Isomer-Dependent Franck-Condon Blockade in Weakly Coupled Bipyridine Molecular Junctions
2014 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 27, 14853-14859 p.Article in journal (Refereed) Published
Franck-Condon blockade is an attractive functionality of molecular junctions, but its tunability is still a challenge that has not been fully addressed. We show here from first-principles calculations that the electron-vibration coupling strength of a weekly coupled bipyridine molecular junction can be largely tuned from weak to strong coupling regime through isomerization. Electron transport properties of four bipyridine isomers, namely 2,6'-bipyridine, 2,4'-bipyridine, 2,2'-bipyridine, and 4,4'-bipyridine, have been exclusively examined. A very strong Franck-Condon blockade is found to be associated with 2,2'-bipyridine and 4,4'-bipyridine molecules and should be observable experimentally. A gate-controlled conductance switch is proposed for a molecular junction with a 4,4'-bipyridine molecule. Our calculations have clearly demonstrated that bipyridine isomers are excellent candidates for the experimental study of vibration-mediated transport properties in a single molecule.
Place, publisher, year, edition, pages
2014. Vol. 118, no 27, 14853-14859 p.
Charge-Transport, Single, Conductance, Fluorescence
IdentifiersURN: urn:nbn:se:kth:diva-149205DOI: 10.1021/jp505871nISI: 000338980400016ScopusID: 2-s2.0-84904281976OAI: oai:DiVA.org:kth-149205DiVA: diva2:738769
FunderSwedish Research Council
QC 201408192014-08-192014-08-182014-08-19Bibliographically approved