Impedance change induced by varying polymerization temperature of conducting polymer thin films

Vyas, Ritesh N.; Wang, Bin

doi:10.1016/j.elecom.2007.12.031

Cited by 11 publications

(5 citation statements)

References 43 publications

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“…Z d accounts for the Warburg impedance due to the mass transfer of the redox species to the electrode as represented by Warburg slope, and R s is the solution resistance. The equivalent circuit provides an excellent fit (<5% error) to the experimental data as summarized in Table 2 [ 48 ]. Compared to sample IV , increases in values of R f by a factor of 1.6, 6.5 and 20, and R ct by a factor of 1.5, 4.8, and 17 were observed for samples I , II , and III , respectively.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Analysis of Conducting Polymer Thin Films

Vyas

Wang

2010

IJMS

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Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene) (PPV), in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values.

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Section: Resultsmentioning

confidence: 99%

Electrochemical Analysis of Conducting Polymer Thin Films

Vyas

Wang

2010

IJMS

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“…Specifically, we employ electrochemical impedance spectroscopy (EIS) to characterize the ionic transport behavior of POM-embedded ultrathin films. EIS has been widely used as a versatile technique to characterize interfacial and transport properties of polymer films adsorbed on surface of an electrode. , The estimation of parameters such as diffusion coefficient and electron-transfer rate constant can explain the kinetics at interfaces; thus this technique becomes relatively easy and accurate as compared to other techniques. – We have employed the EIS technique to study ionic mass transfer in the conducting polymer LbL structure and oxygen reduction reaction in POM LbL films . In applying EIS for electrochemical system analysis, an important consideration is to fit experimental data to a suitable model .…”

Section: Introductionmentioning

confidence: 99%

“…39,40 The estimation of parameters such as diffusion coefficient and electron-transfer rate constant can explain the kinetics at interfaces; thus this technique becomes relatively easy and accurate as compared to other techniques. [41][42][43] We have employed the EIS technique to study ionic mass transfer in the conducting polymer LbL structure 44 and oxygen reduction reaction in POM LbL films. 45 In applying EIS for electrochemical system analysis, an important consideration is to fit experimental data to a suitable model.…”

Section: Introductionmentioning

confidence: 99%

Modifying Randles Circuit for Analysis of Polyoxometalate Layer-by-Layer Films

Vyas

Wang

2010

J. Phys. Chem. B

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Multilayer films with anionic phosphomolybidic acid (PMo(12)) clusters have been fabricated via the electrostatic layer-by-layer (LbL) method. The charged mass transport phenomena of these thin films have been studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with [Fe(CN)(6)](3-/4-) and [Ru(NH(3))(6)](3+/2+) as the redox probes. By adding a film resistance and a film capacitance to the conventional Randles equivalent circuit, we can calculate the diffusion coefficient values that help understand the microscopic nature of the thin films. When the negatively charged probe [Fe(CN)(6)](3-/4-) was used, lower diffusion coefficients were obtained for multilayers deposited from higher ionic strength solutions. This relationship was less obvious when the positively charged probe [Ru(NH(3))(6)](3+/2+) was used, in which the electrostatic attraction between PMo(12) clusters and the probe ions complicates the mass-transfer process. It is believed that the addition of salt to dipping solutions increases the tortuosity of the films so the mass transport takes longer paths, inducing lower diffusion coefficients. Higher PMo(12) loading causes lower diffusion coefficients due to the polyoxometalate clusters blocking the paths for charged probe ions.

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“…When working on POM films, by adjusting the potential, we can probe both ionic and electronic diffusions in the same structure. We can also incorporate conducting polymers [4,5] and utilize the doping/dedoping method to probe such diffusions. Other than the LbL method, Langmuir-Blodgett (LB) technique can be used to produce nanoscale films.…”

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confidence: 99%