Convective Self-Assembly of 2D Nonclose-Packed Binary Au Nanoparticle Arrays with Tunable Optical Properties

Abstract

The controllable assembly of nanoparticles into nonclosepacked (NCP) arrays exhibits unusual optical properties [e.g., surface lattice resonances (SLRs)] but are challenging to construct, especially for NCP binary arrays composed of diversified nanoparticles. Here, we show the construction of two-dimensional (2D) NCP binary Au nanoparticle arrays by modulating the convective self-assembly of colloidal nanoparticles on a templating NCP nanoparticle array. By dramatically inhibiting the coffee ring effect during convective evaporation, this convective assembly approach allows colloidal nanoparticles to stack around the templating nanoparticles, forming a "core-satellite" basic architecture. Moreover, this approach is generalized for various types, shapes, and periodicities of building nanoparticles. The assembled 2D NCP binary Au arrays attain multiple tunable optical properties, including photonic band gaps, plasmonic SLRs, and dynamic surface-enhanced Raman scattering activity, based on tunable plasmonic coupling. The anticounterfeiting application of these NCP binary arrays is demonstrated by taking advantage of their unique optical properties. This convective assembly approach can pave the way for the development of a new category of NCP binary arrays and help to explore their collective unconventional properties.

Electrostatic self-assembly of 2D Janus PS@Au nanoraspberry photonic-crystal array with enhanced near-infrared SERS activity

“…1b presents the typical SEM image of 2D PS photonic crystal array with a diameter of 500 nm in hexagonally close-packed (HCP) arrangement used for the electrostatic self-assembly, which is fabricated through the air/water interfacial self-assembly. 6,12,29,[43][44][45] Fig. 1c and 1d show the SEM images of the PS@Au nanoraspberry photonic-crystal array, where the small Au nanoparticles (55 ± 5 nm, as confirmed from the TEM image in the Fig.…”

“…Surface-enhanced Raman scattering (SERS) is a powerful nondestructive analysis technique based on its unique molecular fingerprint recognition 1, 2 , which has been broadly applied in biosensing, [3][4][5] environmental monitoring, 6 medical diagnoses, 7,8 chemical reaction monitoring 9,10 and so on. 11,12 In decades, achieving a superior SERS activity has been dominantly relied on the plasmonic nanostructures (i.e., Au and Ag particles) by taking advantage of localized surface plasmon resonance (LSPR) property. 13,14 Meanwhile, it preferentially requires the matching of the LSPR extinction position with the incident laser wavelength to excite the strongest electromagnetic field (known as the 'hotspot') [15][16][17][18][19][20][21][22][23] .…”

Soft Plasmonics: Design, Fabrication, Characterization, and Applications

“…As described earlier, the mechanoplasmonic properties of soft plasmonic nanostructures can be controlled by chemical stimuli; hence, the resulting SERS sensors may be affected by external stimuli including pH [ 30 ] and heat. [ 118 ] A pH‐sensitive chitosan‐glutaraldehyde hydrogel has been applied to dynamically tune the SERS performance of nonclose‐packed binary AuNP arrays with “core–satellite” architecture.…”

“…To date, soft plasmonic materials and devices have exhibited interesting mechanical properties [ 13 ] and novel mechanoplasmonic properties controlled by force, [ 7–12,14–17 ] heat, [ 18–21 ] electrical potential, [ 22,23 ] light, [ 24–27 ] and chemicals. [ 28–30 ] A few earlier review/perspective articles reported until around 2015 described flexible terahertz and optical metasurfaces and metamaterials, as well as flexible nanoplasmonic sensing. [ 31–33 ] This review comprehensively describes the field of soft plasmonics.…”

From Dilute to Multiple Layers: Bottom‐Up Self‐Assembly of Rough Gold Nanorods as SERS Platform for Quantitative Detection of Thiram in Soil

“…[ 10–15 ] To date, several techniques have been proposed to develop SERS‐active substrates including in situ growth, [ 16,17 ] top‐down lithography, [ 18–23 ] and bottom‐up self‐assembly technique. [ 24–26 ] Among these techniques, bottom‐up self‐assembly is a simple, scalable, and low‐cost approach to achieve uniform and highly effective SERS substrates, such as droplet evaporation, [ 27–29 ] electrostatic interaction, [ 30,31 ] and interface self‐assembly. [ 32–37 ]…”