Metallic temperature dependence of resistivity in polypyrrole and poly(3-methylthiophene) at low temperatures with and without pressure

Masubuchi, S.; Fukuhara, Tadashi; Kazama, S.

doi:10.1016/s0379-6779(96)04070-2

Cited by 14 publications

(19 citation statements)

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“…The frequency-dependent complex conductivity of conducting polymers is one of the most important properties of these materials, [1][2][3][4] associated with the 2000 Nobel Prize in Chemistry. THz time-domain spectroscopy ͑THz-TDS͒ has recently been shown to be the ideal tool to characterize the carrier dynamics in conducting polymers, 3 similar to the previous THz-TDS characterizations of semiconductors.…”

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confidence: 99%

Electrical and optical characterization of conducting poly-3-methylthiophene film by THz time-domain spectroscopy

Jeon

Grischkowsky

Mukherjee

et al. 2001

Applied Physics Letters

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Using THz time-domain spectroscopy ͑THz-TDS͒, we have measured the absorption and dispersion of 7.5/͑⍀ cm͒ conducting poly-3-methylthiophene film from low frequencies up to 4 THz. From these measurements the complex conductance that increases with increasing frequency was obtained over this frequency range. The results do not follow simple Drude theory and are not comparable with normal metal and semiconductors; the results were well fit by the localization-modified Drude theory. © 2001 American Institute of Physics. ͓DOI: 10.1063/1.1427754͔The frequency-dependent complex conductivity of conducting polymers is one of the most important properties of these materials, 1-4 associated with the 2000 Nobel Prize in Chemistry. THz time-domain spectroscopy ͑THz-TDS͒ has recently been shown to be the ideal tool to characterize the carrier dynamics in conducting polymers, 3 similar to the previous THz-TDS characterizations of semiconductors.5-10 It is not possible to electrically characterize conducting polymers by simple electrical measurements using mechanical contacts, e.g., Hall effect measurements. For such characterization ohmic contacts would have to be fabricated on the polymer itself. The previous far-infrared Fourier transform spectroscopy reflectivity measurements for conducting polymers require the Kramers-Kronig analysis to calculate the absorption and dispersion of the samples.1,2 In our THz-TDS measurements we directly measure both the absorption and dispersion of the conducting polymer film.In the simple Drude theory picture of conduction the key parameters describing the dynamics of free carriers in a material are the plasma frequency p and the carrier damping rate ⌫ϭ1/, where is the carrier collision time. Because p and ⌫ characteristically have THz values, measurements spanning the values of these parameters must be performed in the THz frequency range.3,5-10 The experiments described in this letter present such THz-TDS measurements on a free standing 15 m thick film of 7.5/͑⍀ cm͒ low conductivity poly-3-methylthiophene, prepared electrochemically at Ϫ40°C. Our results determine, for the first time, the absorption and index of refraction from low frequencies to beyond 4 THz. The fact that the measured frequency-dependent absorption and index of refraction are mostly due to the free carriers allows the complex conductivity to be determined from the measurements over the full frequency range. In contrast to the previous THz-TDS measurement of the 215/ ͑⍀ cm͒ high conductivity polypyrrole which was well fit by Drude theory, 3 here for a 30 times lower conductivity 7.5/ ͑⍀ cm͒ sample of poly-3-methylthiophene, the results can only be fit by the localization-modified Drude theory. For the THz-TDS system, a GaAs transmitting antenna with a simple coplanar transmission line geometry and a silicon on sapphire receiving antenna consisting of a micron size dipole antenna embedded in a coplanar transmission line are optoelectronically driven by 16 mW average power beams of 65 fs pulses from a mode-locked Ti:sapphi...

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confidence: 99%

Electrical and optical characterization of conducting poly-3-methylthiophene film by THz time-domain spectroscopy

Jeon

Grischkowsky

Mukherjee

et al. 2001

Applied Physics Letters

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“…T for 1 H below 150 K is less for p3MT-1 than for p3MT-2. 5.Unlike 1 H-T1, 19 F relaxation rate (Fig. 4b) show a crossover in relaxation rate between these two samples at T ~ 25 K; i.e., …”

Section: B Presentation Of the 1 H And 19 F Nmr T1 Datamentioning

confidence: 85%

“…Measurement of the doping level in the two samples has been carried out at 0.9 T, by taking the ratio of the number of 19 F spins to that of 1 H spins. For this purpose, the experiment has been conducted in the following manner.…”

