Spectroelectrochemical Studies of Electrochemically Prepared Poly‐3‐Methylthiophene

Hoier, Sally N.; Ginley, David S.; Park, Su‐Moon

doi:10.1149/1.2095597

Cited by 40 publications

(15 citation statements)

References 14 publications

(27 reference statements)

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“…This low n value is probably due to the fact that the redox species are in the solid state and therefore not really in equilibrium. Similar relations have been reported for polyalkylthiophenes 8 and for polymethylthiophene from UV-visible experiments, 34 with comparable values of the number of transferred electrons.…”

Section: Sers On Ag and Cu Massive Electrodes Ex Situ Sers Analysessupporting

confidence: 85%

Ex situ and in situ SERS analyses of polybithiophene using roughened Ag and Cu electrodes and multilayer SERS‐active systems

Bazzaoui¹,

Aubard

Félidj

et al. 2005

J Raman Spectroscopy

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Electrochemical deposition of polybithiophene (PbT) films on suitably roughened silver and copper electrodes enabled us to record surface-enhanced Raman scattering (SERS) spectra of oxidized and reduced species showing the important changes in the spectral features of the different oxidation states of the polymer film. The comparison between SERS spectra and Raman spectra of PbT electrosynthesized on platinum allowed the identification of vibrational modes which are the most sensitive to the surface enhancement effect. The orientation and the anchorage mode of the polymer rings, during the first stages of electropolymerization, were estimated according to the SERS selection rules. In situ SERS analyses revealed that the spectral changes observed during the doping process are due to a transition from aromatic to quinoid structure and to an increase in structural defects along the polymer chain. Ex situ and in situ SERS studies were also carried out using various multilayer SERS-active systems in which the polymer is either electrodeposited on a thin layer of a SERS-active metal coating an iron electrode or sandwiched between the thin SERS-active layer and the iron support.

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Section: Sers On Ag and Cu Massive Electrodes Ex Situ Sers Analysessupporting

confidence: 85%

Ex situ and in situ SERS analyses of polybithiophene using roughened Ag and Cu electrodes and multilayer SERS‐active systems

Bazzaoui¹,

Aubard

Félidj

et al. 2005

J Raman Spectroscopy

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“…The spectra shown in Figure 2a-c are in excellent agreement with those published previously in the literature. 21,22,25 The band at about 490 nm, which represents the band gap of this polymer, is the result of the ir-ir* transition, whereas one at about 720 nm has been assigned to be one of two bands arising from the bipolaron. 22,27,28 The NIR spectra shown in Figure 2d can be characterized as having two broad absorption peaks at about 1200 and 1600 nm depending on the applied potential.…”

Section: Resultsmentioning

confidence: 99%

“…Although the potential region where the signal rises and decays is somewhat similar for these two transitions (Figure 3a,b), their spectroscopic behaviors are reported to be different. 25 DCVA signals at 720 nm recorded for various film thicknesses are shown in Figure 4a. While the shapes of DCVA signals are similar to each other, the potential, at which maximum DCVA signals are observed, becomes more positive from about 0.50 to about 0.75 V as the thickness increases.…”

Section: Resultsmentioning

confidence: 99%

Electrochemistry of conductive polymers. 11. Spectroelectrochemical studies of poly(3-methylthiophene) oxidation

Hoier¹,

Park²

1992

J. Phys. Chem.

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The oxidation of electrochemically grown poly(3-methylthiophene) and its other spectroscopic properties have been studied by in-situ spectroelectrochemlcal techniques as well as in-situ conductivity measurements, and the results are reported. An absorptivity of 1.1 X 105 cm'1 is reported for the absorption band at 490 nm for a neutral, reduced polymer film grown in propylene carbonate. The oxidation of the neutral polymer to the cation radical, or polaron, and its further oxidation to the dication, or bipolaron, are shown to take place at about 0.45 and 0.80 V, respectively, and be controlled by the diffusion of counterions. In-situ conductivity measurements of the film show that both the polaron and bipolaron are charge carriers. We conclude from the results that at least two chemically and optically different species, radical cation and dication, and perhaps other products, are produced in different potential regimes upon oxidation of poly(3-methylthiophene).

