| 1. |
- Dong, Bin, et al.
(författare)
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Local and Remote Charge-Transfer-Enhanced Raman Scattering on One-Dimensional Transition-Metal Oxides
- 2010
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Ingår i: Chemistry - An Asian Journal. - : Wiley. - 1861-4728. ; 5:8, s. 1824-1829
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Tidskriftsartikel (refereegranskat)abstract
- The one-dimensional (1D) transition-metal oxide MoO3 belt is synthesized and characterized with Xray diffraction, scanning electron microscopy, and Raman spectroscopy. Charge-transfer-(CT) enhanced Raman scattering of 4-mercaptobenzoic acid (4-MBA) on a 1D MoO3 belt was investigated experimentally and theoretically. The chemical enhancement of surface-enhanced Raman scattering (SERS) of 4-MBA on the MoO3 belt by CT is in the order of 10(3). The SERS of 4-MBA was investigated theoretically by using a quantum chemical method. The remote SERS of 4-MBA along the 1D MoO3 belt (the light excitation to one side of the MoO3 belt, and the SERS spectrum is collected on the other side of the MoO3 belt) is also shown experimentally, which provides potential applications of SERS. The incident polarization dependence of remote SERS spectra has also been investigated experimentally.
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| 2. |
- Fang, Yurui, et al.
(författare)
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Branched Silver Nanowires as Controllable Plasmon Routers
- 2010
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 10:5, s. 1950-1954
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Tidskriftsartikel (refereegranskat)abstract
- Using polarization dependent scattering spectroscopy, we investigate plasmon propagation on branched silver nanowires. By controlling the polarization of the incident laser light, the wire plasmons can be routed into different wire branches and result in light emission from the corresponding wire ends. This routing behavior is found to be strongly dependent on the wavelength of light. Thus for certain incident polarizations, light of different wavelength will be routed into different branches. The branched nanowire can thus serve as a controllable router and multiplexer in integrated plasmonic circuits.
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| 3. |
- Huang, Yingzhou, et al.
(författare)
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Surfactant-Promoted Reductive Synthesis of Shape-Controlled Gold Nanostructures
- 2009
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 9:2, s. 858-862
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Tidskriftsartikel (refereegranskat)abstract
- We describe a surfactant-promoted reductive route for the shape-controlled synthesis of gold nanostructures by hydrothermal treatment of chloroauric acid in the presence of the surfactant hexadecyltrimethylammonium bromide (CTAB) without using reducing agent. The results show that the cationic surfactant CTAB provides the dual function of promoting Au-III reduction to Au-0 and size- and shape-controlled synthesis of the gold nanocrystals. More importantly, the benefit of the present work stems from the first report on the controlled synthesis of gold nanostructures by hydrothermal treatment of chloroauric acid in the presence of the surfactant CTAB without using reducing agent. The kinetics of the reduction could be manipulated through changes in the CTAB concentration to produce gold nanostructures with shapes ranging from three-dimensional (313) octahedra, triangles, to two-dimensional (213) hexagonal nanoplates in high yields. Growth of gold nanostructures in the CTAB solution with concentration was monitored by microscopic and spectroscopic techniques.
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| 4. |
- Li, Zhipeng, et al.
(författare)
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Correlation between Incident and Emission Polarization in Nanowire Surface Plasmon Waveguides
- 2010
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 10:5, s. 1831-1835
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Tidskriftsartikel (refereegranskat)abstract
- Nanowire plasmons can be launched by illumination at one terminus of the nanowire and emission can be detected at the other end of the wire. Using polarization dependent dark-held scattering spectroscopy, we measure how the polarization of the emitted light depends on the polarization of the incident light. We observe that the shape of the nanowire termination plays an important role in determining this polarization change. Depending on termination shape, a nanowire can serve as either a polarization-maintaining waveguide, or as a polarization-rotating, nanoscale half-wave plate. The understanding of how plasmonic waveguiding influence the polarization of the guided light is important for optimizing the structure of integrated plasmonic devices
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| 5. |
- Li, Zhipeng, et al.
(författare)
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Directional Light Emission from Propagating Surface Plasmons of Silver Nanowires.
