Abstract
A nanoparticle’s shape and size determine its optical properties. Nanorods are nanoparticles that have double absorption bands associated to surface plasmon oscillations along their two main axes. In this work, we analize the optical response of gold nanorods with numerical simulations and spectral absorption measurements to evaluate their local field enhancement—which is key for surface-enhanced Raman spectroscopic (SERS) applications. Our experimental results are in good agreement with finite element method (FEM) simulations for the spectral optical absorption of the nanoparticles. We also observed a strong dependence of the optical properties of gold nanorods on their geometrical dimension and shape. Our numerical simulations helped us reveal the importance of the nanorods’ morphology generated during the synthesis stage in the evaluation of absorption and local field enhancement. The application of these gold nanorods in surface-enhancement Raman spectroscopy is analyzed numerically, and results in a amplification factor when comparing the values obtained for the nanorod deposited on a dielectric substrate compared to the nanorod immersed in water.
Highlights
A nanoparticle’s shape and size determine its optical properties
Geometry, and material composition [13–17] Metallic nanoparticles have attracted great interest in biomedical applications due to their optical, electrical, and magnetic properties as a function of their size and morphology which can be tuned during the synthesis process [18–21]
Considering the metallic character of our nanorods, we can assume that absorption is much stronger than scattering, and the results for σabs describes well the spectral behavior of these nanoparticles
Summary
A nanoparticle’s shape and size determine its optical properties. Nanorods are nanoparticles that have double absorption bands associated to surface plasmon oscillations along their two main axes. We analize the optical response of gold nanorods with numerical simulations and spectral absorption measurements to evaluate their local field enhancement—which is key for surface-enhanced Raman spectroscopic (SERS) applications. Our numerical simulations helped us reveal the importance of the nanorods’ morphology generated during the synthesis stage in the evaluation of absorption and local field enhancement The application of these gold nanorods in surface-enhancement Raman spectroscopy is analyzed numerically, and results in a 5.8 × 104 amplification factor when comparing the values obtained for the nanorod deposited on a dielectric substrate compared to the nanorod immersed in water. The two characteristic lengthts of the nanorod’s geometry are intrinsically related to the excitation of surface plasmons at two different wavelengths The presence of these two modes gives them an advantage over other nanoparticle shapes. This characteristic can help amplify the Raman effect—strong field enhancement that increase the optical response—for two wavevelengths with a single nanoparticle [29–33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
