Abstract
One of the main goals of molecular electronics is to achieve electronic functions from devices consisting of tailored organic molecules connecting two metal electrodes. The fabrication of nanometre-scale spaced electrodes still results in expensive, and often scarcely reproducible, devices1,2,3,4. On the other hand, the ‘conductance’ of long organic molecules—generally dominated by the tunnelling mechanism—is very poor5,6,7,8,9. Here, we show that by incorporating a large number of metal centres into rigid molecular backbones we can obtain very long (up to 40 nm) and highly ‘conductive’ molecular wires. The metal-centre molecular wires are assembled in situ on metal surfaces via a sequential stepwise coordination of metal ions by terpyridine-based ligands10,11. They form highly ordered molecular films of elevated mechanical robustness. The electrical properties, characterized by a junction based on Hg electrodes5,6, indicate that the ‘conductance’ of these metal-centre molecular wires does not decrease significantly even for very long molecular wires, and depends on the nature of the incorporated redox centre. The outstanding electrical and mechanical characteristics of these easy-to-assemble molecular systems open the door to a new generation of molecular wires, able to bridge large-gap electrodes, and to form robust films for organic electronics.
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Change history
10 February 2009
In the version of this article originally published, the y axes labels of Fig. 4b and c appeared incorrectly as ln J (A cm−2); they should have been log J (A cm−2). The errors have now been corrected on the HTML and PDF versions.
References
Reed, M. A., Zhou, C., Muller, C. J., Burgin, T. P. & Tour, J. M. Conductance of a molecular junction. Science 278, 252–254 (1997).
Park, H., Lim, A. K. L., Alivisatos, A. P., Park, J. & McEuen, P. L. Fabrication of metallic electrodes with nanometer separation by electromigration. Appl. Phys. Lett. 75, 304–303 (1999).
Krahne, R. et al. Fabrication of nanoscale gaps in integrated circuits. Appl. Phys. Lett. 81, 730–732 (2002).
Johnston, D. E., Strachan, D. R. & Johnson, A. T. C. Parallel fabrication of nanogap electrodes. Nano Lett. 7, 2474–2477 (2007).
Holmlin, R. E. et al. Electron transport through thin organic films in metal–insulator–metal junctions based on self-assembled monolayers. J. Am. Chem. Soc. 123, 5075–5085 (2001).
Holmlin, R. E. et al. Correlating electron transport and molecular structure in organic films. Angew. Chem. Int. Engl. Ed. 40, 2316–2320 (2001).
Wang, W., Lee, T. & Reed, M. A. Mechanism of electron conduction in self-assembled alkanethiol monolayer devices. Phys. Rev. B 68, 035416–035425 (2003).
Nitzan, A. & Ratner, M. A. Electron transport in molecular wire junctions. Science 300, 1384–1389 (2003).
Akkerman, H. B., Blom, P. W. M., De Leeuw, D. M. & de Boer, B. Towards molecular electronics with large-area molecular junctions. Nature 441, 69–72 (2006).
Auditore, A. et al. Organized assemblies of thiol-terpyridine and thiophenol on gold surfaces: Preferential composition of mixed species evidenced. Chem. Commun. 19, 2494–2495 (2003).
Tuccitto, N. et al. Stepwise formation of ruthenium(II) complexes by direct reaction on organized assemblies of thiol-terpyridine species on gold. ChemPhysChem 8, 227–230 (2007).
Surridge, N. et al. Electron self exchange dynamics between redox sites in polymers (Royal Society Electrochemical Group Medal Award Lecture, Oxford Univ., 9/89). Discuss. Faraday Soc. 1, 88 (1990).
Nishimori, Y., Kanaizuka, K., Murata, M. & Nishihara, H. Synthesis of molecular wires of linear and branched bis(terpyridine)-complex oligomers and electrochemical observation of through-bond redox conduction. Chem. Asian. J. 2, 367–376 (2007).
Tao, N. J. Probing the redox density of states of individual molecules with scanning tunneling microscopy. Phys. Rev. Lett. 76, 4066–4069 (1996).
Park, J. et al. Coulomb blockade and the Kondo effect in single atom transistors. Nature 417, 722–725 (2002).
