Peculiarities of the SERS Spectra of the Hydroquinone Molecule Adsorbed on Titanium Dioxid

TL;DR

This paper investigates the SERS spectra of hydroquinone on titanium dioxide nanoparticles, revealing size-dependent enhancement, forbidden lines due to quadrupole interactions, and agreement with semiconductor SERS theory.

Contribution

It demonstrates the influence of nanoparticle size on SERS enhancement and highlights the role of quadrupole interactions in forbidden line appearance on dielectric substrates.

Findings

Stronger enhancement with larger nanoparticles.

Presence of forbidden lines in the spectra.

Quadrupole light-molecule interactions are significant.

Abstract

The SERS spectrum of hydroquinone, adsorbed on nanoparticles of titanium dioxide is analyzed. It is pointed out that the enhancement is stronger for larger mean size of nanoparticles that is in an agreement with the electrostatic approximation. In addition it is found that there are the lines, which are forbidden in usual Raman spectra. Along with this there is the enhancement, caused both by the normal and tangential components of the electric field. This result is in agreement with the theory of SERS on semiconductor and dielectric substrates. Discovery of the forbidden lines indicates sufficiently large role of the strong quadrupole light-molecule interaction in such a system.