Topic
Surface plasmon resonance
About: Surface plasmon resonance is a research topic. Over the lifetime, 24909 publications have been published within this topic receiving 810976 citations. The topic is also known as: Surface plasmon resonance & SPR (technology).
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TL;DR: The SERS performance of nanoparticle-functionalized paper can be optimized by controlling the 3D distribution of the metallic nanoparticles, and such control is critical if these systems are to be implemented as a low-cost and highly sensitive bioassay platform.
Abstract: This work investigates the effect of gold nanoparticle (AuNP) addition to paper substrate and examines the ability of these composite materials to amplify the surface enhanced Raman scattering (SERS) signal of a dye adsorbed. Paper has a three-dimensional (3D), porous, and heterogeneous morphology. The manner in which paper adsorbs the nanoparticles is crucial to its SERS properties, particularly with regards to aggregation. In this work, we sought to maintain the same degree of aggregation, while changing the concentration of nanoparticles deposited on paper. We achieved this by dipping paper into AuNP solutions of different, known concentration and found that the initial packing density of AuNPs in solutions was retained on paper with the same degree of aggregation. The surface coverage of AuNPs on paper was found to scale linearly to their concentration profile in solutions. The SERS performances of the AuNP-treated papers were evaluated with 4-aminothiophenol (4-ATP) as the Raman molecule, and their SERS intensities increased linearly with the AuNPs' concentration. Compared to AuNP-treated silicon, the Raman enhancement factor (EF) from paper was relatively higher due to a more uniform and greater degree of adsorption of AuNPs. The effect of the spatial distribution of AuNPs in their substrates on SERS activity was also investigated. In this experiment, the number of AuNPs was kept constant (a 1 μL droplet of AuNPs was deposited on all substrates), and the distribution profile of AuNPs was controlled by the nature of the substrate: paper, silicon, and hydrophobized paper. The AuNP droplet on paper showed the most reproducible and sensitive SERS signal. This highlighted the role of the z-distribution (through film) of AuNPs within the bulk of the paper, producing a 3D multilayer structure to allow inter- and intralayer plasmon coupling, and hence amplifying the SERS signal. The SERS performance of nanoparticle-functionalized paper can thus be optimized by controlling the 3D distribution of the metallic nanoparticles, and such control is critical if these systems are to be implemented as a low-cost and highly sensitive bioassay platform.
212 citations
TL;DR: In this article, the authors determine ideal distributions of spherical metallic nanoparticles, both nanospheres and nanoshells, that match the AM 1.5 solar spectrum in a mixed component, submonolayer geometry.
Abstract: The large optical cross sections of metallic nanoparticles at wavelengths corresponding to their plasmon resonance make them highly attractive for harvesting solar energy for a variety of applications. Here the authors determine ideal distributions of spherical metallic nanoparticles, both nanospheres and nanoshells, that match the AM 1.5 solar spectrum in a mixed component, submonolayer geometry. Both absorbing and scattering distributions are determined and their properties compared to conventional broad spectrum absorbing and scattering media.
211 citations
TL;DR: In this article, the authors reported abnormally large positive and negative lateral optical beam shifts at a metal-air interface when the surface plasmon resonance of the metal is excited and identified the optimal thickness for minimal resonant reflection as the critical thickness above which a negative beam displacement is observed.
Abstract: We report abnormally large positive and negative lateral optical beam shifts at a metal–air interface when the surface plasmon resonance of the metal is excited. The optimal thickness for minimal resonant reflection is identified as the critical thickness above which a negative beam displacement is observed. Experimental results show good agreement with theoretical predictions and the large observed bidirectional beam displacements also indicate the existence of forward and backward surface propagating waves at the surface plasmon resonance of the metal.
211 citations
TL;DR: In this article, a dumbbell-like structure was successfully synthesized through the nucleation and decomposition of zinc hydroxide at the surface of pre-existing Au and Ag nanoparticles, respectively.
Abstract: Au- and Ag-ZnO composite nanocrystals having a dumbbell-like structure were successfully synthesized through the nucleation and decomposition of zinc hydroxide at the surface of pre-existing Au and Ag nanoparticles, respectively. The average size of the Au and Ag nanoparticles used was ∼4 nm and that of the ZnO nanocrystals was ∼10 nm. The composite nanocrystals show strong crystallinity of face-centered cubic and wurztite structures from Au or Ag and ZnO, respectively. The composite nanocrystals show enhanced UV light emission due not only to the surface electron transfer from the Au or Ag to the ZnO by the surface plasmon resonance (SPR) but also to the extension of the Fermi energy level to the ZnO. The Au-ZnO composite nanocrystals showed significantly suppressed visible light luminescence, while the Ag-ZnO did not show any apparent difference compared to the ZnO nanocrystals.
211 citations
TL;DR: In this paper, surface plasmon resonance (SPR) was used for real-time analysis of toxin binding under conditions that mimic the natural cell surface venue of these interactions and without any requirement for labeling of toxin or receptor.
211 citations