Tran, E., Rampi, M. A. & Whitesides, G. M. Electron transfer in a Hg-SAM//SAM-Hg junction mediated by redox centers. Angew. Chem. Int. Engl. Ed. 43, 3835–3839 (2004).
Kushmerick, J. G., Whitaker, C. M., Pollack, S. K., Schull, T. L. & Shashidar, R. Tuning current rectification across molecular junctions. Nanotechnology 15, S489–S493 (2004).
Guo, X. et al. Covalently bridging gaps in single-walled carbon nanotubes with conducting molecules. Science 311, 356–359 (2006).
Tang, J. et al. Encoding molecular wire formation within nanoscale sockets. Angew. Chem. Int. Ed. 46, 3892–3895 (2007).
Mahapatro, A. K., Ying, J., Tong, R. & Janes, D. B. Electronic transport through ruthenium-based redox-active molecules in metal–molecule–metal nanogap junctions. Nano Lett. 8, 2131–2136 (2008).
Schubert, U. S., Hofmeier, H. & Newkome, G. R. Modern Terpyridine Chemistry (Wiley–VCH, 2006).
Benninghoven, A. Chemical analysis of inorganic and organic surfaces and thin films by static time-of-flight secondary ion mass spectrometry (TOF-SIMS). Angew. Chem. Int. Engl. Ed. 33, 1023–1043 (1994).
Kalyuzhny, G. et al. Differential plasmon spectroscopy as a tool for monitoring molecular binding to ultrathin gold films. J. Am. Chem. Soc. 123, 3177–3178 (2001).
Wilbur, L. et al. Microcontact printing of self-assembled monolayers: Applications in micro fabrication. Nanotechnology 7, 452–457 (1996).
Kolb, U. et al. The solid-state architecture of a metallosupramolecular polyelectrolyte. Proc. Natl Acad. Sci. 103, 10202–10206 (2006).
Haag, R., Rampi, M. A., Holmlin, R. E. & Whitesides, G. M. Electrical breakdown of aliphatic and aromatic self-assembled monolayers used as nanometer-thick organic dielectrics. J. Am. Chem. Soc. 121, 7895–7906 (1999).
Sikes, H. D. et al. Adiabatic interfacial electron transfer over 26 Å through oligophenylenevinylenes. Science 291, 1519–1523 (2001).
Salomon, A. et al. Comparison of electronic transport measurements on organic molecules. Adv. Mater. 15, 1881–1890 (2003).
He, J. et al. Electronic decay constant of carotenoid polyenes from single-molecule measurements. J. Am. Chem. Soc. 127, 1384–1385 (2005).
Choi, S. H., Kim, B. & Frisbie, C. D. Electrical resistance of long conjugated molecular wires. Science 320, 1482–1486 (2008).
Sedghi, et al. Single molecule conductance of porphyrine wires with ultralow attenuation. J. Am. Chem. Soc. 130, 8582–8583 (2008).
Perrine, T.P. & Dunietz, B.D. Conductance of a Co(II) terpyridine complex molecular transistor: A computational analysis. J. Phys. Chem. A 112, 2043–2048 (2008).
Nitzan, A. Electron transmission through molecules and molecular interfaces. Annu. Rev. Chem. 52, 681–750 (2001).
Davis, W. B., Svec, W. A., Ratner, M. A. & Wasielewski, M. R. Molecular wire behaviour in p-phenylenevinylene oligomers. Nature 396, 60–63 (1998).
Ashwell, G.J. et al. Single-molecule electrical studies on a 7 nm long molecular wire. Chem. Commun. 4706–4708 (2006).
Acknowledgements
We thank F. Scandola for discussion. Financial support of MURST (PRIN 2006 2006030320_002), EU (contract STRP-032202—EMDPA) and ‘PROMO’ CNR-INSTM is gratefully acknowledged.
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Project planning, A.L., M.A.R.; synthesis of the ligands, M.C., S.Q.; assembly and surface spectroscopy of the MWs, N.T., A.L., G.Z.; electrical measurements and data interpretation, V.F., N.T., M.A.R.
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Tuccitto, N., Ferri, V., Cavazzini, M. et al. Highly conductive ∼40-nm-long molecular wires assembled by stepwise incorporation of metal centres. Nature Mater 8, 41–46 (2009). https://doi.org/10.1038/nmat2332
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DOI: https://doi.org/10.1038/nmat2332
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