Single Silver Nanoparticles as Real-Time Optical Sensors with Zeptomole Sensitivity

McFarland, Adam D.; Duyne, Richard P. Van

doi:10.1021/nl034372s

Cited by 1,545 publications

(1,304 citation statements)

References 27 publications

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“…Plasmonic nanoparticles (PNPs) have long been utilized for chemical and biological sensing 31 , owing to their unique size, shape and composition as well as local environment-dependent optical properties 32,33 . Compared with fluorescent organic molecules, PNPs are very bright, photostable and easy to prepare.…”

Section: Doi: 101038/ncomms2722mentioning

confidence: 99%

Highly sensitive sulphide mapping in live cells by kinetic spectral analysis of single Au-Ag core-shell nanoparticles

et al. 2013

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Hydrogen sulphide (H 2 S) is a gaseous signalling agent that has important regulatory roles in many biological systems but remains difficult to measure in living biological specimens. Here we introduce a new method for highly sensitive sulphide mapping in live cells via singleparticle plasmonic spectral imaging that uses Au-Ag core-shell nanoparticles as probes. This strategy is based on Ag 2 S formation-induced spectral shifts of the nanoprobes, which is not only highly selective towards sulphide but also shows a linear logarithmic dependence on sulphide concentrations from 0.01 nM to 10 mM. A theoretical model was established that successfully explained the experimental observations, suggesting that the local sulphide concentration as well as its oscillations can be determined indirectly from kinetic measurements of the spectral shifts of the nanoprobes. We demonstrated for the first time the realtime mapping of local variations of sulphide levels in live cells with nM sensitivity.

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Section: Doi: 101038/ncomms2722mentioning

confidence: 99%

Highly sensitive sulphide mapping in live cells by kinetic spectral analysis of single Au-Ag core-shell nanoparticles

et al. 2013

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“…Waveguiding over distances of 0.5 m has been demonstrated in linear chains of metal nanoparticles, 1 and numerous theoretical and experimental studies [2][3][4][5] indicate the possibility of multicentimeter plasmon propagation in thin metallic films. Moreover, the locally enhanced field intensities observed in plasmonic structures promise potential for molecular biosensing, [5][6][7][8][9][10] surface enhanced Raman spectroscopy, [11][12][13] and nonlinear optical device applications. [14][15][16][17][18] In planar metallodielectric geometries, surface plasmons represent plane-wave solutions to Maxwell's equations, with the complex wave vector determining both field symmetry and damping.…”

Section: Introductionmentioning

confidence: 99%

Plasmon slot waveguides: Towards chip-scale propagation with subwavelength-scale localization

et al. 2006

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We present a numerical analysis of surface plasmon waveguides exhibiting both long-range propagation and spatial confinement of light with lateral dimensions of less than 10% of the free-space wavelength. Attention is given to characterizing the dispersion relations, wavelength-dependent propagation, and energy density decay in two-dimensional Ag/ SiO 2 / Ag structures with waveguide thicknesses ranging from 12 nm to 250 nm. As in conventional planar insulator-metal-insulator ͑IMI͒ surface plasmon waveguides, analytic dispersion results indicate a splitting of plasmon modes-corresponding to symmetric and antisymmetric electric field distributions-as SiO 2 core thickness is decreased below 100 nm. However, unlike IMI structures, surface plasmon momentum of the symmetric mode does not always exceed photon momentum, with thicker films ͑d ϳ 50 nm͒ achieving effective indices as low as n = 0.15. In addition, antisymmetric mode dispersion exhibits a cutoff for films thinner than d = 20 nm, terminating at least 0.25 eV below resonance. From visible to near infrared wavelengths, plasmon propagation exceeds tens of microns with fields confined to within 20 nm of the structure. As the SiO 2 core thickness is increased, propagation distances also increase with localization remaining constant. Conventional waveguiding modes of the structure are not observed until the core thickness approaches 100 nm. At such thicknesses, both transverse magnetic and transverse electric modes can be observed. Interestingly, for nonpropagating modes ͑i.e., modes where propagation does not exceed the micron scale͒, considerable field enhancement in the waveguide core is observed, rivaling the intensities reported in resonantly excited metallic nanoparticle waveguides.

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“…It allows heterometallic nanogaps to be associated with organic molecules exhibiting diode behavior. 5 Furthermore, self-assembled molecular diodes can be coated at the surface of arrays of metallic nanostructures (nano-particles or nanoantennas) aiming at obtaining opto-electronic devices such as sensors, 6 selective filters, 7 or nano-rectennas. 8,9 Molecular diodes made of ferrocenyl-containing alkanethiols are of great interest since they exhibit strong asymmetries, leading to remarkably large forward-to-reverse current rectification ratios (RR).…”

Section: Introductionmentioning

confidence: 99%

Model of self assembled monolayer based molecular diodes made of ferrocenyl-alkanethiols

Duché

Planchoke

Dang

et al. 2017

Journal of Applied Physics

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There has been significant work investigating the use of self assembled monolayers (SAMs) made of ferrocenyl terminated alkanethiols for realizing molecular diodes, leading to remarkably large forward-to-reverse current rectification ratios. In this study, we use a multiband barrier tunneling model to examine the electrical properties of SAM-based molecular diodes made of HSC 9 Fc, HSC 11 Fc, and HSC i FcC 13Ài (0 i 13). Using our simple physical model, we reproduce the experimental data of charge transport across various ferrocenyl substituted alkanethiols performed by Nijhuis, Reus, and Whitesides [J. Am. Chem. Soc. 132, 18386-184016 (2010)] and Yuan et al.[Nat. Commun. 6, 6324 (2015)]. Especially, the model allows predicting the rectification direction in HSC i FcC 13Ài (0 i 13) based molecular diodes depending on the position of the ferrocenyl (Fc) moiety within the molecules. We show that the asymmetry of the barrier length at both sides of the Highest Occupied Molecular Orbital of the ferrocenyl moiety strongly contributes to the rectifying properties of ferrocenyl-alkanethiol based molecular junctions. Furthermore, our results reveal that bound and quasi-bound states play an important role in the charge transport. Published by AIP Publishing. [http://dx

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Single Silver Nanoparticles as Real-Time Optical Sensors with Zeptomole Sensitivity

Cited by 1,545 publications

References 27 publications

Highly sensitive sulphide mapping in live cells by kinetic spectral analysis of single Au-Ag core-shell nanoparticles

Highly sensitive sulphide mapping in live cells by kinetic spectral analysis of single Au-Ag core-shell nanoparticles

Plasmon slot waveguides: Towards chip-scale propagation with subwavelength-scale localization

Model of self assembled monolayer based molecular diodes made of ferrocenyl-alkanethiols

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