Understanding the wetting of transition metal dichalcogenides from an ab initio perspective

Abstract

Transition metal dichalcogenides (TMDs) are a class of two-dimensional (2D) materials that have been widely studied for emerging electronic properties. In this paper, we use computational simulations to examine the water adsorption on TMDs systematically and the wetting property of tungsten diselenide ) specifically. We start with density functional theory (DFT) based random phase approximation (RPA), assessing the performance of exchange-correlation functionals and comparing water adsorption on various TMDs. We also perform ab initio molecular dynamics (AIMD) simulations on WSe_{2}, from which we find that the distribution of interfacial water is sensitive to the exchange-correlation functional selected and a reasonable choice leads to a diffusive contact layer where water molecules prefer the “flat” configuration. Classical molecular dynamics (MD) simulations of water droplets on surfaces using appropriately parameterized water-surface interaction further confirm the dependence of water contact angle on the interaction and the interfacial water structure reproduced by different DFT functionals. Our study highlights the sensitivity of wetting to the water-substrate interaction and provides a starting point for a more accurate theoretical investigation of water-TMD interfaces.