Molecular and plasmonic resonances on tip-enhanced Raman spectroscopy

Xinmiao Qiu; Yuqing Cheng; Mengtao Sun

doi:10.1016/j.saa.2021.120360

Molecular and plasmonic resonances on tip-enhanced Raman spectroscopy

Spectrochim Acta A Mol Biomol Spectrosc. 2022 Jan 15:265:120360. doi: 10.1016/j.saa.2021.120360. Epub 2021 Sep 4.

Authors

Xinmiao Qiu¹, Yuqing Cheng², Mengtao Sun³

Affiliations

¹ School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, PR China; School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, PR China.
² School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, PR China.
³ School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, PR China. Electronic address: mengtaosun@ustb.edu.cn.

PMID: 34509891
DOI: 10.1016/j.saa.2021.120360

Abstract

Plasmon has been widely investigated and applied, because it can greatly enhance molecular Raman spectral intensity. In this study, the resonance Raman effect of the tetra-tert-butylnaphthalocyanine (TTBN) is analyzed, including the Raman wave number shift and enhancement factor, resulting from light of different incident wavelengths. Furthermore, the optical properties of TTBN are obtained, such as charge transfer, the electronic circular dichroism (ECD) spectrum, etc. Lastly, we study the tip-enhanced Raman spectroscopy (TERS) by adjusting the parameters of the metal tip to achieve the highest electromagnetic enhancement at different incident wavelengths. Combining the resonance excitation effect and the tip enhanced Raman effect, the enhancement factor of TERS can reach up to 10⁸-10⁹. This study provides significant help for a profound understanding of the TERS mechanism.

Keywords: Molecular resonance; Plasmonic resonance; Tip-enhanced Raman spectroscopy.