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Quasi-fractal Gold Nanoparticles for Sers: Effect of Nanoparticle Morphology and Concentration

preprint
submitted on 18.12.2018 and posted on 19.12.2018 by Richard Darienzo, Olivia Chen, Maurinne Sullivan, Tatsiana Mironava, Rina Tannenbaum

Quasi-fractal gold nanoparticles can be synthesized via a modified and temperature controlled procedure initially used for the synthesis of star-like gold nanoparticles. The surface features of nanoparticles leads to improved enhancement of Raman scattering intensity of analyte molecules due to the increased number of sharp surface features possessing numerous localized surface plasmon resonances (LSPR). The LSPR is affected by the size and shape of surface features as well as inter-nanoparticle interactions, as these affect the oscillation modes of electrons on the nanoparticle surfaces. The effect of the particle morphologies on the LSPR and further on the surface-enhancing capabilities of these nanoparticles is explored by comparing different nanoparticle morphologies and concentrations. We show that in a fixed nanoparticle concentration regime, Quasi-fractal gold nanoparticles provide the highest level of surface enhancement, whereas spherical nanoparticles provide the largest enhancement in a fixed gold concentration regime. The presence of highly branched features enables these nanoparticles to couple with a laser wavelength despite having no strong absorption band and hence no single surface plasmon resonance. This cumulative LSPR may allow these nanoparticle to be used in a variety of applications where laser wavelength flexibility is beneficial, such as in medical imaging applications where fluorescence at short laser wavelengths may be coupled with non-fluorescing long laser wavelengths for molecular sensing.

Funding

Department of Energy DE-SC0012704

History

Email Address of Submitting Author

irena.tannenbaum@stonybrook.edu

Institution

Stony Brook University

Country

USA

ORCID For Submitting Author

0000-0001-9389-045X

Declaration of Conflict of Interest

No conflict of interest

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