Kontorova model, offers a comprehensive description of the "subtle interplay" between intermolecular and molecule−substrate interactions and provides a qualitative and quantitative predictive capability in the design and fabrication of 2D molecular nanostructures at surfaces.

Control of the deprotonation of terephthalic acid assemblies on Ag(111) studied by DFT calculations and low temperature scanning tunneling microscopy

“…Their apparent depth is about 50 pm for a bias voltage of 100 mV. These dark contrasts look like those presented by White et al 17 for TPA on Cu(111) but without the structural difference reported by these authors. Indeed, during our experiments, the intermolecular distances around the defects remain identical to those measured in the pristine lattice.…”

“…Physisorption of single TPA also results in the absence of spectroscopic features that could be due to the molecule electronic levels (contrary to the selfassemblies where the metallic surface state is shifted above the Fermi level and becomes an interface state). The electronic surface state around the molecules is not disturbed, contrary to what is observed on Cu(111) where dark depressions appear on the molecule extremities simply after their adsorption on the susbtrate 17 .…”

“…On the same surface, different studies demonstrate the formation of three different lattices depending on the temperature of the metallic surface during molecule deposition, these networks being also linked to a partial or total deprotonation of TPA 2,15,16 . Recently, White et al use the same molecules on Cu(111) as a model system to study the well-known interplay between intermolecular and adsorbate-substrate interactions 17 . The possible deprotonation states of these molecules, the intermolecular interactions inside the layers as well as the role of the H atoms appear of fundamental importance for the understanding of the self assemblies.…”

Molecular self-assembly of substituted terephthalic acids at the liquid/solid interface: investigating the effect of solvent

“…A possible reason for this may be the effect of the substrate, i.e. the relationship between the substrate periodicity and the intra-chain periodicity, 71 and the possibility of inter-chain interactions (either weak or strong, depending on the presence of OH groups) modulating the substrate interactions.…”

Tailoring molecular island shapes: influence of microscopic interaction on mesostructure

“…In many cases, the molecule-substrate interaction has been recognized to be governed by the electronic structure of the substrate, which, in turn, impacts the structural properties of self-assembled nanomaterials on various substrates; e.g., bulk metals [9][10][11][12][13][14][15], twodimensional materials [16,17], and polar oxide surfaces [18][19][20]. Tuning the subtle balance between molecule-molecule and molecule-surface interactions [21] has opened up new pathways for creating an impressive variety of molecular structures on surfaces [22][23][24][25][26]. For example, structures ranging from perfectly ordered two-dimensional layers [27], unidirectional rows [28,29], porous networks [30,31] to complex structures have been presented as a function of the specific molecular design [27,32,33].…”