Tuning the conductance of a molecular wire by the interplay of donor and acceptor units

Dmitry Skidin (1, 2) , Tim Erdmann (2, 3) , Seddigheh Nikipar (1) , Frank Eisenhut (2, 1) , Justus Krüger (1, 2) , Florian Günther (2, 4) , Sibylle Gemming (2, 4, 5) , Anton Kiriy (3, 2) , Brigitte Voit (2, 3) , Dmitry Ryndyk (6) , Christian Joachim (7) , Francesca Moresco (2, 1) , Gianaurelio Cuniberti (2, 1, 8)

1 Max Bergmann Center of Biomaterials Dresden
2 CFAED - Center for Advancing Electronics in Dresden
3 IPF - Leibniz-Institut für Polymerforschung Dresden e.V.
4 Institute of Ion Beam Physics and Materials Research [Dresden]
5 Chemnitz University of Technology / Technische Universität Chemnitz
6 Universität Bremen
7 CEMES-GNS - Groupe NanoSciences
8 Dresden Center for Computational Materials Science

We investigate the conductance of optimized donor–acceptor–donor molecular wires obtained by on-surface synthesis on the Au(111) surface. A careful balance between acceptors and donors is achieved using a diketopyrrolopyrrole acceptor and two thiophene donors per unit along the wire. Scanning tunneling microscopy imaging, spectroscopy, and conductance measurements done by pulling a single molecular wire at one end are presented. We show that the conductance of the obtained wires is among the highest reported so far in a tunneling transport regime, with an inverse decay length of 0.17 Å−1. Using complex band structure calculations, different donor and acceptor groups are discussed, showing how a balanced combination of donor and acceptor units along the wire can further minimize the decay of the tunneling current with length.

Domaines: Physique [physics]

Dmitry Skidin, Tim Erdmann, Seddigheh Nikipar, Frank Eisenhut, Justus Krüger, et al.. Tuning the conductance of a molecular wire by the interplay of donor and acceptor units. Nanoscale, 2018, 10 (36), pp.17131-17139. ⟨10.1039/c8nr05031g⟩. ⟨hal-02160076⟩