Plasmonics for the Characterization of Metal Organic Films and Nanoparticles

Rosso, Tommaso Del; Margulis, Walter; Fontana, Jake; Carvalho, Isabel C. S.

doi:10.1016/b978-0-08-102378-5.00010-6

Cited by 2 publications

(2 citation statements)

References 103 publications

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“…The performances of the DLWGs in NP counting were studied by SPR spectroscopy and AFM in a range of σ between ~20 and 200 NP/µm 2 , in order to prevent the effects of dipole-dipole interparticle interaction as highlighted in Section 3.2. Prior to the optical sensing experiments, the optical constants and thickness of the gold and SiO 2 layers constituting the DLWGs were characterized by two-color SPR spectroscopy using the experimental procedure reported in [41]. In Table 1, the values obtained for the parameters of the DLWGs at the experimental wavelength of 783 nm are shown.…”

Section: Resultsmentioning

confidence: 99%

Limits of the Effective Medium Theory in Particle Amplified Surface Plasmon Resonance Spectroscopy Biosensors

Costa

Zaman

Costa

et al. 2019

Sensors

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The resonant wave modes in monomodal and multimodal planar Surface Plasmon Resonance (SPR) sensors and their response to a bidimensional array of gold nanoparticles (AuNPs) are analyzed both theoretically and experimentally, to investigate the parameters that rule the correct nanoparticle counting in the emerging metal nanoparticle-amplified surface plasmon resonance (PA-SPR) spectroscopy. With numerical simulations based on the Finite Element Method (FEM), we evaluate the error performed in the determination of the surface density of nanoparticles σ when the Maxwell-Garnett effective medium theory is used for fast data processing of the SPR reflectivity curves upon nanoparticle detection. The deviation increases directly with the manifestations of non-negligible scattering cross-section of the single nanoparticle, dipole-dipole interactions between adjacent AuNPs and dipolar interactions with the metal substrate. Near field simulations show clearly the set-up of dipolar interactions when the dielectric thickness is smaller than 10 nm and confirm that the anomalous dispersion usually observed experimentally is due to the failure of the effective medium theories. Using citrate stabilized AuNPs with a nominal diameter of about 15 nm, we demonstrate experimentally that Dielectric Loaded Waveguides (DLWGs) can be used as accurate nanocounters in the range of surface density between 20 and 200 NP/µm2, opening the way to the use of PA-SPR spectroscopy on systems mimicking the physiological cell membranes on SiO2 supports.

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Section: Resultsmentioning

confidence: 99%

Limits of the Effective Medium Theory in Particle Amplified Surface Plasmon Resonance Spectroscopy Biosensors

Costa

Zaman

Costa

et al. 2019

Sensors

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“…It is known that the presence of the metallic Cr adhesive layer broadens and distorts the SPR curve because of enhanced absorption of plasmon resonance energy at the SF4 glass interface, which is responsible for the high value of the imaginary part the dielectric constant of the Cr/Au interface reported in Table . The enhanced absorption is related to the intrinsic higher imaginary part of the dielectric constant of Cr and intermetallic diffusion of Cr into the Au thin film during e-beam deposition, leading to a nanostructured metal–dielectric interface, which acts like an SPP scatterer .…”

Section: Discussionmentioning

confidence: 99%

Water Diffusion Effects at Gold–Graphene Interfaces Supporting Surface Plasmon Polaritons

et al. 2022

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We present a detailed investigation on the effects of water diffusion at the different interfaces of gold−graphene plasmonic sensors on the propagation of the supported surface plasmon polaritons (SPPs). The substrate/metal interfacial chemical reactions are investigated by monitoring the full width at half-maximum of the SPR reflectivity curve. Although protection by singlelayer graphene (SLG) grown by chemical vapor deposition inhibits the chemical reactions happening at the metal−dielectric interfaces, SPR experimental results confirm that water diffusion paths through the borders of graphene domains are still present into the plasmonic sensors. Density functional theory calculations show that the doping level of SLG after the transfer on gold as well as interfacial charge transfer can be tuned in the presence of water molecules. On these bases, we propose a simplified effective medium approach for heterogeneous metal−carbon interfaces, where the interaction between the surface atomic layers of the gold thin film, water molecules, and the SLG induces the creation of an extended charge density difference region crossing the Au/H 2 O/SLG/H 2 O heterointerface. The latter is modeled as an ultrathin effective medium with a thickness and extraordinary optical susceptivity and conductivity that are different from those of the free-standing graphene. In this context, the extraordinary refractive index and thickness of the graphene−gold effective medium are measured in the near-infrared on the low-damping SPR platforms by applying the two-medium SPR method. The results are coherent with graphene n-doping in water environment, showing that the optically excited electrons along the extraordinary axis have a substantial bonding character and that the enhancement of the sensitivity of the gold−graphene plasmonic sensors is not related to a shift in the plasma frequency of the metal layer but to the changes in the extraordinary polarizability of graphene. The research highlights the importance of the SLG−substrate and SLG−environment interactions in graphene-protected plasmonics and optoelectronics.

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Plasmonics for the Characterization of Metal Organic Films and Nanoparticles

Cited by 2 publications

References 103 publications

Limits of the Effective Medium Theory in Particle Amplified Surface Plasmon Resonance Spectroscopy Biosensors

Limits of the Effective Medium Theory in Particle Amplified Surface Plasmon Resonance Spectroscopy Biosensors

Water Diffusion Effects at Gold–Graphene Interfaces Supporting Surface Plasmon Polaritons

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