A new technique that mimics the ancient Japanese art of kirigami may offer an easier way to fabricate complex 3D nanostructures. Kirigami enhances the Japanese artform of origami — which involves folding paper to create 3D structural designs — by strategically incorporating cuts to the paper prior to folding.
Researchers used kirigami at the nanoscale to create complex 3D nanostructures that have been difficult to fabricate because current nanofabrication processes are based on the technology used to fabricate microelectronics, which only use planar, or flat, films. Without kirigami techniques, complex 3D structures would be much more complicated to fabricate or simply impossible to make.
If force is applied to a uniform structural film, nothing happens other than stretching it a bit, like what happens when a piece of paper is stretched. But when cuts are introduced to the film and forces are applied in a certain direction, a structure pops up — similar to when a kirigami artist applies force to a cut paper. The geometry of the planar pattern of cuts determines the shape of the 3D architecture.
By introducing minimum changes to the dimensions of the cuts in the film, the researchers drastically changed the 3D shape of the pop-up architectures, creating nanoscale devices that can tilt or change their curvature just by changing the width of the cuts a few nanometers.
Kirigami-style nanoengineering enables the development of machines and structures that can change from one shape to another, or morph, in response to changes in the environment. One example is an electronic component that changes shape in elevated temperatures to enable more airflow within a device to keep it from overheating. The technique will allow the development of adaptive flexible electronics that can be incorporated onto surfaces with complicated topography, such as a sensor resting on the human brain. The concepts could be used to design sensors and actuators that can change shape and configuration to perform a task more efficiently; for example, structures that can change shape with minuscule changes in temperature, illumination, or chemical conditions.
Researchers will focus on applying these kirigami techniques to materials that are one atom thick as well as thin actuators made of piezoelectrics. These 2D materials open new possibilities for applications of kirigami-induced structures; for example, generation of miniature machines that are atomically flat and are more responsive to changes in the environment.