Programming Shape, Composition Patterns and Dynamics of 2D Transition Metal Dichalcogenide Alloys*

The properties of 2D materials can be tuned through alloying and phase and strain engineering. I will present a novel approach, combining phase/strain engineering with shape programming, to form 3D objects by patterned alloying of 2D transition metal dichalcogenide (TMD) monolayers. Conjugately, monolayers can be compositionally patterned using non-flat substrates. For concreteness, we focus on the TMD alloy MoSe_2cS_2(1-c); i.e., MoSeS. These 2D materials down-scale shape/composition programming to nanoscale objects/patterns, provide control of both bending and stretching deformations, are reversibly actuatable with electric fields, and possess the extraordinary and diverse properties of TMDs. Utilizing a first principles-informed continuum model, we demonstrate how a variety of shapes/composition patterns can be programmed and reversibly modulated across length scales. I will also demonstrate the mechanical actuation of 2D TMD alloy films through application of electric fields.