Year: 2026
Type: preprint
Abstract: Atomically precise graphene nanoribbons (GNRs) exhibit tunable electronic and magnetic properties governed by edge topology and finite-size effects, which make them versatile platforms for next-generation electronic and spintronic applications. However, the unpaired pi-electrons responsible for their magnetic properties simultaneously make them highly susceptible to chemical degradation under ambient conditions. This intrinsic reactivity poses a central experimental challenge: accessing vibrational and electronic signatures of air-sensitive GNRs during synthesis and under controlled environments without breaking vacuum. Once the material has been exposed to air, standard characterization techniques would probe oxidized or chemically modified species rather than the pristine form. Here, we overcome this limitation by developing a home-built ultra-high vacuum (UHV) Raman platform designed to preserve sample integrity by preventing air exposure and to enable in situ investigation of material properties. The portable Raman vacuum suitcase (RVS) integrates temperature control and precise gas dosing, allowing direct monitoring of growth kinetics, lattice dynamics, and reactive-edge responses under well-defined thermal and chemical environments. Using this platform, we monitor the on-surface synthesis of 7- and 9-atom-wide armchair GNRs (7- and 9-AGNRs), quantify the evolution of 7-AGNR Raman modes over a wide temperature range (162-748 K), and resolve chemical changes upon controlled O2 exposure that are consistent with oxidation at the reactive zigzag sites. These results establish UHV Raman spectroscopy with the RVS as a route to accessing the intrinsic vibrational signatures of low-dimensional quantum materials under controlled environments.
Source: arXiv (Cornell University)
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: Graphene Flagship, European Commission, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Eidgenössische Technische Hochschule Zürich, Centro Svizzero di Calcolo Scientifico, HORIZON EUROPE Framework Programme, Staatssekretariat für Bildung, Forschung und Innovation, National Center of Competence in Research Materials’ Revolution: Computational Design and Discovery of Novel Materials
Awards: G1115220305, G1414291015, Three-terminal particle-exchange heat engines for efficient energy conversion at the nanoscale, G2115222242, G3482134774, G3615212929, NCCR MARVEL: Materials’ Revolution: Computational Design and Discovery of Novel Materials (phase III), Graphene nanoRibbons as Atomically controlled Light sources (Graal), On-surface synthesis of carbon-based quantum spin systems (SYNC), Graphene Flagship Core Project 3, G6200526706, G9000371698
OpenAlex ID: W7214757206