A1 Refereed original research article in a scientific journal
In situ resonant Raman and ESR spectroelectrochemical study of electrochemically synthesized poly(p-phenylenevinylene)
Authors: Damlin P, Kvarnstrom C, Petr A, Ek P, Dunsch L, Ivaska A
Publisher: SPRINGER-VERLAG
Publication year: 2002
Journal:: Journal of Solid State Electrochemistry
Journal name in source: JOURNAL OF SOLID STATE ELECTROCHEMISTRY
Journal acronym: J SOLID STATE ELECTR
Volume: 6
Issue: 5
First page : 291
Last page: 301
Number of pages: 11
ISSN: 1432-8488
DOI: https://doi.org/10.1007/s100080100240
Abstract
The electrochemical synthesis of poly(p-phenylenevinylene) (PPV) and different modifications in the electronic distribution upon electrochemical p-doping (oxidation) and n-doping (reduction) of this polymer film have been studied in situ by resonance Raman spectroscopy, optical absorption spectroscopy and ESR spectroscopy. The polymer film has been prepared by electrochemical reduction of alpha,alpha,alpha',alpha'-tetrabromo-p-xylene in dimethylformamide using tetraethylammonium tetrafluoroborate as the electrolyte salt. During electrochemical polymerization the position and relative intensities of the Raman bands change regularly as the chain length increases and finally converge on values reported for chemically prepared PPV. The Raman spectra for electrochemically polymerized PPV is compared to infrared-active vibration bands for electrochemically n-doped PPV. When the polymer undergoes redox reactions (doping-dedoping), shifts and broadening of Raman bands, compared to neutral PPV, are observed. Interpretation of the Raman spectra and the ESR results led to the conclusion that charge transfer in this system is mainly accomplished by polaron species formed upon doping of the polymer. In this reaction the quinoid structure is formed rather than the benzenoid structure.
The electrochemical synthesis of poly(p-phenylenevinylene) (PPV) and different modifications in the electronic distribution upon electrochemical p-doping (oxidation) and n-doping (reduction) of this polymer film have been studied in situ by resonance Raman spectroscopy, optical absorption spectroscopy and ESR spectroscopy. The polymer film has been prepared by electrochemical reduction of alpha,alpha,alpha',alpha'-tetrabromo-p-xylene in dimethylformamide using tetraethylammonium tetrafluoroborate as the electrolyte salt. During electrochemical polymerization the position and relative intensities of the Raman bands change regularly as the chain length increases and finally converge on values reported for chemically prepared PPV. The Raman spectra for electrochemically polymerized PPV is compared to infrared-active vibration bands for electrochemically n-doped PPV. When the polymer undergoes redox reactions (doping-dedoping), shifts and broadening of Raman bands, compared to neutral PPV, are observed. Interpretation of the Raman spectra and the ESR results led to the conclusion that charge transfer in this system is mainly accomplished by polaron species formed upon doping of the polymer. In this reaction the quinoid structure is formed rather than the benzenoid structure.
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