Electronic Structure of Isolated Graphene Nanoribbons in Solution Revealed by Two-Dimensional Electronic Spectroscopy

Research output: Contribution to journalResearch articleContributedpeer-review


  • Tetsuhiko Nagahara - , Polytechnic University of Milan, Kyoto Institute of Technology (Author)
  • Franco V.A. Camargo - , National Research Council of Italy (CNR) (Author)
  • Fugui Xu - , Shanghai Jiao Tong University (Author)
  • Lucia Ganzer - , Polytechnic University of Milan (Author)
  • Mattia Russo - , Polytechnic University of Milan (Author)
  • Pengfei Zhang - , Shanghai Jiao Tong University (Author)
  • Antonio Perri - , Polytechnic University of Milan (Author)
  • Gabriel de la Cruz Valbuena - , Polytechnic University of Milan (Author)
  • Ismael A. Heisler - , Universidade Federal do Paraná (Author)
  • Cosimo D’Andrea - , Polytechnic University of Milan (Author)
  • Dario Polli - , Polytechnic University of Milan (Author)
  • Klaus Müllen - , Max Planck Institute for Polymer Research (Author)
  • Xinliang Feng - , Chair of Molecular Functional Materials (cfaed) (Author)
  • Yiyong Mai - , Shanghai Jiao Tong University (Author)
  • Giulio Cerullo - , Polytechnic University of Milan, National Research Council of Italy (CNR) (Author)


Structurally well-defined graphene nanoribbons (GNRs) are nanostructures with unique optoelectronic properties. In the liquid phase, strong aggregation typically hampers the assessment of their intrinsic properties. Recently we reported a novel type of GNRs, decorated with aliphatic side chains, yielding dispersions consisting mostly of isolated GNRs. Here we employ two-dimensional electronic spectroscopy to unravel the optical properties of isolated GNRs and disentangle the transitions underlying their broad and rather featureless absorption band. We observe that vibronic coupling, typically neglected in modeling, plays a dominant role in the optical properties of GNRs. Moreover, a strong environmental effect is revealed by a large inhomogeneous broadening of the electronic transitions. Finally, we also show that the photoexcited bright state decays, on the 150 fs time scale, to a dark state which is in thermal equilibrium with the bright state, that remains responsible for the emission on nanosecond time scales.


Original languageEnglish
Pages (from-to)797-804
Number of pages8
JournalNano letters
Issue number3
Publication statusPublished - 24 Jan 2024

External IDs

PubMed 38189787



  • graphene nanoribbons, inhomogeneous broadening, two-dimensional electronic spectroscopy, ultrafast spectroscopy, vibronic coupling