Graphene Nanoribbons by Chemists: Nanometer-Sized, Soluble, and Defect-Free

摘要

Structural perfection is of key importance in the synthesis of graphene nanoribbons (GNRs), since there is a fundamental connection between the electrical properties and the width, the edge periphery, and the occurrence of defects.Graphene itself is a zero-band-gap semimetal, whereas GNRs with a width smaller than 10 nm show semiconducting behavior that renders them suitable active materials for electronic devices. A considerable longitudinal extension would enable ready processing and device fabrication with single ribbons. The synthetic challenge is the preparation of such defined graphene structures with high aspect ratios (length/width) that until now could not be attained by physical methods. Top-down approaches (Figure 1), such as the reduction of graphite oxide, lithography, the unzipping of carbon nanotubes, or the mechanical exfoliation of graphene,-have so far lacked any means of control over the size and edge structure of the resulting products' and have thus led to poorly defined graphene materials.