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 language | English (US) |
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Pages (from-to) | 14263-14269 |
Number of pages | 7 |
Journal | Journal of Physical Chemistry C |
Volume | 127 |
Issue number | 29 |
DOIs | |
State | Published - Jul 27 2023 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- General Energy
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films