scholarly journals Tuning the Optical Properties of Large Gold Nanoparticle Arrays

2001 ◽  
Vol 676 ◽  
Author(s):  
Beomseok Kim ◽  
Steven L. Tripp ◽  
Alexander Wei
Keyword(s):  
Near Infrared ◽  
High Surface ◽  
Experimental Investigations ◽  
Transmission Electron ◽  
Surface Enhanced ◽  
Air Water Interface ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Infrared Wavelengths ◽  
Aggregate Structures

ABSTRACTGold nanoparticles in the mid-nanometer size regime can undergo self-organization into densely packed monoparticulate films at the air-water interface under appropriate passivation conditions. Films could be transferred onto hydrophilic Formvar-coated Cu grids by horizontal (Langmuir-Schaefer) deposition or by vertical retraction of immersed substrates. The latter method produced monoparticulate films with variable extinction and reflectance properties. Transmission electron microscopy revealed hexagonally close-packed arrays on the micron length scale. The extinction bands of these arrays shifted by hundreds of nanometers to near-infrared wavelengths and broadened enormously with increasing periodicity. Large particle arrays also demonstrated extremely high surface-enhanced Raman scattering (SERS), with enhancement factors greater than 107. Signal enhancements could be correlated with increasing periodicity and are in accord with earlier theoretical and experimental investigations involving nanoparticle aggregate structures.

Laser-induced fabrication of porous gold nanoshells

Nanoscale ◽  
2018 ◽  
Vol 10 (43) ◽  
pp. 20108-20112 ◽  
Author(s):  
Tae-Hyeon Park ◽  
Du-Jeon Jang
Keyword(s):  
Raman Scattering ◽  
Laser Irradiation ◽  
High Surface ◽  
Gold Nanoshells ◽  
Nanosecond Laser ◽  
Scattering Efficiency ◽  
Porous Gold ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Hollow and porous gold nanoshells with high surface-enhanced Raman scattering efficiency have been fabricated through utilizing nanosecond laser irradiation.

scholarly journals Nanoporous Ag-Au Bimetallic Triangular Nanoprisms Synthesized by Galvanic Replacement for Plasmonic Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hongmei Qian ◽  
Shoaib Anwer ◽  
G. Bharath ◽  
Shahid Iqbal ◽  
Lijuan Chen
Keyword(s):  
Metallic Nanoparticles ◽  
Galvanic Replacement ◽  
Transmission Electron ◽  
Surface Plasmon Coupling ◽  
Surface Enhanced ◽  
Particle Aggregates ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Good Biocompatibility ◽  
Elementary Mapping

Galvanic replacement is a versatile method of converting simple noble metallic nanoparticles into structurally more complex porous multimetallic nanostructures. In this work, roughened nanoporous Ag-Au bimetallic triangular nanoprisms (TNPs) are synthesized by galvanic replacement between smooth Ag triangular plates and AuCl4− ions. Transmission electron microscope and the elementary mapping measurements show that numerous protrusions and pores are formed on the {111} facets, and Ag and Au atoms are homogeneously distributed on the triangular plates. Due to the additional “hot spots” generated by the surface plasmon coupling of the newly formed protrusions and pores, the roughened nanoporous Ag-Au TNP aggregates demonstrate a higher surface-enhanced Raman scattering enhancement factor (seven times larger) and better reproducibility than that of smooth Ag triangular particle aggregates. These synthesized roughened nanoporous Ag-Au bimetallic TNPs are a promising candidate for the applications in analytical chemistry, biological diagnostics, and photothermal therapy due to their excellent plasmonic performances and good biocompatibility.

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