Particle‐in‐a‐Frame Nanostructures with Interior Nanogaps

Abstract

Designing plasmonic hollowc olloids with small interior nanogaps would allows tructural properties to be exploited that are normally linked to an ensemble of particles but within as ingle nanoparticle.N ow,asynthetic approach for constructing an ew class of frame nanostructures is presented. Fine control over the galvanic replacement reaction of Ag nanoprisms with Au precursors gave unprecedented Au particle-in-a-frame nanostructures with well-defined sub-2 nm interior nanogaps.T he prepared nanostructures exhibited superior performance in applications,such as plasmonic sensing and surface-enhanced Raman scattering, over their solid nanostructure and nanoframe counterparts.T his highlights the benefit of their interior hot spots,w hichc an highly promote and maximizet he electric field confinement within as ingle nanostructure.

Plasmonic Coupling Architectures for Enhanced Photocatalysis

“…[ 96 ] Monocomponent metal nanostructures with tunable plasmonic coupling effect, such as Au nanoframes, Au nanocages, and Au NP clusters, can be prepared via different colloidal synthesis methods. [ 97–100 ] External and internal plasmonic resonances will hybridize to establish strong plasmonic coupling in these nanostructures. [ 99 ] For example, Han et al.…”

“…synthesized Au particle‐in‐a‐frame nanostructures with sub‐2 nm nanogaps using the galvanic replacement method, which could generate 57.5 times enhanced EM field due to the plasmonic coupling effect. [ 97 ]…”

Core–Shell Bimetallic Nanoparticle Trimers for Efficient Light-to-Chemical Energy Conversion

“…The preservation of the NP trimer structure in colloidal solution can be attributed to the van der Waals interaction between the constituent NPs, which is mediated by PVP. 7,8,46 The presence of residual PVP in the Au NP trimers and the removal of PVP from the Au NP trimers were identified by Fourier transform infrared (FTIR) spectroscopy measurements (Figure S3 in the SI). In fact, when the Au NP trimers were treated with an excessive amount of NaBH4, which can act as a role of removing PVP from the surface of NPs, 49 the Au NP timers were destroyed and aggregated each other (Figure S3c-e in the SI), In order to clarify the Au NP trimers formation mechanism, we performed a time-dependent TEM imaging study together with a high-angle annular dark-field scanning TEM (HAADF-STEM)-EDS elemental mapping (Figure 1c and d).…”

“…50 As time goes on, the further growth of each Au corner NPs takes place by the reduction of the Au precursors with reducing agents (Figure 1c1-c4 and 1d1-d4). Unlike the previous strategies, 7,8,46 we conducted the galvanic replacement reactions at -2 ℃ using a weak reducing agent (NH2OH•HCl) to decelerate the kinetics of the galvanic replacement reaction, which could maximize the siteselective growth of Au to produce Au NP trimers. Notably, the same reaction performed at elevated temperatures, such as 24, 60, and 85 ℃, resulted in a strong decrease in the yield of Au NP trimers or even the synthesis of single NPs (Figure S4 After the synthesis of the Au NP trimers, we coated them with a thin layer of catalytically active metals: Pd and Pt.…”

Gold semicontinuous thin-film-coated mesoporous TiO2 for SERS substrates

“…Most common SERS sensors are built using metallic nanoparticles (NPs) such as gold [17], silver [18], and copper [19], either in solution or supported onto substrates. The enhancement of inelastic scattering by the plasmonic effect in the metallic nanosized particles and films are related to the size, shape, morphology, inter-particle distance and arrangement of the plasmonic nanostructure [20][21][22][23].…”