Interfacial Coupling Controls Molecular Epitaxy of HMTP on Graphene/SiC

Interfacial Coupling Controls Molecular Epitaxy of HMTP on Graphene/SiC

Článek WoS

Epitaxial growth critically influences the structural and electronic properties of organic semiconductors. Graphene serves as a prominent van der Waals template for molecular self-assembly; however, graphene on SiC is intrinsically heterogeneous, with decoupled monolayer graphene coexisting with residuals of a covalently bound buffer layer, which may affect molecular ordering. Here, we track the ordering of the molecular donor, 2,3,6,7,10,11-hexamethoxytriphenylene (HMTP), from the first layer to thin films, combining low-energy electron microscopy and diffraction with X-ray diffraction. HMTP forms highly ordered epitaxial layers on single-layer graphene, whereas growth on the buffer layer initiates as amorphous and evolves into polycrystalline films with weak orientation with respect to the substrate. Crucially, hydrogen intercalation decouples the buffer layer, converting it into quasi-freestanding monolayer graphene and restoring epitaxial growth. These findings demonstrate that interfacial coupling governs molecular epitaxy on graphene/SiC, and interface engineering via hydrogen intercalation provides a scalable route to control organic thin-film crystallinity on graphene.

Epitaxial growth critically influences the structural and electronic properties of organic semiconductors. Graphene serves as a prominent van der Waals template for molecular self-assembly; however, graphene on SiC is intrinsically heterogeneous, with decoupled monolayer graphene coexisting with residuals of a covalently bound buffer layer, which may affect molecular ordering. Here, we track the ordering of the molecular donor, 2,3,6,7,10,11-hexamethoxytriphenylene (HMTP), from the first layer to thin films, combining low-energy electron microscopy and diffraction with X-ray diffraction. HMTP forms highly ordered epitaxial layers on single-layer graphene, whereas growth on the buffer layer initiates as amorphous and evolves into polycrystalline films with weak orientation with respect to the substrate. Crucially, hydrogen intercalation decouples the buffer layer, converting it into quasi-freestanding monolayer graphene and restoring epitaxial growth. These findings demonstrate that interfacial coupling governs molecular epitaxy on graphene/SiC, and interface engineering via hydrogen intercalation provides a scalable route to control organic thin-film crystallinity on graphene.

molecular epitaxy, graphene/SiC, interfacialcoupling, X-ray diffraction, low-energy electronmicroscopy

molecular epitaxy, graphene/SiC, interfacialcoupling, X-ray diffraction, low-energy electronmicroscopy

VARSHNEY, D.; PROCHÁZKA, P.; STARÁ, V.; SHESTOPALOV, M.; KUNC, J.; NOVÁK, J.; ČECHAL, J.

29.04.2026

Amer Chemical Soc

ACS Applied Materials & Interfaces

18

16

Spojené státy americké

23839

23847

9

https://pubs.acs.org/doi/10.1021/acsami.6c03070?src=getftr&utm_source=clarivate&getft_integrator=clarivate