Efficient electronic coupling and improved stability with dithiocarbamate-based molecular junctions

• Published in: Nature nanotechnology Vol. 5; no. 8; pp. 618 - 624
• Main Authors: von Wrochem, Florian, Wessels, Jurina M, Gao, Deqing, Scholz, Frank, Nothofer, Heinz-Georg, Nelles, Gabriele
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2010; Nature Publishing Group
• Subjects: 639/925/357/341; 639/925/357/995; 639/925/927/1007; Amines; Chemistry and Materials Science; Crystallization - methods; Electrodes; Electron Transport; Electronics industry; Electrons; Equipment Design; Equipment Failure Analysis; Ferrous Compounds - chemistry; Gold; Injection; Macromolecular Substances - chemistry; Materials Science; Materials Testing; Metals; Microelectrodes; Molecular Conformation; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology; Nanotechnology - instrumentation; Nanotechnology and Microengineering; Particle Size; Spectroscopy; Surface Properties; Thiocarbamates - chemistry
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/nnano.2010.119

Molecular electronic devices require stable and highly conductive contacts between the metal electrodes and molecules. Thiols and amines are widely used to attach molecules to metals, but they form poor electrical contacts and lack the robustness required for device applications. Here, we demonstrate that dithiocarbamates provide superior electrical contact and thermal stability when compared to thiols on metals. Ultraviolet photoelectron spectroscopy and density functional theory show the presence of electronic states at 0.6 eV below the Fermi level of Au, which effectively reduce the charge injection barrier across the metal−molecule interface. Charge transport measurements across oligophenylene monolayers reveal that the conductance of terphenyl–dithiocarbamate junctions is two orders of magnitude higher than that of terphenyl–thiolate junctions. The stability and low contact resistance of dithiocarbamate-based molecular junctions represent a significant step towards the development of robust, organic-based electronic circuits. Dithiocarbamates are used to form contacts between metal electrodes and molecules, producing molecular junctions that display a low contact resistance and good thermal stability.