Distinct armchair and zigzag charge transport through single polycyclic aromatics

Abstract

In aromatic systems with large π-conjugated structures, armchair and zigzag configurations can affect each material’s electronic properties, determining their performance and generating certain quantum effects. Here, we explore the intrinsic effect of armchair and zigzag pathways on charge transport through single hexabenzocoronene molecules. Theoretical calculations and systematic experimental results from static carbon-based single-molecule junctions and dynamic scanning tunneling microscope break junctions show that charge carriers are preferentially transported along the hexabenzocoronene armchair pathway, and thus, the corresponding current through this pathway is approximately one order of magnitude higher than that through the zigzag pathway. In addition, the molecule with the zigzag pathway has a smaller energy gap. In combination with its lower off-state conductance, it shows a better field-effect performance because of its higher on-off ratio in electrical measurements. This study on charge transport pathways offers a useful perspective for understanding the electronic properties of π-conjugated systems and realizing high-performance molecular nanocircuits toward practical applications.

Unveiling Energy Transfer Mechanisms in Nanographene-Incorporated Metal–Organic Frameworks

“…Nanographenes are a class of large (over 1 nm) polycyclic aromatic hydrocarbons, − which can be synthesized through a bottom-up approach in organic synthesis to provide unique chemical and physical properties by precisely controlling the length, width, and edge of graphene substructures. − Over the past decade, nanographenes attracted significant interest in a wide range of applications such as nanoelectronics, − chemical sensing, catalysis, and others. − Despite these interesting properties, major drawbacks include extremely low solubility in common organic solvents and self-aggregation due to strong π–π interactions, which hinders the effective use of their π-conjugated exposed surfaces for advanced functionalities. , …”