Self-Assembly of MoS2 Monolayer Sheets by Desulfurization

PQ Cao and JY Wu, LANGMUIR, 37, 4971-4983 (2021).

DOI: 10.1021/acs.langmuir.1c00369

Self-assembled structures of two-dimensional (2D) materials exhibit novel physical properties distinct from those of their parent materials. Herein, the critical role of desulfurization on the self-assembled structural morphologies of molybdenum disulfide (MoS2) monolayer sheets is explored using molecular dynamics (MD) simulations. MD results show that there are differences in the atomic energetics of MoS2 monolayer sheets with different desulfurization contents. Both free-standing and substrate-hosted MoS2 monolayer sheets show diversity in structural morphologies, for example, flat plane structures, wrinkles, nano-tubes, and folds, depending on the desulfurization contents, planar dimensions, and ratios of length to width of MoS2 sheets. Particularly, at the critical desulfurization content, they can roll up into nanotubes, which is in good agreement with previous experimental observations. Importantly, these observed differences in the molecular structural morphologies between free-standing and substrate-hosted MoS2 monolayer sheets can be attributed to interatomic interactions and interlayer van der Waals interactions. Furthermore, MD results have demonstrated that the surface-driven stability of MoS2 structures can be indicated by the desulfurization contents on one surface of MoS2 monolayer sheets, and the self-assembly of MoS2 monolayer sheets by desulfurization can emerge to adjust their surface-driven stability. The study provides important atomic insights into tuning the self-assembling structural morphologies of 2D materials through defect engineering in the future science and engineering applications.