Graphene and MoS2 adhesion to metallic surfaces by a high throughput first principles approach

Friction and wear happening at the sliding interface of mechanical components strongly influence their performance, effectiveness, and longevity. 2D materials play a crucial role as solid lubricants in reducing friction and wear in mechanical systems. Their importance arises from their unique structural properties: their strong inter-layer covalent bonds and weak interlayer vdW interaction enable low friction sliding and high chemical stability. The degree of adhesion between 2D-materials and metallic substrates is essential for the 2D material to work as solid lubricant. A balance must be achieved: the strength of the 2D material's binding to the substrate should keep the lubricant stably attached, at the same time, the 2D/substrate interaction should not compromise the chemical inertness of the 2D layer. Graphene and MoS2 prototypes were chosen as model systems due to their well-established roles as solid lubricants and inherent different nature. The main objectives of the thesis are two-fold: on one side assessing the reliability of the computationally affordable, PBE-D3 scheme for an automatized study of 2D-metal interfaces, secondly to identify the main factors that come into play in determining the strength of metal 2D-adhesion. We performed calculations within TribChem, an advanced software for the automatized ab-initio calculations of tribological properties of solid interfaces recently developed within our group. D3 showed its reliability starting from the bulk results, to the description of metal 2D adhesion yielding results in close agreement with RPA results. The analysis of metal/graphene and metal/MoS2 interfaces show how the factors that dictate adhesion are multiple: as expected the chemistry of the interface, namely the 2D material and the nature of the metals play a major role, at the same time, the superlattice geometry, which dictates the local atomic configurations, further modulates the adhesion values enhancing or reducing it.