Excitonic emission from atomically precise graphene nanoribbons (GNRs) synthesised on a metal surface is probed with atomic-scale spatial resolution using a scanning tunneling microscopy (STM) approach. A STM-based strategy to transfer the GNRs to a partially insulating surface is used to prevent light emission quenching of the ribbons by the metal substrate. Sub-nanometer resolved STM-induced fluorescence spectra reveal emission from localized dark excitons build upon the topological end states of the GNRs. A low frequency vibronic emission comb whose characteristics change with the GNR length is attributed to longitudinal acoustic modes confined to a finite box. Overall, our study provides a novel path to investigate the interplay between excitons, vibrons and topology in atomically precise graphene nanostructures.
@article{arxiv.2209.01471,
title = {Topologically localized excitons in single graphene nanoribbons},
author = {Song Jiang and Tomas Neuman and Alex Boeglin and Fabrice Scheurer and Guillaume Schull},
journal= {arXiv preprint arXiv:2209.01471},
year = {2023}
}