Dihydroazulene Photoswitch Operating in Sequential Tunneling Regime: Synthesis and Single-Molecule Junction Studies
Artikel i vetenskaplig tidskrift, 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.

photoswitch

temperature

spectroscopy

devices

Suzuki coupling

photochromism

charge transport

derivatives

surfaces

dihydroazulene

conductance

electron transistor

molecular electronics

Författare

S. L. Broman

Köbenhavns Universitet

Samuel Lara Avila

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

C. L. Thisted

Köbenhavns Universitet

A. D. Bond

Syddansk Universitet

Sergey Kubatkin

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Andrey Danilov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

M. B. Nielsen

Köbenhavns Universitet

Advanced Functional Materials

1616-301X (ISSN)

Vol. 22 4249-4258

Ämneskategorier

Fysik

DOI

10.1002/adfm.201200897