Self‐Assembly of Large Nanographene Into Ordered Structures on Au(111)

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) offer a unique platform for bridging molecular design and nanoscale functionality owing to their tunable structures. Beyond their intrinsic electronic properties, PAHs exhibit significant potential for directed self‐assembly, enabling the formation of ordered nanostructures with tailored functionalities. Here, we report the on‐surface self‐assembly of quantum dot‐like nanostructures and nanoribbons from two closely related PAH molecules, C₉₆H 2 4 (C₁ 2 H 2 5 )₆ (C96‐A) and C₉₆H 3 ₀ (C96), deposited on Au(111) via molecular beam epitaxy. Scanning tunneling microscopy and spectroscopy (STM/STS) reveal a structural evolution from ordered single molecules to extended nanoribbons, with the latter exhibiting a narrow electronic bandgap of 0.8 eV. X‐ray photoelectron spectroscopy (XPS) indicates a single carbon chemical environment, while near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy confirms a flat‐lying molecular orientation. Density functional theory (DFT) calculations corroborate the experimental findings and provide insight into the self‐assembly mechanisms. These results highlight the potential of engineered PAHs for the bottom‐up fabrication of nanoscale electronic materials.