Template‐Confined Synthesis of Shape‐Engineered Single‐Crystal Gold Microplates in Lithographically‐Defined Polymeric Patterns

ABSTRACT Ultrathin single‐crystal gold microplates are highly functional two‐dimensional wafer‐based nanomaterials with an application space that is limited by synthetic methods that are unable to promote deterministic positioning and which yield broad, uncontrolled distributions in the microplate size, shape, and thickness. Herein, a template‐confined synthesis is demonstrated that has the potential to exert high‐level control over all of these parameters. The methodology sees a lithographically‐defined pattern overlaid onto an array of gold seeds that are specifically designed to promote the growth of flat‐lying microplates, where custom‐shaped windows in the photoresist expose a centrally located seed. When immersed in a microplate growth solution with a suitably chosen capping agent, lateral growth fronts emerge from the seed and continue to propagate until halted by an encounter with the contours of the resist. With growth confined on all sides by the combined influences of the resist, capping agent, and substrate, the resulting microplates assume predefined dimensions at addressable coordinates. By forwarding these capabilities, the devised approach could elevate the status of ultrathin single‐crystal gold microplates as a technologically viable, high‐performance device platform and offer a modality for shaping and forming other two‐dimensional nanomaterials.