Conductance of a single flexible molecular wire composed of alternating donor and acceptor units

Christophe Nacci (1, 2) , Francisco Ample (3) , David Bleger (4) , Stefan Hecht (4) , Christian Joachim (5, 6) , Leonhard Grill (1, 2)

1 FHI - Fritz-Haber-Institut der Max-Planck-Gesellschaft
2 Karl-Franzens-Universität Graz
3 IMRE - Institute of Materials Research and Engineering
4 IRIS Adlershof, Berlin, Germany
5 CEMES-GNS - Groupe NanoSciences
6 International Center for Materials Nanoarchitectonics (MANA)

Molecular-scale electronics is mainly concerned by understanding charge transport through individual molecules. A key issue here is the charge transport capability through a single—typically linear—molecule, characterized by the current decay with increasing length. To improve the conductance of individual polymers, molecular design often either involves the use of rigid ribbon/ladder-type structures, thereby sacrificing for flexibility of the molecular wire, or a zero band gap, typically associated with chemical instability. Here we show that a conjugated polymer composed of alternating donor and acceptor repeat units, synthesized directly by an on-surface polymerization, exhibits a very high conductance while maintaining both its flexible structure and a finite band gap. Importantly, electronic delocalization along the wire does not seem to be necessary as proven by spatial mapping of the electronic states along individual molecular wires. Our approach should facilitate the realization of flexible ‘soft’ molecular-scale circuitry, for example, on bendable substrates.

Domaines: Physique [physics]

Christophe Nacci, Francisco Ample, David Bleger, Stefan Hecht, Christian Joachim, et al.. Conductance of a single flexible molecular wire composed of alternating donor and acceptor units. Nature Communications, 2015, 6 (1), ⟨10.1038/ncomms8397⟩. ⟨hal-01712772⟩