Conformation Diversity of a Fused‐Ring Pyrazine Derivative on Au(111) and Highly Ordered Pyrolytic Graphite

Abstract

Heterocyclic aromatic compounds have attracted considerable attention because of their high carrier mobility that can be exploited in organic field-effect transistors. This contribution presents a comparative study of the packing structure of 3,6-didodecyl-12-(3,6-didodecylphenanthro[9,10-b]phenazin-13-yl)phenanthro[9,10-b]phenazine (DP), an N-heterocyclic aromatic compound, on Au(111) and highly ordered pyrolytic graphite (HOPG). High-resolution scanning tunneling microscopy (STM) combined with atomistic simulations provide a picture of the interface of this organic semiconductor on an electrode that can have an impact on the field-effect transistor (FET) performance. DP molecules adsorb with different conformational isomers (R/S: trans isomers; C: cis isomer) on HOPG and Au(111) substrates. All three isomers are found in the long-range disordered lamella domains on Au(111). In contrast, only the R/S trans isomers self-assemble into stable chiral domains on the HOPG surface. The substrate-dependent adsorption configuration selectivity is supported by theoretical calculations. The van der Waals interaction between the molecules and the substrate dominates the adsorption binding energy of the DP molecules on the solid surface. The results provide molecular evidence of the interface structures of organic semiconductors on electrode surfaces.

One Chain Fixed, One Chain Modified by −C5H10–: An Efficient Strategy on Fabricating Structural Diversity for 2D Self-Assembly

“…Controlling and inducing the self-assembled nanostructures in the field of two-dimensional (2D) crystal engineering is a subject that has received intense attention. − In recent decades, structural diversity for organic molecules on solid surfaces has been widely reported, using scanning tunneling microscopy (STM) as the visualization tool. − These surfaces are used as templates or as functional elements which have potential application for catalysis, sensing, crystal growth, organic electronic devices, and so on. − For the purpose of fabricating diverse nanostructures, 2D self-assembly has been recognized as a promising methodology based on the bottom-up principle in nanoscience and nanotechnology. − Molecular self-assembly is a process which is sensitive to the delicate balance among the noncovalent interactions, including hydrogen bonds, π–π stacking, dipolar interaction, van der Waals (vdWs) interaction, and so on. − Moreover, the self-assembled networks are able to be regulated by changing the concentration, , solvent, , voltage, temperature, , the chain length, , and functional groups. , …”

Structural transition control between dipole–dipole and hydrogen bonds induced chirality and achirality

“…Exploring and controlling the 2D pattern formation of organic molecules on the surface have attracted extensive attention and been an active research area. [1][2][3][4][5][6][7][8] Chirality is a common phenomenon in nature, and surface chirality has gained widespread interest. Studies of the induction, transformation, and amplification of chirality provide a fundamental understanding and potential applications on enantioselective catalysis, chiral separation and many other physical, chemical and biological topics.…”

Two-dimensional molecular networks at the solid/liquid interface and the role of alkyl chains in their building blocks

“…However, it is important to note that the kinds of substrate have influence on the 2D molecular self-assemblies. 2D structures on metallic surfaces, such as Au (111), are different from those on a HOPG surface, even if the molecular building blocks are the same [62][63][64]. This is because of the different molecule-substrate interactions on Au (111) and HOPG.…”