Molecular junctions based on SAMs of cruciform oligo(phenylene ethynylene)s

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Zhongming Wei, Tao Li, Karsten Stein Jennum, Marco Santella, Nicolas Emile Bovet, Wenping Hu, Mogens Brøndsted Nielsen, Thomas Bjørnholm, Gemma C. Solomon, Bo Wegge Laursen, Kasper Nørgaard

Cruciform oligo(phenylene ethynylene)s (OPEs) with an extended tetrathiafulvalene (TTF) donor moiety (OPE5-TTF and OPE3-TTF) and their simple analogues (OPE5-S and OPE3) without conjugated substituents were used to form high quality self-assembled monolayers (SAMs) on ultra-flat gold substrates. Molecular junctions based on these SAMs were investigated using conducting-probe atomic force microscopy (CP-AFM). The TTF substituent changes the molecular orbital energy levels and decreases the HOMO-LUMO energy gap, resulting in a nine-fold increase in conductance for both TTF cruciform OPEs compared to the unsubstituted analogues. The difference in electrical transport properties of the SAMs was reproduced by the theoretical transport calculations for the single molecules.
OriginalsprogEngelsk
TidsskriftLangmuir
Vol/bind28
Udgave nummer8
Sider (fra-til)4016–4023
Antal sider8
ISSN0743-7463
DOI
StatusUdgivet - 2012

ID: 37432877