Nanotransport in polyacetylene single fiber: Toward the intrinsic properties

Park, J.G.; Kim, G.T.; Krstić, Vojislav; Kim, B.; Lee, S.H.; Roth, S.; Burghard, Marko; Park, Y.W.

doi:10.1016/s0379-6779(00)00689-5

Cited by 40 publications

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“…In previous reports on the transport behavior of polymer nanostructures, G(T ) and I (V ) are described as a 3D variable-range hopping (VRH) model for PANI and polypyrrole tubes 34,35 or a fluctuation-induced tunneling model for PA nanofibers. 36 Additionally, the G(T ) of self-assembled PANI nanostructures are described using a 1D VRH model. 37 Even the transport results for one kind of polymer nanostructure are not consistent with respect to the synthesis method, and there is no generally accepted model for the dominant transport mechanism.…”

Section: Temperature Dependence Of 1d Conductionmentioning

confidence: 99%

Probing spin-charge relation by magnetoconductance in one-dimensional polymer nanofibers

et al. 2012

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Polymer nanofibers are one-dimensional organic hydrocarbon systems containing conducting polymers where the nonlinear local excitations such as solitons, polarons, and bipolarons formed by the electronphonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here, we report our observations of a qualitatively differentMC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA, the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite)MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge). Polymer nanofibers are one-dimensional organic hydrocarbon systems containing conducting polymers where the nonlinear local excitations such as solitons, polarons, and bipolarons formed by the electron-phonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here, we report our observations of a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA, the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite) MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge). Disciplines Physical Sciences and Mathematics | Physics

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Section: Temperature Dependence Of 1d Conductionmentioning

confidence: 99%

Probing spin-charge relation by magnetoconductance in one-dimensional polymer nanofibers

et al. 2012

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“…Individual polyacetylene nanofibres of diameter 10-40 nm placed over electrodes separated by 100-200 nm provide a new way of probing for the intrinsic properties of polyacetylene that are not evident from bulk samples [9,10]. An advantage of the short length is that conduction at electric fields above 10 5 V=cm can be investigated by applying a potential difference of only a few volts across the electrodes.…”

Section: Introductionmentioning

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 view of these results the question arises whether Coulomb-blockade effects can also be observed in such inherent quasi-1D systems as conducting polymer nanofibers. In this connection polyacetylene (PA) nanofibers are of particular interest as the model system for nanotransport studies because of the simple chemical structure, well defined polycrystallinity [9], and good ability for doping [10][11][12]. It is shown that at temperature 30 K < T < 300 K doped polymer nanofibers demonstrate some transport features characteristic of quasi-1D systems, namely, series of Luttinger liquids separated by intra molecular barriers [13].…”

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confidence: 99%

Coulomb-blockade transport in quasi-one-dimensional polymer nanofibers

et al. 2005

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We report the low temperature current-voltage (I-V) characteristics studies in quasi one-dimensional conducting polymer nanofibers. We find a threshold voltage V t below which little current flows at temperatures below 30 -40 K. For V > V t current scales as (V/V t -1) ζ , where ζ ~ 1.8 -2.1 at high biases. Differential conductance oscillations are observed whose magnitude increases as temperature decreases below 10 K. We attributed the observed low temperature I-V behavior to Coulomb blockade effects with a crossover to Luttinger liquid-like behavior at high temperature. We demonstrate that at low temperatures such a doped conjugated polymer fiber can be considered as an array of small conducting regions separated by nanoscale barriers, where the Coulomb blockade tunneling is the dominant transport mechanism.PACS numbers: 71.30.+h, 72.20.Ee, 72.80.Le Complex structures built of nanosize conducting objects provide model systems for investigation of transport phenomena on the mesoscopic scale, where quantum confinement and Coulomb charging play an important role [1]. Electronic transport through an array of metallic nanocrystals separated by nanobarriers is determined by the interplay between single-electron charging of an individual conducting region and tunneling between adjacent islands. In such systems both the tunneling resistance between neighboring regions is large, R T >> h/e 2 and the charging energy E C = e 2 /2C of an excess electron on a site is larger than k B T (C is the capacitance of the region). In the presence of both charge and structural disorder this interplay leads to highly nonOhmic current-voltage (I-V) characteristics. Coulomb blockade theory predicts that at low temperatures, there is no current below a specific threshold voltage, V t , while above V t the current follows a power law:with ζ ~ 1 in one dimensional (1D) and 5/3 or 2 in twodimensional (2D) systems [2]. V t depends on the nanocrystal number, the capacitance of the conducting regions and the capacitance between the each region and the back gate. Such a behavior with scaling exponents between 1 and 2.3 has been found, for example, in narrow chains of carbon nanoparticles [3], and in 100 nm wide multilayer of gold particles which exhibited ζ ~ 1.6 [4]. Coulomb-blockade effects have also been observed in multiwalled carbon nanotubes [5], organic thin-film transistors based on highly ordered molecular materials [6] as well as in single-molecular transistor structures [7]. It is evident that the nature of the individual regions: metallic, semiconducting, quantum dots -is irrelevant for this phenomenon to be observed [8]. In view of these results the question arises whether Coulomb-blockade effects can also be observed in such inherent quasi-1D systems as conducting polymer nanofibers. In this connection polyacetylene (PA) nanofibers are of particular interest as the model system for nanotransport studies because of the simple chemical structure, well defined polycrystallinity [9], and good ability for doping [10][11][12]. It is...

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Nanotransport in polyacetylene single fiber: Toward the intrinsic properties

Cited by 40 publications

References 0 publications

Probing spin-charge relation by magnetoconductance in one-dimensional polymer nanofibers

Probing spin-charge relation by magnetoconductance in one-dimensional polymer nanofibers

Charge Transport in Conducting Polymers: Polyacetylene Nanofibres

Coulomb-blockade transport in quasi-one-dimensional polymer nanofibers

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