Humidity-Controlled Dynamic Engineering of Buckling Dimensionality in MoS2 Thin Films

Abstract

Dynamic engineering of buckling deformation is of vital importance as it provides multiphase modulation of thin film devices. In particular, dynamic switch of buckles between one-dimensional (1D) and two-dimensional (2D) configurations in a single film system on rigid substrates is intriguing but very challenging. The current approach to changing buckling configuration is mainly achieved by varying the built-in stress at the film-substrate interface, but it is difficult to realize dynamic engineering on rigid substrates. Herein, we report a dynamic engineering of buckling deformation in MoS2 thin films by humidity-tuned interfacial adhesion. With the change of humidity, the MoS2 thin films deform from 1D telephone-cord buckles to 2D web-like buckles due to the hydrophilic nature of both MoS2 and substrate. Such 1D-to-2D evolution of buckles is attributed to the weakened interfacial adhesion of mixed deformation modes induced by humidity, which is verified by finite-element modeling. These buckled films further find potential applications as patterned templates for liquid condensation and sensing units for tactile sensors. Our work not only demonstrates the humidity-controlled dimensionality engineering of buckles in MoS2 thin films but also sheds light on the functional applications of buckled films based on their profile features.