Near-Field and Far-Field Sensitivities of LSPR Sensors

Kamińska, Izabela; Maurer, Thomas; Nicolas, Rana; Renault, M.; Lerond, Thomas; Salas‐Montiel, Rafael; Herro, Ziad; Kazan, M.; Niedziółka‐Jönsson, Joanna; Plain, Jérôme; Adam, Pierre‐Michel; Boukherroub, Rabah; Szunerits, Sabine

doi:10.1021/acs.jpcc.5b00566

Cited by 29 publications

(30 citation statements)

References 25 publications

(32 reference statements)

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“…This value is consistent with the previous value reported for gold nanorods 45 as well as similarly sized Au nanospheres. 46 Finally, eqn (1) can be used to estimate the effective SAM thicknesses on the Au stars. These estimated values are 0.59, 0.92, and 1.34 nm for 3-MPA, 6-MHA, and 11-MUA, respectively.…”

Section: Resultsmentioning

confidence: 99%

SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size

Forbes

Haes

2016

Analyst

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The radius of curvature of gold (Au) nanostar tips but not the overall particle dimensions can be used for understanding the large and quantitative surface-enhanced Raman scattering (SERS) signal of the uranyl (UO2)(2+) moiety. The engineered roughness of the Au nanostar architecture and the distance between the gold surface and uranyl cations are promoted using carboxylic acid terminated alkanethiols containing 2, 5, and 10 methylene groups. By systematically varying the self-assembled monolayer (SAM) thickness with these molecules, the localized surface plasmon resonance (LSPR) spectral properties are used to quantify the SAM layer thickness and to promote uranyl coordination to the Au nanostars in neutral aqueous solutions. Successful uranyl detection is demonstrated for all three functionalized Au nanostar samples as indicated by enhanced signals and red-shifts in the symmetric U(vi)-O stretch. Quantitative uranyl detection is achieved by evaluating the integrated area of these bands in the uranyl fingerprint window. By varying the concentration of uranyl, similar free energies of adsorption are observed for the three carboxylic acid terminated functionalized Au nanostar samples indicating similar coordination to uranyl, but the SERS signals scale inversely with the alkanethiol layer thickness. This distance dependence follows previously established models assuming that roughness features associated with the radius of curvature of the tips are considered. These results indicate that SERS signals using functionalized Au nanostar substrates can provide quantitative detection of small molecules and that the tip architecture plays an important role in understanding the resulting SERS intensities.

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Section: Resultsmentioning

confidence: 99%

SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size

Forbes

Haes

2016

Analyst

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“…[35][36][37][38][39][40][41] More recently, the knowledge acquired about plasmonic materials is being studied for the development of chemical and biological (LSPR) sensors. [42][43][44][45][46][47][48][49][50][51] . Furthermore, taking the advantage of Raman scattering from molecules located on top of plasmonic materials, the Surface-Enhanced Raman Scattering (SERS) effect is often used in chemical sensing, since it may allow single molecule detection.…”

mentioning

confidence: 99%

Broadband Optical Absorption Caused by the Plasmonic Response of Coalesced Au Nanoparticles Embedded in a TiO₂ Matrix

Borges

Pereira²,

Rodrigues³

et al. 2016

J. Phys. Chem. C

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The effect of Au nanoparticles (NPs) concentration, size and spatial distribution within a TiO 2 dielectric matrix on the Localized Surface Plasmon Resonance (LSPR) band characteristics, were experimentally and theoretically studied. The results of the analysis of the Au NPs' size distributions allowed to conclude that isolated NPs grow only up to 5-6 nm in size, even for the highest annealing temperature used. However, for higher volume fractions of Au, the coalescence of closely located NPs yields elongated clusters, which are much larger in size and cause a considerable broadening of the LSPR band. This effect was confirmed by Monte Carlo modeling results. Coupled dipole equations were solved to find the electromagnetic modes of a supercell, where isolated and coalesced NPs were distributed, from which an effective dielectric function of the nanocomposite material was calculated and used to evaluate the optical transmittance and reflectance spectra. The modeling results suggested that the observed LSPR band broadening is due to a wider spectral distribution of plasmonic modes, caused by the presence of coalesced NPs (in addition to the usual damping effect). This is particularly important for detection applications via Surface-Enhanced Raman Spectroscopy (SERS), where it is desirable to have a spectrally broad LSPR band in order to favor the fulfillment of the conditions of resonant matching, to electronic transitions in detected species.

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“…Such experimental route provides the strong enhancement of plasmon resonance and can enhance the SPR sensor sensitivity. It should also be noted that plasmon supported fiber sensors, whose responses are based on the excitation of surface plasmon resonance on the surface of the thin metal film, are usually considered more sensitive to refractive index changes than localized surface plasmon resonance-based sensors (i.e., metal nanoparticles based sensors) [29,30]. However, their combination can significantly increase the general structure sensitivity, as demonstrated previously [28].…”

Section: Introductionmentioning

confidence: 90%

Enhancement of Surface Plasmon Fiber Sensor Sensitivity Through the Grafting of Gold Nanoparticles

et al. 2019

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The optical fibers, coated with plasmonic active metal films, represent the simple and unpretentious sensors, potentially useful for measurements of physical or chemical quantities and wide range of analytical application. All fiber-based plasmonic sensors operate on the same physical principle based on changes in the position of the plasmon absorption peak induced by a variation of surrounding medium refractive index. However, the observed spectral differences are often weak, and thus an enhancement of sensor sensitivity is strongly required. In this paper, we propose the immobilization of gold nanoparticles with sharp edges on the thin gold layer, deposited on the multimode fiber surface for improvement of the sensor functionality. The morphological and compositional changes in the gold covered fiber surface were determined by using the atomic force microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy methods. As a result of gold nanoparticles immobilization, the pronounced plasmon energy concentration near the fiber surface occurred, thus enhancing the response of the proposed hybrid plasmonic system to the variation of ambient refractive index. The position of plasmon absorption in the case of the created plasmonic structure was shown to be more sensitive to the changes in the surrounding medium in comparison with the standard sensors based on the bare gold layer.

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Near-Field and Far-Field Sensitivities of LSPR Sensors

Cited by 29 publications

References 25 publications

SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size

SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size

Broadband Optical Absorption Caused by the Plasmonic Response of Coalesced Au Nanoparticles Embedded in a TiO₂ Matrix

Enhancement of Surface Plasmon Fiber Sensor Sensitivity Through the Grafting of Gold Nanoparticles

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Near-Field and Far-Field Sensitivities of LSPR Sensors

Cited by 29 publications

References 25 publications

SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size

SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size

Broadband Optical Absorption Caused by the Plasmonic Response of Coalesced Au Nanoparticles Embedded in a TiO2 Matrix

Enhancement of Surface Plasmon Fiber Sensor Sensitivity Through the Grafting of Gold Nanoparticles

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Broadband Optical Absorption Caused by the Plasmonic Response of Coalesced Au Nanoparticles Embedded in a TiO₂ Matrix