TY - JOUR
T1 - Dihydroazulene photoswitch operating in sequential tunneling regime
T2 - synthesis and single-molecule junction studies
AU - Broman, Søren Lindbæk
AU - Lara-Avila, Samuel
AU - Thisted, Christine Lindbjerg
AU - Bond, Andrew
AU - Kubatkin, Sergey
AU - Danilov, Andrey
AU - Nielsen, Mogens Brøndsted
PY - 2012/10/23
Y1 - 2012/10/23
N2 - 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-MeSC 6H 4 end-groups. Molecules are prepared by Suzuki cross-couplings on suitable halogenated derivatives of DHA. The synthesis presents an expansion of our previously reported bromination-elimination-cross- 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-MeSC 6H 4 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. A dihydroazulene (DHA) photoswitch containing one methylsulfide anchoring group is synthesized and placed by sublimation in a silver nanogap. Conductance measurements show that transport through the molecule goes by sequential tunneling (weak coupling to one electrode). Reversible switching between DHA (OFF) and its vinylheptafulvene isomer (VHF; ON) is successfully controlled by gate voltage, bias voltage, temperature, and light.
AB - 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-MeSC 6H 4 end-groups. Molecules are prepared by Suzuki cross-couplings on suitable halogenated derivatives of DHA. The synthesis presents an expansion of our previously reported bromination-elimination-cross- 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-MeSC 6H 4 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. A dihydroazulene (DHA) photoswitch containing one methylsulfide anchoring group is synthesized and placed by sublimation in a silver nanogap. Conductance measurements show that transport through the molecule goes by sequential tunneling (weak coupling to one electrode). Reversible switching between DHA (OFF) and its vinylheptafulvene isomer (VHF; ON) is successfully controlled by gate voltage, bias voltage, temperature, and light.
U2 - 10.1002/adfm.201200897
DO - 10.1002/adfm.201200897
M3 - Journal article
SN - 1057-9257
VL - 22
SP - 4249
EP - 4258
JO - Advanced Materials for Optics and Electronics
JF - Advanced Materials for Optics and Electronics
IS - 20
ER -