Characterizing Optical Properties of Self-Assembled Gold Nanoparticles for Surface Plasmon Resonance Device Applications

Abstract

In this study, the optical constants of gold nanoparticles are evaluated for surface plasmon-based sensor applications. Using an effective medium approximation (EMA) and ellipsometry, approaches to monitor the self-assembly of gold nanoparticles are also demonstrated. Spectroscopic ellipsometric parameters measured ðtan É; cos ÁÞ before and after adding gold nanoparticles to a substrate are used to calculate the optical constants of gold nanoparticles. The film thickness is measured by grazing incidence X-ray reflectivity (XRR). The optical constants (refractive index, extinction coefficient) of gold nanoparticles can be obtained from the measured ellipsometric parameters and thickness. We also show that particles density can be well predicted and detected nondestructively by this method.

Using Spectroscopic Ellipsometry to Characterize and Apply the Optical Constants of Hollow Gold Nanoparticles

“…We can, however, compare our results with those for the optical constants ( n < 1.2; k < 0.15) reported by Kooij et al for monolayer Au NPs. Previously, we reported much higher values for the optical constants of monolayer Au NPs than those reported by Kooij. For a saturated monolayer of Au NPs having a diameter of ca.…”

“…We also compared the values of the optical constants of our monolayer HGNs with those reported previously for solid Au NPs. − , For instance, Evans characterized very high refractive index values ( n max = 2.6; k max = 1.4) for self-assembled Au NPs, although we note that their Au NP film was a 12-layer structure rather than a monolayer, so their results are not directly comparable with ours. We can, however, compare our results with those for the optical constants ( n < 1.2; k < 0.15) reported by Kooij et al for monolayer Au NPs.…”

“…These large discrepancies in the values of n resulted from the nature of the NP structures. Several other groups have also studied the relationship between the optical constants and the particle density of Au NP films. − Besides, SE has also been applied to investigate the optical constants of different metals. , To date, however, no studies of the optical constant of self-assembled HGNs have been reported, especially for sensing applications.…”

Polarized-Electrochemiluminescence Biosensor Based on Surface Plasmon Coupling Strategy and Fluorine-Doped BN Quantum Dots

“…Figure A illustrated that ECL signals of F-BN QDs with Au NPs at different polarization angles. Au NPs surface plasmon resonance absorption has a good overlap with the emission spectra of QDs . In the SPC-ECL, the excited state of F-QDs resonated with the electronic oscillation of Au NPs, which caused a significant increase in emission intensity .…”

“…Au NPs surface plasmon resonance absorption has a good overlap with the emission spectra of QDs. 34 In the SPC-ECL, the excited state of F-QDs resonated with the electronic oscillation of Au NPs, which caused a significant increase in emission intensity. 35 Furthermore, the isotropic ECL coupled with surface plasmon effect can generate directional emission.…”