Achieving Ultralow, Zero, and Inverted Tunneling Attenuation Coefficients in Molecular Wires with Extended Conjugation

Molecular tunnel junctions are organic devices miniaturized to the molecular scale. They serve as a versatile toolbox that can systematically examine charge transport behaviors at the atomic level. The electrical conductance of the molecular wire that bridges the two electrodes in a junction is significantly influenced by its chemical structure, and an intrinsically poor conductance is a major barrier for practical applications toward integrating individual molecules into electronic circuitry. Therefore, highly conjugated molecular wires are attractive as active components for the next-generation electronic devices, owing to the narrow highest occupied molecular orbital-lowest occupied molecular orbital gaps provided by their extended pi-building blocks. This article aims to highlight the significance of highly conductive molecular wires in molecular electronics, the structures of which are inspired from conductive organic polymers, and presents a body of discussion on molecular wires exhibiting ultralow, zero, or inverted attenuation of tunneling probability at different lengths, along with future directions.

Automated summary

Molecular tunnel junctions are organic devices miniaturized to the molecular scale, serving as a versatile toolbox for systematically examining charge transport behaviors at the atomic level. Highly conductive molecular wires, inspired by conductive organic polymers, are attractive for next-generation electronic devices due to their narrow HOMO-LUMO gaps. This article highlights the significance of highly conductive molecular wires in molecular electronics and discusses future directions for molecular wires exhibiting different tunneling probabilities at varying lengths.