Counterion-induced processibility of polyaniline: Thermoelectric power

Yoon, C.O.; Reghu, M.; Moses, D.; Heeger, Alan J.; Cao, Yong

doi:10.1103/physrevb.48.14080

Cited by 106 publications

(80 citation statements)

References 24 publications

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“…These values are significantly smaller than in typical metal (ϳ10 22 cm Ϫ3 ), but also considerably larger than in a typical semiconductor (ϳ10 15 Table II, suggesting, in accordance with the theory, 7 that disorder induces the free carrier localization at low frequencies. From the differences in the number of carriers between these two models, the percentage of the localized carriers, L, can be estimated.…”

supporting

confidence: 76%

“…4,8,12,15 They can provide a qualitative sense of the extent of the disorder present in the sample, since the conductivity is dependent upon the relaxation time, which is controlled by the scattering processes occurring in the material and is, therefore, sensitive to the presence of any disorder in the system. In order to achieve this, the activation energy Wϭd(ln )/d(ln T), being far more sensitive than the conductivity itself 16 can be used, when the sample shows a weakly negative TCR, at temperatures usually below 40 K. W has a positive temperature coefficient for a sample in the metallic regime, it is temperature independent for a sample in the critical regime and has a negative temperature coefficient for a sample at the insulating side of the I-M transition.…”

Section: A Temperature-dependent Conductivity Measurementsmentioning

confidence: 99%

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Doping-dependent studies of the Anderson-Mott localization in polyaniline at the metal-insulator boundary

et al. 2002

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Publisher's copyright statement:Reprinted with permission from the American Physical Society: Physical Review B 66, 085202 c 2002 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Temperature-dependent dc conductivity measurements and infrared reflectivity measurements ͑20-9000 cm Ϫ1͒ were performed on a series of polyaniline samples with two different dopant acids at various doping levels. The typical fingerprints of a disordered metal such as a positive temperature coefficient of resistivity at high temperatures, a very high reflectivity in the far infrared, and a plasma resonance have been observed. The results were analyzed in the framework of the Anderson-Mott localization model and considerable consistency between transport studies and optical measurements was obtained. Various parameters enabling a comparative classification of the materials are also reported.

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supporting

confidence: 76%

Section: A Temperature-dependent Conductivity Measurementsmentioning

confidence: 99%

Doping-dependent studies of the Anderson-Mott localization in polyaniline at the metal-insulator boundary

et al. 2002

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“…Polyacetylene nanofibres have been found to show a temperature-independent highly nonlinear Zener-type behaviour at low temperatures, but FIGURE 4 Thermopower of conducting polymers polyacetylene (PA) [20], polyaniline (PAni) [21], polypyrrole (PPy) [22] and polythiophene (PT) [23] (a) compared to the thermopower of the superconductor Ni 0.64 Zr 0.36 [25] (T c ¼ 2.54 K) (b). The fits are to the electron-phonon thermopower enhancement theory [24] for Ni 0.64 Zr 0.36 and PT, while linear fits are shown for the other polymers.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, as shown in Figure 4(a), the most highly conducting polymers [20][21][22][23] show surprisingly good metallic diffusion thermopower behaviour (linear in temperature) over a wide temperature range. There is little evidence for the nonlinearities due to phonon drag effects seen in good crystalline metals.…”

Section: Thermopower and Implications For Superconductivitymentioning

confidence: 99%

Charge Transport in Conducting Polymers: Polyacetylene Nanofibres

Kaiser

Rogers

Park

2004

Molecular Crystals and Liquid Crystals

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The preparation of individual polyacetylene nanofibres has allowed a more probing investigation of the properties of polyacetylene. A significant discovery is that at low temperatures, polyacetylene nanofibres show temperature-independent Zener-type tunnelling, that we suggest is tunnelling of the conjugated-bond pattern along single polyacetylene chains. At higher temperatures, the current shows a strong increase with temperature and the nonlinearity of the current-voltage characteristics decreases. We make a comparison with similar behaviour found in single-wall carbon nanotube networks, and show that the decrease in nonlinearity is consistent with our generic calculations for fluctuation-assisted tunnelling and thermal excitation. There is no evidence for superconductivity in resistance measurements on polyacetylene. The thermoelectric power of polyacetylene and other bulk organic conducting polymers indicates the absence of significant superconductivity arising from the conventional electron-phonon mechanism.

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“…In case of variable-range hopping conductivity the thermopower has form like BT T A [8][9][10][11][12], and in case the nearest neighbors hopping conductivity BT T A / [13][14][15]. Cleanly linear temperature dependence [16,17] is often observed also. Similar behavior is peculiar to metals, in which thermopower is described by Mott formula…”

Section: Introductionmentioning

confidence: 99%

On the temperature dependence of the thermoelectric power in disordered semiconductors

Parfenov

Shklyaruk

2007

Semiconductors

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At low temperature using thermodynamics of irreversible processes the general expressions for the temperature dependence of the thermopower in the case of the hopping conductivity for disordered materials are found. The account of influence of impurity levels degeneration on the thermopower is lead. In a view of received results experimental data of the thermopower in amorphous and impurity semiconductors are discussed.

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Counterion-induced processibility of polyaniline: Thermoelectric power

Cited by 106 publications

References 24 publications

Doping-dependent studies of the Anderson-Mott localization in polyaniline at the metal-insulator boundary

Doping-dependent studies of the Anderson-Mott localization in polyaniline at the metal-insulator boundary

Charge Transport in Conducting Polymers: Polyacetylene Nanofibres

On the temperature dependence of the thermoelectric power in disordered semiconductors

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