PMID- 22352944
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20120725
LR  - 20120321
IS  - 1520-5126 (Electronic)
IS  - 0002-7863 (Linking)
VI  - 134
IP  - 11
DP  - 2012 Mar 21
TI  - Correlations between molecular structure and single-junction conductance: a case 
      study with oligo(phenylene-ethynylene)-type wires.
PG  - 5262-75
LID - 10.1021/ja211555x [doi]
AB  - The charge transport characteristics of 11 tailor-made dithiol-terminated 
      oligo(phenylene-ethynylene) (OPE)-type molecules attached to two gold electrodes 
      were studied at a solid/liquid interface in a combined approach using an STM 
      break junction (STM-BJ) and a mechanically controlled break junction (MCBJ) 
      setup. We designed and characterized 11 structurally distinct dithiol-terminated 
      OPE-type molecules with varied length and HOMO/LUMO energy. Increase of the 
      molecular length and/or of the HOMO-LUMO gap leads to a decrease of the 
      single-junction conductance of the linearly conjugate acenes. The experimental 
      data and simulations suggest a nonresonant tunneling mechanism involving hole 
      transport through the molecular HOMO, with a decay constant beta = 3.4 +/- 0.1 nm(-1) 
      and a contact resistance R(c) = 40 kOmega per Au-S bond. The introduction of a 
      cross-conjugated anthraquinone or a dihydroanthracene central unit results in 
      lower conductance values, which are attributed to a destructive quantum 
      interference phenomenon for the former and a broken pi-conjugation for the latter. 
      The statistical analysis of conductance-distance and current-voltage traces 
      revealed details of evolution and breaking of molecular junctions. In particular, 
      we explored the effect of stretching rate and junction stability. We compare our 
      experimental results with DFT calculations using the ab initio code SMEAGOL and 
      discuss how the structure of the molecular wires affects the conductance values.
FAU - Kaliginedi, Veerabhadrarao
AU  - Kaliginedi V
AD  - Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, 
      CH-3012 Berne, Switzerland.
FAU - Moreno-Garcia, Pavel
AU  - Moreno-Garcia P
FAU - Valkenier, Hennie
AU  - Valkenier H
FAU - Hong, Wenjing
AU  - Hong W
FAU - Garcia-Suarez, Victor M
AU  - Garcia-Suarez VM
FAU - Buiter, Petra
AU  - Buiter P
FAU - Otten, Jelmer L H
AU  - Otten JL
FAU - Hummelen, Jan C
AU  - Hummelen JC
FAU - Lambert, Colin J
AU  - Lambert CJ
FAU - Wandlowski, Thomas
AU  - Wandlowski T
LA  - eng
PT  - Journal Article
DEP - 20120306
PL  - United States
TA  - J Am Chem Soc
JT  - Journal of the American Chemical Society
JID - 7503056
EDAT- 2012/02/23 06:00
MHDA- 2012/02/23 06:01
CRDT- 2012/02/23 06:00
PHST- 2012/02/23 06:00 [entrez]
PHST- 2012/02/23 06:00 [pubmed]
PHST- 2012/02/23 06:01 [medline]
AID - 10.1021/ja211555x [doi]
PST - ppublish
SO  - J Am Chem Soc. 2012 Mar 21;134(11):5262-75. doi: 10.1021/ja211555x. Epub 2012 Mar 
      6.