ORCID Profile
0000-0003-4818-8885
Current Organisation
Nanyang Technological University
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Publisher: American Chemical Society (ACS)
Date: 24-01-2017
DOI: 10.1021/ACS.LANGMUIR.6B03721
Abstract: We study the degradation process of closely spaced silver and gold nanocubes under high-energy electron beam irradiation using transmission electron microscopy (TEM). The high aspect ratio gaps between silver and gold nanocubes degraded in many cases as a result of protrusion and filament formation during electron beam irradiation. We demonstrate that the molecular coating of the nanoparticles can act as a protective barrier to minimize electron-beam-induced damage on passivated gold and silver nanoparticles.
Publisher: American Chemical Society (ACS)
Date: 25-07-2016
Abstract: We study the galvanic replacement reaction of silver nanocubes in dilute, aqueous ethylenediaminetetraacetic acid disodium salt (EDTA)-capped gold aurate solutions using in situ liquid-cell electron microscopy. Au/Ag etched nanostructures with concave faces are formed via (1) etching that starts from the faces of the nanocubes, followed by (2) the deposition of an Au layer as a result of galvanic replacement, and (3) Au deposition via particle coalescence and monomer attachment where small nanoparticles are formed during the reaction as a result of radiolysis. Analysis of the Ag removal rate and Au deposition rate provides a quantitative picture of the growth process and shows that the morphology and composition of the final product are dependent on the stoichiometric ratio between Au and Ag.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA16826D
Abstract: Quantum plasmon resonances have been recently observed across molecular tunnel junctions. The present work extends these studies theoretically using a generalized space-charge corrected electromagnetic model for a wider range of molecules.
Publisher: Springer Science and Business Media LLC
Date: 02-07-2014
DOI: 10.1038/SREP05537
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-03-2014
Abstract: Electron tunneling across cavities could potentially induce a quantum mechanical plasmon mode that would be important in nano-electronics, catalysis, nonlinear optics, or single-molecule sensing, but has been expected to occur only at length scales beyond the reach of current state-of-the-art technology. Using a system of plasmonic dimers comprising silver nanocubes bridged by a molecular self-assembled monolayer, Tan et al. (p. 1496 see the Perspective by Nordlander ) observed quantum plasmonic tunneling between the resonators and were able to tune the frequency of this tunneling plasmon resonance via selection of the molecular tunnel junctions. Moreover, the effects were observed at length scales that are technologically accessible.
Publisher: American Chemical Society (ACS)
Date: 13-04-2016
DOI: 10.1021/JACS.6B00594
Abstract: We study the overgrowth process of silver-on-gold nanocubes in dilute, aqueous silver nitrate solution in the presence of a reducing agent, ascorbic acid, using in situ liquid-cell electron microscopy. Au-Ag core-shell nanostructures were formed via two mechanistic pathways: (1) nuclei coalescence, where the Ag nanoparticles absorbed onto the Au nanocubes, and (2) monomer attachment, where the Ag atoms epitaxially deposited onto the Au nanocubes. Both pathways lead to the same Au-Ag core-shell nanostructures. Analysis of the Ag deposition rate reveals the growth modes of this process and shows that this reaction is chemically mediated by the reducing agent.
Publisher: Springer Science and Business Media LLC
Date: 21-02-2013
DOI: 10.1038/SREP01312
Publisher: Springer Science and Business Media LLC
Date: 03-10-2016
DOI: 10.1038/NCHEM.2618
Abstract: The nucleation and growth of solids from solutions impacts many natural processes and is fundamental to applications in materials engineering and medicine. For a crystalline solid, the nucleus is a nanoscale cluster of ordered atoms that forms through mechanisms still poorly understood. In particular, it is unclear whether a nucleus forms spontaneously from solution via a single- or multiple-step process. Here, using in situ electron microscopy, we show how gold and silver nanocrystals nucleate from supersaturated aqueous solutions in three distinct steps: spinodal decomposition into solute-rich and solute-poor liquid phases, nucleation of amorphous nanoclusters within the metal-rich liquid phase, followed by crystallization of these amorphous clusters. Our ab initio calculations on gold nucleation suggest that these steps might be associated with strong gold-gold atom coupling and water-mediated metastable gold complexes. The understanding of intermediate steps in nuclei formation has important implications for the formation and growth of both crystalline and amorphous materials.
Location: United States of America
No related grants have been discovered for Shu Fen Tan.