Graphyne- and graphdiyne-like model systems have attracted much attention from many structural, theoretical, and synthetic scientists because of their promising electronic, optical, and mechanical properties, which are crucially affected by the presence, abundance and distribution of triple bonds within the nanostructures. In this work, we performed the two-step bottom-up on-surface synthesis of graphyne- and graphdiyne-based molecular wires on the Au(111). We characterized their structural and chemical properties both (UHV conditions) through STM and XPS and (in air) through Raman spectroscopy.
View Article and Find Full Text PDFThe growth of controlled 1D carbon-based nanostructures on metal surfaces is a multistep process whose path, activation energies, and intermediate metastable states strongly depend on the employed substrate. Whereas this process has been extensively studied on gold, less work has been dedicated to silver surfaces, which have a rather different catalytic activity. In this work, we present an experimental and theoretical investigation of the growth of poly--phenylene (PPP) chains and subsequent narrow graphene ribbons starting from 4,4″-dibromo--terphenyl molecular precursors deposited at the silver surface.
View Article and Find Full Text PDFCross-sectional area and volume become difficult to define as material dimensions approach the atomic scale. This limits the transferability of macroscopic concepts such as Young's modulus. We propose a new volume definition where the enclosed nanosheet or nanotube average electron density matches that of the parent layered bulk material.
View Article and Find Full Text PDFWe demonstrate that free graphene sheet edges can curl back on themselves, reconstructing as nanotubes. This results in lower formation energies than any other nonfunctionalized edge structure reported to date in the literature. We determine the critical tube size and formation barrier and compare with density functional simulations of other edge terminations including a new reconstructed Klein edge.
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