Generalization of Self‐Assembly Toward Differently Shaped Colloidal Nanoparticles for Plasmonic Superlattices

Abstract

Periodic superlattices of noble metal nanoparticles have demonstrated superior plasmonic properties compared to randomly distributed plasmonic arrangements due to near-field coupling and constructive far-field interference. Here, a chemically driven, templated self-assembly process of colloidal gold nanoparticles is investigated and optimized, and the technology is extended toward a generalized assembly process for variously shaped particles, such as spheres, rods, and triangles. The process yields periodic superlattices of homogenous nanoparticle clusters on a centimeter scale. Electromagnetically simulated absorption spectra and corresponding experimental extinction measurements demonstrate excellent agreement in the far-field for all particle types and different lattice periods. The electromagnetic simulations reveal the specific nano-cluster near-field behavior, predicting the experimental findings provided by surface-enhanced Raman scattering measurements. It turns out that periodic arrays of spherical nanoparticles produce higher surface-enhanced Raman scattering enhancement factors than particles with less symmetry as a result of very well-defined strong hotspots.

Multivariate design and data analysis for plasmonic sensing

“…Plasmonic sensing can be modified and exploited by introducing metallic nanostructures, acting as nanoantennas, to generate localized surface plasmon resonances (LSPR); periodic arrangements provide complex lattice effects due to near and far-field coupling; and propagating plasmons can be exploited at the same time under appropriate experimental settings 2,3 . By using colloidal nanoparticles, hybridization of plasmons lead to even more complex phenomena that cannot easily be predicted 4 . Apart from introducing nanostructures, Gaussian beam shaping improves the sensing performance, and specific figures of merit (FOMs) can be further enhanced by multivariate analysis (MVA) methods using multiple features of the resonance curves instead of relying on a single parameter as in univariate analysis (UVA) 5 .…”

Polymer-Free Side-Patched Gold Nanorods Synthesized via Salt-Assisted Anisotropic Structural Tuning of Silica Shells

“…Gold nanorods (AuNRs) are highly versatile and are widely utilized in various applications owing to the strong electric fields on their surfaces. − They have been employed in surface-enhanced Raman scattering (SERS) sensors, , plasmon-enhanced fluorescence platforms, − smart drug delivery systems, − photothermal heaters, − and photocatalysts. , To fully exploit the potential of AuNRs for these applications, surface modification is necessary to enhance their compatibility, colloidal stability, and functionality.…”

Self-Assembly of Silver Nanowire Films for Surface-Enhanced Raman Scattering Applications

“…The chip-based periodic nanostructure offers the possibility to gain reproducible and reliable Raman signals. Although nano-fabrication methods, such as electron-beam lithography Nanomaterials 2023, 13, 1358 2 of 11 (EBL) [16][17][18] and nanoimprinting lithography (NIL) [19][20][21], can be applied to fabricate substrates with a well-ordered nanostructure, they either require expensive equipment or prefabricated high-density and precise templates. The previous research results have shown that preparing a desired SERS substrate with an ordered "hot spot" that satisfies all requirements of high stability, high sensitivity, low cost, and convenience is still challenging.…”