Introduction
Kirigami, although coined in 1962 from Japanese words kiri (meaning “cut”) and kami (meaning “paper”), is actually one of the most traditional Chinese arts (named “paper-cuts” or “jianzhi”) that has been widely used in window decorations, gift cards, festivals, ceremonies, etc., since ~1500 years ago. Through cutting and folding flat objects into 3D shapes, the knowledge of kirigami has recently aroused tremendous interests in both sciences and technologies, including deployable designs of solar arrays, biomedical devices and micro-/nano- electromechanical systems (MEMS/NEMS).
A paper-based kirigami (Chinese "pulling flower") and a focused-ion-beam based nano-kirigami.
Nano-kirigami, inspired by a traditional Chinese paper-cut named “pulling flower”, was firstly demonstrated by us in 2018. It utilizes focused ion beam (FIB) instead of knives/scissors to cut a precise pattern in a free-standing gold nanofilm, and uses the same FIB irradiation instead of hands to gradually “pull” the 2D pattern into a complex 3D shape. The “pulling” forces are induced by heterogeneous vacancies and the implanted ions within the gold nanofilm during FIB irradiation. By utilizing the topography-guided stress equilibrium, versatile 3D shape transformations such as upward buckling, downward bending, complex rotation and twisting of nanostructures have been precisely achieved. The resulted unprecedented 3D nanogeometries could enable exceptional and flexible functionalities in optical, mechanical, thermal, acoustic, electric, magnetic, and biological areas. See the Video File.