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“…One of the most interesting aspects of these polymers is their spectroelectrochemical behavior (5)(6)(7). For these electroconducting polymers, spectroelectrochemical studies have been intensively carried out (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The absorption spectra are quantitatively analyzed using the Nernst equation, and the formal electrode potentials and "n-values" (the number of electrons transferred during the redox reactions) are then obtained (8)(9)(10)(11).…”

mentioning

confidence: 99%

“…For these electroconducting polymers, spectroelectrochemical studies have been intensively carried out (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The absorption spectra are quantitatively analyzed using the Nernst equation, and the formal electrode potentials and "n-values" (the number of electrons transferred during the redox reactions) are then obtained (8)(9)(10)(11). Furthermore, Marque and Roneali (11) carried out comparative spectroelectrochemical studies of three-substituted polythiophenes and analyzed the deviations of the Nernst plots…”

mentioning

confidence: 99%

Analyses of Spectroelectrochemical Behavior of Polypyrrole Films Using the Nernst Equation: “Monomer Unit Model” and Polaron/Bipolaron Model

Amemiya

Hashimoto

Fujishima

et al. 1991

J. Electrochem. Soc.

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q ABSTRACT A series of the absorption spectrum changes in polypyrrole films were analyzed using the Nernst equation by two models. One is the " m o n o m e r unit model" and the other is the "polaron/bipolaron model." In the first model, formal electrode potentials and the n-values were obtained and usec~ to fit calculated hAbs vs. E curves to the experimental plots at three wavelengths. In the second model, the "apparent" excess chemical potentials were introduced to correct for the large deviations between the Nernst equation and the Nernst plots obtained from the absorption spectra. The calculated hAbs vs. E curves were then fitted to the experimental plots. The "apparent" excess chemical potentials were assigned as corrections for species concentrations. Advantages of the monomer unit model over the polaron/bipolaron model are pointed out in the precise analyses of the spectroelectrochemical behavior of the films.Electroconducting polymers, such as polypyrroles, polythiophenes, and polyanilines, have been recently receiving m u c h attention because they can be easily prepared by electrochemical polymerization, are stable in air, and also have unique electronic, electrochemical, and optical properties (1-4). One of the most interesting aspects of these polymers is their spectroelectrochemical behavior (5-7). For these electroconducting polymers, spectroelectrochemical studies have been intensively carried out (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The absorption spectra are quantitatively analyzed using the Nernst equation, and the formal electrode potentials and "n-values" (the number of electrons transferred during the redox reactions) are then obtained (8-11). Furthermore, Marque and Roneali (11) carried out comparative spectroelectrochemical studies of three-substituted polythiophenes and analyzed the deviations of the Nernst plots) from linearity in terms of (i) the coulombic interactions between charged sites, and (ii) the mechanical work required to expand the polymer lattice by the insertion of counterions and solvent molecules. The c o m m o n and important points and/or assumptions in these studies (8)(9)(10)(11) are that the redox reactions of these polymers can be described by one " m o n o m e r unit," not by several m o n o m e r units of the polymers. From now on, we call the treatment of the redox reactions of electroconducting polymers in terms of m o n o m e r units as "monomer unit model."In addition, redox reactions (including spectroelectrochemical behavior) of the electroconducting polymer (polypyrrole) can be analyzed (12, 13) using the Nernst equation in terms of a polaron/bipolaron model (3). This model treats the polymers in several monomer units having +1 or +2 charges, and describes the redox reactions of the polymers by these units. Therefore, the number of electrons transferred during the redox reactions are + 1 or +2 by this model. According to such analyses (13), excess chemical potentials must be introduced to explain nonNernstian behavior of the polymer. They we...

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Spectroelectrochemical Studies of Electrochemically Prepared Poly‐3‐Methylthiophene

Cited by 40 publications

References 14 publications

Ex situ and in situ SERS analyses of polybithiophene using roughened Ag and Cu electrodes and multilayer SERS‐active systems

Ex situ and in situ SERS analyses of polybithiophene using roughened Ag and Cu electrodes and multilayer SERS‐active systems

Electrochemistry of conductive polymers. 11. Spectroelectrochemical studies of poly(3-methylthiophene) oxidation

Analyses of Spectroelectrochemical Behavior of Polypyrrole Films Using the Nernst Equation: “Monomer Unit Model” and Polaron/Bipolaron Model

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