Soft Plasmene Helical Nanostructures

Abstract

AbstractPlasmene is recently defined as 2D arrays of plasmonic nanoparticles, which could be fabricated by the bottom‐up self‐assembly approach and demonstrated a wide range of applications in sensing, energy harvesting, nanophotonics and encryption. Herein, this work further demonstrates a 3D helical plasmonic nanostructures that can be fabricated from 2D plasmene nanosheet. Inspired by chocolate curls‐making process, a micro‐spatula‐based strategy is developed to selectively scrape substrate‐supported plasmene to free space, which spontaneously folds the plasmene nanosheet into various complex helical nanostructures with controlled dimensions. 3D nanospirals can also be obtained by focus ion beam (FIB)‐based lithography on free‐standing plasmene. Helical plasmene structures are robust, exhibiting elastic mechanical properties and chiral optical response. This methodology represents a versatile fabrication route combining both bottom‐up and top‐down approaches to create soft plasmonic helical structures for potential applications in next‐generation flexible nanophotonic devices.