Liquid-solid surface phase transformation of fluorinated fullerene on monolayer tungsten diselenide
Zheng, Yu Jie
Huang, Yu Li
Thye Shen Wee, Andrew
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractHybrid van der Waals heterostructures constructed by the integration of organic molecules and two-dimensional (2D) transition metal dichalcogenide (TMD) materials have useful tunable properties for flexible electronic devices. Due to the chemically inert and atomically smooth nature of the TMD surface, well-defined crystalline organic films form atomically sharp interfaces facilitating optimal device performance. Here, the surface phase transformation of the supramolecular packing structure of fluorinated fullerene (C60F48) on single-layer tungsten diselenide (WSe2) is revealed by low-temperature scanning tunneling microscopy, from thermally stable liquid to solid phases as the coverage increases. Statistical analysis of the intermolecular interaction potential reveals that the repulsive dipole-dipole interaction induced by interfacial charge transfer and substrate-mediated interactions play important roles in stabilizing the liquid C60F48 phases. Theoretical calculations further suggest that the dipole moment per C60F48 molecule varies with the surface molecule density, and the liquid-solid transformation could be understood from the perspective of the thermodynamic free energy for open systems. This study offers insights into the growth behavior at 2D organic/TMD hybrid heterointerfaces.
CitationSong Z, Wang Q, Li M-Y, Li L-J, Zheng YJ, et al. (2018) Liquid-solid surface phase transformation of fluorinated fullerene on monolayer tungsten diselenide. Physical Review B 97. Available: http://dx.doi.org/10.1103/PhysRevB.97.134102.
SponsorsA.T.S.W. acknowledges financial support from MOE AcRF Tier 1 Grant No. R-144-000-321-112 and the Graphene Re- search Centre. Y.L.H. and D.C. acknowledge the A-STAR SERC grant support for the 2D Growth Project under the 2D Pharos Program (SERC 1527000012). Calculations were performed on the Graphene Research Centre cluster supported by Prof. Su Ying Quek.
PublisherAmerican Physical Society (APS)
JournalPhysical Review B