Self-Assembly of N,N′-Di(n-butyl)-1,3,8,10-tetramethylquinacridone Governed by Metallic Surface Features of a Ag(110) Substrate

Abstract

We present scanning tunneling microscopy (STM) measurements combined with density functional theory (DFT) calculations to study the relationship between self-assembly characteristics and interaction motifs for organic molecules [here, N,N′-di­(n-butyl)-1,3,8,10-tetramethylquinacridone (TMDBQA)] on a Ag(110) surface, which exhibits a distinctive surface, featuring regions, such as atomically flat terraces and steps. It was found that Ag atoms on the surface terraces are weaker in chemical reactivity than those on the step edges, which leads to the different molecule–substrate interactions and thereby, the different self-assembly structures. The carbonyl oxygen on TMDBQA forms strong coordinative bonds with Ag atoms at the step edge, which is responsible for the formation of adsorbate-induced facets, and directs the arrangement of the molecules with respect to the steps. The DFT calculations demonstrate that with the facet formation, the adsorption energy between the molecule and substrate increases and the intermolecular binding energy decreases. By comparing the hydrogen-bonded self-assembled monolayer of N,N′-di­(n-butyl)­quinacridone on the Ag(110) surface, we concluded that the formation of adsorbate-induced facets is not favored when molecules bind to each other by strong and directional intermolecular interactions.

Odd-Even Effect on Supramolecular Co-Assemblies: Control over the Two-Dimensional Self-Assemblies of a Fluorenone Derivative with Asymmetrically Substituted Alkyl Chains

“…In recent years, surface supramolecular self-assembly has been an active research area, aimed at the realization of nanoscale functional devices, such as organic photovoltaic cells, organic light-emitting diodes, and organic field-effect transistors. − In this context, inducing and regulating diverse self-assembly structures are subjects of interest. Researchers have explored the self-assembly polymorphs of π-conjugated molecules via changing the solvent, , concentration, , temperature, , scanning tunneling microscopy (STM) bias, − molecular functional group, , the length of the alkyl chains, , and the substrate. , The used substrate contains highly oriented pyrolytic graphite (HOPG), Au (111), Ag (111), Si (111), Cu (110), and so on. − In particular, STM is the widely used visualization tool due to its atomic-level resolution. The driving forces that stabilize the self-assembled nanostructures include the weak hydrogen bonds, van der Waals interaction, dipolar interaction, halogen bonds, and π–π attractions. − …”

Scanning Tunneling Microscopy and Computational Simulation Studies of a Fluorenone-Based Organic Optoelectronic Material

“…In recent years, surface supramolecular self-assembly has been an intensively studied topic owing to its potential applications including surface modification, molecular-based devices, and two-dimensional (2D) crystal engineering. − Self-assembly is an effortless means for surface patterning, which involves reversible noncovalent interactions, and is a process where molecules adsorb onto and desorb from an atomically flat surface, for example, highly oriented pyrolytic graphite (HOPG), Au (111), Ag (111), and Cu (110). − The underlying driving forces include hydrogen bonds, halogen bonds, van der Waals interactions, and π–π attractions. − Scanning tunneling microscopy (STM) is the main analytical tool used due to its submolecular resolution.…”