Unusual conductance of polyyne-based molecular wires

TL;DR

This paper presents ab initio calculations showing that polyyne-based molecular wires exhibit unusually high conductance, making them nearly perfect conductors due to their electronic structure and Fermi level positioning.

Contribution

The study provides the first detailed ab initio analysis of polyyne conductance, revealing their superior electrical properties compared to other conjugated molecules.

Findings

Polyynes have conductance an order of magnitude higher than other conjugated oligomers.

Conductance is weakly dependent on bias voltage.

Conductance remains nearly constant regardless of molecular chain length.

Abstract

We report a full self-consistent ab initio calculation of the current-voltage curve and the conductance of thiolate capped polyynes in contact with gold electrodes. We find the conductance of polyynes an order of magnitude larger compared with other conjugated oligomers. The reason lies in the position of the Fermi level deep in the HOMO related resonance. With the conductance weakly dependent on the applied bias and almost independent of the length of the molecular chain, polyynes appear as nearly perfect molecular wires.