Fullerene-Based Anchoring Groups for Molecular Electronics
摘要:
We present results on a new fullerne-based anchoring group for molecular electronics. Using lithographic mechanically controllable break junctions in vaccum we have determined the conductance and stability of single-molecule junctions of 1,4-bis(fullero[c]pyrrolidin-1-yl)benzene. The compound can be self-assembled from solution and has a low-bias conductance of 3 x 10(-4) G(0). Compared to 1,4-benzenedithiol the fullerene-anchored molecule exhibits a considerably lower conductance spread. In addition, the signature of the new compound in histograms is more significant than that of 1,4-benzenediamine, probably owing to a more stable adsorption motif. Statistical analyses of the breaking of the junctions confirm the stability of the fullerene-gold bond.
Fullerene-Based Anchoring Groups for Molecular Electronics
作者:Christian A. Martin、Dapeng Ding、Jakob Kryger Sørensen、Thomas Bjørnholm、Jan M. van Ruitenbeek、Herre S. J. van der Zant
DOI:10.1021/ja804699a
日期:2008.10.8
We present results on a new fullerne-based anchoring group for molecular electronics. Using lithographic mechanically controllable break junctions in vaccum we have determined the conductance and stability of single-molecule junctions of 1,4-bis(fullero[c]pyrrolidin-1-yl)benzene. The compound can be self-assembled from solution and has a low-bias conductance of 3 x 10(-4) G(0). Compared to 1,4-benzenedithiol the fullerene-anchored molecule exhibits a considerably lower conductance spread. In addition, the signature of the new compound in histograms is more significant than that of 1,4-benzenediamine, probably owing to a more stable adsorption motif. Statistical analyses of the breaking of the junctions confirm the stability of the fullerene-gold bond.
Fulleropyrrolidine End-Capped Molecular Wires for Molecular Electronics—Synthesis, Spectroscopic, Electrochemical, and Theoretical Characterization
In continuation of previous studies showing promising metal molecule contact properties a variety of C-60 end-capped "molecular wires" for molecular electronics were prepared by variants of the Prato 1,3-dipolar cycloaddition reaction. Either benzene or fluorene was chosen as the central wire, and synthetic protocols for derivatives terminated with one or two fullero[c]pyrrolidine "electrode anchoring" groups were developed. An aryl-substituted aziridine could in some cases be employed directly as the azomethine ylide precursor for the Prato reaction without the need of having an electron-withdrawing ester group present. The effect of extending the pi-system of the central wire from 1,4-phenylenediamine to 2,7-fluorenediamine was investigated by absorption, fluorescence, and electrochemical methods. The central wire and the Co-60 end-groups were found not to electronically communicate in the ground state. However, the fluorescence of C60 was quenched by charge transfer from the wire to C-60. Quantum chemical calculations predict and explain the collapse of coherent electronic transmission through one of the fulleropyrrolidine-terminated molecular wires.