Dihydroazulene Photoswitch Operating in Sequential Tunneling Regime: Synthesis and Single-Molecule Junction Studies
Journal article, 2012

Molecular switches play a central role for the development of molecular electronics. In this work it is demonstrated that the reproducibility and robustness of a single-molecule dihydroazulene (DHA)/vinylheptafulvene (VHF) switch can be remarkably enhanced if the switching kernel is weakly coupled to electrodes so that the electron transport goes by sequential tunneling. To assure weak coupling, the DHA switching kernel is modified by incorporating p-MeSC6H4 end-groups. Molecules are prepared by Suzuki cross-couplings on suitable halogenated derivatives of DHA. The synthesis presents an expansion of our previously reported brominationeliminationcross-coupling protocol for functionalization of the DHA core. For all new derivatives the kinetics of DHA/VHF transition has been thoroughly studied in solution. The kinetics reveals the effect of sulfur end-groups on the thermal ring-closure of VHF. One derivative, incorporating a p-MeSC6H4 anchoring group in one end, has been placed in a silver nanogap. Conductance measurements justify that transport through both DHA (high resistivity) and VHF (low resistivity) forms goes by sequential tunneling. The switching is fairly reversible and reenterable; after more than 20 ON-OFF switchings, both DHA and VHF forms are still recognizable, albeit noticeably different from the original states.



charge transport

molecular electronics



Suzuki coupling


electron transistor






S. L. Broman

University of Copenhagen

Samuel Lara Avila

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

C. L. Thisted

University of Copenhagen

A. D. Bond

University of Southern Denmark

Sergey Kubatkin

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Andrey Danilov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

M. B. Nielsen

University of Copenhagen

Advanced Functional Materials

1616-301X (ISSN)

Vol. 22 20 4249-4258

Subject Categories

Physical Sciences



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9/6/2018 1