Probing optical excitations in chevron-like armchair graphene nanoribbons

TL;DR

This study investigates optical excitations in chevron-like armchair graphene nanoribbons, revealing that their excited states are dominated by strongly bound excitons, with spectral signatures tracing their fabrication process.

Contribution

It provides the first detailed analysis of excitonic properties in chevron GNRs using combined spectroscopic techniques and ab-initio simulations.

Findings

Excited states in chevron GNRs are dominated by strongly bound excitons.

Spectral fingerprints can track the fabrication stages of GNRs.

Spectroscopy and simulations confirm exciton build-up during synthesis.

Abstract

The bottom-up fabrication graphene nanoribbons (GNRs) has opened new opportunities to specifically control their electronic and optical properties by precisely controlling their atomic structure. Here, we address excitations in GNRs with periodic structural wiggles, so-called Chevron GNRs. Based on reflectance difference and high-resolution electron energy loss spectroscopies together with ab-initio simulations, we demonstrate that their excited-state properties are dominated by strongly bound excitons. The spectral fingerprints corresponding to different reaction stages in their bottom-up fabrication are also unequivocally identified, allowing us to follow the exciton build-up from the starting monomer precursor to the final ribbon structure.