Wet‐chemical synthesis of two‐dimensional complex nanorings for near‐field focusing

Abstract

Plasmonic nanorings are promising building blocks for a variety of applications, including optical and biological sensing, and energy because the open inner spaces of the nanorings exhibit a high surface‐to‐area ratio and possess unique optical properties that are different from solid nanostructures. However, the simple architecture of mono‐rim based structures leads to low electromagnetic near‐field confinement, which requires a more complex structure to facilitate effective interaction with light. Herein, we report on recent progress of synthetic strategies for fabricating plasmonic nanorings using both top‐down and bottom‐up approaches. First, we introduce the conventional methods for achieving classical ring architectures. Then, we discuss rationally designed synthesis methods for creating advanced and structurally unique nanostructures to increase near‐field enhancement. This process involves multi‐step chemical toolkits that enable control over the shape and the introduction of repeated units in a single entity. Then, we explore the potential applications of complex nanoring architectures.