- 2009
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 9:Online September 21, 2009, s. 4383-4386
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Tidskriftsartikel (refereegranskat)abstract
- Thin metallic nanowires are highly promising candidates for plasmonic waveguides in photonic and electronic devices. We have observed that light from the end of a silver nanowire, following excitation of plasmons at the other end of the wire, is emitted in a cone of angles peaking at nominally 45-60 degrees from the nanowire axis, with virtually no light emitted along the direction of the nanowire. This surprising characteristic can be explained in a simple picture invoking Fabry-Perot resonances of the forward- and back-propagating plasmons on the nanowire. This strongly angular-dependent emission is a critical property that must be considered when designing coupled nanowire-based photonic devices and systems.
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| 6. |
- Liang, Hongyan, et al.
(författare)
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Controlled Synthesis of Uniform Silver Nanospheres
- 2010
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:16, s. 7427-7431
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Tidskriftsartikel (refereegranskat)abstract
- We describe a new route, in which the polyethylene glycol (PEG) is used both as a solvent and reducing reagent and the polymer polyvinglpyrrolidone (PVP) is used as capping agent, for the synthesis of monodisperse silver nanoparticles. Uniform nanospheres with an average diameter of 54 nm can be routinely synthesized in high yield through this approach by using a PVP/AgNO3 molar ratio of 8 at 260 degrees C. Both the reaction temperature and the PVP/AgNO3 molar ratio are crucial for the diameters and size distributions of the nanospheres.
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| 7. |
- Sun, Mengtao, et al.
(författare)
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The pH-Controlled Plasmon-Assisted Surface Photocatalysis Reaction of 4-Aminothiophenol to p,p '-Dimercaptoazobenzene on Au, Ag, and Cu Colloids
- 2011
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:19, s. 9629-9636
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we report experimentally and theoretically a surface photocatalysis reaction of 4-aminothiophenol (PATP) to p,p'-dimercaptoazobenzene (DMAB) on Au, Ag, and Cu colloids. Surface enhanced Raman scattering (SEAS) spectra of PATP on Au and Cu colloids are significantly different from the normal Raman spectrum of PATP powder. Quantum chemical calculations reveal that PATP on Au and Cu colloids is converted to DMAB by a surface photocatalysis reaction, and all the strongly enhanced Raman peaks are the symmetric Ag vibrational mode by surface plasmon. The pH value effects on surface photocatalysis reaction were also investigated experimentally. It is found that plasmon-assisted surface photocatalysis reaction can be efficiently controlled by different pH values. The possibility of protonation of PATP adsorbed on Au and Ag nanoparticles at pH 3 is investigated theoretically. The molecular mechanism is proposed for controlling surface photocatalysis reaction by pH values.
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| 8. |
- Wei, Hong, et al.
(författare)
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Polarization dependence of surface-enhanced Raman scattering in gold nanoparticle-nanowire systems
- 2008
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 8:8, s. 2497-2502
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Tidskriftsartikel (refereegranskat)abstract
- We study the polarization dependence of surface-enhanced Raman scattering (SERS) in coupled gold nanoparticle-nanowire systems. The coupling between the continuous nanowire plasmons and the localized nanoparticle plasmons results in significant field enhancements and SERS enhancements comparable to those found in nanoparticle dimer junctions. The SERS intensity is maximal when the incident light is polarized across the particle and the wire, and the enhancement is remarkably insensitive to the detailed geometrical structures of the nanoparticles.
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| 9. |
- Zhang, Shunping, et al.
(författare)
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Reduced linewidth multipolar plasmon resonances in metal nanorods and related applications
- 2013
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 5:15, s. 6985-6991
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Tidskriftsartikel (refereegranskat)abstract
- Using dark-field scattering spectroscopy, we study the multipolar plasmon resonances in single crystallized silver nanorods. The lineshapes and homogenous linewidths of the surface plasmon resonances (SPRs) of different orders are analyzed and compared. The high-order resonances are found to sustain asymmetric Fano lineshapes and their linewidths are narrower than the dipolar resonance. A quantitative comparison using the finite element method reveals more than a three times reduction in the linewidth for the third order resonance, as compared with the dipolar one. These narrow linewidths result from the smaller radiative damping of the multipolar SPRs. Benefiting from the reduced damping, multipolar SPRs in nanorods are better candidates for many plasmonic applications, including increased-sensitivity single particle SPR sensors and reduced-threshold nanolasers.
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