Shaping and structuring 2D materials via kirigami and origami

Two-dimensional (2D) materials such as graphene and molybdenum disulfide et al. offer significant new prospects for electronics, optics, and biosensing applications due to their unique physical and chemical properties. The controlled manipulation of such materials to create three-dimensional (3D) architectures is an intriguing approach to favorably tuning their properties and creating new types of 3D devices with small form factors. However, 2D materials exhibit extremely low bending stiffnesses compared with traditional functional materials, therefore, it is rather challenging to obtain stable 3D structures under van der Waals (vdW) interaction despite the easier out-of-plane manipulation. The centuries-old paper-shaping techniques named as ‘kirigami’ and ‘origami’ may provide a potential solution to this deadlock. The general idea is that through pre-patterning and mechanical deformations, 2D materials can be reshaped and transformed into 3D structures on demand, which extends the application of kirigami/origami from conventional functional films to atomically thin nanosheets. This kind of shaping and structuring strategy not only integrates 2D materials with 3D micro/nano-structures in a controllable manner, but also offers a new paradigm for tailoring the properties of 2D materials, thus enabling more functions beyond the capability of planar geometry. Such 3D micro/nano-architectures containing engineered 2D materials can provide a platform to explore the frontier physics and produce micro/nano-devices with improved performance or unprecedented functionalities. Hence, it is necessary to review the recent progress in this emerging field, which combines the exemplary kirigami/origami strategy with promising 2D materials to increasingly inspire the multidisciplinary applications. This review focuses on 2D materials kirigami/origami, including intrinsic and engineered properties, mechanisms, methods and applications. The research challenges and opportunities are also discussed to promote future theoretical and technological studies in this blooming interdisciplinary field.