Stepwise on-surface synthesis of nitrogen-doped porous carbon nanoribbons.

Precise synthesis of carbon-based nanostructures with well-defined structural and chemical properties is of significance towards organic nanomaterials, but remains challenging. Herein, we report on a synthesis of nitrogen-doped porous carbon nanoribbons through a stepwise on-surface polymerization. Scanning tunneling microscopy revealed that the selectivity in molecular conformation, intermolecular debrominative aryl-aryl coupling and inter-chain dehydrogenative cross-coupling determined the well-defined topology and chemistry of the final products. Density functional theory calculations predict that the ribbons are semiconductors, and the band gap can be tuned by the width of the ribbons. The atomically precise on-surface synthesis of carbon-based nanostructures is of relevance for electronic and optoelectronic devices, but achieving control over such architectures remains challenging. Here, the authors demonstrate the selective stepwise on-surface synthesis of nitrogen-doped porous carbon nanoribbons with well-defined topologies and structures, and predict variable band gaps dependent on ribbon width. [ABSTRACT FROM AUTHOR]