preparation-and-characterization-of-c60graphene-hybrid-nanostructures

Preparation and Characterization of C<sub>60</sub>/Graphene Hybrid Nanostructures

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We ...

Virginia Tech

We report the preparation of novel quasi-one-dimensional (quasi-1D) C60 nanostructures on rippled graphene. Through careful control of the subtle balance between the linear periodic potential of rippled graphene and the C60 surface mobility, we demonstrate that C60 molecules can be arranged into a quasi-1D C60 chain structure with widths of two to three molecules. At a higher annealing temperature, the quasi-1D chain structure transitions to a more compact hexagonal close packed quasi-1D stripe structure. This first experimental realization of quasi-1D C60 structures on graphene may pave a way for fabricating new C60/graphene hybrid structures for future applications in electronics, spintronics and quantum information. 

Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene.

In this work we report fabrication and characterization of phenyl-C61-butyric acid methyl ester (PCBM) bilayer structures on graphene and highly oriented pyrolytic graphite (HOPG). Through careful control of the PCBM solution concentration (from 0.1 to 2 mg ml) and the deposition conditions, we demonstrate that PCBM molecules self-assemble into bilayer structures on graphene and HOPG substrates. Interestingly, the PCBM bilayers are formed with two distinct heights on HOPG, but only one unique representative height on graphene. At elevated annealing temperatures, edge diffusion allows neighboring vacancies to merge into a more ordered structure. This is, to the best of our knowledge, the first experimental realization of PCBM bilayer structures on graphene. This work could provide valuable insight into fabrication of new hybrid, ordered structures for applications to organic solar cells.

Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM.

To ensure practical applications of atomically thin transition metal dichalcogenides, it is essential to characterize their structural stability under external stimuli such as electric fields and currents. Using vacancy monolayer islands on TiSe surfaces as a model system, we have observed nonlinear area evolution and growth from triangular to hexagonal driven by scanning tunneling microscopy (STM) subjected electrical stressing. The observed growth dynamics represent a 2D departure from the linear area growth law expected for bulk vacancy clustering. Our simulations of monolayer island evolution using phase-field modeling and first-principles calculations are in good agreement with our experimental observations, and point toward preferential edge atom dissociation under STM scanning driving the observed nonlinear area growth. We further quantified a parabolic growth rate dependence with respect to the tunneling current magnitude. The results could be potentially important for device reliability in systems containing ultrathin transition metal dichalcogenides and related 2D materials subject to electrical stressing.

Article	Year
Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene. Scientific reports\| PubMed ID: 26391054	2015
Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM. Nanotechnology\| PubMed ID: 29451137	2018
Electrical Stressing Induced Monolayer Vacancy Island Growth on TiSe. Nano letters\| PubMed ID: 29461061	2018

Chuanhui Chen

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