Crack-assisted, localized deformation of van der Waals materials for enhanced strain confinement

Abstract

The crumpling of two-dimensional (2D) materials is one of the most widely used ways to create three-dimensional (3D) out-of-plane structures from 2D materials and to apply in-plane strain for strain-induced material property modulation. Although the elastic compressive strain induced crumpling of 2D materials is a simple and versatile way to form 3D structures, the resulting structures are rather simple where crumples are formed in a delocalized manner. Here, we report a new approach inspired by crack lithography to localize deformation and achieve localized crumpling of 2D materials. As a result, a mixed-dimensional structure composed of flat (2D) and crumpled (3D) structure is formed monolithically in 2D materials. We present structural analysis of our mixed-dimensional structure of graphene, where the localized prestrain was amplified to be 330% of the macroscale prestrain. In addition, we demonstrate the material densification and the strain localizations of our mixed-dimensional structure of monolayer MoS 2 and graphene based on Raman and photoluminescence spectral characterizations. Finally, our mixed-dimensional graphene structure is fabricated into a stretchable strain sensor, where it exhibits four times enhanced gauge factor compared to that of delocalized crumpled graphene.

Disordered Heteronanostructures of MoS2 and TiO2 for Unclonable Cryptographic Primitives

“…The height of MoS 2 nanoflakes is optimized to maximize the PL intensity at the emission wavelength (λ em = 655 nm) (Figure S2). Vertically oriented MoS 2 nanoflakes have relatively high PL emission originating from the inherently distinctive structures (e.g., defect, strain, and densification), − even though it is composed of multilayers. The strongest PL signal of disordered MoS 2 nanoflakes with a height of 250 nm can be attributed to mono- or bilayers of MoS 2 optimally formed in the edge of nanoflakes (Figure S1a).…”

Stretchable Graphene Thin Film Enabled Yarn Sensors with Tunable Piezoresistivity for Human Motion Monitoring

“…For another, it is lacking of a systematic work investigating the structure dependent sensitivity, deformability, and reliability, which is crucial for unveiling the sensing mechanism. With effective capability to alter and control different microscopic features such as micro-cracks 36 , wrinkles 37 , and packing densities 35 , the pre-stretch process has already become a commonly-applied strategy to tune the performance of varied nanocarbon sensors, including processing efficiency 38 , mechanical/electrical stability 39 , as well as sensing sensitivity 37 . Following this line of thought, the application of pre-stretch toward the understanding of process dependent sensing property and mechanism for the unique graphene enabled smart yarn is highly significant.…”

Hierarchical Nanoscale Structuring of Solution-Processed 2D van der Waals Networks for Wafer-Scale, Stretchable Electronics

“…17−21 These three-dimensional (3D) structures accommodate tensile strain until they completely flatten, thereby enabling the entire area of 2D semiconductors to be stretched beyond their intrinsic fracture limit without cracking. 21,22 In addition, λ and A can also be changed reversibly to enable facile tuning of the physical properties of 2D semiconductors via external strain. 18,21,22 Achieving strain-independent functional responses is also important for wearable transistors and photodetectors, but maintaining a constant device output remains challenging.…”