Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 101: Molecular Films: Electronics, Photovoltaics and Structure
O 101.7: Talk
Friday, April 4, 2014, 12:00–12:15, WIL A317
On-surface Synthesis of Extended Graphdiyne Wires by Stepped Surface Templating of Terminal Alkyne Homo-Coupling — Borja Cirera1, Yi-Qi Zhang1, Jonas Björk2, Svetlana Klyatskaya3, Zhi Chen3, Mario Ruben3, Johannes V. Barth1, and •Florian Klappenberger1 — 1Physik Department E20, TU München, Germany — 2Department of Physics, Chemistry and Biology (IFM), Linköping University, Sweden — 3Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
The success of carbon allotropes strongly refreshed the attraction towards low-dimensional hydrocarbon materials like carbyne, graphyne, or graphdiyne originally targeted by acetylenic solution chemistry. Recently, we introduced homo-coupling of terminal alkynes on a noble metal surface to the field of covalent on-surface synthesis. Here, we overcome the missing chemoselectivity of this method by templating the coupling reaction of linear diethynyl-terphenyl monomers with step edge alignment on the vicinal Ag(877) surface. This approach allowed us to suppress side-reactions resulting in irregularly-branched polymers on the planar surface and rendering possible the fabrication of 300 Å-long strands of a novel 1D hydrocarbon material. The extended-graphdiyne molecular wire is classified by density functional theory electronic structure calculations as a direct band gap semiconductor material. Our method puts a great variety of carbon-rich materials within reach and should also be applicable to other classes of tectons.