A1 Refereed original research article in a scientific journal
UV-Vis and Raman spectroelectrochemistry of electrodeposited polypyrrole in hexafluorophosphate
Authors: Kepas A, Grzeszczuk M, Kvarnstrom C, Lindfors T, Ivaska A
Publisher: POLISH CHEMICAL SOC
Publication year: 2007
Journal:: Polish Journal of Chemistry
Journal name in source: POLISH JOURNAL OF CHEMISTRY
Journal acronym: POL J CHEM
Volume: 81
Issue: 12
First page : 2207
Last page: 2214
Number of pages: 8
ISSN: 0137-5083
Abstract
UV-Vis and Raman spectroscopy are very useful and powerful techniques to characterize the structure of conjugated polymers in various states. Spectroelectrochemical measurements were performed in a three-electrode cell containing polypyrrole (PPY) films as active layers in contact with NaPF6 aqueous electrolyte. UV-Vis spectroscopy was used to characterize the neutral (undoped) and oxidized (p-doped) states of polypyrrole upon electrochemical p-doping. Raman measurements were done with the excitation wavelengths of 5 14, 633 and 780 nm. It is shown how the vibrational modes of PPY were influenced by the applied laser wavelength. The neutral form was found to be strongly resonance enhanced with the 514 nm excitation wavelength and the corresponding Raman bands dominate the spectra. Spectra obtained using the 633 nm excitation wavelength displayed a strong contribution of the neutral form, but noticeable bands due to the radical cation and dication were also visible. The spectra recorded using the 780 nm excitation line are dominated by Raman bands of the radical cation and dication.
UV-Vis and Raman spectroscopy are very useful and powerful techniques to characterize the structure of conjugated polymers in various states. Spectroelectrochemical measurements were performed in a three-electrode cell containing polypyrrole (PPY) films as active layers in contact with NaPF6 aqueous electrolyte. UV-Vis spectroscopy was used to characterize the neutral (undoped) and oxidized (p-doped) states of polypyrrole upon electrochemical p-doping. Raman measurements were done with the excitation wavelengths of 5 14, 633 and 780 nm. It is shown how the vibrational modes of PPY were influenced by the applied laser wavelength. The neutral form was found to be strongly resonance enhanced with the 514 nm excitation wavelength and the corresponding Raman bands dominate the spectra. Spectra obtained using the 633 nm excitation wavelength displayed a strong contribution of the neutral form, but noticeable bands due to the radical cation and dication were also visible. The spectra recorded using the 780 nm excitation line are dominated by Raman bands of the radical cation and dication.
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