Facile Fabrication of Flexible Regulatable 3D Nanocluster Arrays by Polymer Pen Lithography for Surface-Enhanced Raman Scattering Substrates

Surface-enhanced Raman scattering (SERS) substrates based on ordered three-dimensional (3D) metallic nanostructures represent a pivotal direction in the evolution of surface-enhanced Raman technology. A fabrication route capable of delivering highly ordered, structurally programmable, and reproducible plasmonic nanoarrays is therefore of immediate practical importance for SERS applications. In this work, a series of SERS substrates based on highly ordered 3D gold nanoparticle cluster (AuNC) arrays were developed by fabricating 3D polyethylenimine (PEI) structures via polymer pen lithography (PPL) and exploiting electrostatic adsorption between amine-terminated polymers and metal nanoparticles (MNPs). Strong interparticle and particle-nanocluster coupling within the array structures generates intense electromagnetic (EM) hot spots, achieving a highly sensitive SERS detection enhancement factor (EF) of 1.67 × 107. The AuNC array substrates exhibit excellent reproducibility with a relative standard deviation (RSD) of <4.73%, attributable to the size controllability of PPL patterns. Crucially, the SERS performance can be flexibly optimized by systematically tuning the array size and pattern architecture through simple adjustment of PPL parameters. This strategy not only provides a versatile platform for systematic optimization of SERS performance through structural tuning but also establishes a scalable route toward custom-designed, high-efficiency SERS chips, while broadening the applications of PPL for fabricating 3D nanostructures in biosensing, chemical analysis, and beyond.