Simultaneous alternating current impedance/electron spin resonance study of electrochemical doping in polypyrrole

Waller, Andrew M.; Compton, Richard G.

doi:10.1039/f19898500977

Cited by 104 publications

(31 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…12,13,[16][17][18] The sub-band transitions of doped COPs were rationalized originally in terms of bipolaron formation since there is no correlation between ESR signals and conductivity. 9,[19][20][21][22] Preference for bipolarons has been questioned by some experimentalists from the start, 17,18,[23][24][25][26] but others rationalized their observations in terms of bipolarons. 13,16,22 Especially after the doping behavior of monodisperse polyenes [27][28][29] and oligothiophenes (OTs) [30][31][32][33][34][35][36][37][38][39][40][41] was investigated in solution, the bipolaron model was challenged.…”

Section: Introductionmentioning

confidence: 99%

“…[49][50][51] In the oligomer studies the issue of bipolaron formation was not addressed and the interpretation of polymer results remains controversial. 8,12,13,16,17,20,22,23,25,[52][53][54][55] Electronic structures of PPy and OPs have been investigated theoretically before; 20,[56][57][58][59][60][61][62][63][64][65][66][67][68][69][70] however, we are not aware of calculations of absorption spectra during the doping process of pyrrole oligomers or polymers. We have recently calculated such spectra for polyenes 71 and OTs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers

Okur

Salzner

2008

J. Phys. Chem. A

View full text Add to dashboard Cite

Changes in absorption spectra during doping of oligopyrroles were investigated with time-dependent density functional theory on optimized structures of neutral, singly, and doubly charged pyrrole oligomers with up to 24 rings. In the absence of counterions, defects are delocalized. Counterions induce localization. For dications two polarons on the same chain are preferred over a bipolaron. Intragap absorptions arise in charged species, no matter whether defects are localized or delocalized. Cations and dications give rise to two sub-band transitions. The cation peaks have lower energies than those of dications. The first excitations of cations have lower oscillator strengths than the second; for dications the second peak is weaker than the first. For very long oligomers, the second sub-band absorption vanishes and a third one appears at higher energy. The behavior of pyrrole oligomers is analogous to that of thiophene oligomers. Theoretical UV spectra for cations and dications of short oligomers (six to eight rings) match experimental spectra of polypyrrole at low and at high doping levels, respectively. The error in the theoretical calculations is about 0.4 eV, slightly larger than for thiophene oligomers at the same level of theory.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers

Okur

Salzner

2008

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…We propose an equivalent circuit to fit our results ( Figure 6) that contains an uncompensated resistance R S , a sub-circuit that consists of the PPy-DS | Electrolyte interface and other sub-circuit related to the Pt | PPy-DS interface. This circuit is derived from the one proposed by Waller and Compton 8 , but in our case we have added a constant phase element, CPE, related to the Warburg element that is responsible for the difusional part of the impedance spectra of the thicker films. The CPE is a general element represented by a general dispersion formula in admittance (Eq.…”

Section: Reduced Ppymentioning

confidence: 99%

Electrochemical impedance spectroscopy of dodecylsulphate doped polypyrrole films in the dark and under illumination

Martini¹,

Matencio²,

Alonso‐Vante³

et al. 2000

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Efeitos de morfologia, espessura, oxidação e iluminação dos filmes de polipirrol dopados com dodecilsulfato podem ser observados qualitativamente por EIS e consistem de variações de valores de resistências e capacitâncias de um circuito equivalente proposto, presentes nas interfaces e no interior do material. O circuito se ajusta bem para filmes sintetizados com densidade de carga de 190 mC cm -2 . Para filmes mais finos os valores calculados por espectroscopia de impedância eletroquímica (EIS) apresentam desvios provavelmente pela ausência de efeitos difusivos. A oxidação dos filmes causa uma diminuição geral da impedância em toda a faixa de freqüências medidas. Os efeitos de morfologia também são observados em todas as freqüências. Os efeitos de iluminação são reversíveis e aparecem, como esperado, apenas quando o polímero está na forma reduzida. A iluminação diminui a resistência interna e a capacitância de carga espacial e aumenta a resistência de transferência de carga e a capacitância de dupla camada.The morphology, thickness, oxidation and illumination effects in dodecylsulphate doped polypyrrole films can be qualitatively observed by EIS and consist in variations of interfacial and bulk resistances and capacitances of a proposed equivalent circuit. The circuit well with the measured spectra of films obtained with 190 mC cm -2 of synthesis charge density. For thinner films the calculated values observed by electrochemical impedance spectroscopy (EIS) deviate probably due to the absence of diffusion effects. The oxidation of the films diminishes the total impedance over the entire frequency range. The morphology effects are also observed in the entire spectra. The illumination effects are reversible and are observed as expected only in the reduced form of the polymer. The illumination reduces the internal resistance and the space-charge capacitance and increases the charge transfer resistance and the double layer capacitance.

show abstract

“…Examples include the electrochemical doping in polypyrrole [129,130] and the anodic oxidation of poly(N -vinylcarbazole) films [131].…”

Section: Modified Electrodesmentioning

confidence: 99%

EPR Spectroscopy in Electrochemistry

Wadhawan

Compton

2003

Encyclopedia of Electrochemistry

Self Cite

View full text Add to dashboard Cite

The sections in this article are Introduction Principles of EPR Spectroscopy EPR Theory The g ‐value Linewidths Spin‐lattice Relaxation Spin–spin Relaxation Hyperfine Structure EPR Instrumentation In Situ Electrochemical EPR : Cell Design The Bard–Goldberg Cell Cell Design Typical Applications The Allendoerfer Cells Cell Design The Coaxial Cell Application The Loop‐gap Resonator Cell Application The Channel Electrode Cell Cell Design Application The Albery In Situ Tube Electrode Cell Cell Design Application The In Situ Coaxial Flow Cell Cell Design Application The Bond In Situ Microelectrode Cell Cell Design Application The In Situ Wall‐jet Electrode Cell Cell Design Application The Dunsch–Petr–Neudeck Cell for In Situ UV ‐ VIS EPR Spectroelectro‐ chemistry Cell Design Application The Dryfe–Webster Cell for Charge Transfer Across a Liquid|Liquid Phase Boundary Cell Design Typical Applications Illustrative Examples of EPR in Electrochemistry Radical and Radical Ion Identification The Anodic Oxidation of para ‐Aminodiphenylamine ( PAD ) The Reduction of Dicyanobenzene The Reduction of C 60 Spin Trapping Electrode Reaction Kinetics and Mechanism EC Versus ECE ECE Versus DISP 1 EC ′ Comproportionation Reactions Photoelectrochemical EPR Modified Electrodes Electrochemical EPR in Ionic Liquids Conclusion Acknowledgments

show abstract

Simultaneous alternating current impedance/electron spin resonance study of electrochemical doping in polypyrrole

Cited by 104 publications

References 2 publications

Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers

Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers

Electrochemical impedance spectroscopy of dodecylsulphate doped polypyrrole films in the dark and under illumination

EPR Spectroscopy in Electrochemistry

Contact Info

Product

Resources

About