Fabrication Strategies of 3D Plasmonic Structures for SERS

Recent advancements in fabricating plasmonic nanostructures have markedly lessened the limitations of conventional optical sensors, in terms of sensitivity, tunability, photostability, and in vivo applicability. The sophisticated design of diverse metallic nanoparticles and formation of two- or threedimensional (3D) assemblies have enhanced the performance of plasmon-based sensing and imaging applications. Especially, the creation of highly localized electromagnetic fields (i.e., hot-spots) in the multidimensional plasmonic structures has enabled ultrasensitive detection of biomolecules at low concentrations via surface-enhanced Raman scattering (SERS). In this review, we summarize representative approaches to obtain 3D plasmonic structures categorized by the fabrication strategies. These include colloidal synthesis of plasmonic nanoparticles with multiple hot-spots and post-integration of the nanoparticles into 3D templates, and self-integration in the course of constructing 3D structures. We also describe notable structural benefits in sensing applications, especially for SERS, that take advantages of such 3D plasmonic nanostructures.