Electron spin resonance and relaxation studies on conducting poly(tetrathiafulvalenes)

Roth, H.-K.; Gruber, H.; Völkel, G.; Brunner, W.; Fanghänel, E.

doi:10.1007/bfb0115436

Cited by 11 publications

(2 citation statements)

References 15 publications

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“…lb). The amount of mobile polarons increases with the dopant concentration [4], due to chemical reaction and increasing mobility of the polymer matrix because of softening by large iodine ions.…”

Section: Nature and Composition Of Pcs In The Pttfmentioning

confidence: 99%

“…la) is a convenient polymer semiconductor for the study of fundamental dynamic processes which take place in conjugated compounds. Various PTTF samples were investigated earlier [4,5] using 3 cm waveband EPR and ESE magnetic resonance methods. It has been shown [5], that the EPR spectrum of doped PTTF is a superposition of fines attributed to immobile PCs with an anisotropic g-tensor and to the mobile centers possessing a singlet EPR fine, the concentration ratio of these PCs being less than 1 : 10.…”

Section: Introductionmentioning

confidence: 99%

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Spin relaxation studies on conducting poly(tetrathiafulvalene)

et al. 1993

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Abstract. Magnetic parameters and the relaxation behavior of paramagnetic centers in ala iodine-doped poly(tetrathiafulvalene) semiconductor with a d.c. conductivity of 10 -5 S" cm -1 have been studied using mainly the 2 mm waveband EPR technique in the temperature range of 110-270 K. The EPR line shape analysis confirms the existence of immobile radicals pinned on short polymer chains and mobile polarons with different relaxation parameters in slightly doped poly(tetrathiafulvalene). The temperature dependences of electron spin-lattice and spin-spin relaxation times of paramagnetic centers of both types have been determined independently using the saturation method at the operation frequency v~ = 140 GHz. An anisotropic slow libration of immobile polarons with an activation energy of 0.02 eV have been registered for the first time using the saturation transfer EPR method. The temperature dependences of intrachain diffusion and interchain hopping rates in poly(tetrathiafulvalene) are determined from the T 1 and T 2 EPR data. The interchain spin dynamics is shown to correlate with libration of polarons trapped on polymer chains and is in good agreement with a hopping charge transport mechanism.

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Section: Nature and Composition Of Pcs In The Pttfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spin relaxation studies on conducting poly(tetrathiafulvalene)

et al. 1993

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Polymer Characterization: Electron Paramagnetic Resonance

Krinichnyi

2018

Encyclopedia of Polymer Science and Technology

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Advantages of multifrequency electron paramagnetic resonance spectroscopy combined with various methods—such as spin labels and probes, microwave saturation, and saturation transfer—for investigating various polymeric systems are presented. Paramagnetic centers that are stabilized and/or initiated as a nanoscope probe can provide detailed information about structure and dynamics of the microenvironment. Correlations of structural, morphological, and dynamic characteristics of polymer systems with magnetic, relaxation, and mobile properties of paramagnetic centers embedded into their bulk are also discussed.

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ESR studies on polymers with particular electronic and magnetic properties

Roth

Krinichnyi

1993

Makromolekulare Chemie. Macromolecular Symposia

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Measurements on insulating and conducting polymers from the polyaniline (PANI) family and investigations on semiconducting poly(tetrathiafulvalenes) (PTTF) have been used for illustration and discussion of some methodical questions of electron spin resonance (ESR). This concerns especially the new possibilities of the recently developed high‐resolution ESR in the 2 mm wave band. It was applied for the study of the nature and dynamics of paramagnetic centres (PC) and charge carriers in PANI and PTTF. The rate of the quasi‐one‐dimensional (1D) intrachain electron motion and of the three‐dimensional (3D) interchain electron hopping has been estimated separately. In iodine ‐ doped PTTF the maximum electrical conductivity is 10−4 S ·cm−1. It is almost identical with the 3D‐conductivity estimated by ESR and shows the typical temperature dependence of a semiconductor. The quasi‐1D‐conductivity is several orders of magnitude higher and shows in its dependence on temperature similarities with a metal. The PANI samples show in the highly doped form a maximum conductivity of about 10 S ·cm−1 and relativly small differences between the 1D‐ and 3D‐conductivity, supporting the model of metallic islands.

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Electron spin resonance and relaxation studies on conducting poly(tetrathiafulvalenes)

Cited by 11 publications

References 15 publications

Spin relaxation studies on conducting poly(tetrathiafulvalene)

Spin relaxation studies on conducting poly(tetrathiafulvalene)

Polymer Characterization: Electron Paramagnetic Resonance

ESR studies on polymers with particular electronic and magnetic properties

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