Hexagonally Ordered Silver Nanostructures from Polystyrene Colloidal Templates: Partial Success and Remaining Challenges

Abstract

Hexagonally ordered metallic nanostructures are of interest for optical and plasmonic studies because their response depends strongly on both local feature shape and long-range periodic arrangement. In this work, a polystyrene (PS) colloidal sphere self-assembly method is explored as a simple template-based route for fabricating hexagonally arranged Ag nanostructures. A PS monolayer is first assembled at the air–water interface and transfer onto a substrate, followed by Ag deposition, particle removal, and post-annealing treatment. Results show that locally ordered hexagonal packing could be obtained in small areas, but larger areas exhibit clear defects, including voids, domain misalignment, aggregation, and non-uniform coverage. After removal of the PS particles, periodic Ag patterns with sharp triangular vertex features are formed, reflecting the geometry of the interparticle gaps. Annealing further transforms these connected sharp features into more rounded and isolated island-like structures. These results confirm the basic feasibility of the method, while also revealing its current limitations in producing large-area, high-quality films.