# Electronic Structure Evolution during the Growth of Graphene Nanoribbons on Au(110)

## TL;DR

This study investigates the electronic structure changes during the formation of graphene nanoribbons on Au(110) using photoemission and DFT, revealing how molecular states evolve and interact with the substrate.

## Contribution

It provides detailed insights into the molecular orbital evolution and energy level alignment during GNR growth on Au(110), combining experimental and theoretical approaches.

## Key findings

- Identification of spectral fingerprint of C-Au interaction in precursors and polymers
- GNRs exhibit stronger interaction with Au(110) than precursors due to flatter conformation
- Evolution of molecular states from monomers to GNRs elucidated

## Abstract

Surface-assisted polymerization of molecular monomers into extended chains can be used as the seed of graphene nanoribbon (GNR) formation, resulting from a subsequent cyclo-dehydrogenation process. By means of valence-band photoemission and ab-initio density-functional theory (DFT) calculations, we investigate the evolution of molecular states from monomer 10,10'-dibromo-9,9'bianthracene (DBBA) precursors to polyanthryl polymers, and eventually to GNRs, as driven by the Au(110) surface. The molecular orbitals and the energy level alignment at the metal-organic interface are studied in depth for the DBBA precursors deposited at room temperature. On this basis, we can identify a spectral fingerprint of C-Au interaction in both DBBA single-layer and polymerized chains obtained upon heating. Furthermore, DFT calculations help us evidencing that GNRs interact more strongly than DBBA and polyanthryl with the Au(110) substrate, as a result of their flatter conformation.