Structurally Driven Environmental Degradation of Friction in MoS2 Films

AbstractWe report an investigation of the friction mechanisms of MoS2 thin films under changing environments and contact conditions using a variety of computational and experimental techniques. Molecular dynamics simulations were used to study the effects of water and molecular oxygen on friction and bonding of MoS2 lamellae during initial sliding. Characterization via photoelectron emission microscopy (PEEM) and Kelvin probe force microscopy (KPFM) were used to determine work function changes in shear modified material within the top few nanometers of MoS2 wear scars. The work function was shown to change with contact conditions and environment, and shown by density functional theory (DFT) calculations and literature reports to be correlated with lamellae size and thickness of the basally oriented surface layer. Results from nanoscale simulations and macroscale experiments suggest that the evolution of the friction behavior of MoS2 is linked primarily to the formation or inhibition of a basally oriented, molecularly thin surface film with long-range order.

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Variations in the work function of doped single- and few-layer graphene assessed by Kelvin probe force microscopy and density functional theory

Physical Review B ◽

10.1103/physrevb.83.235434 ◽

2011 ◽

Vol 83 (23) ◽

Cited By ~ 141

Author(s):

D. Ziegler ◽

P. Gava ◽

J. Güttinger ◽

F. Molitor ◽

L. Wirtz ◽

...

Keyword(s):

Density Functional Theory ◽

Work Function ◽

Density Functional ◽

Kelvin Probe Force Microscopy ◽

Kelvin Probe ◽

Functional Theory ◽

Force Microscopy ◽

Layer Graphene ◽

Few Layer Graphene

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Stress dependence of the suspended graphene work function: Vacuum Kelvin probe force microscopy and density functional theory

Applied Physics Letters ◽

10.1063/1.4982931 ◽

2017 ◽

Vol 110 (19) ◽

pp. 193101 ◽

Cited By ~ 4

Author(s):

A. Volodin ◽

C. Van Haesendonck ◽

O. Leenaerts ◽

B. Partoens ◽

F. M. Peeters

Keyword(s):

Density Functional Theory ◽

Work Function ◽

Density Functional ◽

Kelvin Probe Force Microscopy ◽

Stress Dependence ◽

Kelvin Probe ◽

Functional Theory ◽

Suspended Graphene ◽

Force Microscopy

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Scanning Kelvin Probe Force Microscopy and Density Functional Theory Studies on the Surface Potential of the Intermetallics in AA7075-T6 Alloys

Journal of Materials Engineering and Performance ◽

10.1007/s11665-019-04160-6 ◽

2019 ◽

Vol 28 (7) ◽

pp. 4289-4301 ◽

Cited By ~ 2

Author(s):

Ni Li ◽

Chaofang Dong ◽

Xin Wei ◽

Chen Man ◽

Jizheng Yao ◽

...

Keyword(s):

Density Functional Theory ◽

Surface Potential ◽

Density Functional ◽

Kelvin Probe Force Microscopy ◽

Kelvin Probe ◽

Functional Theory ◽

Force Microscopy ◽

Scanning Kelvin Probe

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Use of energy-filtered photoelectron emission microscopy and Kelvin probe force microscopy to visualise work function changes on diamond thin films terminated with oxygen and lithium mono-layers for thermionic energy conversion

International Journal of Nanotechnology ◽

10.1504/ijnt.2014.063789 ◽

2014 ◽

Vol 11 (9/10/11) ◽

pp. 796 ◽

Cited By ~ 2

Author(s):

H.D. Andrade ◽

M.Z. Othman ◽

K.M. O' ◽

N.A. Donnell ◽

J.H. Lay ◽

...

Keyword(s):

Thin Films ◽

Energy Conversion ◽

Work Function ◽

Kelvin Probe Force Microscopy ◽

Kelvin Probe ◽

Photoelectron Emission ◽

Force Microscopy ◽

Emission Microscopy ◽

Thermionic Energy Conversion ◽

Thermionic Energy

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Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.12.35 ◽

2021 ◽

Vol 12 ◽

pp. 432-439

Author(s):

Zhao Liu ◽

Antoine Hinaut ◽

Stefan Peeters ◽

Sebastian Scherb ◽

Ernst Meyer ◽

...

Keyword(s):

Density Functional ◽

Kelvin Probe ◽

Functional Theory ◽

Double Line ◽

Force Microscopy ◽

Atomic Force ◽

Local Charge ◽

Charge Displacement ◽

Work Functions ◽

The Difference

A novel reconstruction of a two-dimensional layer of KBr on an Ir(111) surface is observed by high-resolution noncontact atomic force microscopy and verified by density functional theory (DFT). The observed KBr structure is oriented along the main directions of the Ir(111) surface, but forms a characteristic double-line pattern. Comprehensive calculations by DFT, taking into account the observed periodicities, resulted in a new low-energy reconstruction. However, it is fully relaxed into a common cubic structure when a monolayer of graphene is located between substrate and KBr. By using Kelvin probe force microscopy, the work functions of the reconstructed and the cubic configuration of KBr were measured and indicate, in accordance with the DFT calculations, a difference of nearly 900 meV. The difference is due to the strong interaction and local charge displacement of the K+/Br− ions and the Ir(111) surface, which are reduced by the decoupling effect of graphene, thus yielding different electrical and mechanical properties of the top KBr layer.

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Graphene adlayer growth between nonepitaxial graphene and Ni(111) substrate: a promising theoretical scheme

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04667a ◽

2020 ◽

Author(s):

Lijuan Meng ◽

Jinlian Lu ◽

Yujie Bai ◽

Lili Liu ◽

Tang Jingyi ◽

...

Keyword(s):

Molecular Dynamics ◽

Density Functional Theory ◽

Chemical Vapor Deposition ◽

Molecular Dynamics Simulations ◽

Vapor Deposition ◽

Density Functional ◽

Chemical Vapor ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

Dynamics Simulations

Understanding the fundamentals of chemical vapor deposition bilayer graphene growth is crucial for its synthesis. By employing density functional theory calculations and classical molecular dynamics simulations, we have investigated the...

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H2 Transformations on Graphene Supported Palladium Cluster: DFT-MD Simulations and NEB Calculations

Catalysts ◽

10.3390/catal10111306 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1306

Author(s):

Francesco Ferrante ◽

Antonio Prestianni ◽

Marco Bertini ◽

Dario Duca

Keyword(s):

Atomic Hydrogen ◽

Density Functional ◽

Hydrogen Molecule ◽

Md Simulations ◽

Vacant Site ◽

Functional Theory ◽

H2 Adsorption ◽

Palladium Cluster ◽

Supported Palladium ◽

Dynamics Simulations

Molecular dynamics simulations based on density functional theory were employed to investigate the fate of a hydrogen molecule shot with different kinetic energy toward a hydrogenated palladium cluster anchored on the vacant site of a defective graphene sheet. Hits resulting in H2 adsorption occur until the cluster is fully saturated. The influence of H content over Pd with respect to atomic hydrogen spillover onto graphene was investigated. Calculated energy barriers of ca. 1.6 eV for H-spillover suggest that the investigated Pd/graphene system is a good candidate for hydrogen storage.

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