Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 87: Poster Session - Nanostructures at Surfaces: 1D and 2D Structures and Networks

O 87.8: Poster

Wednesday, March 18, 2020, 18:15–20:00, P2/1OG

Thermal- vs. Light-Induced on-Surface Polymerization — •Christophe Nacci and Leonhard Grill — Department of Physical Chemistry, University of Graz, 8010 Graz, Austria

The on-surface synthesis of covalently linked molecular precursors via Ullmann coupling reaction is an efficient approach to produce novel functional materials. The dissociation of specific bonds and the formation of new covalent ones can be induced by using different external stimuli. While many studies exist on the thermal control of the reaction, very few studies have reported a photochemical approach to form polymers at single-crystal surfaces. The purpose of this work is to get insight into the reaction pathways from individual molecular species to one-dimensional polymers by driving the reaction either by heat or by light illumination. The molecular precursors were deposited in ultra-high vacuum onto a Au(111) surface where polymerization occurs. Two stimuli, thermal- and photo-induced polymerization by using UV light, were employed and systematically compared. The structural characterization of the product results by low-temperature scanning tunneling microscopy and the corresponding polymer length distributions will be shown.