Section: Methodsmentioning

confidence: 99%

“…Proton and Fluorine NMR relaxation rate has been studied as a function of temperature (3-300 K) and field (for protons at 0.9 T, 9.0 T, 16 μ 〈 T 〈 TBPP, the temperature where the contribution from the reorientation motion to the T1 is insignificant) -relaxation mechanism is via spin diffusion to the paramagnetic centers (SDPC) and (c) in the high temperature regime and atlow Larmor frequency-the relaxation follows the modified Bloembergen, Purcell and Pound (BPP) model.T1 data analysis has been carried out in the light of these models depending upon the temperature and frequency range of study.Fluorine relaxation data has been analyzed and attributed to the PF6 reorientation. The cross relaxation among the 1 H and 19 F nuclei has been observed in the entire temperature range suggesting the role of magnetic dipolar interaction modulated by the reorientation of the symmetric molecular sub-groups.The data analysis shows that the enhancement in Korringa ratio is more in less conducting sample. Intra and inter chain hopping of charge carriers is found to be a dominant relaxation mechanism at low temperature.…”

mentioning

confidence: 89%

“…The 1 H measurements in the p3MT-1 sample were done at four values of B (0.9, 9.0, 16.4 and 23.4 T) as shown in Fig. 4a, while the p3MT-2 sample was measured only at 0.9 T. 19 F-T1 measurement at 9.0Tis also doneusing FID signals (Fig. 4b).…”

Section: Introductionmentioning

confidence: 99%

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NMR relaxation studies in doped poly-3-methylthiophene

et al. 2015

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Abstract:NMR relaxation rates (1/T1), magnetic susceptibility, and electrical conductivity studies in doped poly-3-methylthiophene (p3MT) are reported in this study. The magnetic susceptibility data show the contributions from both Pauli and Curie spins, with the size of the Pauli term depending strongly on the doping level. Proton and Fluorine NMR relaxation rate has been studied as a function of temperature (3-300 K) and field (for protons at 0.9 T, 9.0 T, 16.4 T, 23.4 T and for fluorine 9.0 T). The temperature dependence of T1 is classified into three regimes: (a) for ( )-relaxation mechanism follows modified Korringa relation due to EEI and disorder. 1 H-T1 is due to the electron-nuclear dipolar interaction in addition to the contact term. (b) for intermediate temperature rangeμ 〈 T 〈 TBPP, the temperature where the contribution from the reorientation motion to the T1 is insignificant) -relaxation mechanism is via spin diffusion to the paramagnetic centers (SDPC) and (c) in the high temperature regime and atlow Larmor frequency-the relaxation follows the modified Bloembergen, Purcell and Pound (BPP) model.T1 data analysis has been carried out in the light of these models depending upon the temperature and frequency range of study.Fluorine relaxation data has been analyzed and attributed to the PF6 reorientation. The cross relaxation among the 1 H and 19 F nuclei has been observed in the entire temperature range suggesting the role of magnetic dipolar interaction modulated by the reorientation of the symmetric molecular sub-groups.The data analysis shows that the enhancement in Korringa ratio is more in less conducting sample. Intra and inter chain hopping of charge carriers is found to be a dominant relaxation mechanism at low temperature. Frequency dependence of

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Conducting Polymers

Foot

Kaiser

2004

Kirk-Othmer Encyclopedia of Chemical Technology

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This article gives an overview of the field of electrically conducting organic polymers. The first major section describes the synthesis of the various types of conjugated conducting polymer as well as conducting polymer blends and composites. This is followed by a discussion of the redox doping required to form charge carriers, the optical properties of the polymers, and the electrical conduction properties of metallic and semiconducting polymers. A short section is devoted to the stability of different conducting polymers. The final section outlines some of the principal applications of these polymers, including electromagnetic shielding and charge dissipation, corrosion‐inhibiting paints, composite materials, charge‐storage batteries, actuators, chemical and biochemical sensors, gas separation membranes, electrochromism, polymer LEDs, laser diodes and photovoltaic cells, and plastic electronics.

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Metallic temperature dependence of resistivity in polypyrrole and poly(3-methylthiophene) at low temperatures with and without pressure

Cited by 14 publications

References 10 publications

Electrical and optical characterization of conducting poly-3-methylthiophene film by THz time-domain spectroscopy

Electrical and optical characterization of conducting poly-3-methylthiophene film by THz time-domain spectroscopy

NMR relaxation studies in doped poly-3-methylthiophene

Conducting Polymers

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