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A surface‐enhanced Raman‐spectroscopic study: Verification of the interparticle gap dependence of field enhancement by triangulation of spherical gold nanoparticle trimers
Author(s) -
Dort Katharina,
Kroth Kathrin,
Klar Peter J.
Publication year - 2019
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5728
Subject(s) - raman scattering , raman spectroscopy , electric field , materials science , nanoparticle , condensed matter physics , scattering , molecular physics , polarization (electrochemistry) , optics , band gap , nanotechnology , chemistry , optoelectronics , physics , quantum mechanics
Strong electric field enhancement in the interparticle gap of resonators formed by two spherical Au nanoparticles occurs for polarization of the incoming light parallel to the dimer axis. This enhancement exhibits a strong dependence on gap width and is the basis of surface‐enhanced Raman scattering or tip‐enhanced Raman scattering. The enhancement factor as a function of gap width can be readily calculated solving Maxwellapos;s equations. However, the derived dependence is difficult to verify experimentally, in particular, because of the large uncertainty in determining the interparticle gap value, which is typically one or two orders of magnitude smaller than the diameters of the Au spherical nanoparticles forming the resonator. We demonstrate that a much more reliable verification of the predicted interparticle gap dependence of the electric field enhancement is possible using an approach analogous to triangulation in surveying and mapping.