Vertically stacked van der Waals structures are promising platforms that enable layer engineering, opening new avenues for the quantum control of elementary excitations, including optically generated bound electron-hole pairs. Here we employ excited-state density functional calculations to demonstrate strong interlayer excitonic coupling in one-dimensional van der Waals nanostructures derived from armchair graphene nanoribbons. The excitonic response exhibits prominent peaks in the near-infrared range, mainly attributed to intralayer excitons, while interlayer excitations with absorption peak strengths of up to 13\% of the maximum absorption are also observed. Both type-I and type-II band alignments are found, which promote the formation of intralayer and interlayer excitons. Notably, interlayer excitons in these systems exhibit long-lived radiative lifetimes at room temperature, ranging from 1 nanosecond to 9.4 microseconds. Our calculations suggest the potential to tune the excitonic response and lifetimes of bilayer graphene nanoribbons via careful engineering of the stacking order.
@article{arxiv.2507.10887,
title = {Tunable Interlayer Excitons in Bilayer Graphene Nanoribbons},
author = {Alexandre R. Rocha and Rodrigo G. Amorim and Wanderlã L. Scopel and Cesar E. P. Villegas},
journal= {arXiv preprint arXiv:2507.10887},
year = {2025}
}