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arXiv · 1606.07638

Π Band Dispersion along Conjugated Organic Nanowires Synthesized on a Metal Oxide Semiconductor

Guillaume Vasseur·Mikel Abadia·Luis A. Miccio·Jens Brede·Aran Garcia-Lekue·Dimas G. de Oteyza·Celia Rogero·Jorge Lobo-Checa·J. Enrique Ortega
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Abstract

Surface confined dehalogenation reactions are versatile bottom-up approaches for the synthesis of carbon-based nanostructures with predefined chemical properties. However, for devices generally requiring low conductivity substrates, potential applications are so far severely hampered by the necessity of a metallic surface to catalyze the reactions. In this work we report the synthesis of ordered arrays of poly(p-phenylene) chains on the surface of semiconducting TiO2(110) via a dehalogenative homocoupling of 4,4"-dibromoterphenyl precursors. The supramolecular phase is clearly distinguished from the polymeric one using low energy electron diffraction and scanning tunneling microscopy as the substrate temperature used for deposition is varied. X ray photoelectron spectroscopy of C 1s and Br 3d core levels traces the temperature of the onset of dehalogenation to around 475 K. Moreover, angle-resolved photoemission spectroscopy and tight-binding calculations identify a highly dispersive band characteristic of a substantial overlap between the precursor's π states along the polymer, considered as the fingerprint of a successful polymerization. Thus, these results establish the first spectroscopic evidence that atomically precise carbon based nanostructures can readily be synthesized on top of a transition-metal oxide surface, opening the prospect for the bottom-up production of novel molecule-semiconductor devices.

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Guillaume Vasseur, Mikel Abadia, Luis A. Miccio, Jens Brede, Aran Garcia-Lekue, Dimas G. de Oteyza, Celia Rogero, Jorge Lobo-Checa, J. Enrique Ortega. 2016-06-24. Π Band Dispersion along Conjugated Organic Nanowires Synthesized on a Metal Oxide Semiconductor. https://doi.org/10.1021/jacs.6b02151

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