Two-dimensional localized vibrational modes of polythiophene around a bipolaron

Xie, Zun; Kang, Yanmei; Li, You-Cheng

doi:10.1103/physrevb.61.1096

Cited by 11 publications

(7 citation statements)

References 13 publications

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“…However, the relative intensities of the 1383 and 1264 cm –1 bands with respect to intensity of the 1129 cm –1 band are low, which is a unique feature of the bipolaron spectrum. The observed 1383, 1264, 1129, and 1068 cm –1 bands are consistent with those predicted theoretically . It is difficult to distinguish polarons from bipolarons in infrared spectra because of the presence of many overlapping bands.…”

Section: Resultssupporting

confidence: 89%

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Electronic and Vibrational Spectra of Positive Polarons and Bipolarons in Regioregular Poly(3-hexylthiophene) Doped with Ferric Chloride

2015

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We studied the carriers generated in regioregular poly(3-hexylthiophene) (P3HT) upon FeCl3 vapor and solution doping using visible/near-infrared (VIS/NIR) absorption, infrared (IR), and Raman spectroscopy. Upon doping with an FeCl3 solution in air, the main carriers that were generated were positive polarons. Upon doping with FeCl3 vapor, positive polarons also formed initially, but at higher doping levels, positive bipolarons formed with the concomitant disappearance of the positive polarons. The Raman and IR spectra of the positive bipolarons and the positive polarons were obtained. Raman spectroscopy is very useful for characterizing positive polarons and bipolarons. The Raman results indicated that the positive bipolarons were converted to polarons upon heating to 85 °C, indicating that the positive bipolarons formed a metastable state. The temporal changes in the electrical conductivity of a P3HT film upon doping with FeCl3 vapor were measured. The conductivity reached a maximum and then decreased by 2 orders of magnitude. This result suggests that the mobility of the polarons is approximately 100 times as high as that of the bipolarons.

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Section: Resultssupporting

confidence: 89%

“…The observed 1383, 1264, 1129, and 1068 cm −1 bands are consistent with those predicted theoretically. 45 It is difficult to distinguish polarons from bipolarons in infrared spectra because of the presence of many overlapping bands.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Electronic and Vibrational Spectra of Positive Polarons and Bipolarons in Regioregular Poly(3-hexylthiophene) Doped with Ferric Chloride

2015

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“…In addition to the usual self-localized charge carries, that is, polarons (spin 1 / 2 , charge ±| e |), a number of experimental and theoretical studies have also shown the existence of bipolarons (spinless species, charge ±2| e |) in doped conjugated conducting polymers. − The formation, stability, and dynamic evolution of polarons and bipolarons have been simulated by many researchers. For example, bipolarons can be created in organic LEDs when a charge injection results in a large concentration of polarons .…”

Section: Introductionmentioning

confidence: 99%

Electroluminescence Enhancement in Polymer Light-Emitting Diodes through Inelastic Scattering of Oppositely Charged Bipolarons

Meng

Wang

et al. 2011

J. Phys. Chem. B

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Combining the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model and the extended Hubbard model (EHM), the scattering and combination of oppositely charged bipolarons in conjugated polymers are investigated using a nonadiabatic evolution method. On the basis of this physical picture, bipolarons can scatter into a singlet biexcitonic state, in which two electrons and two holes are trapped together by a lattice distortion. This biexcitonic state can emit one photon to an exciton state, which can subsequently decay to the ground state. The results indicate that the scattering and combination of oppositely charged bipolarons may provide guidance for improving the internal quantum efficiency for electroluminescence to as high as 75% in polymer light-emitting diodes.

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“…The existence of bipolarons is likely to play an important role in understanding the operation of these optoelectronic devices based on conjugated polymers. 5 There have been considerable amounts of research works devoted to the properties of bipolarons, for example, the formation and stability of bipolaron, [9][10][11][12][13][14] the infrared active vibrational modes around a bipolaron, 15,16 and the bipolaron lattice at metal-polymer interface. 17 However, most of these works were focusing on the static properties of bipolarons.…”

Section: Introductionmentioning

confidence: 99%

Correlation effects on the dynamics of bipolarons in nondegenerate conjugated polymers

Zhao

Chen

Zhang

et al. 2009

The Journal of Chemical Physics

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By employing an adaptive time-dependent density-matrix-renormalization-group method, we investigate the dynamics of a charged bipolaron in the presence of both electron-phonon and electron-electron interactions. We use a Su-Schrieffer-Heeger model modified to include electron-electron interactions via a Hubbard Hamiltonian, a Brazovskii-Kirova symmetry-breaking term, and an external electric field. Our results show that the velocity of the bipolaron increases first and then decreases with the increasing of the on-site Coulomb interaction, U. Furthermore, the dependence of the bipolaron velocity, bipolaron effective mass, and bipolaron stability on the lattice structures is discussed.

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Two-dimensional localized vibrational modes of polythiophene around a bipolaron

Cited by 11 publications

References 13 publications

Electronic and Vibrational Spectra of Positive Polarons and Bipolarons in Regioregular Poly(3-hexylthiophene) Doped with Ferric Chloride

Electronic and Vibrational Spectra of Positive Polarons and Bipolarons in Regioregular Poly(3-hexylthiophene) Doped with Ferric Chloride

Electroluminescence Enhancement in Polymer Light-Emitting Diodes through Inelastic Scattering of Oppositely Charged Bipolarons

Correlation effects on the dynamics of bipolarons in nondegenerate conjugated polymers

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