Au–Ag Core–Shell Nanoparticle Array by Block Copolymer Lithography for Synergistic Broadband Plasmonic Properties

Keun, Seung; Mun, Jeong Ho; Chang, Taeyong; Kim, SangYun; Kim, Ju Young; Jin, Hyeong Min; Lee, Jun Young; Shin, Jisoo; Kim, Kwang Ho; Kim, Sang Ouk

doi:10.1021/acsnano.5b01641

Cited by 135 publications

(116 citation statements)

References 62 publications

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“…The results presented here as well as those recently reported by Liu et al[16a] and Cha et al demonstrate that the seed‐mediated syntheses of core–shell nanostructures can occur at the liquid–substrate interface using substrate‐immobilized seeds arranged in periodic arrays. Such syntheses could advance a growing list of potential applications which take advantage of substrate‐based nanostructures with the nanocube geometry .…”

Section: Discussionsupporting

confidence: 87%

Citrate‐Induced Nanocubes: A Re‐Examination of the Role of Citrate as a Shape‐Directing Capping Agent for Ag‐Based Nanostructures

Hajfathalian

Gilroy

Hughes

et al. 2016

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Seed-mediated syntheses utilizing facet-selective surface passivation provide the necessary chemical controls to direct noble metal nanostructure formation to a predetermined geometry. The foremost protocol for the synthesis of (111)-faceted Ag octahedra involves the reduction of metal ions onto pre-existing seeds in the presence of citrate and ascorbic acid. It is generally accepted that the capping of (111) facets with citrate dictates the shape while ascorbic acid acts solely as the reducing agent. Herein, a citrate-based synthesis is demonstrated in which the presence or absence of ascorbic acid is the shape-determining factor. Reactions are carried out in which Ag(+) ions are reduced onto substrate-immobilized Ag, Au, Pd, and Pt seeds. Syntheses lacking ascorbic acid, in which citrate acts as both the capping and the reducing agent, result in a robust nanocube growth mode able to withstand wide variations in the concentration of reactants, reaction rates, seed material, seed orientation and faceting, pH, and substrate material. If, however, ascorbic acid is included in these syntheses, then the growth mode reverts to one that advances the octahedral geometry. The implication of these results is that citrate, or one of its oxidation products, selectively caps (100) facets, but where this capability is compromised by ascorbic acid.

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Section: Discussionsupporting

confidence: 87%

Citrate‐Induced Nanocubes: A Re‐Examination of the Role of Citrate as a Shape‐Directing Capping Agent for Ag‐Based Nanostructures

Hajfathalian

Gilroy

Hughes

et al. 2016

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“…In addition, the Au-AgNFs exhibit fringe periodicity of 0.235 nm in the HR-TEMi mages ( Figure S5 and S6), which corresponds to the (111)l attice spacings of Au (0.235 nm) and Ag (0.236 nm). [60] Capping agentsb earing amine groups, such as melamine, barely adsorb on the (111) surfaces of gold and silver as compared to their (100) and (110) surfaces. [61,62] Therefore, Au-Ag NFs are formed through growth along their (111)-crystal facets owing to the selective adsorption properties of melamineo nA ua nd Ag surfaces.…”

Section: Resultsmentioning

confidence: 99%

Au–Ag Nanoflower Catalysts with Clean Surfaces for Alcohol Oxidation

Imura

Akiyama

Furukawa

et al. 2019

Chemistry An Asian Journal

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Shape‐controlled metal nanocrystals, such as nanowires and nanoflowers, are attractive owing to their potentially novel catalytic properties and bimetallic nanocrystals composed of two distinct metals are expected to act as highly active catalysts. However, their catalytic activities are limited because of the capping agents adsorbed on the metal surfaces, which are necessary for the preparation and dispersion of these nanocrystals in solvents. Therefore, the preparation of bimetallic shape‐controlled noble metal nanocrystals with clean surfaces, devoid of almost all capping agents, are expected to have high catalytic activity. Herein, we report the preparation of bimetallic Au–Ag nanoflowers using melamine as the capping agent. The bimetallic Au–Ag nanoflowers with a clean surface were subsequently obtained by a support and extraction method. The bimetallic nanoflowers with a clean surface were then used for the aerobic oxidation of 1‐phenylethyl alcohol and they exhibited high rates for the formation of acetophenone compared to Au nanoflowers and spherical nanoparticles with almost the same size and Au/Ag ratio. We also show that Au–Ag nanoflowers containing only 1 % Ag (Au99–Ag1NFs) exhibit the highest rate of acetophenone formation among Au–Ag nanoflowers with different Au/Ag ratios owing to an increase in the electron density of the Au atoms that act as active sites for the oxidation of 1‐phenylethyl alcohol.

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“…Just before using the biochip, a simple aqueous rinsing step completely removed the MOF protective layer, restoring the biofunctionality of the sensor surface (Figure 1). Owing to the high sensitivity, cost-efficiency and great potential of use in point-of-care (POC) diagnostics,[18] a plasmonic nanobiosensor based on refractive index sensitivity of localized surface plasmon resonance (LSPR) is used as the platform to monitor various fabrication stages including conjugation of the antibody to the surface of the plasmonic nanostructures, formation and removal of the MOF, as well as bioanalyte detection. Proof-of-concept is initially established by employing IgG/anti-IgG as a test system, showing that the MOF layer remarkably improves the stability of the model antibody at room temperature, 40 and 60 °C.…”

mentioning

confidence: 99%