Adsorption and reaction of an alkyne molecule on diverse oxygen-reconstructed Cu(110) surfaces

Abstract

Studying the adsorption and reaction behaviors of organic molecules on solid surfaces holds great significance for producing high-performance organic films. Alkynes recently gain increasing popularity in on-surface self-assembly and reaction due to the peculiar nature of alkynyl groups. Here, we deposited 4-ethynyl-1,1′-biphenyl molecules (EBPs) on various oxygen-reconstructed Cu(110) surfaces derived from controllable oxidations. Both the structures of reconstructed surfaces and the adsorption/reaction properties of EBPs were investigated by scanning tunneling microscopy (STM), complemented with low energy electron diffraction (LEED) and synchrotron radiation photoelectron spectroscopy (SRPES). It is revealed that on the striped Cu-O nanotemplate surface, dehydrogenated EBPs prefer to decorate Cu region and form V-shaped dimers in large proportion. At the Cu/Cu-O interface, EBPs are aligned with their long axis along the Cu-O chain growth direction. Annealing to elevated temperatures merely induces intermolecular reactions among a few monomers. On the complete Cu(110)-(2 × 1)O surface, intact EBPs self-assemble into ordered and well-defined islands, where EBPs are confined by channels between Cu-O chains. On Cu(110)-c(6 × 2)O structure, non-covalent EBP dimers are dominant species. The orientation of these dimers is found to be dictated by corrugation between super Cu atom rows. Moreover, a Cu(110)-p(2 × 3)O surface is attained for the first time in this work, which, however, hardly anchor EBPs. In general, this work serves a model system for the research on adsorption and reaction of alkyne molecules on metal oxide surfaces.