Porphyrin-fused graphene nanoribbons

Researchers from this department, the Department of Chemistry, the Max Planck Institute, Utrecht University, the University of Nottingham and the University of Waterloo collaborated to explain in this paper* how they created the first aromatic graphene systems to include metals (in particular, porphyrins).

Graphene nanoribbons (GNRs) are nanometre-wide strips of graphene and are also promising materials for fabricating electronic devices.  Many GNRs have been reported, yet no scalable strategies are known for synthesising GNRs with metal atoms and heteroaromatic units at precisely defined positions in the conjugated backbone, which would be valuable for tuning their optical, electronic and magnetic properties.  

The authors report the solution-phase synthesis of a porphyrin-fused graphene nanoribbon (PGNR) which had metalloporphyrins fused into a twisted fjord-edged GNR backbone.  It consisted of long chains (>100nm), with a narrow optical bandgap (~1.0 eV) and high local charge mobility (>400 cm²V^-1s^-1 by terahertz spectroscopy).  This PGNR was used to fabricate ambipolar field-effect transistors with appealing switching behaviour, and single-electron transistors which displayed multiple Coulomb diamonds.  

The results open an avenue to π-extended nanostructures with engineerable electrical and magnetic properties by transposing the coordination chemistry of porphyrins into graphene nanoribbons.

*'Porphyrin-fused graphene nanoribbons' as published by Nature Chemistry.