Superlubricity of a graphene/MoS₂ heterostructure: a combined experimental and DFT study

Abstract

Graphene and other two-dimensional materials have been proved to be able to offer low friction. Here we assembled van der Waals heterostructures with graphene and molybdenum disulphide monolayers. The Raman spectrum together with a modified linear chain model indicate a two-orders-of-magnitude decrease in the interlayer lateral force constant, as compared with their homogeneous bilayers, indicating a possible routine to achieve superlubricity. The decrease in the interlayer lateral force constant is consistent with the ultrasmall potential energy corrugation during sliding, which is derived from density functional theory calculations. The potential energy corrugation is found to be determined by the sliding-induced interfacial charge density fluctuation, suggesting a new perspective to understand the physical origin of the atomic scale friction of two-dimensional materials.

The Atomic and Electronic Structure of 0° and 60° Grain Boundaries in MoS2

“…The ultraflat surfaces of graphite and MoS2 may lead to ultralow friction between them, which should facilitate the sliding. [41][42][43] As demonstrated by darker contrasts in the STM image, even though GB-0° has a well-stitched structure, the local electronic structure at GB-0° is different from that of its peripheral places. To see the differences in the electronic structures, we carried out STS and dI/dV mapping to visualize the local density of states.…”

Theoretical study of superlubric nanogenerators with superb performances

“…These advances make superlubric nanogenerators (SLNGs) feasible. In this Letter we demonstrate that SSL technology [7][8][9][10][11]22 provides a revolutionary approach to invent nanogenerators with superb performances and enduring lifespans.…”

Structural Superlubricity Based on Crystalline Materials

“…The crystalline materials discussed include but not limited to 2D materials. Generally, structural superlubric contacts can be divided into homogeneous (graphite/graphite, MoS 2 /MoS 2 , carbon nanotube/carbon nanotube) and heterogeneous (W/Si, Sb/graphite, Sb/MoS 2 , gold/graphite, graphite/MoS 2 , graphite/hexagonal boron nitride) contacts ( Figure ). This kind of friction reduction scheme is one of the most interesting concepts in modern tribology .…”

“…Copyright 2017, Macmillan Publishers Ltd; 2018 Reproduced with permission . Copyright 2018, American Chemical Society; 2017 Reproduced with permission . Copyright 2017, Royal Society of Chemistry; 2018 Reproduced with permission .…”