SERS Detection of Charge Transfer at Electrochemical Interfaces Using Surface-Bound Ferrocene

Ruoxi Li, Imran Chaudhry, Cindy Tseng, Sizhe Weng, Yu Wang, Bofan Zhao, Indu Aravind, Zhi Cai, Jahan Dawlaty, Lasse Jensen, Stephen B. Cronin

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We present the novel use of surface-enhanced Raman scattering spectroscopy to detect charge transfer in ferrocene/ferrocenium (Fc/Fc+) bound to an active electrode under electrochemical working conditions. Ferrocene has a 6-carbon linker with a thiol tether (6-(ferrocenyl)hexanethiol) and produces Fc/Fc+ couple voltammograms exhibiting charge transfer above 0.4 V versus Ag/AgCl. By observing in situ micro-Raman spectroscopy with a water immersion lens, we observe significant changes in the spectra that correspond to the charge state oxidation of ferrocenium (Fc+). In particular, the Fc+ state is characterized by the disappearance of the Cp-breathing mode (1104 cm-1 peak) and an 11-fold increase in the hexanethiol tail mode around 1072 cm-1. Raman spectra calculated by density functional theory exhibit predominant peaks that agree well with our experimental observations and indicate that the Fc → Fc+ transition is associated with a change in the orientation, which gives rise to dramatic changes in the Raman spectra.

Original languageEnglish (US)
Pages (from-to)14263-14269
Number of pages7
JournalJournal of Physical Chemistry C
Volume127
Issue number29
DOIs
StatePublished - Jul 27 2023

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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