Multisegmented Metallic Nanorods: Sub‐10 nm Growth, Nanoscale Manipulation, and Subwavelength Imaging

Abstract

Multisegmented metallic nanorods (MS‐M‐NRs) have attracted increasing attention thanks to their integrated structures and complex functions. The integration of nanoscale segments in 1D enables maximum exposure of each segment and enhanced interaction between adjacent segments. Such structural integration will induce functional complexity in the nanorods, leading to superior properties for the individual components. Herein, recent progress on the development of MS‐M‐NRs is reviewed. Their precise fabrication, nanoscale manipulation, and subwavelength imaging, as well as simultaneous manipulation and imaging are discussed, respectively. Specifically, precise fabrication of MS‐M‐NRs focuses on porous anodic alumina (PAA) templated electrodeposition, which enables sub‐10 nm growth of the segments and their interfaces/fronts. Nanoscale manipulation of MS‐M‐NRs introduces the fundamental methods that are employed for delicate movement control on the nanorods through internal or external stimulations. Subwavelength imaging of MS‐M‐NRs highlights the achievements on identification and location of constituent nanoscale segments/gaps based on their differences and interactions. Simultaneous manipulation and imaging of MS‐M‐NRs addresses the significance and potential applications of the nanorods with magnetic–plasmonic dual modulation. The development of MS‐M‐NRs will greatly contribute to materials science and nanoscience/nanotechnology.

Synthesis, Assembly, Optical Properties, and Sensing Applications of Plasmonic Gap Nanostructures

“…For example, both Pt and Au are oxidation-resistant noble metals, whereas Ag and Ni can be easily removed by acids and oxidants. [121][122][123][124][125][126] Hence, the latter are used to form a sacrificial layer in the production of Pt or Au wires. The nanowires prepared by the OWL method with sacrificial materials feature intergaps of ≈2 nm to tens of µm depending on the electrodeposition rate and time.…”

From multi-segmented to core/shell nanorods: morphology evolution in Fe–Au nanorods by tuning fabrication conditions

“…Meanwhile Au has strong and uniquely tunable optical properties such as surface plasmonic resonance, surfaceenhanced luminescence and surface Raman scattering [13]. A number of approaches have been successfully adopted for the fabrication of nanorods namely, pulsed-laser ablation/chemical vapor deposition [14], vapor-solid-liquid growth processes evaporation of mixed powders [15], lithography combined with reactive iron etching [16], hard template method [17][18][19] etc. The template assisted synthesis is the most common method for the fabrication of multisegmented nanorods in which the deposition of desired material is done in cylindrical and monodisperse template pores.…”

Nanopore/Nanosphere‐Induced Optical Enhancement of Monolayer MoS2

“…[19,20] Porous anodic alumina (PAA) membranes are ideal templates for fabrication of plasmonic heterostructures by electrochemical deposition. [21][22][23][24][25] PAA membranes are universal platforms as well as for assembling colloidal nanoparticles for control of their optical performances. [26,27] So far, heterostructures combining monolayer MoS 2 , PAA membranes, and plasmonic gold nanoparticles (AuNPs) remain largely unexplored.…”