Surface-enhanced Raman spectroscopy on single Fe₂O₃@Au spindle nanoparticle: polarization dependence and FDTD simulation

Abstract

The surface-enhanced Raman scattering (SERS) effect was critically dependent on the shape of the plasmonic nanostructures. It still remains a significant challenge in exploring the correlation between the SERS effect and the shape of nanostructures. Here, the polarized SERS combined with finite difference time domain (FDTD) calculation was developed to elucidate the origination of the SERS effect on an anisotropic spindle-shaped Fe 2 O 3 @Au nanoparticle. The surface enhancement factor for spindle-shaped Fe 2 O 3 @Au nanoparticles was estimated to be about sixorders by using pyridine as model molecules. A dramatic variation in SERS effect was observed by changing the excitation polarization direction. The maximum SERS intensity was detected when the excitation polarization was parallel to the long axes of Fe 2 O 3 @Au nanoparticles, while the minimum intensity was observed at the perpendicular orientation. The remarkable polarization-dependent SERS effects can be attributed to the local enhanced electric field that strongly depends on the polarization direction. The theoretical simulation based on the FDTD method was performed to evaluate the distribution of a local electromagnetic field on Fe 2 O 3 @Au single nanoparticles. It was in good agreement with the experimental results. This strategy provided deeper insight into the distribution of the SERS effect on a single anisotropic nanoparticle.

Polymer nanopillar array with Au nanoparticle inlays as a flexible and transparent SERS substrate

“…The EF can reach an order of magnitude of 10 6 by using the method mentioned in a previous report. 30 Thus, this novel substrate can efficiently enhance the Raman signal intensities of molecules adsorbed on it.…”

Design of Inverted Nano-Cone Arrayed SERS Substrate for Rapid Detection of Pathogens

“…where λ is the incident wavelength and λ s is the Raman scattering wavelength, E is the local electric field intensity, and E 0 is the incident electric field intensity. Since the frequency shift due to Raman scattering is small compared to the incident wavelength, the enhancement factor (EF) can be written as [12]:…”

Special issue on surface-enhanced Raman spectroscopy

“…The increase of SERS efficiency by the generation of the plasmonic intercouplings, known as hot spots, [20] and some of their methods of preparation are reported for gold nanoparticle monolayer films [21,22], gold nanorods [23] or discrete plasmonic microparticles [24]. Regarding the preparation of the plasmonic materials for SERS, here we include examples of gold nanostars [25], hybrid magnetic plasmonic particles [26], hybrid polymer nanoparticle films [27] and silica coated plasmonic films [28] and particles [29]. Finally, the potential of SERS to solve real life applications is illustrated through monitoring of the molecular dynamics of a chromophore [30]; the ultrasensitive detection of the chemotherapeutic agent paclitaxel [31], glucose [32] or DNA [33] and their modifications [34]; and the 3D intracellular monitoring of the transportation of nanoparticles in the cytosol [35].…”